2. 1. Which of the following, if any, accurately describe what is meant by dual dipole tag ? ❑ A. A tag that is configured to have two chips, giving it more processing power ❑ B. A type of tag’s antenna that is designed to reflect energy on multiple planes ❑ C. A tag that has overlapping layers of copper coils ❑ D. A tag that works on dual frequencies Dual dipole tags were originally made with the orientation of the dipoles set 90 degrees apart. Today, however, multiple variations of this type of tag are available, with the dipoles arranged in many different patterns. They ensure tag reads regardless of orientation. Most of them are designed so that they even read on edge or turned so they are perpendicular to the antenna. This is critical for retail applications where many boxes are being read, and orientation cannot be assured. Answer A is not correct because the question refers to the antenna on the substrate, not the chip. Answer C is incorrect because dual dipole does not refer to induction coils. Answer D is also incorrect because tags cannot work on dual frequencies, and they are not referred to as dual dipoles.
3. 2. Which of the following, if any, are parts of the etching process? ❑ A. A mask ❑ B. Various chemical solutions ❑ C. Protection from oxidation ❑ D. All of the above In the copper etching process, a mask is used to “ burn” an image into the photopolymer layer. The substrate, or copper film, and photo resist are subjected to a chemical solution, which removes all of the copper except where the image was burned. A different chemical solution is used to remove the “burned” photo resist. Then the finished copper antenna goes through additional processes to protect the copper surface from oxidation. Etching The etching process works as follows: 1. A mask is used to “burn” an image into the photopolymer layer. 2. The substrate, metal film, and photo resist are subjected to a chemical solution that removes all of the metal except where the image was burned. 3. A different chemical solution is used to remove the “burned” photo resist. 4. The finished antenna goes through additional processes to protect the metal surface from oxidation. Various methods and materials are used for antenna construction. The principle methods are ➤ Etching (using copper, aluminum, or silver) ➤ Foil stamping ➤ Screen printing
4. 3. What is dwell time? ❑ A. The time a tag is in the interrogation zone ❑ B. The time it takes one tag to go from the pallet to the warehouse floor ❑ C. The rating system used to track build processes ❑ D. None of the above Dwell time refers to the momentary time interval during which a detector is able to, or allowed to, sense incoming electromagnetic radiation within its intended instantaneous field of view or how long the tag stays in the interrogation zone. Ensuring that the antennas are oriented properly to maximize the interrogation field is very important because, if the tags are in the interrogation zone for too short of a period, they may not collect enough energy to power up fully and report to the reader. Answer B is not correct because the dwell time is not the time of palletizing and inventory. Answer C is not correct because dwell time has no bearing on a rating system. Answer D is incorrect by default.
5. 4. When referring to RFID antennas, what does the acronym ERP mean? ❑ A. Enterprise Resource Planning ❑ B. Effective rate of protection ❑ C. Effective radiated power ❑ D. Unit of power input ❑ E. All of the above Effective radiated power (ERP) is the power supplied to an antenna multiplied by the antenna gain in a given direction or as the product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction. Answer A is not a term used when referring to RFID antennas; however, Enterprise Resource Planning is a valid term in the business arena. Answer B is not correct because it is a fictitious term. ERP is not a unit of power input but a power radiated out of the antenna; therefore, answer D is incorrect.
6. 5. When implementing an RFID system in Australia, what ITU region are you in? ❑ A. Region 1 ❑ B. Region 2 ❑ C. Region 3 ❑ D. Regions 1 and 2 The International Telecommunication Union (ITU) Regions are ➤ Region 1 —Includes Europe, Africa, the Middle East west of the Persian Gulf and including Iraq, and the former Soviet Union. ➤ Region 2 —Includes the Americas. ➤ Region 3 —Contains Asia (excluding the former Soviet Union), including Iran, Australia, and Oceania.
7. 6. What memory bank is used for User memory in EPC Class 1 Generation 2 tags? ❑ A. Bank 0 ❑ B. Bank 3 ❑ C. Bank A ❑ D. Bank B ➤ Bank 0—Reserved Memory —Reserved memory holds the tag’s passwords and can be read locked. ➤ A 32-bit Kill password allows a tag to be permanently silenced. The default Kill password value is zero. The Kill command executes only if the password has been set; that is, it is something other than zero. ➤ A 32-bit Access password allows the tag to transition to the Secured state (a tag in the Secured state can execute all Access commands, including writing to locked blocks). ➤ Bank 1—EPC Memory —EPC memory contains 32 bits for different protocol controls and a 96-bit EPC (Electronic Product Code) of the object the tag is attached to. ➤ Bank 2—Tag Identification Memory (TID Memory) —TID memory contains an 8-bit ISO allocation class identifier, a 12-bit tag maskdesigner ID, and a 12-bit tag model number. Manufacturers can include other information, if required—for example, a tag serial number. ➤ Bank 3—User Memory —User memory is an optional area of memory (usually 32-bits but can be larger) that contains user-specific data. The memory organization is user defined.
8. 7. Which of the following is/are characteristics of an active tag? ❑ A. An active tag is powered by a battery to send and receive RFID information. ❑ B. An active tag can be applied to any surface and has the ability to transport itself from one location to the next. ❑ C. An active tag can be interrogated within a few inches of the interrogator, and it is powered by the interrogator. ❑ D. An active tag does not have its own transmitter in comparison to a passive tag. Active tags have an internal battery to power them and are usually able to be rewritten and/or modified. Active tags can transmit their data over longer distances; the tag itself is larger than a passive tag and has a limited operational life span. Answer B is incorrect because active tags cannot “magically” transport themselves; they are carried on a product. Answer C is incorrect because active tags are not generally powered by interrogator; they have their own power source. Active tags have their own transmitter; therefore, answer D is also incorrect.
9. 8. What are some of the uses for a Low Frequency RFID tag? ❑ A. Pet tracking ❑ B. Smart shelves ❑ C. Paper plates ❑ D. Access control systems Low Frequency RFID tags are commonly used for animal identification. Pets, cattle, or endangered species can be implanted with small chips so that they may be returned to their owners if lost or stolen or for scientific purposes. Low Frequency systems are best for tracking and identification of dense objects in small ranges because they provide good penetration. Therefore, answer C is incorrect because paper plates are not a barrier to RF and are not usually tracked with LF systems. Answer B is incorrect because LF systems are not usually used in “smart shelves.”
10. 9. What does the term inductive coupling mean? ❑ A. A method of connecting different devices together ❑ B. A way of fusing data to the back-end application ❑ C. The process of fixating the fixtures of the antenna so they do not move ❑ D. A method of transmitting data between tags and readers Inductive coupling is the method of transmitting data between passive tags and readers in which the antenna from the reader picks up changes in the tag’s antenna. Answers A and B are not correct because the term refers to data transmission, not connection of devices or data subject to back-end systems. Answer C is not correct because the term does not refer to attachment of hardware.
