This technical report discusses the components and system design of radar systems. It describes some key subsystems including antennas, duplexers, and the radio frequency subsystem. It also discusses digital waveform generators and frequency synthesizers/oscillators. Antennas are the interface between the radar system and free space, transmitting energy in beams and collecting echo signals. Duplexers use circulators to switch the radar between transmit and receive modes. The radio frequency subsystem includes antennas, duplexers, and filters to transmit signals and filter received signals. Digital waveform generators store and output signals using digital memories and D/A converters. Frequency synthesizers and oscillators generate the radio frequencies used.
Radar 2009 a 6 detection of signals in noiseForward2025
This document summarizes a lecture on radar signal detection. It discusses detecting signals in noise, the radar detection problem, basic target detection tests, and how detection performance is affected by factors like signal-to-noise ratio and number of integrated pulses. It outlines concepts like probability of detection, probability of false alarm, and the tradeoff between the two. Integration of multiple pulses can improve performance through coherent or non-coherent integration. Fluctuating targets are also addressed.
This document discusses prediction of range performance in radar systems. It introduces radar and the radar equation, which relates range to characteristics of the transmitter, receiver, antenna, target, and environment. It describes how transmitter power, pulse width, pulse repetition frequency, and radar operating frequency affect range performance. The radar equation is an important tool for assessing radar performance, designing new systems, and specifying requirements for new radars. All parameters of the radar system, including these factors, will impact performance in some way.
The document discusses microwave filters and resonators. It covers:
1. Different types of resonators used in filters including LC resonators using inductors and capacitors, transmission line resonators using short or open circuited transmission lines, and cavity resonators using rectangular or circular waveguides.
2. Properties of filters like passband, stopband, insertion loss, and group delay.
3. Design of microwave filters including the insertion loss method, filter responses for low pass filters, impedance and frequency scaling, and applying the techniques to different filter types like low pass, high pass, band pass and band stop filters.
Multiple access techniques allow multiple users to share the same wireless spectrum simultaneously. Common techniques include frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (CDMA). FDMA assigns each user a different frequency band. TDMA assigns each user time slots on the same frequency. CDMA spreads each user's signal across the entire frequency band using unique codes.
2. wireless propagation models free space propagationJAIGANESH SEKAR
This document discusses wireless communication propagation mechanisms and propagation models. It explains that when a signal hits an obstacle, it can be reflected, diffracted, or scattered depending on the surface properties. Propagation models are used to predict the average received signal power and design wireless systems by characterizing radio wave propagation based on factors like frequency and distance. Small-scale fading models predict power fluctuations over short ranges, while large-scale models predict average power decreases over large distances between transmitter and receiver.
This document summarizes key propagation models including Okumura, Hata, and COST231 models. It describes the models' parameters and equations. The Okumura model is empirical and based on extensive measurements in Japan. It accounts for factors like frequency, distance, and antenna heights. The Hata and COST231 models extend Okumura's validity to other frequencies and environments through curve-fitting. The document also explains how to extract data from the models' graphs using a web tool and simulate the models in MATLAB.
This document discusses mobile radio propagation and propagation models. It begins by introducing how radio channels are random and time-varying. It then covers the free space propagation model and how received power decreases with distance. Reflection, diffraction, and scattering are described as the main propagation mechanisms. The two-ray ground reflection model is presented to model propagation over large distances. Diffraction is explained using the knife-edge diffraction model. Fresnel zones and diffraction gain are also defined.
This document discusses key concepts related to antennas including:
1. It defines radiation power density as the power radiated per unit surface area from the antenna surface.
2. It explains that directivity is a measure of the directional properties of an antenna and is defined as the ratio of radiation intensity in a given direction compared to an isotropic source.
3. Gain accounts for both the directional properties and efficiency of an antenna, defined as the ratio of intensity in a given direction compared to an isotropic source radiating the same total power.
4. Additional concepts covered include beamwidth, radiation patterns, and parameters related to receiving performance such as effective length and capture area.
Radar 2009 a 6 detection of signals in noiseForward2025
This document summarizes a lecture on radar signal detection. It discusses detecting signals in noise, the radar detection problem, basic target detection tests, and how detection performance is affected by factors like signal-to-noise ratio and number of integrated pulses. It outlines concepts like probability of detection, probability of false alarm, and the tradeoff between the two. Integration of multiple pulses can improve performance through coherent or non-coherent integration. Fluctuating targets are also addressed.
This document discusses prediction of range performance in radar systems. It introduces radar and the radar equation, which relates range to characteristics of the transmitter, receiver, antenna, target, and environment. It describes how transmitter power, pulse width, pulse repetition frequency, and radar operating frequency affect range performance. The radar equation is an important tool for assessing radar performance, designing new systems, and specifying requirements for new radars. All parameters of the radar system, including these factors, will impact performance in some way.
The document discusses microwave filters and resonators. It covers:
1. Different types of resonators used in filters including LC resonators using inductors and capacitors, transmission line resonators using short or open circuited transmission lines, and cavity resonators using rectangular or circular waveguides.
2. Properties of filters like passband, stopband, insertion loss, and group delay.
3. Design of microwave filters including the insertion loss method, filter responses for low pass filters, impedance and frequency scaling, and applying the techniques to different filter types like low pass, high pass, band pass and band stop filters.
Multiple access techniques allow multiple users to share the same wireless spectrum simultaneously. Common techniques include frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (CDMA). FDMA assigns each user a different frequency band. TDMA assigns each user time slots on the same frequency. CDMA spreads each user's signal across the entire frequency band using unique codes.
2. wireless propagation models free space propagationJAIGANESH SEKAR
This document discusses wireless communication propagation mechanisms and propagation models. It explains that when a signal hits an obstacle, it can be reflected, diffracted, or scattered depending on the surface properties. Propagation models are used to predict the average received signal power and design wireless systems by characterizing radio wave propagation based on factors like frequency and distance. Small-scale fading models predict power fluctuations over short ranges, while large-scale models predict average power decreases over large distances between transmitter and receiver.
This document summarizes key propagation models including Okumura, Hata, and COST231 models. It describes the models' parameters and equations. The Okumura model is empirical and based on extensive measurements in Japan. It accounts for factors like frequency, distance, and antenna heights. The Hata and COST231 models extend Okumura's validity to other frequencies and environments through curve-fitting. The document also explains how to extract data from the models' graphs using a web tool and simulate the models in MATLAB.
