Lecture on pifa a ntenna1

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Lecture on pifa a ntenna1

  1. 1. Presented By : Akhilesh Verma NITTTR, Chandigarh
  2. 2. Outline  Introduction o What is antenna o How antennas work o Need of antenna o Use of antenna o Parameters of antenna  Types of antenna use in mobile phone o External antenna o Internal antenna  Antennas use in different cell phones  Handset Design Evolution 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 2
  3. 3. What is an antenna  An Antenna is a device used to transform an RF signal, travelling on a conductor into an EM wave in free space or vice versa. or o An antenna is a transducer between a guided wave and a radiated wave, or vice versa.  The structure that “guides” the energy to the antenna is most evident as a coaxial cable attached to the antenna. The radiated energy is characterized by the antenna’s radiation pattern. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 3
  4. 4. Continued…  Antennas demonstrate a property known as reciprocity , which means that an antenna will maintain the same characteristic regardless if it is transmitting or receiving.  Antennas can be broadcast or receive only.  A special license is needed to broadcast but not to receive. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 4
  5. 5. How antennas work?  First of all to work properly the antenna system must be matched to the transmitter.  All modern transmitter have an output impedance of 50Ω.  There are several ways to match them: o Pruning the length of the antenna o Using an antenna tuner o Matching the antenna with the length of transmission line called a matching section.  To understand the working of antenna, firstly you have to understand electromagnetism. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 5
  6. 6. Continued…  If two poles of direct current(DC) voltage source to the two ends of a coil of wire, current will flow through the coil of wire and it will become magnetized. The magnetized coil is known as electromagnet.  If voltage and current can cause a coil to become magnetized, the reverse is true i.e a magnetic field can produce a voltage and a current in a coil, this is known as faradays principle of magnetic induction.  A voltage will produced at the ends of the coil of wire as we move any permanent magnet close to and parallel to the coil.  Move the magnet in one direction, and current will flow in one direction, reverse the direction the magnet is moving and the current will flow in the opposite direction. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 6
  7. 7. Continued…  Moving the magnet back and forth produces alternating current.  Any moving magnetic field can induce current in another coil, if that moving magnetic field passes through a second nearby coil, it will induce an alternating current in the second coil.  A straight wire that has an AC current flowing through it also has a magnetic field surrounding it. The magnetic field from the wire radiate out into and become weaker with distance.  The radiating magnetic field from a wire is known as “electromagnetic radiation”, the wire that radiates becomes the transmitting antenna.  Some distance away, a second wire in the path of these waves has current induced into it by the passing electromagnetic waves. This second wire will be the receiving antenna. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 7
  8. 8. Need of antenna  For transmission  For reception 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 8
  9. 9. Uses of antennas  Antennas are used for: o Radio o TV o Satellite o Cellular o Wifi o Radar o Space communications 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 9
  10. 10. Parameters of antenna 1. Input impedance 2. Return loss 3. Bandwidth 4. Directivity 5. Gain 6. Radiation pattern 7. Beamwidth 8. Side lobes 9. Nulls 10. Polarization National Institute of Technical Teacher's Training & Research, Chandigarh 10
  11. 11. Continued… 1. Input impedance o For an efficient transfer of energy, the impedance of the radio, of the antenna and of the transmission cable connecting them must be the same. o Transceivers and their transmission lines are typically designed for 50Ω impedance. o If the antenna has an impedance different from 50Ω, then there is a mismatch and an impedance matching circuit is required. 2. Return loss o The return loss is another way of expressing mismatch. o It is a logarithmic ratio measured in dB that compares the power reflected by the antenna the power that is fed into the antenna from the transmission line. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 11
  12. 12. Continued…  1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 12
  13. 13. Continued… 4. Directivity o Directivity is the ability of an antenna to focus energy in a particular direction when transmitting, or to receive energy better from a particular direction when receiving. o In a static situation, it is possible to use the antenna directivity to concentrate the radiation beam in the wanted direction. o In a dynamic system where the transceiver is not fixed, the antenna should radiate equally in all directions, and this is known as an omni-directional antenna. 5. Gain o The gain of an antenna (in any given direction) is defined as the ratio of the power gain in a given direction to the power gain of a reference antenna in the same direction. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 13