11. 10. What is the EPC network? ❑ A. It is a network like the Internet, also storing and retrieving information on EPC products. ❑ B. It is a network protocol that allows only the environmental specialist access to data on the Internet. ❑ C. It is a computer storage location that holds information on all electronic codes. ❑ D. None of the above. The EPC network is architecture similar to the Internet; it is designed to link, store, and allow access to data related to EPCs. For example, it provides detailed item information such as description, ingredients, size, weight, and cost; manufacturing information about the specific lot, such as when and where it was produced and expiration dates; and distribution information about where it has been, including addresses, dates, and times. The data can be as detailed as including environmental factors such as temperatures during manufacturing or storage. Answer B is not correct because the question refers to RFID terms. Answer C is not correct because the EPC network contains only data related to the EPC global system. Therefore, answer D is incorrect as well. The EPCglobal network is composed of three key elements: ➤ EPC Information Services (EPC-IS) ➤ EPC Discovery Services ➤ Object Name Service (ONS)
12. 11. In a conveyor system, why is it important to test the tunnel interrogator radiated field? ❑ A. Metal areas are not an issue in testing. ❑ B. There is no special need to test on a standard conveyor system. ❑ C. Typical conveyor systems are made of metal, and the radiated signal can be configured in a way that the interrogator reads tags from another belt system nearby, resulting in failed or error reads. ❑ D. You need to ensure that the tags are read as far as possible from the tunnel to increase efficiency. Most conventional conveyor roller sections are made of metal, and the metal structure acts as a boundary condition to the radiated flux field. Thus, consideration must be given to prevent the absorption and distortion of the magnetic and radio field energy. Answer A is not correct because metal areas are of high concern in an RFID solution. Answer B is incorrect because testing is extremely important to any system. If you increase the power input into the antennas in the RFID tunnel, the interrogation field may expand beyond the tunnel, and that could cause false or undesirable reads; therefore, answer D is incorrect.
13. 12. What does the term inlay refer to? ❑ A. An RFID microchip attached to an antenna and mounted on a substrate ❑ B. The process that fuses a chip to a container ❑ C. The method of regenerating a tag ❑ D. A chip mounted on a strap An inlay is an RFID microchip attached to an antenna and mounted on a substrate. Inlays are essentially unfinished RFID labels. They are usually sold to label converters who turn them into smart labels. Answers B and C are not correct because an inlay is not defined as the ability to connect a tag to a container, nor is it a method of writing data to a tag. Inlay does not refer to a chip on a strap; therefore, answer D is also incorrect.
14. 13. What is a circular polarized antenna? ❑ A. An antenna that can receive signals from both vertical and horizontal planes ❑ B. A round antenna ❑ C. A disc-shaped antenna ❑ D. None of the above Antennas with circular polarization can receive signals from both the vertical and horizontal planes; however, there is a slight loss of signal strength. Answers B and C are not correct because the question refers to the planes on which the antenna can read tags. Answer D is incorrect by default. Polarization can be either circular or linear. Linear polarization is relative to the surface of the earth. Linear polarization can also be either horizontal or vertical: ➤ Horizontally polarized signals propagate parallel to the earth. ➤ Vertically polarized signals propagate perpendicular to the earth. Antennas with circular polarization can receive signals from both the vertical and horizontal planes by injecting the signal at two points on the antenna radiated slightly out of phase creating a rotating effect on the field. However, there is a slight loss of signal strength, due to the constructive and deconstructive effect of the field being slightly out of phase.
15. 14. Which of the following, if any, are characteristics of a tethered interrogator? ❑ A. Have limited mobility ❑ B. Do not need a self-contained power source ❑ C. Connect directly into the IT infrastructure ❑ D. All of the above ❑ E. None of the above Tethered interrogators are tied directly into the IT infrastructure, and they do not need their own power because they are typically connected to a power source through a power cable. They have limited mobility due to their wired connections to other devices and to their external power source.
16. 15. Microwave (uW) tags operate at what frequency? ❑ A. 860–960 MHz ❑ B. 2.45 GHz ❑ C. 120–140 KHz ❑ D. 13.56 MHz Microwave tags operate at 2.45 GHz. Answer A is incorrect because Ultra High Frequency (UHF) tags use the 860–960 MHz band. Answer C is incorrect because Low Frequency (LF) tags operate in the 120–140 KHz band. Answer D is incorrect because High Frequency (HF) tags operate at 13.56 MHz. The four primary frequency bands for RFID tags are ➤ Low Frequency or LF (120–140 KHz) ➤ High Frequency or HF (13.56 MHz) ➤ Ultra High Frequency or UHF (860–960 MHz) ➤ Super High Frequency/Microwave (2.45 GHz and above)
17. 16. What is a hybrid interrogator? ❑ A. A reader that has been altered with firmware to function as an FM radio ❑ B. A reader that has multiple read modes, such as the ability to read bar codes as well as RFID tags ❑ C. An interrogator that also can function under water ❑ D. All of the above Depending on their type, interrogators can have various capabilities such as reading bar codes or other Automatic Data Collection (ADC) capabilities. These are called hybrid interrogators. Answer A is not correct because RFID does not function as an FM radio. Answer C is incorrect because interrogators that can function under water are not called hybrid . Consequently, answer D is incorrect as well.
18. 17. What indicates the efficiency of energy in an RFID chip? ❑ A. Q factor ❑ B. E factor ❑ C. H field ❑ D. E field The Q factor indicates the ratio of the energy stored in it to the energy lost during one cycle of operation. Answer B is incorrect because the E factor is not defined. Answer C is incorrect because H field is a name for a magnetic field that can be created around the tag. Answer D is incorrect because the E field is the electrical field caused by electric current. Calculation of a Q factor for an electrically resonant system is following: Where fc is a resonant frequency (center frequency). Calculation of a Q factor in a tuned radio frequency receiver is following: Where R is resonance, L is inductance, and C is capacitance.
19. 18. How would you protect your interrogator against extreme temperatures? ❑ A. No special protection is needed. Interrogators usually have a built-in component that detects overheating of the device and turns the device off. ❑ B. By enclosing the interrogator in a NEMA box with heating and/or a cooling device. ❑ C. By installing a fan near the interrogator. ❑ D. Interrogators are built to work in extreme temperatures. It is only necessary to protect interrogators from liquids. As far as we know, interrogators do not yet have a built-in detector from overheating. Therefore, answer A is incorrect. Answer C is incorrect, because although a fan could help, in extremely warm or cold temperatures, this would not be sufficient to prevent damage of the interrogator’s circuitry. Answer D is also incorrect. It is necessary to protect interrogators from extreme temperatures as well as liquids and other harsh environmental conditions.