This document discusses mobile radio propagation and propagation models. It begins by introducing how radio channels are random and time-varying. It then covers the free space propagation model and how received power decreases with distance. Reflection, diffraction, and scattering are described as the main propagation mechanisms. The two-ray ground reflection model is presented to model propagation over large distances. Diffraction is explained using the knife-edge diffraction model. Fresnel zones and diffraction gain are also defined.
This document discusses key concepts related to antennas including:
1. It defines radiation power density as the power radiated per unit surface area from the antenna surface.
2. It explains that directivity is a measure of the directional properties of an antenna and is defined as the ratio of radiation intensity in a given direction compared to an isotropic source.
3. Gain accounts for both the directional properties and efficiency of an antenna, defined as the ratio of intensity in a given direction compared to an isotropic source radiating the same total power.
4. Additional concepts covered include beamwidth, radiation patterns, and parameters related to receiving performance such as effective length and capture area.
The document discusses several outdoor propagation models used to predict radio signal strength over long distances. It focuses on the Longley-Rice and Okumura models. The Longley-Rice model predicts transmission loss using terrain profiles and diffraction losses from obstacles. It is available as a computer program that inputs frequency, path length, antenna heights and terrain parameters. The Okumura model uses curves to predict median signal attenuation relative to free space over distances from 1-100 km based on frequency, distance from base station, and terrain factors. It is widely used for cellular predictions in urban environments.
Radar 2009 a 15 parameter estimation and tracking part 1Forward2025
The document discusses a lecture on parameter estimation and tracking in radar systems. It covers topics like observable estimation including range, angle, Doppler, and amplitude measurement accuracy. It also discusses single target tracking techniques such as amplitude monopulse, phase comparison monopulse, sequential lobing, and conical scanning. The outline indicates it will cover multiple target tracking and provide a summary. Diagrams are included to illustrate concepts like angular tracking error sources and Doppler estimation.
The document provides an overview of microwave engineering and rectangular waveguides. It defines microwave frequencies as ranging from 1 GHz to 300 GHz. Rectangular waveguides transmit electromagnetic waves through successive reflections from inner walls. Modes in waveguides include transverse electric (TE) and transverse magnetic (TM) modes. The document analyzes the TM and TE modes in rectangular waveguides through solving Maxwell's equations with boundary conditions. Cut-off frequencies above which modes can propagate are determined. Examples demonstrate calculating waveguide parameters and resonant frequencies of cavity resonators.
By completing this presentation will be have a clear idea about Antenna's working principles, Antenna's Types & Antenna's Parameters. At the end to this document you'll have a brief idea about Antenna's Tilt vs Distance Calculation & Cluster wise optimum Antenna Selection procedure. Impact of antenna PIM & VSWR have been described elaborately in this document as well.
S-parameters are a useful method for representing a circuit as a "black box" whose external behavior can be predicted without knowledge of its internal contents. S-parameters are measured by sending a signal into the black box and detecting the waves that exit each port. They depend on the network, source and load impedances, and measurement frequency. Common S-parameters include S11 for the reflected signal at port 1 and S21 for the signal exiting port 2 due to a signal entering port 1.
This document provides an overview of a communication systems course taught by Ass. Prof. Ibrar Ullah. The course objectives are to develop basic concepts of communication systems using the textbook "Modern Digital And Analog Communication Systems". Students will be evaluated based on homework, tests, quizzes, and a final exam. Key topics covered include analog versus digital communication, modulation techniques, and the relationship between signal-to-noise ratio, channel bandwidth, and rate of communication.
The document discusses digital signal processing techniques for moving target indication radar. It describes how digital signal processing allows for greater flexibility in filter design compared to analog filters, including the ability to easily implement multiple pulse repetition frequencies. It provides an example of an airport surveillance radar system that uses a 3 pulse canceller, 8 pulse Doppler filter bank, and dual PRFs to detect targets while eliminating clutter.
A directional coupler is a passive device that couples part of the transmission power from one transmission line to another. It has four ports: input, transmitted, coupled, and isolated. Key parameters are coupling factor, loss, isolation, and directivity. Directional couplers are commonly used to monitor power and frequency without interrupting the main signal, for frequency and power measurements, and combining signals to a receiver when isolation is high.
This document provides an overview of the course content for Unit 1 of a radar systems course. The key topics covered include the modified radar range equation, signal-to-noise ratio, probability of detection and false alarms, integration of radar pulses, radar cross section of targets, creeping waves, transmitter power, pulse repetition frequency and range ambiguities, and system losses. The document also provides qualitative explanations and equations for several radar concepts.
The aperture is defined as the area, oriented perpendicular to the direction of an incoming radio wave, which would intercept the same amount of power from that wave as is produced by the antenna receiving it. A horn antenna or microwave horn is an antenna that consists of a flaring metal waveguide shaped like a horn to direct radio waves in a beam. Horns are widely used as antennas at UHF and microwave frequencies, above 300 MHz.
Microwave antennas can take several forms. Horn antennas are popular and can achieve gains up to 25 dB, with directional patterns. Parabolic antennas, like satellite dishes, typically have very high gain between 30-40 dB and low cross polarization. Slot antennas are often used instead of line antennas for greater pattern control and are found in radar and cell antennas. Dipole antennas are half wave resonant conductors that radiate omnidirectionally at right angles to their axis. Their gain is approximately 2 dBi. Dielectric antennas use a traveling surface wave along a dielectric rod to radiate maximally along the rod axis.
This presentation covers:
Different types of antennas used in satellite communication
Role of an antenna
Antenna temperature
Cassegrain feed Antenna
Parabolic antenna
Hello everyone. This is a short presentation on path loss and shadowing. I have not covered all the topics but a brief idea is given on path loss and wireless channel propagation models.
Hope you find it useful.
Thanks
Optical Fiber Communication Part 3 Optical Digital ReceiverMadhumita Tamhane
Current generated by photodetector is very weak and is adversely effected by random noises associated with photo detection process. When amplified, this signal further gets corrupted by amplifiers. Noise considerations are thus important in designing optical receivers.
Most meaningful criteria for measuring performance of a digital communication system is average error probability, and in analog system, it is peak signal to rms noise ratio. ...