  14. 14. Continued… o isotropic radiator as the reference antenna in this definition. o isotropic radiator would be lossless and that it would radiate its energy equally in all directions. o An antenna gain of 3 dB compared to an isotropic antenna would be written as 3 dBi. 6. Radiation pattern o The radiation or antenna pattern describes the relative strength of the radiated field in various directions from the antenna, at a constant distance. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 14
  15. 15. Continued… 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 15
  16. 16. Continued… Dipole Antenna 3D radiation pattern Omni-Directional 3D pattern 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 16
  17. 17. Continued… 7. Beamwidth o The angular distance between the half power points is defined as the beamwidth. o Half the power expressed in decibels is —3dB, so the half power beamwidth is sometimes referred to as the 3dB. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 17
  18. 18. Continued… 8. Side lobes o No antenna is able to radiate all the energy in one preferred direction. Some is inevitably radiated in other directions. The peaks are referred to as side lobes, commonly specified in dB down from the main lobe. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 18
  19. 19. Continued… 9. Nulls o In an antenna radiation pattern, a null is a zone in which the effective radiated power is at a minimum. o A null often has a narrow directivity angle compared to that of the main beam. 10. Polarization o Polarization is defined as the orientation of the electric field of an electromagnetic wave. o Polarization is in general described by an ellipse. o Two special cases of elliptical polarization are linear polarization and circular polarization. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 19
  20. 20. Continued… o With linear polarization the electric field vector stays in the same plane all the time. o Vertically polarized radiation is somewhat less affected by reflections over the transmission path. o Omnidirectional antennas always have vertical polarization. o With horizontal polarization, such reflections cause variations in received signal strength. o In circular polarization the electric field vector appears to be rotating with circular motion about the direction of propagation, making one full turn for each RF cycle. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 20
  21. 21. Continued… 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 21
  22. 22. Antennas for Mobile devices • The type of antenna that is used with a particular type of phone is normally determined by dimensional considerations and specific absorption rate (SAR) regulations. • SAR(specific absorption rate) is a measurement of how much electromagnetic radiation is absorbed by body tissue while using a mobile phone. Higher the SAR more radiation will absorbed. • In the United States, the Cellular Telecommunications and Internet Association (CTIA) requires all cell phones to comply with the Federal Communications Commission (FCC) SAR limit of 1.6 W/kg in 1g of tissue. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 22
  23. 23. Data Sheet of SAR Values for Diff. Mobile Phones http://www.s21.com/sar.htm 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 23 Manufacturer Model SAR (W/Kg) Apple iPhone 3G S 1.19 Apple iPhone 5 1.25 BlackBerry Curve 8900 1.01 BlackBerry Curve 9320 1.56 Samsung Chat S3350 0.817 Samsung Galaxy Nexus 0.456 Motorola A830 0.69 Motorola Z3 1.02 Nokia 2100 0.55 Nokia N97 0.66 Sony Xperia Z Ultra 0.339
  24. 24. Bad Effect of Cellphone on Health  Impaired Concentration o Excess use of mobile phones reduces your ability to focus. o You take more time to do a task whether it’s solving mathematical question or approaching the car breaks to avoid an accident.  General Sickness o The moment you touch the mobile screen , 20% to 30% of all Virus and bacteria were transmitted to your hands and finally into your body. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 24
  25. 25. Bad Effect of Cellphone on Health  Eye problems o The combination of holding your phone too close to your Eyes along with staring at its viciously small font can lead to eye strain, headaches, dry eye and blurred vision.  Risk to Unborn o Use of Cellphones during pregnancy slows down the rate of brain development of the fetus or may lead to hyper activity. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 25
  26. 26. Bad Effect of Cellphone on Health  Neurodegenerative Disorders o The harmful radiations emitted by the cell phones can damage DNA o DNA damage in brain cells can affect neurological functions o This can possibly lead to neurodegenerative diseases  Heart risks o Radiations from cordless phones (including mobile phones) can cause irregularities in normal functioning of heart 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 26