20. 19. What is a dwell time? ❑ A. The time that a tag is in the radiated signal to allow for operations such as write and read to occur ❑ B. The time when the conveyor belt opens the trip light ❑ C. The trigger device time used to start an interrogation process ❑ D. Time between the tag application and tag verification ❑ E. All of the above An RFID tag, once energized, requires a certain amount of time to power up, and then it can respond to the interrogator. It is important that the RF energy that is energizing the tag remain at a level sufficient to sustain the tag’s functionality until it has successfully retrieved data from or stored data to its memory. Because the tag can be powered only when it is in the beam of the RFID antenna(s), the tag must remain in the beam long enough for the required operations to occur. This is known as “dwell time.” If the dwell time is too short, the tag may power down prematurely, and the read or write operation will not be completed. One way to maximizethe tag’s dwell time or time in beam is to position the antennas so that the sweet spot is as large as is practical. Answers B and C are not correct because the question refers to the amount of time it takes for the tag to power up and send data back to the interrogator while the interrogator is emitting a signal, not the hardware triggering devices. Answer D is incorrect because dwell time refers to the time in the interrogation signal, not time between application and verification.
21. 20. What is the use of an RTLS? ❑ A. Rotational Training and Limited Support is used to evaluate systems with other electronic devices. ❑ B. Reality Television Life Stories are based on reporting of personal experiences on reality television programs. ❑ C. RTLS is used to track and locate tagged RFID items. ❑ D. RTLS is used to measure ambient noise. ❑ E. None of the above. Real-Time Location System (RTLS) uses RFID technology to transmit the physical location of RFID-tagged objects. An RTLS requires some type of RFID tag to be attached to each object that needs to be tracked and RF transmitters/receivers located throughout the facility to determine the location that sent that location information back to a computerized tracking system. Answer A is not correct because the term RTLS means Real-Time Location System , not Rotational Training and Limited Support . Answer B is not correct because RFID at this time has nothing to do with television or programming. RTLS is not used to measure ambient noise; for this purpose, the RF spectrum analyzer is used. Therefore, answer D is incorrect.
22. 21. Consistent failed tag reads indicate that the tag supplier is at fault. ❑ A. This statement is true. ❑ B. This statement is false because consistent failed tag reads can indicate interrogator problems. ❑ C. This statement is false because consistent failed tag reads indicate a problem with the tag antenna. ❑ D. This statement is true only for UHF tags. Consistent failed tag reads should immediately raise a “red flag” that the interrogator is not functioning properly. A replacement interrogator (possibly a handheld unit) should be used to verify a second time if the tags are functioning. Answer C is not correct because, if the tag’s antenna was damaged, this would cause only a few tags to be invalid but not consistent failure with all tags. Answers A and D are incorrect.
23. 22. How can you achieve full 14-digit Global Trade Item Number (GTIN) from a data carrier of a shorter digit length? ❑ A. Add zeros to the back of the number to achieve 14 digits. ❑ B. Add zeros in front of the number to achieve 14 digits. ❑ C. Add a code assigned by EPCglobal to the front of the number. ❑ D. Add a code assigned by EPCglobal to the back of the number. To achieve full 14-digit GTIN from a data carrier that uses less digits, for example EAN.UCC-13, EAN.UCC-8 or UCC-12 (UPC), add zeros to the front of the number. Therefore, answer A is incorrect. EPCglobal does not provide a code to add to the number to convert it to 14-digit GTIN.
24. 23. For which of the following are RFID systems used? ❑ A. Tracking assets ❑ B. Toll collection ❑ C. Security purposes in entertainment parks ❑ D. All of the above RFID systems can be used for many applications, including asset tracking, clothing tags, missiles, pet tags, and food. RFID can be used to track transportation variances such as temperature, humidity, and expiration dates. RFID tags can store simple information such as a pet owner’s name and address, whether the pet has had all of its shots, and if those shots are current, to complex data such as instructions on how to assemble a computer. Some manufacturers use RFID systems to move objects through assembly lines. At each successive stage of production, the RFID tag tells the back-end system where it is in the build process and what the next step of assembly is. This information can then be presented to the intended purchaser of the item through web page applications or telephone response systems. RFID can also be used for security purposes to allocate persons in a facility or area, as well as for toll collection.
25. 24. What is an RS-232 serial data port? ❑ A. An Electronics Industries Association standard asynchronous serial line, which is used commonly for modems, computer terminals, and serial printers. RS-232 uses a 25-pin or 9-pin connector. ❑ B. A serial input/output standard that allows for compatibility between data communication equipment made by various manufacturers. ❑ C. A method of sending data over wires. It is often used to communicate between interrogators and printers or computers, as well as the backend systems. ❑ D. This is the de facto standard for communication through PC serial ports. It can refer to cables and ports that support the RS-232 standard. ❑ E. All of the above. RS-232 is a standard that defines the communication rules for serial ports and how they communicate with readers and back-end systems. Therefore, answers A, B, C, and D are incorrect.
26. 25. What is a mono-static antenna? ❑ A. An antenna that has two distinct radiated signals in one case. ❑ B. An antenna that can be coupled with only one interrogator. ❑ C. A single antenna that works as a transmitter as well as a receiver. ❑ D. Mono-static antenna is another name for single dipole antenna. ❑ E. All of the above. Depending on the design, the antennas can be either mono-static or bi-static. Mono-static antennas are based on a principle wherein a single antenna works as a transmitter as well as a receiver, and these functions are switched in fractions of seconds. Answer A is not correct because the question refers to the hardware, not the signals that can be generated. Answer B is not correct because the question refers to how the system transmits, not how it connects to the system. The term mono-static is not interchangeable with single dipole ; therefore, answers D and E are incorrect. Bi-static antennas include two antennas, where one antenna is dedicated to transmitting, and the other antenna is dedicated to receiving. Both dedicated antennas can be but do not have to be in the same casing. In bi-static antenna, a circulator is not required, which improves the performance and sensitivity of the antenna.
27. 26. Which of the following is a part of an RFID system? ❑ A. An antenna ❑ B. A transceiver ❑ C. A processing device ❑ D. A tag ❑ E. All of the above An RFID system consists of an antenna and a transceiver, which read the radio frequency signals and transfer the information to a processing device; and a transponder, or tag, which is an integrated circuit containing the RF circuitry and information to be transmitted.
28. 27. Which of the following are uses of microwave RFID tags? ❑ A. Collecting electronic tolls ❑ B. Tracking microwavable food ❑ C. Opening and unlocking the microwave door ❑ D. None of the above Microwave RFID tags are typically used in electronic toll collection. However, they are becoming access control devices used for long-range access control for vehicles as a part of OnStar systems in many General Motors vehicles sold today. Answers B and C are not correct because the question does not refer to a microwave oven. Consequently, answer D is incorrect as well.
29. 28. What is a bi-static antenna? ❑ A. An antenna that has two distinct radiated signals. ❑ B. An antenna device that allows one antenna to connect to two interrogators. ❑ C. An antenna that combines two antennas (sometimes within one case): one for transmitting and the other for receiving. ❑ D. Bi-static antenna is another name for dual dipole antenna. Depending on the design, the antennas can be mono-static or bi-static. A bi-static antenna combines two antennas that can sometimes be within one case. One antenna is dedicated to transmitting, and the other antenna is dedicated to receiving. Answer A is not correct because the question refers to the hardware, not the signals that can be generated. Answer B is not correct because the question refers to how the system transmits, not how it connects to the system. Although the bi-static antenna can be dual dipole, the terms are not generally interchangeable. Therefore, answer D is incorrect.