Multiple access techniques allow multiple users to share finite radio spectrum resources simultaneously. They can be categorized as narrowband or wideband. Common techniques include FDMA, TDMA, CDMA, and SDMA. FDMA divides the total bandwidth into narrow channels that are allocated to users. TDMA divides each channel into time slots that are allocated to users. CDMA spreads the signal over a wide bandwidth using pseudo-random codes and allows multiple signals to overlap in both time and frequency.
This document discusses multiple-input multiple-output (MIMO) systems. It begins by outlining the motivations and aspirations for developing MIMO systems, including achieving high data rates near 1 gigabit/second while maintaining quality of service. It then provides an overview of MIMO system modeling and capacity studies. Key topics covered include diversity versus spatial multiplexing design criteria, example architectures, MIMO with orthogonal frequency-division multiplexing, and networking applications involving MAC protocols.
This document discusses various types of pulse modulation techniques used in analog and digital communication systems. It begins by defining pulse amplitude modulation (PAM) and describing how the amplitude of pulses varies proportionally to the message signal. It then discusses different types of PAM based on the sampling technique used - ideal, natural, and flat-top sampling. Flat-top sampling uses sample-and-hold circuits and can introduce amplitude distortion known as the aperture effect. The document also covers pulse width modulation (PWM), pulse position modulation (PPM), pulse code modulation (PCM), delta modulation (DM), and their advantages. It explains the sampling theorem and proves it through Fourier analysis. Finally, it discusses bandwidth requirements, transmission, drawbacks
Radar was invented in the early 1900s and applied during World War II to detect aircraft. The basic principles of radar involve transmitting electromagnetic signals that are reflected off targets and detected. A typical radar system includes a transmitter, antenna, receiver, and display. The radar range equation relates key variables such as transmitted power, wavelength, target radar cross-section, and system losses to the maximum detectable range. Integration of multiple radar returns can improve the signal-to-noise ratio and increase detection range.
This document discusses the history and uses of radar. It begins by explaining that bats use a basic form of radar to navigate and avoid obstacles. Early human radar, the telemobiloscope, was used to detect ships and avoid collisions. Radar was kept secret during WWII but is now commonly used for weather forecasting, air traffic control, speed detection by police, construction mapping, and military applications like detecting enemy weapons and positioning friendly forces. The document concludes that radar technology will continue advancing and have even more widespread applications in the future.
The document discusses several outdoor propagation models used to predict radio signal strength over long distances. It focuses on the Longley-Rice and Okumura models. The Longley-Rice model predicts transmission loss using terrain profiles and diffraction losses from obstacles. It is available as a computer program that inputs frequency, path length, antenna heights and terrain parameters. The Okumura model uses curves to predict median signal attenuation relative to free space over distances from 1-100 km based on frequency, distance from base station, and terrain factors. It is widely used for cellular predictions in urban environments.
Radar 2009 a 15 parameter estimation and tracking part 1Forward2025
The document discusses a lecture on parameter estimation and tracking in radar systems. It covers topics like observable estimation including range, angle, Doppler, and amplitude measurement accuracy. It also discusses single target tracking techniques such as amplitude monopulse, phase comparison monopulse, sequential lobing, and conical scanning. The outline indicates it will cover multiple target tracking and provide a summary. Diagrams are included to illustrate concepts like angular tracking error sources and Doppler estimation.
The document provides an overview of microwave engineering and rectangular waveguides. It defines microwave frequencies as ranging from 1 GHz to 300 GHz. Rectangular waveguides transmit electromagnetic waves through successive reflections from inner walls. Modes in waveguides include transverse electric (TE) and transverse magnetic (TM) modes. The document analyzes the TM and TE modes in rectangular waveguides through solving Maxwell's equations with boundary conditions. Cut-off frequencies above which modes can propagate are determined. Examples demonstrate calculating waveguide parameters and resonant frequencies of cavity resonators.
By completing this presentation will be have a clear idea about Antenna's working principles, Antenna's Types & Antenna's Parameters. At the end to this document you'll have a brief idea about Antenna's Tilt vs Distance Calculation & Cluster wise optimum Antenna Selection procedure. Impact of antenna PIM & VSWR have been described elaborately in this document as well.
S-parameters are a useful method for representing a circuit as a "black box" whose external behavior can be predicted without knowledge of its internal contents. S-parameters are measured by sending a signal into the black box and detecting the waves that exit each port. They depend on the network, source and load impedances, and measurement frequency. Common S-parameters include S11 for the reflected signal at port 1 and S21 for the signal exiting port 2 due to a signal entering port 1.
This document provides an overview of a communication systems course taught by Ass. Prof. Ibrar Ullah. The course objectives are to develop basic concepts of communication systems using the textbook "Modern Digital And Analog Communication Systems". Students will be evaluated based on homework, tests, quizzes, and a final exam. Key topics covered include analog versus digital communication, modulation techniques, and the relationship between signal-to-noise ratio, channel bandwidth, and rate of communication.
The document discusses digital signal processing techniques for moving target indication radar. It describes how digital signal processing allows for greater flexibility in filter design compared to analog filters, including the ability to easily implement multiple pulse repetition frequencies. It provides an example of an airport surveillance radar system that uses a 3 pulse canceller, 8 pulse Doppler filter bank, and dual PRFs to detect targets while eliminating clutter.
A directional coupler is a passive device that couples part of the transmission power from one transmission line to another. It has four ports: input, transmitted, coupled, and isolated. Key parameters are coupling factor, loss, isolation, and directivity. Directional couplers are commonly used to monitor power and frequency without interrupting the main signal, for frequency and power measurements, and combining signals to a receiver when isolation is high.
This document provides an overview of the course content for Unit 1 of a radar systems course. The key topics covered include the modified radar range equation, signal-to-noise ratio, probability of detection and false alarms, integration of radar pulses, radar cross section of targets, creeping waves, transmitter power, pulse repetition frequency and range ambiguities, and system losses. The document also provides qualitative explanations and equations for several radar concepts.
The aperture is defined as the area, oriented perpendicular to the direction of an incoming radio wave, which would intercept the same amount of power from that wave as is produced by the antenna receiving it. A horn antenna or microwave horn is an antenna that consists of a flaring metal waveguide shaped like a horn to direct radio waves in a beam. Horns are widely used as antennas at UHF and microwave frequencies, above 300 MHz.