  27. 27. Bad Effect of Cellphone on Health  Loss of Hearing o The radiation emitted by cell phones can damage delicate workings of the inner ear o People who are subjected to long-term mobile phone use are at a higher risk of developing hearing loss  Brain Cancer o Cell phone radiation may be slowly damaging your brain o radio frequency field generated by your cell phone triggers heating up of brain tissue 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 27
  28. 28. How to reduce your exposure to phone radiation o Do not use your phone more than necessary and keep your calls short. o Send a text instead of making a call. o Try to avoid using your phone if the signal strength is low - find a better location to make a call. o Try to use the phone outdoors rather than inside, or move close to a window to make a call. o Keep the phone (and particularly the aerial) as far as possible from your head. o Switch off your phone when not in use. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 28
  29. 29. Antennas for Mobile devices Following are main types of antennas used in cellular phones:  External Antennas • Monopoles • Helical 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 29
  30. 30. Continued… Following are main types of antennas used in cellular phones:  Internal Antennas  Microstrip antennas(MSA)  Planar inverted F antennas(PIFA)  Menader line antennas(MLA) 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 30
  31. 31. Planar inverted F antenna  The inverted F Antenna (IFA) typically consists of a rectangular planar element located above a ground plane, a short circuiting plate or pin, and a feeding mechanism for the planar element.  The inverted F antenna is a variant of the monopole where the top section has been folded down so as to be parallel with the ground plane.  This is done to reduce the height of the antenna, while maintaining a resonant training length.  PIFA can be considered as a kind of linear inverted F antenna (IFA) with the wire radiator element replaced by a plate to expand the bandwidth. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 31
  32. 32. Continued…  Advantages of PIFAAntenna o It can be hiding into the housing of the mobile while comparable to whip/rod/helix antennas. o It reduces the backward radiation toward the user’s head, minimizing specific absorption rate (SAR).  Disadvantage of PIFAAntenna o Narrow bandwidth characteristic of PIFA is one of the limitations for its commercial application for wireless mobile. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 32
  33. 33. Antennas use in different cell phones 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 33 Model Antenna Frequency bands Apple iPhone 2G Planar Monopole GSM850/900/1800/1900 Apple iPhone 3G Planar Monopole GSM850/900/1800/1900 +3G Blackberry 8100 Planar Monopole GSM850/900/1800/1900 Motorola E398 PIFA GSM900/1800/1900 Motorola L2000/P7389 Helix GSM900/1800/1900 Motorola W208 PIFA GSM900/1800 Nokia 2626 PIFA GSM900/1800 Nokia 2652 PIFA GSM900/1800 Sony Ericsson K660i PIFA GSM850/900/1800/1900 +3G Nokia 5300 Planar Monopole GSM900/1800/1900 Nokia 6210 PIFA GSM900/1800 Samsung Helix GSM900/1800
  34. 34. Handset Design Evolution 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 34
  35. 35. 1 June 2014 Cell Phone Antennas 35 The first DynaTAC phone weighted around 2.2 Kgs (approx.) The battery life would last for only 20 minutes Nicknamed the ‘The BRICK’ Its cost was around 4,000 US Dollars Quick Facts About the First Cell Phone
  36. 36. How the handset antennas get evolved in the past 20 years? 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 36
  37. 37. 1G(Analog) in 1980s-800 MHz 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 37
  38. 38. 2G(Digital) in 1990s-GSM900 MHz And 1800 MHz  New services came-text messaging, multimedia, internet access ,etc operated at GSM 900 MHz, later introduced at 1800 MHz 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 38
  39. 39. Continued… 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 39
  40. 40. Dual Band Internal Antenna 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 40
  41. 41. Single Band PIFA 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 41
  42. 42. First Dual Band PIFA 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 42
  43. 43. First 2G Mobile with Fully Internal Antenna 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 43
  44. 44. 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 44
  45. 45. First Triple Band PIFA 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 45
  46. 46. Handset Antennas in 2000s-3G0 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 46
  47. 47. Location of antennas in different mobile phones 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 47
  48. 48. Continued… 1 June 2014 National Institute of Technical Teacher's Training & Research, Chandigarh 48
  49. 49. 6/1/2014 Intrusion Detection Systems 49

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