30. 29. When referring to RFID technology, what does the acronym EIRP mean? ❑ A. Enterprise international resource planning ❑ B. Effective isotropic radiated power ❑ C. Effective independent rotational potential ❑ D. None of the above Effective isotropic radiated power (EIRP) is the arithmetic product of the power supplied to an antenna and its gain relative to an isotropic source. EIRP = Power input * antenna gain in dBi. Answers A and C are fictitious terms. Answer D is incorrect by default.
31. 30. In a dense interrogator environment, the presence of many interrogators transmitting simultaneously at the same frequency can ❑ A. add additional power to a tag so that it can backscatter farther than with one interrogator transmitting to it. ❑ B. potentially cancel each other out by emanating large amounts of background noise that will overpower all the interrogators if not configured properly. ❑ C. be solved by designing the interrogator placement and their configurations. ❑ D. Overload the power circuits. Signals transmitted to a tag from one interrogator can easily be “stepped on” by another interrogator. In addition, the reply signal from a tag can easily be stepped on as well. Correct placement of the interrogators can help avoid this type of interference from occurring. Answer A is incorrect because it is physically impossible to accumulate RF signals at a tag prior to backscattering. Answer D is incorrect because the circuit overload in the dense interrogator environment is not the best answer here.
32. 31. Define slap and ship . ❑ A. A minimal compliance step ❑ B. An advanced stage of RFID implementation ❑ C. A method of using RFID as an inventory control system ❑ D. None of the above Many companies are simply trying to comply with mandates, and they begin doing so by using RFID devices in distribution centers immediately before shipping the products to the mandating customer. RFID printers/encoders can be quickly and relatively easily implemented, and as long as there is a small volume of goods being shipped, they are quite effective. This initial step of minimal compliance has been called slap and ship . Answers B and C are not correct because the question refers to the compliance of a mandate and a method of application using RFID technology. Answer D is therefore incorrect as well.
33. 32. What is ambient RF noise? ❑ A. Radio signals that enhance the reception of the target RF signal ❑ B. RF signals emitted by several devices into the environment ❑ C. Another term for white noise that allows the operator to concentrate on the task ❑ D. An interchangeable term for interrogation signal Ambient noise is RF signals generated by something other than the transmitter. It usually sounds like a hiss—static or harsh. Radio frequency interference (RFI) may be AM or FM, but the effect is that it either alters the audio signal or adds background noise to the audio signal. Answer A is not correct because of the term noise, which is not desirable in the RF signal as it can cause read failures. Answer C is not correct because the RF signal has nothing to do with the operator and the concentration level of the operator. Although the interrogation signal can produce ambient noise, these terms are not interchangeable. Therefore, answer D is incorrect.
34. 33. My interrogator is reading the tag data, but it is not being recognized by my application as valid data for the products it is supposed to be associated with. The tag manufacturer sent me the wrong lot of tags. ❑ A. This statement is true. ❑ B. This statement is false; the problem is in the interrogator. ❑ C. This statement is false; the problem is in the configuration of the application. ❑ D. This statement is false; the situation indicates that the tags are all killed. In a situation in which tags that have been programmed and attached to products are not being recognized in a database application, the application that performs the filtering should be checked to make sure it is configured for the expected tag data format. In many situations, the application has not been properly configured to match the tag data format. Answers A, B, and D are incorrect. Answer B is incorrect because the interrogator was proven to be reading tags; the problem appeared in the application software. Answer D is incorrect because the interrogator was successfully reading tags; if the tags were killed, the interrogator would not receive any response from the tags.
35. 34. A light stack is generally used to verify that a reader is turned on. ❑ A. This statement is true. ❑ B. This statement is false because a light stack is used to indicate that the reader is turned off. ❑ C. This statement is false because the light stack is a feedback device to indicate whether the tag functions. ❑ D. This statement is false because light stacks are not used in RFID systems. The light stack is primarily used as an indicator that the tag is functional and replying to interrogation commands. Therefore, answers A, B, and D are incorrect.
36. 35. The EPC number can be found in EPC Class 1, Generation 2 memory bank number ❑ A. 0. ❑ B. 1. ❑ C. 5. ❑ D. None. There are four memory banks in EPC Class 1, Generation 2. These banks are numbered 0, 1, 2, and 3, and the EPC number is allocated in the bank 1 called EPC memory. Therefore, answers A, C, and D are incorrect.
37. 36. What is the capability of a read-write tag? ❑ A. The ability to erase the tag data ❑ B. The ability to read data from the tag as well as write data to the tag ❑ C. The ability to kill the tag (EPC tags) ❑ D. All of the above The read-write characteristics of the tag give the ability to read and write data to the tag from any location, making the tag reusable, as well as the ability to remove most data and the ability to kill the tag when talking about EPC tags.
38. 37. Which of the following are uses for UHF RFID tags? ❑ A. Pallet tracking ❑ B. Container tracking ❑ C. Tracking laptops ❑ D. Tracking airplane parts UHF RFID tags are commonly used commercially in pallet and container tracking. These tags operate between 860 MHz and 960 MHz. UHF tags are able to send and receive data faster and at greater distances than LF and HF tags. In addition, these tags are limited due to the fact that the radio waves at these high frequencies do not perform well around water and metal, so they are not usually used for tracking laptops and airplane parts due to their high metal content. Therefore, answers C and D are incorrect.
39. 38. The manufacturing process by which chips are taken directly from a wafer and attached to an antenna is known as ❑ A. Flip chipping ❑ B. High rolling ❑ C. Fluidic Self-Assembly ❑ D. Strap attachment The chip is taken directly from a wafer by robotic hand, flipped and, with adhesive and pressure, attached directly to the antenna. Answer B is incorrect because high rolling is what everyone wishes to do when in Las Vegas. Answer C is incorrect because Fluidic Self-Assembly is the process of placing chips on the strap or antenna, where chips cut out of the wafer are floating in a liquid, and due to their shape, they fall into precut holes. When the chips are taken directly from a wafer and attached to an antenna, they do not use a strap attachment; therefore, answer D is incorrect.
40. 39. What is a smart label? ❑ A. A smart label is an applied label that adheres to a container without the need for adhesion. ❑ B. A smart label is a printed label that has all the shipping information printed to the substrate. ❑ C. A smart label is a type of tag that is a flat, thin, flexible form using usually paper or very thin plastic. It is used in RFID printers and applicators. ❑ D. None of the above Smart labels are labels that contain an RFID tag. Smart labels have limited memory capacity—currently between 32–256 bytes—that can be read or written to multiple times by means of an interrogator that connects to a PC. Answer A is incorrect because a smart label is not a label without a need for adhesion; it is a special type of label with an RFID tag embedded. Answer B is also incorrect; this type of label is a pure shipping label, and if it does not contain an RFID tag, this label cannot be called “smart.”