Microwave antennas can take several forms. Horn antennas are popular and can achieve gains up to 25 dB, with directional patterns. Parabolic antennas, like satellite dishes, typically have very high gain between 30-40 dB and low cross polarization. Slot antennas are often used instead of line antennas for greater pattern control and are found in radar and cell antennas. Dipole antennas are half wave resonant conductors that radiate omnidirectionally at right angles to their axis. Their gain is approximately 2 dBi. Dielectric antennas use a traveling surface wave along a dielectric rod to radiate maximally along the rod axis.
This presentation covers:
Different types of antennas used in satellite communication
Role of an antenna
Antenna temperature
Cassegrain feed Antenna
Parabolic antenna
Hello everyone. This is a short presentation on path loss and shadowing. I have not covered all the topics but a brief idea is given on path loss and wireless channel propagation models.
Hope you find it useful.
Thanks
Optical Fiber Communication Part 3 Optical Digital ReceiverMadhumita Tamhane
Current generated by photodetector is very weak and is adversely effected by random noises associated with photo detection process. When amplified, this signal further gets corrupted by amplifiers. Noise considerations are thus important in designing optical receivers.
Most meaningful criteria for measuring performance of a digital communication system is average error probability, and in analog system, it is peak signal to rms noise ratio. ...
Multiple access techniques allow multiple users to share finite radio spectrum resources simultaneously. They can be categorized as narrowband or wideband. Common techniques include FDMA, TDMA, CDMA, and SDMA. FDMA divides the total bandwidth into narrow channels that are allocated to users. TDMA divides each channel into time slots that are allocated to users. CDMA spreads the signal over a wide bandwidth using pseudo-random codes and allows multiple signals to overlap in both time and frequency.
This document discusses multiple-input multiple-output (MIMO) systems. It begins by outlining the motivations and aspirations for developing MIMO systems, including achieving high data rates near 1 gigabit/second while maintaining quality of service. It then provides an overview of MIMO system modeling and capacity studies. Key topics covered include diversity versus spatial multiplexing design criteria, example architectures, MIMO with orthogonal frequency-division multiplexing, and networking applications involving MAC protocols.
This document discusses various types of pulse modulation techniques used in analog and digital communication systems. It begins by defining pulse amplitude modulation (PAM) and describing how the amplitude of pulses varies proportionally to the message signal. It then discusses different types of PAM based on the sampling technique used - ideal, natural, and flat-top sampling. Flat-top sampling uses sample-and-hold circuits and can introduce amplitude distortion known as the aperture effect. The document also covers pulse width modulation (PWM), pulse position modulation (PPM), pulse code modulation (PCM), delta modulation (DM), and their advantages. It explains the sampling theorem and proves it through Fourier analysis. Finally, it discusses bandwidth requirements, transmission, drawbacks
Radar was invented in the early 1900s and applied during World War II to detect aircraft. The basic principles of radar involve transmitting electromagnetic signals that are reflected off targets and detected. A typical radar system includes a transmitter, antenna, receiver, and display. The radar range equation relates key variables such as transmitted power, wavelength, target radar cross-section, and system losses to the maximum detectable range. Integration of multiple radar returns can improve the signal-to-noise ratio and increase detection range.
This document discusses the history and uses of radar. It begins by explaining that bats use a basic form of radar to navigate and avoid obstacles. Early human radar, the telemobiloscope, was used to detect ships and avoid collisions. Radar was kept secret during WWII but is now commonly used for weather forecasting, air traffic control, speed detection by police, construction mapping, and military applications like detecting enemy weapons and positioning friendly forces. The document concludes that radar technology will continue advancing and have even more widespread applications in the future.
The document discusses various applications of radar technology across several fields. It describes how radar is used for military purposes like air defense systems and targeting weapons. It also outlines applications in remote sensing, air traffic control, law enforcement, aircraft and ship safety, space exploration, and more. Some specific examples mentioned include using ground penetrating radar to locate buried objects and map landfills, and impulse radar to search rubble for trapped people.
RADAR stands for Radio Detection and Ranging. It uses electromagnetic waves to detect objects like aircraft, ships, vehicles, weather formations and terrain by determining their range, altitude, direction or speed. The basic principles of radar involve transmitting pulses and measuring their time of return to determine characteristics of detected objects like distance, direction and elevation angle. Interference from noise, clutter and jamming can reduce radar detection capabilities.
Tutorial Content
This tutorial provides a broad-based discussion of radar system, covering the following topics:
-Introduction to Radars in Military and Commercial Applications
-Radar System Block Diagram
-Radar Antennas (slotted waveguide array, planar array), Transmitter (magnetron, solid-state), Receiver, Pedestal and Radome
-Plot Extraction, Tracking Algorithms and Display
-Radar Range Equation, Detection Performance
-Wave Propagation and Radar Cross Section
-Emerging and Advanced Radar Systems (phased-array, multi-beam, multi-mode, FMCW, solid-state)
In the discussion, practical systems, technical specifications and data will be used to enhance learning.In addition, simulation results will also be used to present findings.
The objective of the tutorial session is to equip participants with solid understanding of radar systems for system level applications and prepare them for advanced and professional radar courses, projects and research.
This tutorial is designed and developed based on the following references:
[1] G. W. Stimson, Introduction to Airborne Radar Second Edition, Scitech Publishing, 1998.
[2] L. V. Blake, A Guide to Basic Pulse-Radar Maximum-Range Calculation, NRL Report 6930, 1969.
[3] K. H. Lee, Radar Systems for Nanyang Technological University, TBSS, 2014.
This document provides an overview of radar systems. It discusses what radar is, the evolution of radar from its initial uses detecting objects with radio waves in the late 1800s. It then explains the basic principles of how radar works to detect objects using radio signal transmission and reflection. Key components of radar systems like transmitters, receivers, antennas and signal processing are described. Applications of radar systems include military, remote sensing, air traffic control, and navigation. The document also discusses radar modulators and antenna design considerations for radar.
Optical remote sensing uses visible, near infrared, and shortwave infrared sensors to form images of the Earth's surface by detecting solar radiation reflected from targets. Different materials reflect and absorb light differently at different wavelengths, allowing targets to be differentiated by their spectral signatures. Optical remote sensing systems are classified as panchromatic, multispectral, hyperspectral, or superspectral depending on the number of spectral bands measured.