41. 40. Which of the following are reasons why you would use a bi-static antenna instead of mono-static antenna? ❑ A. Bi-static antennas do not use a circulator for switching between receiving and transmitting functions, therefore, they are more efficient. ❑ B. Bi-static antennas are cheaper. ❑ C. Bi-static antennas use a circulator for switching between receiving and transmitting functions, therefore, they are more efficient. ❑ D. Bi-static antennas are used only with active RFID systems. For passive systems, you would only use mono-static antennas. Since bi-static antennas do not use a circulator for switching between receiving and transmitting, they are more efficient. Answer B is incorrect. The price of the antenna depends on the design and manufacturer of the antenna and not whether it is bi-static or mono-static. Answer C is incorrect because bi-static antennas do not use a circulator for switching between receiving and transmitting functions. Answer D is incorrect because active and passive RFID systems use both kinds of antennas.
42. 41. What is shadowing? ❑ A. One tag is in front of another, causing the second tag to have a depreciated signal or no signal at all. ❑ B. All the tags that are not in the light of the tunnel cannot be read until they are illuminated. ❑ C. This term defines what happens when the tag completely blocks the interrogation signal coming from the interrogator. ❑ D. Shadowing occurs when the tag is in the “hole” of antenna coverage. Shadowing is a situation in which tags are right behind each other and the RF signal produced by the reader’s antenna is used by the first tag to generate a response, while the second tag gets minimal or no signal and has no chance to respond to interrogation. The second tag is “in the shadow” of the first tag. Answer B is not correct because “the light” in the tunnel does not perform a task of reading a tag. Answer C is not correct because the tags are not capable of blocking completely the interrogation signal. When the tag is in the “hole” of antenna coverage, this occurrence is not called shadowing ; therefore, answer D is incorrect.
43. 42. What is the definition of a read range? ❑ A. The device that reads RFID tags ❑ B. The area of the signal, such as the zone ❑ C. The maximum distance that a reader can send or receive data to or from an RFID tag ❑ D. None of the above The read range is the maximum distance at which a reader can send data to or receive data from an RFID tag. Answers A and B are not correct because the question refers to range or distance, not devices such as an interrogator or a zone. Answer D is incorrect by default.
44. 43. What is diffraction? ❑ A. A deflected signal that expands as it travels ❑ B. A trigger that is tripped by a light diode ❑ C. Signaling that allows for wave-like action to occur ❑ D. None of the above ❑ E. All of the above The process whereby RF signals or sound waves are in certain circumstances deflected from their normal straight-line path by physical objects is called diffraction . Diffraction is the apparent bending and spreading of waves when they meet an obstruction. It can occur with any type of wave including electromagnetic waves such as radio waves. Answer B is not correct because the question refers to the signal behavior, not actual hardware interaction. Answer C is not correct because signals already have wave-like behavior, and the question refers to a signal that encounters an obstacle. Answers D and E are therefore incorrect as well.
45. 44. What does antenna gain mean? ❑ A. The ability to increase the height of the antenna ❑ B. The relative increase in radiation at the maximum point ❑ C. The ratio of the radiated signal divided by the distance to the tag ❑ D. The amount of power an antenna can receive ❑ E. All of the above Gain is the relative increase in radiated signal, usually expressed in dB, transmitted by a given antenna as compared to an isotropic or dipole antenna. Antenna gain can be achieved only by making an antenna directional, which means better performance in one direction than in others, thus improving attenuation. Answer A is not correct because gain refers to the signal strength, not the height of the antenna. Answer C is a fictitious reply, which has no meaning in RFID technology. Answer D is incorrect because antenna gain is not the amount of power an antenna can receive. The power input is specified in the manufacturer’s manual and is limited by the standards and regulations.
46. 45. Which of the following are characteristics of EPC Gen 2 systems compared to EPC Gen 1 systems? ❑ A. A more advanced Dense Reader Mode ❑ B. Faster read rates ❑ C. Larger ASIC chips in tags ❑ D. Using 16-bit lock password Part of the EPC Gen 2 specifications are better functionality in a dense reader environment and faster read rates. The new ASIC chips used in EPC Gen 2 tags are actually smaller then Gen 1 chips, therefore, answer C is incorrect. Answer D is incorrect because EPC Gen 2 tags use 32-bit kill and 32-bit lock password.
47. 46. EPC Class 1, Gen 2 describes the Air Interface Protocol as well as the data standard for communications between a Class 1, Gen 2 interrogator and the tag. ❑ A. This statement is true. ❑ B. This statement is false; the protocol defines only the communication between interrogator and back-end systems. ❑ C. This statement is false; the protocol covers just the Air Interface. ❑ D. This statement is false; the protocol defines only EPC Class 0. The protocol covers the Air Interface Protocol and data standard; therefore, answer C is incorrect. The protocol, however, has nothing to do with the physical interface between a reader and other devices such as database servers, and so on. Therefore, answer B is incorrect. The Air Interface Protocol is defined for every official EPC class—class 0 as well as class 1. Therefore, answer D is incorrect.
48. 47. What is RS-422? ❑ A. The serial standard for connecting a viewable television monitor to a handheld device ❑ B. A Radio Shack connector 422 copper three-wire phone line ❑ C. A differential pair of wires, as one signal is transmitted across two separate wires in opposite states—one inverted and one noninverted used mainly to connect a printer to a workstation ❑ D. None of the above RS-422 is a port to allow systems to print tags, if the tag printer uses this type of port. Answer A is not correct; you would not connect a viewable monitor to a handheld device because most have built-in LCD displays. Answer B is incorrect because RS- 422 is a port used to connect a printer. Answer D is incorrect by default.
49. 48. Which of the following are applications for which High Frequency RFID tags are not usually used? ❑ A. Pallet tracking ❑ B. Library books ❑ C. Electronic Article Surveillance ❑ D. Smart shelves ❑ E. All of the above High Frequency RFID tags are not usually used for pallet tracking but are used in library books and bookstore tracking, building access control, airline baggage tracking, and apparel item tracking. They are used in smart shelves due to their small size and small range. High Frequency tags are widely used in identification badges, replacing the magnetic stripe cards that are similar to credit card systems. These High Frequency RFID badges need to be held within a certain distance of the reader to authenticate the holder. Therefore, answers B, C, D, and E are incorrect.
50. 49. What is a tag’s write range? ❑ A. The device that writes RFID tags with the correct data ❑ B. The distance between a reader and an RFID tag over which data-writing operations can be reliably performed ❑ C. The space of the substrate that allows for proper printing ❑ D. None of the above Write range is the maximum distance between a reader and an RFID tag over which data-writing operations can be reliably performed. Answers A and C are not correct because the question refers to distance, not the actual hardware of the system or the components of a tag. Answer D is incorrect by default.
51. 50. Vehicle mounted interrogators ❑ A. are typically mounted on forklifts or clamp trucks. ❑ B. use the slotted Aloha protocol to communicate with tags. ❑ C. can withstand submersion in water. ❑ D. all of the above. Answer B is incorrect because the Gen 2 protocol is not the same as the slotted Aloha protocol. Answer C is incorrect for this question, but it is possible that a manufacturer can make such a claim. Answer D is incorrect by default.
52. 51. A new version of interrogator firmware should always be downloaded into a reader when ❑ A. it is commercially available to keep the interrogator in tip-top shape. ❑ B. it seems that the interrogator is not working properly. ❑ C. it is released to fix problems discovered in a previous version. ❑ D. it appears on the manufacturer’s website. Interrogators need not necessarily have their firmware upgraded if the existing configuration proves to provide the necessary functionality. It is useful to upgrade the firmware if it is released to fix problems in the previous version, or if the interrogator is not working properly and the problem may be caused by “ bugs” in the firmware. Answer A is not correct because the firmware should not be upgraded just because a new version is available, if the system functions properly. When new firmware appears on the manufacturer’s website, this is not a sufficient reason to upgrade the firmware right away. Therefore, answer D is incorrect.
53. 52. Electrostatic Discharge (ESD) is often used to power up tags and provide the needed energy to transmit back to an interrogator. ❑ A. This statement is true. ❑ B. This statement is true only with passive RFID systems. ❑ C. This statement is false because ESD is harmful to tags. Electrostatic Discharge (ESD) is very harmful to tags and can often destroy them. Therefore, answers A, B, and D are incorrect.
54. 53. What is multiplexing? ❑ A. Doing many tasks at one time ❑ B. Applying various substrates together ❑ C. Switching between multiple antennas connected to one interrogator ❑ D. Combining two or more information channels onto a common transmission medium using hardware called a multiplexer that is not used in RFID In this method, a single interrogator is connected through a switching box to multiple antennas. The interrogator output is directed to each antenna in turn, again ensuring that only one antenna is transmitting at a time. Answer A is not correct because multitasking is defined as doing more than one task at a time. Answer B is not correct because the question does not refer to tags but rather to antennas and interrogators. Multiplexing is a method of combining two or more information channels onto a common transmission medium using hardware called a multiplexer, but it is used in RFID; therefore, answer D is incorrect.
55. 54. What is the definition of an interrogation signal? ❑ A. A radiated signal sent to a zone or area intended to activate a reply from a tag ❑ B. The area or zone that is built for tags to pass through ❑ C. Often called the interrogation zone or Faraday Cage ❑ D. All of the above An interrogation signal is meant to be received by a tag, and while passing over the tag, it activates the tag, causing it to waken and reply to the interrogator with the data stored. Answers B and C are not correct because the question refers to a signal, not a zone or a device. Answer D is incorrect by default.
56. 55. What acts as a protective shield for an interrogator or an antenna? ❑ A. A padded bollard ❑ B. Foam rubber tape ❑ C. Corrugated cardboard ❑ D. All of the above Answer B is incorrect because B can comprise a bollard. Answer C is not correct because cardboard (corrugated or otherwise) does not afford enough cushioning. Answer D is incorrect by default.
57. 56. What is a linear polarized antenna? ❑ A. An antenna that radiates a signal in a conical shape ❑ B. An antenna that is designed to work in a cold environment ❑ C. An antenna that is set to a plane, either horizontal or vertical, and the tags must be in the same plane ❑ D. An antenna that radiates signals whose strength linearly decreases with distance from the antenna When using a linear polarized antenna, the tag reader and antenna reader must be in alignment to achieve the longest reading distance. If that tag antenna is aligned vertically and the reader is sending out signals horizontally, only a small portion of the energy emitted by the reader will hit the tag antenna. Answer A is not correct because the question refers to the planes (horizontal or vertical), not the actual shape of the signal. Answer B is not correct because the polarization of the antenna defines the plane that it can read from, not the temperature of the environment. The radiated signal does not decrease in a linear manner with distance because the loss is not linear. Therefore, answer D is incorrect.
58. 57. What is the meaning of read-only ? ❑ A. The data on the tag can be only read and not written by the interrogator. ❑ B. Read-only means that the tag is readable only when in the Faraday Cage. ❑ C. Read-only is defined as the ability to read the tag many times but still allow rewriting the tag at any time. ❑ D. Data on read-only tags can be read and written only by the tag manufacturer. The tag is capable only of being read many times, but not modified or rewritten. Answer B is not correct because a working interrogator can read any functional tag without the need for a tunnel that works as Faraday Cage. Answer C is not correct; readonly means that the tag cannot be written to again because the data is prewritten by the manufacturer. Answer D is incorrect because the read-only tag can be read by an interrogator, not just by the manufacturer.
59. 58. A ground loop is an unwanted current that flows in a conductor connecting two points that are normally at the same ground potential, but are actually at different potential causing a current flow from the point with lower potential to the point with higher potential. ❑ A. This statement is true. ❑ B. This statement is false because a ground loop occurs when a building is struck by lightning. ❑ C. This statement is false because a ground loop is a connection between interrogators and a way it is attached to the ground. ❑ D. This statement is false because a ground loop results from current flowing from the point with higher potential to the point with lower potential. In reality, the two points are at what may appear to be the same potential but in reality are at different potentials. Current flow results from the point of higher potential to the lower potential point. Therefore, answers A, B, and C are incorrect.
60. 59. Air interface protocol defines ❑ A. the rules of communications between the interrogator and the tag ❑ B. the tag architecture and the memory size available ❑ C. anti-collision algorithm as well as modulation and bit-encoding rules ❑ D. design rules for manufacturers of RFID devices Air interface protocol does not specify the tag architecture or memory size available, nor design rules for manufacturers of RFID devices; therefore, answers B and D are incorrect.
61. 60. Back-end systems should be considered suspect of failure when ❑ A. tag data is not associated with a particular product it is attached to. ❑ B. the interrogator firmware load needs to be upgraded. ❑ C. EPC numbers are not being recognized as valid. ❑ D. products are deleted from inventory after being read. Tag data is basically associated with a database record. If there are consistently no associations, then the configuration of the back-end system should be checked. Answer B is incorrect unless no tags are being read at all. Then it might be a hardware or software (firmware) issue. When products are being deleted from inventory after being read, the back-end systems are not failing; therefore, answer D is incorrect.
62. 61. Which of the following can provide a function of an antenna in an RFID tag? ❑ A. A coiled spring ❑ B. An induction frequency adapter ❑ C. An internal diode ❑ D. An induction coil An induction coil used mainly in Low to High Frequency tags is a passive electronic component that stores energy in the form of a magnetic field. In its simplest form, an induction coil consists of a wire loop or coil. The inductance is directly proportional to the number of turns in the coil. Inductance also depends on the radius of the coil and on the type of material around which the coil is wound. Certain tags use antennas instead of the induction coil; these are Ultra High Frequency tags. Answer A is not correct because tags do not have springs as part of their anatomy. Answer B is not correct because the term induction frequency adapter is not defined in RFID, and answer C is incorrect because the anatomy does not include an internal diode.