This document discusses a new type of gated continuous wave (CW) radar that offers improvements over traditional gated CW radars. It operates using a pulsed transmit signal and gated receive path, along with a receiver bandwidth restricted to only the central frequency components of the received pulse spectrum. This new gated CW radar uses a Performance Network Analyzer in place of a vector network analyzer for higher data acquisition speeds and other enhancements. It provides better accuracy, circularity and lower cost than an equivalent pulsed intermediate frequency radar while maintaining the efficiency advantages of gated CW radars for indoor use.
The document describes a group project to design a light sensing robotic vehicle using a PIC18F4520 microcontroller board, stepper motors, sensors, and switches. The task is for the robot to search for a light source within a bounded area, stop within 15cm of the light, and re-negotiate its path when obstacles are encountered. The group divided responsibilities and spent four weeks implementing the hardware, writing software, and integrating everything onto the robotic platform. By the end of the project, the light sensing robot was able to follow light, avoid boundaries, react to obstacles, and stop at the desired distance from the light source, as demonstrated in videos of its operation.
This document describes the design and functioning of a light following robot. The robot uses light dependent resistors (LDRs) to sense light and an op-amp circuit to compare the light readings from the LDRs. When more light falls on one LDR, the op-amp output activates the corresponding transistor which drives the motor on that side, causing the robot to turn towards the light source. The robot aims to follow a light source such as a flashlight by moving its motors based on the LDR sensor readings processed by the op-amp circuitry. Applications include uses in street lights, alarms, and devices that adjust screen brightness based on ambient lighting.
Radar uses radio waves to detect objects by transmitting pulses that bounce off objects and return to a receiving dish. The time it takes and the strength of the returned signal can reveal an object's distance, direction, speed and other characteristics. Radar was developed secretly before and during WWII and is used for applications like air traffic control, weather monitoring, military defense systems and more. It works on the same echo and Doppler shift principles as sound but uses radio waves which travel far and are easy to detect.
This document discusses the basic concepts and components of radar systems. It begins by defining radar and describing its applications. It then explains the basic concept of radar, which uses radio waves reflected off objects to determine their location, shape, and speed. The key components needed for a basic radar system are identified as a signal transmitter, receiver, and antennas. The document outlines the purpose and function of common radar components like modulators, mixers, and amplifiers. It also describes digital signal processing techniques and how signal modulation addresses limitations in radar frequencies.
The document describes the design and simulation of an E-shaped microstrip patch antenna. Key details include:
1) The antenna has a proposed patch length of 29mm and width of 37mm, with cuts of 6mm and 18mm.
2) The antenna was simulated in IE3D from 1-9GHz with a dielectric constant of 4.3, thickness of 1.5mm, and loss tangent of 0.019.
3) The simulation results showed dual-band behavior with best return losses of -27.69dB at 2GHz, -13.71dB at 6GHz, and -20.35dB at 8GHz. VSWR was lowest at 2GHz at 1.
Radar uses radio waves to detect distant objects by transmitting pulses and measuring their reflection. It can determine an object's range, angle, speed, and other features. Originally developed for military use, radar is now widely used in civil applications like weather monitoring. It works by transmitting microwave pulses and measuring properties of the returning echo, allowing it to calculate characteristics of detected objects.
These are the steps to be followed to use the Optimetrics feature in HFSS. This feature lets a user to optimize his/her design and its parameters by employing several techniques.
ATI's Radar Systems Analysis & Design using MATLAB Technical Training Short C...Jim Jenkins
This course provides a comprehensive description of radar systems analyses and design. A design case study is introduced and as the material coverage progresses throughout the course, and new theory is presented, requirements for this design case study are changed and / or updated, and the design level of complexity is also increased. This design process is supported with a comprehensive set of MATLAB-7 code developed for this purpose. By the end, a comprehensive design case study is accomplished. This will serve as a valuable tool to radar engineers in helping them understand radar systems design process. Each student will receive the instructor’s textbook MATLAB Simulations for Radar Systems Design as well as course notes.
The development of a system simulation platform for Adaptive Cruise Control (ACC) radar working at 77 GHz is presented. The simulation platform allows us to test different radar architectures, modulation formats and detection algorithms as well as to simulate different scenarios, which improves the decision-making before and during the hardware development.
This document is the preface to the second edition of the book "Microstrip and Printed Antenna Design" by Randy Bancroft. It provides an overview of the additions and improvements made for the second edition, including new analysis methods for circular polarization bandwidth, expanded sections on omnidirectional and PIFA antennas, and the addition of impedance matching techniques. The preface expresses the goal of the book as providing practical and manufacturable antenna designs while also offering references for more complex designs. It is intended as a handbook for microstrip antenna designers.
Artificial intelligence in the design of microstrip antennaRaj Kumar Thenua
This work presents a Neural Network model for the design of Microstrip Antenna for a desired frequency between 3.5 GHz to 5.5 GHz. The results obtained from the proposed method are compared with the results of IE3D and are found to be in good agreement. The advantage of the proposed method lies with the fact that the various parameters required for the design of specific Microstrip antenna at a particular frequency of interest can be easily extracted without going into the rigorous time consuming, iterative design procedures using a costly software package. In this work, a general design procedure is suggested for the Microstrip antennas using artificial neural networks and this is demonstrated using the rectangular patch geometry.
This document summarizes a seminar report on the design and implementation of a log-periodic antenna. It was submitted by three students - Shruti Nadkarni, Gargi Mohokar, and Sneha Vyavahare - to the Department of Electronics and Telecommunication at Pune's Modern College of Engineering as partial fulfillment of their degree requirements. The report describes the design of a log-periodic antenna with an operational bandwidth of 1150MHz from 350MHz to 1500MHz. It will use two such antennas pointing in four cardinal directions connected to a receiver to determine the direction of signal interference.
This document provides an overview of antenna properties and types. It discusses key antenna properties like gain, aperture, directivity, bandwidth, polarization, and effective length. It then describes several common antenna types including dipole antennas, monopole antennas, loop antennas, log-periodic antennas, travelling wave antennas like helical and Yagi-Uda, and reflector antennas like corner reflectors and parabolic reflectors. Radiation patterns are also characterized in terms of main beam, sidelobes, half power beamwidth, and sidelobe level.
This document provides a seminar report on the design of microstrip patch antennas. It includes an abstract, table of contents, and sections on antenna parameters, types of antennas including dipoles and Yagi antennas, and software aspects of designing microstrip patch antennas including feed techniques. The report was submitted by a student in partial fulfillment of requirements for a Bachelor of Technology degree.