63. 62. Which international standard specifies the air interface communications at 860 to 960 MHz? ❑ A. ANSI NCTIS 256 ❑ B. ISO 18000 Part 2 ❑ C. ISO 18000 Part 6 ❑ D. EN 300 220 ❑ D. This statement is false because ESD is used to power interrogators. ISO 18000 Part 6 specifies the air interface communications at a frequency band 860 to 960 MHz. Answer A is incorrect because ANSI NCTIS 256 is a standard for item management that describes three 2.4 GHz interfaces, 2 UHF interfaces, and the 13.56 MHz interface. Answer B is incorrect, because ISO 18000 Part 2 sets the parameters for air interface communications below 135 kHz. Answer D is also incorrect because EN 300 220 is provided by the European Telecommunications Standards Institute (ETSI) and is not valid internationally and specifies power, bandwidth and duty cycle.
64. 63. Which of the following is/are characteristics of a passive tag? ❑ A. A passive tag usually has its own power source. ❑ B. A passive tag usually has a range of 100 feet or more. ❑ C. A passive tag generally draws all of its power from the radio waves transmitted by an RFID reader. ❑ D. A passive tag uses beaconing to let the reader knows it is in its interrogation zone. Passive RF tags obtain operating power from the RF reader. They are smaller and lighter than active tags but have a shorter communication range and require a high-powered reader. Answer A is incorrect because passive tags usually do not have their own power source. Answer B is incorrect because passive tags usually do not achieve such long read ranges; they vary from 1 inch up to 30 feet. Passive tags do not have their own transmitter and so cannot beacon. Therefore, answer D is also incorrect.
65. 64. In terms of RFID, what does the acronym WORM stand for? ❑ A. Write once, read many ❑ B. A virus that affects the tag’s data, making it read as 00001100 ❑ C. A program or algorithm that replicates itself over a computer network and usually performs malicious actions, such as using up the computer’s resources and possibly shutting down the system ❑ D. Write many, read man WORM means write once, read many times. In addition, WORM refers to both Class 0+ and Class 1 tags, where Class 0+ is not an official tag classification. Answer B is not correct because, in terms of RFID technology, the data from a tag is not able to interface directly with the back-end system. Answer C is not correct because this is an RFID term and does not refer to a virus. Although the tags with WORM technology can be technically read and written to many times, the official term, WORM , refers to write once, read many. Therefore, answer D is incorrect.
66. 65. Which of the following, if any, accurately describe what is meant by single dipole ? ❑ A. An antenna with one connect point but multiple axes ❑ B. A single-axis antenna ❑ C. An array of antennas lined up in a criss-cross pattern ❑ D. Antennas that are overlapping ❑ E. None of the above In the early days of RFID, tags were only single dipole. This means that there is essentially one antenna aligned on a single axis. The resulting correlation of the tag to the field is the meaning of a single-axis antenna, or single dipole. For a field with specific polarization, these types of tags must be aligned so that they are parallel with the read field. For example, if linear antennas are used and are aligned horizontally, the tags must be horizontally aligned and facing the antennas to read successfully. These tags work well in manufacturing lines where the tag orientation and position can be assured. Answer A is not correct because the term multiple refers to more than one, and the question asks about a “single dipole.” Answer C is also incorrect because it refers to more than one antenna configuration. Answer D is not correct because like answer C, it refers to more than one antenna configuration. Answer E is incorrect as well.
67. 66. Part 15–compliant interrogators can operate at a maximum transmitted power of 1 watt or up to ____ watts with a gained antenna. ❑ A. 2 ❑ B. 4 ❑ C. 6 ❑ D. 100 The maximum allowed level of power with gained antenna is 4 watts. Therefore, answers A, C, and D are incorrect.
68. 67. Divert gates are most often used to ❑ A. divert products that have bar codes. ❑ B. separate HF-tagged products from UHF-tagged products. ❑ C. divert products with invalid tags off a production line. ❑ D. divert interrogator signals. Divert gates can be configured to divert products with bar codes, separate HF-tagged products from UHF-tagged products, or divert products with invalid tags off a production line. Divert gates do not divert interrogator signals; therefore, answer D is incorrect.
69. 68. Which of the following organization’s safety rules and regulations have to be followed when installing RFID systems in facilities in the US? ❑ A. World Health Organization (WHO) ❑ B. Occupational & Safety Administration (OSHA) ❑ C. EPC global ❑ D. Office of Telecommunications Authority (OFTA) The Occupational & Safety Administration or OSHA is responsible for employee and facility safety in the US. All RFID installations in the US need to comply with OSHA regulations. Answer A is incorrect because the World Health Organization produces only recommendations and it is up to each individual country to enforce these recommendations as a law and penalize non-compliance. Answer C is incorrect, because EPCglobal does not govern installation safety. Answer D is also incorrect; the Office of Telecommunications Authority (OFTA) is a government organization in Hong Kong and does not have jurisdiction over the US.
70. 69. What are the current EPC classes? ❑ A. Class 0 ❑ B. Class 1 ❑ C. Class 1, Generation 2 ❑ D. All of the above ❑ E. None of the above EPC classes include Classes 0 and 1, which pertain to passive tags. Generation 1, Class 0 is read-only; Class 1 is write once, read many (WORM). EPC also defines Class 1, Generation 2 for passive tags, which are fully rewritable.
71. 70. What is a Faraday Cage? ❑ A. A cage to hold Faraday birds ❑ B. A system to control radiated signals by containing them or shielding from them, and in most cases both are achieved ❑ C. A set of trigger panels configured into a circle ❑ D. None the above A Faraday Cage is an electrical apparatus designed to prevent the passage of radiated signals and waves by either containing them in or excluding them from its interior space. It is named for physicist Michael Faraday, who built the first one in 1836. Answer A is not correct and is a fictitious reply. Answer C is not correct because the question refers to antenna configuration, not triggering devices. Answer D is incorrect by default.
72. 71. Why do passive HF tags have a relatively shorter read range compared to passive UHF tags? ❑ A. Passive HF tags have a smaller antenna than UHF tags; therefore they have shorter read range. ❑ B. Passive HF tags use inductive coupling that utilizes a magnetic field that is propagated only in short distances within the allowed power parameters. ❑ C. Passive HF tags utilize an electric field that in conjunction with their induction coil allows only for a short read range. ❑ D. Passive HF tags have shorter read range because of their ASIC chip design. Answer A is incorrect because the size of the antenna usually increases with decreasing frequency due to the relationship between the wavelength and antenna size. The read range depends on communication method and power, not on the size of tag’s antenna. Answer C is incorrect, passive HF tags utilize a magnetic field and not an electric field. Answer D is also incorrect. The read range for passive HF tags depends on the method of energy transfer and communication and generally not on the chip design.
73. 72. What is passive backscatter ? ❑ A. The term is used to describe how one interrogator sends a signal to another interrogator. ❑ B. A reader sends out an RF signal, and then a tag replies to the signal by breaking up the signal into ones and zeros. ❑ C. A tag that has the substrate removed, allowing the radiated signal to bounce around. ❑ D. All of the above. UHF and microwave passive tags have antennas (as opposed to having an induction coil) and communicate with a reader using passive backscatter (also called modulated backscatter). The reader transmits a continuous-wave RF signal into the reading environment. When a tag appears in the area, it receives the signal and modulates (or breaks up) the RF signal into patterns of ones and zeros that define the tag’s digital data while reflecting it back to the reader. Answer A is not correct because the passive backscatter refers to interrogator/tag communication. Answer C is not correct because passive backscatter refers to the signal to and from the interrogator, not the materials used to create the tag. Therefore, answer D is incorrect.
74. 73. What are interrogation tunnels? ❑ A. Places where people are questioned ❑ B. Arrays of antennas fixed in a tunnel shape to allow for accurate reads no matter the orientation of the package traveling through the tunnel ❑ C. An array of antennas at a dock door portal ❑ D. All of the above Interrogation tunnels are structures placed over conveyor roller assemblies that provide a convenient and efficient means for high-performance antennas to be fixed. The best design for a tunnel antenna allows the reader’s energy field to be uniformly radiated. A homogeneous radiation pattern enables the reader to interrogate tags regardless of their relative orientation. Answer A is not correct because it is a fictitious reply. Answer C is not correct because this option refers to an array on a dock door, which is referred to as a portal, not a tunnel. Consequently, answer D is incorrect as well.
75. 74. Define front-to-back ratio? ❑ A. When a radiated signal is focused into a beam, the signal has a diffraction effect, causing some of the signal not to be focused. This diffracted signal does, in fact, bounce back into the antenna. ❑ B. The size of the reflector * the power used to generate a signal. ❑ C. The beam shape as it is directed to the focal point. ❑ D. None of the above. Front-to-back ratio is defined as when a doughnut radiation pattern is achieved, and it is squeezed into a beam off the front of the antenna. The reflector used for focusing the beam does not stop all the radiated energy, and some is radiated toward the rear (or, in the case of reception, bypasses the reflector and is intercepted by the dipole). The tips of the metal cause some signals to “bend” on the edges of the reflector and toward the rear (or, in the case of reception, from the rear toward the dipole). Answer B is not correct because the question asks you to define a term, and this answer defines a formula. Answer C is not correct because the term defines how the beam moves, not the shape as it is transmitted. Consequently, Answer D is incorrect as well.
76. 75. If you were tagging a case of ketchup bottles that will be traveling on a conveyor, where would you place the RFID tag? ❑ A. On the bottom of the case avoiding barcodes. ❑ B. On one of the sides of the case avoiding barcodes and manufacturer’s logos. ❑ C. On the top of the case anywhere. ❑ D. On the top of the case, avoiding manufacturer’s logos or barcodes. When tagging any product, care should be given not to cover any barcodes or manufacturer logos or marketing material. Answer A is incorrect. Conveyors usually have metal rollers, which would pose a problem for reading the tag from the bottom. Since ketchup is liquid and any antenna trying to read the tag from the top would have to penetrate through the ketchup, placing the tag on the bottom of the case would not work either. Answer C is also incorrect. When tagging a product you should not just place the tag anywhere, but you should avoid logos, barcodes and other things that are identifying components on the packaging.
77. 76. What does modulation mean? ❑ A. Changing the number of boxes that go through a reader ❑ B. Changing the properties of the radio waves ❑ C. Making adjustments to the conveyor belt to speed the boxes ❑ D. None of the above Modulation means changing the properties of the radio waves traveling between the reader and the transponder in ways that enable the transmission of information. Radio waves can be changed in a variety of ways that can be picked up by the reader and turned into zeros of binary code. Answer A is not correct because the question refers to the radio waves, not the number of tagged items moving through the interrogator. Answer C is not correct because the question does not refer to the speed that a tagged item is moving across the system. Consequently, answer D is incorrect as well.
78. 77. Which of the following is/are components of an RFID tag? ❑ A. Antenna/induction coil ❑ B. Silicon chip ❑ C. Modulation circuitry ❑ D. Nonvolatile memory ❑ E. All of the above An RFID tag is composed of an antenna/induction coil and a silicon chip that includes basic modulation circuitry and nonvolatile memory. The RFID tag is energized by a time-varying electromagnetic radio frequency (RF) wave that is transmitted by the interrogator. The radiated signal is called a carrier signal. When the RF field passes through the antenna coil, an AC voltage is generated, activating the coil. This voltage is rectified to supply power to the tag. The information stored in the tag is transmitted back to the interrogator.
79. 78. From the following choices, what key difference or differences are there between RFID and bar-code technology? ❑ A. RFID eliminates the need for line-of-sight reading that bar coding depends on. ❑ B. RFID scanning can be done at greater distances than bar-code scanning. ❑ C. All RFID devices are able to identify only RF tags, and bar-code devices are able to identify only bar codes. ❑ D. RFID requires a line of sight. Some of the key differences between RFID and bar-code technology are that RFID technology eliminates the need for line-of-sight reading that bar coding depends on. In addition, RFID scanning can be done at greater distances than bar-code scanning. Ultra High Frequency RFID systems (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) offer transmission ranges of more than 90 feet. Answer C is incorrect because some of the RFID interrogators are also capable of reading bar codes (mainly the handheld devices). RFID does not require a line of sight; therefore, answer D is incorrect.
80. 79. What is the difference between time required to read a tag and write to tag? ❑ A. The time to read the tag and write to tag is approximately the same. ❑ B. It takes longer to read the tag than write to tag. ❑ C. The time to write to tag is approximately 110% of the time to read the tag. ❑ D. The time to write the tag is about 5 times longer than the time to read the tag. It takes longer to write to tag than read the tag; therefore, answers A and B are incorrect. It takes about 150 to 170% of a read time to write to tag; therefore, answer C is also incorrect.
81. 80. Which of the following is/are characteristics of a semi-passive tag? ❑ A. A semi-passive tag functions sometimes as passive and sometimes as active. ❑ B. A semi-passive tag uses a battery to run the microchip’s circuitry but not transmit information to the RFID reader. ❑ C. A semi-passive tag is an RFID tag that cannot be used for capturing additional data, such as temperature of the environment. ❑ D. A semi-passive tag can beacon. Semi-passive tags use a battery to run the microchip’s circuitry but not to communicate with the RFID reader. They contain a power source, such as a battery, to power the microchip’s circuitry. Unlike active tags, semi-passive tags do not use the battery to send the signal to the interrogator. Some semi-passive tags are dormant until activated by a signal from a reader. This conserves battery power and can lengthen the life of the tag. Answer A is incorrect because semi-passive tags use a passive communication technique (inductive coupling, passive backscatter) and do not have their own transmitter. Therefore, answer D is also incorrect. This is reserved for the active tags. Answer C is incorrect because semipassive tags can carry various sensors on board that capture information about the outside environment.