This document discusses various types of antennas. It begins by outlining the learning objectives, which are to classify antennas, analyze antenna parameters, and compare different antenna types. It then defines an antenna as a structure that converts electrical signals to radio waves and vice versa. Key parameters discussed include polarization, radiation pattern, directivity, impedance, bandwidth, and electrical/physical length. Standard antenna types like isotropic radiators and dipoles are introduced. Specific antenna designs covered include half-wave and folded dipoles, and quarter-wave monopoles. Near-field and far-field regions are also defined.
This document provides an overview of radar systems used for fire control and describes their main components. It discusses how radar works by transmitting radio waves and detecting their reflection off objects. Fire control radars emit narrow beams to accurately track targets and guide weapons. They are part of larger fire control systems along with gun data computers and directors to assist weapon systems in hitting targets faster and more precisely. The majority of the work involves radar systems that control the direction and firing of guns and missiles.
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1. Technical Report
Radar System Components and System Design
November 22, 2002
Revision No. 1
Prepared by:
Lav Varshney
Syracuse Research Corporation
6225 Running Ridge Road
North Syracuse, NY 13212-2509
2. Introduction
Radars are very complex electronic and electromagnetic systems. Often they are
complex mechanical systems as well. Radar systems are composed of many different
subsystems, which themselves are composed of many different components. There is a great
diversity in the design of radar systems based on purpose, but the fundamental operation and
main set of subsystems is the same. In this paper, I will discuss some of the subsystems and
important components that are found in typical portable monostatic pulsed ground surveillance
radar systems. I follow a bottom-up approach in developing this paper, first discussing
components, then subsystems, and finally whole systems.
Antennas
The radar antenna acts as the interface between the radar system and free space through
which radio waves are transmitted and received. The purpose of the radar antenna is to
transduce free space propagation to guided wave propagation during reception and the opposite
during transmission. During transmission, the radiated energy is concentrated into a shaped
beam which points in the desired direction in space. During reception, the antenna collects the
energy contained in the echo signal and delivers it to the receiver. In the radar range equation,
these two roles were expressed by the transmitter gain, G, and effective receiving aperture, Ae,
given by
4πR 2 PT (1)
G=
Pin
Preceived (2)
Ae =
Pincident
These two values are proportional, so optimizing for both transmitting and receiving is possible.
The proportionality is given by
λ2 (3)
Ae = G
4π
One of the most widely used microwave antennas is the parabolic reflector. The
geometric properties of the parabola are very useful in concentrating energy during reception,
and creating plane constant-phase wavefronts during transmission. When a point source of
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3. radiation is placed at the focus, energy is emitted in all directions, striking points on the surface,
such as A in Figure 1. This energy is reflected perpendicular to the axis. The distance in all such
lines is the same, resulting in a constant-phase wavefront.
Figure 1. Parabola
A few different types of paraboloids are used in making parabolic reflectors. One of the
commonly used paraboloids is the orange-peel paraboloid, shown in Figure 2. This is a section
of a complete circular paraboloid. Since the reflector is narrow in the vertical plane, and wide in
the horizontal plane, it produces a beam that is wide in the vertical plane and narrow in the
horizontal plane. The microwave energy is sent into the parabolic reflector by an antenna feed
(not shown in Figure 2).
Figure 2. Orange-peel Paraboloid
Antenna feeds, or sources of illumination for parabolic reflectors, may employ either
coaxial lines or waveguides and may be classified as front or rear feeds. In a rear feed, the line
or guide projects through the reflector, whereas in a front feed, the line or guide approaches the
reflector from the front. An antenna feed must satisfy two requirements: shape & location so as
to illuminate the reflector in the correct manner; and termination of the waveguide or coaxial line
so that the standing-line ratio is near unity in the line or feed. Horn radiators, fed by waveguides,
are often used with orange-peel parabolic reflectors. The horn radiation pattern covers nearly the
entire shape of the reflector, so almost all of the microwave energy strikes the reflector and very
little escapes at the sides. The sectoral horn radiator is formed by flaring the wide cross-
sectional dimension of a rectangular waveguide. The length and flare angle of the horn
determine the directivity of the radiation that energizes the reflector and also the terminating
impedance of the waveguide.
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4. The reflecting surface of the parabolic reflector may be made of a solid sheet metal such
as aluminum or steel. Often wire screen, metal grating, perforated metal, or expanded metal
mesh is used to provide low wind resistance, light weight, and low cost. Reflector surfaces may
also be formed from fiberglass resinated laminates with the reflecting surface made of embedded
mesh.
Duplexer
When a single antenna is used for both transmission and reception, as in most monostatic
radar systems, a duplexer must be used. A duplexer switches the radar system from transmit
mode to receive mode. There are four main requirements that must be met by an effective radar
duplexing system. During transmission, the switch must connect the antenna to the transmitter
and disconnect it from the receiver. The receiver must be thoroughly isolated from the
transmitter during the transmission of the high-power pulse to avoid damage to sensitive receiver
components. After transmission, the switch must rapidly disconnect the transmitter and connect
the receiver to the antenna. For targets close to the radar to be detected, the action of the switch
must be extremely rapid. The switch should have very little insertion loss during both
transmission and reception.
The simplest solution to the duplexer problem is to use a switch to transfer the antenna
connection from the receiver to the transmitter during the transmitted pulse and back to the
receiver during the return pulse. Since no practical mechanical switches are available that can
open and close in a few microseconds, electronic switches are used. For radars with waveguide
antenna feeds, waveguide junction circulators are often used as duplexers. A circulator is a
nonreciprocal ferrite device, which contains three or more ports. A three-port ferrite junction
circulator, called the Y-junction circulator, is most commonly used. The Y-junction circulator
uses spinel ferrites or garnet ferrites in the presence of a magnetic bias field, to provide a non-
reciprocal effect. A schematic diagram is shown in Figure 3.
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5. Figure 3. Circulator Schematic
If a signal is applied at the transmitter port, it will emerge from the antenna port with a
loss characteristic called insertion loss. Typical values of insertion loss are 0.1 to 0.5 dB. In the
reverse direction, there will be leakage at the receiver port from the incoming signal at the
transmitter port. This leakage, called isolation, is typically 20 dB below incoming power at the
transmitter port. Due to the symmetry of the Y-junction, the behavior is the same for the other
ports, with respect to other port pairs.
Radio Frequency Subsystem
The Radio Frequency (RF) system takes a signal from the transmitter and eventually
propagates it in free space during transmission. The RF system takes a signal from free space
and passes it to the receiver during reception. The RF system generally consists of an antenna
feed and antenna, a duplexer, and some filters. Often devices are needed to convert waveguide
propagation into coaxial cable propagation. Filtering is used to attenuate out-of-band signals
such as images and interference from other radars or high-powered electrical devices during
reception. During transmission, filtering is used to attenuate harmonics and images. The
preselector filter is a device that accomplishes these two filtering objectives. The duplexer
provides isolation between the transmitter and receiver to protect the sensitive receiver during
the high energy transmit pulse. The antenna feed collects energy as it is received from the
antenna or transmits energy as it is transmitted from the antenna. The antenna is the final stage
in the RF system during transmission or the first stage during reception. It is the interface with
the medium of radio wave propagation.
Digital Waveform Generator
Digital waveform generators are constructed by linking a digital signal source with a
digital to analog (D/A) converter. In general, digital memories are used to store the signal
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6. waveform. The memory is read out based on the timing characteristics of the desired waveform.
There is a great deal of flexibility with digital waveform generators, which is not present for
analog signal generators. Waveform design is a complex topic that will not be treated in this
paper. The purpose of the radar, and the expected characteristics of the targets, in addition to the
demands of moving target indication (MTI), electromagnetic compatibility (EMC), and
electronic counter-countermeasures (ECCM) are some of the factors that determine waveform
design.
Frequency Synthesizers and Oscillators
Oscillators represent the basic microwave energy source for microwave systems such as
radars. A typical oscillator essentially consists of an active device and a passive frequency-
determining resonant element. Dielectric resonant oscillators (DROs) are fixed-frequency
oscillators that use a dielectric resonator as the frequency-determining element. Tunable
oscillators often use varactors as the tunable oscillator. A voltage controlled oscillator (VCO) is
an oscillator where the principal variable or tuning element is a varactor diode. The VCO is
tuned across its band by a clean direct current (DC) voltage applied to the varactor diode. Phase
Locked Loop (PLL) circuits are used for frequency control of VCOs. A PLL is basically a
feedback control system that controls the phase of a VCO. The input signal is applied to one
input of a phase detector. The other input is connected to the output of a divider. The output of
the phase detector is a voltage proportional to the phase difference between the two inputs. This
signal is applied to a loop filter. The filtered signal controls the VCO. Dual modulus prescalers
are often used as the divider in PLL circuits.
Mixer
Mixers are used to transform signals in one spectrum range to some other spectrum
range. In radar transmitters, mixers are used to transform intermediate frequency (IF) signals
produced by the waveform generator into RF signals. This process is called upconversion. In
radar receivers, the opposite operation is performed. RF signals are downconverted into IF
signals. This process is demonstrated in Figure 4.
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7. Figure 4. Upconversion and Downconversion Operations of a Mixer
Mixing is accomplished by combining either the RF or IF signal with another signal of known
frequency from the local oscillator (LO), as shown in Figure 5. What results is either the sum or
difference between the two, for upconversion and downconversion, respectively. Various kinds
of oscillators and frequency synthesizers are used as the LO. Silicon point-contact and Schottky-
barrier diodes based on the nonlinear resistance characteristics of metal-to-semiconductor
contacts have been used as the mixing element.
Figure 5. Mixer Schematic
Power Amplifier
Power amplifiers are used to amplify the RF waveform for transmission. Historically,
tube amplifiers, such as grid controlled tubes, magnetrons, klystrons, traveling-wave tubes
(TWTs), and crossed field amplifiers (CFAs) have been used as power amplifiers for radar
transmitters. These amplifiers generate high power, but usually operate with low duty cycle.
The klystron amplifier offers higher power than the magnetron at microwave frequencies, and
also allows the use of more complex waveforms. The TWT is similar to the klystron, but with
wider bandwidth. CFAs are characterized by wide bandwidth, modest gain, and compactness.
Solid State Power Amplifiers (SSPAs) support long pulses and high duty cycle waveforms.
Individual SSPA elements can be combined to produce sufficient amplification, despite the fact
that individual SSPA elements have low power amplification. Silicon Bipolar transistors, and
gallium arsenide Metal Semiconductor Field Effect Transistors (MESFETs), bulk-effect diodes,
and avalanche diodes are some of the solid state elements used in SSPAs.
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8. Transmitter Subsystem
The transmitter system is generally the main consumer of the power, cost, and weight
budgets, and is the prime thermal load of radar systems. The transmitter must be of adequate
power to obtain the desired radar range. The radar range equation shows that the transmitter
power depends on the fourth power of radar range. Hence, to double the range, it is necessary to
increase transmitter power 16-fold. The three main components in transmitters are the waveform
generator, the upconverting mixer, and the power amplifier, although it is possible to leave out
one of these components. The transmission waveform is generated by the digital waveform
generator. This waveform is in the baseband frequency range. The waveform is converted into
the RF frequency range by a mixer or series of mixers, the mixers using either fixed or variable
oscillators as the LO. Finally the power amplifier provides amplification for the transmit signal
before it enters the RF system.
Low Noise Amplifier
The purpose of a low noise amplifier (LNA) is to boost the desired signal power while
adding as little noise and distortion as possible so that retrieval of this signal is possible in the
later stages in the system. An LNA is an amplifier with low noise figure. Noise figure is defined
as the input signal to noise ratio (SNR) divided by the output SNR. For an amplifier, it can also
be interpreted as the amount of noise introduced by the amplifier seen at the output besides that
which is caused by the noise of the input signal. LNAs are used as the front end of radar
receivers. There are a few different kinds of amplifiers that can provide suitably low noise
figures. Parametric amplifiers have low noise figure, especially at high microwave frequencies.
The transistor amplifier can be applied over most of the range frequencies used for radar. The
silicon bipolar transistor and the gallium arsenide field effect transistor have also been used as
amplifiers. The lower the noise figure of the receiver, the less need there is for be transmitter
power for the same performance. In addition to noise figure, cost, burnout, and dynamic range
must also be considered when selecting a receiver front end.
Receiver Subsystem
The function of the radar receiver is to detect wanted echo signals in the presence of
noise, clutter, and interference. It must separate desired signals from undesired signals, and
amplify the desired signals for later processing. Receiver design depends on the design of the
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9. transmitted waveform, the nature of the targets, and the characteristics of noise, clutter, and
interference. The goal of receivers is to maximize the SNR of the returned echo signal. The
receiver system generally consists of an LNA, and downconverting mixers. Limiters are often
built into the front end to prevent inadvertent damage from reflected transmitter power or the
high power signal which may enter the system. Sometimes analog to digital (A/D) converters
are placed at the end of the receiver signal path, if digital signal processing is to take place.
Signal Processing/Data Processing/Control Subsystems
Various signal processing techniques can be performed on raw receiver signals. Some
common radar signal processing techniques are correlation, apodization, Doppler filtering, image
rejection, detection processing, and tracking. Almost all modern radars use digital signal
processors to perform these signal processing operations. These digital processors are very
complex chips, implementing very complex algorithms. Specific signal processing techniques
will not be discussed in this paper.
Data processors are used to convert data produced by the signal processor into a form that
is readily interpretable by radar operators. Human machine interface (HMI) designs are
generally implemented in the data processing system. Data processors are also used to process
inputs received from the operator. Often times tactical information is stored and used by the data
processing system
The different subsystems of the radar are coordinated by the Control subsystem. Precise
timing of events is required to optimize performance. As an example, the switch between
transmit and receive mode for a pulsed radar requires a complete transformation that must occur
in as little time as possible. Often the entire radar system is synchronized to a single clock,
produced and distributed by the control subsystem.
Antenna Positioning System
In some radar systems, antennas are positioned manually. In others, motors are used to
rotate and position radar antennas. If an antenna is required merely to rotate at constant speed, a
simple motor is sufficient. If several different motions, such as constant-speed rotation, scanning
over a sector, and tracking a moving object, are required, then servomechanisms are used.
Servomechanisms supply the large torque necessary to turn radar antennas, and also determine
the antenna position. A servomechanism is comprised of an error indicator and a controller
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10. connected to an input shaft and an output shaft. The object of the servomechanism is to cause
the output shaft to mirror the motion of the input shaft by keeping the error angle, deviation in
angular position of output shaft from input shaft, as close to zero as possible. The error indicator
determines the magnitude and direction of the error angle. Under control of the signal from the
error indicator, the controller exerts a torque on the output shaft in a direction to reduce the error.
The servo is a feedback system, because a signal applied to the controller causes rotation of the
output shaft and thus changes the error angle with the result that an additional signal is applied to
the controller. The error indicator is most frequently a synchro. A synchro is a small a-c
machine used for the transmission of angular position data. The controller must include a
servomotor or some other device for developing output torque. Most radar servos use electric
servomotors.
Power System
Radars are complex electromechanical systems. Each of the components requires power
to operate. In general, different components need different voltage levels. To satisfy these
different voltage requirements, using only a single external voltage source, voltage converters are
required. A DC to DC converter is a device that accepts a DC input voltage and produces a DC
output voltage. Typically the output produced is at a different voltage level than the input. DC to
DC converters often use switching regulators. A switching regulator is a circuit that uses an
inductor, a transformer, or a capacitor as an energy-storage element to transfer energy from input
to output in discrete packets. Feedback circuitry regulates the energy transfer to maintain a
constant voltage within the load limits of the circuit. The basic circuit can be configured to step
up (boost), step down (buck), or invert output voltage with respect to input voltage. Using a
transformer as the energy-storage element also allows the output voltage to be electrically
isolated from the input voltage. The one disadvantage of the switching regulator is noise. Any
time charge is moved in discrete packets, noise or ripple is created. The noise can often be
minimized by using specific control techniques, such as synchronization.
Whole System
A radar system is composed of many different subsystems. The main subsystems were
discussed in previous sections. In a pulsed radar system, there is a portion of time devoted to
transmission, and another portion of time devoted to reception. The transmission time is called
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11. the pulse width. A pulse is transmitted at regular intervals. The repetition interval is called the
pulse repetition interval (PRI). During transmission, the transmitter produces a waveform. This
is passed to the RF system, through which the waveform is transmitted into the medium of
propagation. When the waveform reaches a target, it is reflected back towards the radar. By
then, the radar system should be in reception mode. At this time, the reflected echo is
intercepted by the RF system. The echo is then passed to the receiver, which passes it on to the
signal processor. After signal processing, the data processor displays data for the operator,
through the HMI. Power and Control are provided to each of the subsystems as necessary. The
antenna is generally repositioned after a certain number of pulse transmissions. A schematic of
the radar system is shown in Figure 6.
Figure 6. Radar System Schematic
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12. List of Acronyms
A/D Analog to Digital
CFA Crossed Field Amplifier
D/A Digital to Analog
DC Direct Current
DRO Dielectric Resonant Oscillator
ECCM Electronic Counter-Countermeasures
EMC Electromagnetic Compatibility
HMI Human Machine Interface
IF Intermediate Frequency
LNA Low Noise Amplifier
LO Local Oscillator
MESFET Metal Semiconductor Field Effect Transistor
MTI Moving Target Indication
PLL Phase Lock Loop
PRI Pulse Repetition Interval
RF Radio Frequency
SNR Signal to Noise Ratio
SSPA Solid State Power Amplifier
TWT Traveling-Wave Tube
VCO Voltage Controlled Oscillator
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13. Figures
Figure 1: Weisstein, Eric W., Parabola, CRC Press LLC, 1999. [Online]. Available:
http://mathworld.wolfram.com/Parabola.html.
Figure 2: Radar Principles, United States Navy Electrical Engineering Training Series. [Online].
Available: http://www.tpub.com/neets/book18/index.htm.
Figure 3: Ferrite Devices, Temex Microwave, [Online]. Available: http://www.temex-
components.com/temex/catalog/agalinfogyro.pdf.
Figures 4,5: Abidi, Asad A., Upconversion and Downconversion Mixers for CMOS Wireless
Transceivers, University of California, Los Angeles. [Online]. Available:
http://www.icsl.ucla.edu/aagroup/PDF_files/shcourse.PDF
References
[1] Abidi, Asad A., Upconversion and Downconversion Mixers for CMOS Wireless
Transceivers, University of California, Los Angeles. [Online]. Available:
http://www.icsl.ucla.edu/aagroup/PDF_files/shcourse.PDF
[2] Dao, A., Integrated LNA and Mixer Basics, National Semiconductor, 1993. [Online].
Available: http://www.sss-mag.com/pdf/wirlna.pdf.
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