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phase-shifters
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Total 42 records
Error Analysis of Electronic Beam Steering in Coupled Oscillator Arrays
, M.Sc. Thesis Sharif University of Technology ; Banayi, Ali (Supervisor)
Abstract
Mutually coupled oscillator arrays have been considered. Detuning of free running frequencies of perimeter elements has been used in these arrays in order to steer the beam without phase shifters. Characteristic equations of transient and steady-state conditions of amplitude and phase of the elements of coupled oscillator arrays has been derived. Literature review is done in coupled oscillator arrays. Sensitivity analysis of beam pointing angle due to free running frequencies of elements in coupled oscillator arrays has been done and the various planar arrays has been compared. Sensitivity analysis of beam pointing angle due to phase error of elements in conventional phased array antennas...
Design and Fabrication of Passive CMOS Phase Shifter
, M.Sc. Thesis Sharif University of Technology ; Medi, Ali (Supervisor) ; Atarodi, Mojtaba (Co-Advisor)
Abstract
This research examines the issues of design and fabrication of Phase Shifter circuits on Silicon substrates. The Phase Shifter circuits are designed to have wide operation band width. They also should have very low sensitivity to process and temperature variation. A six bit phase shifter is designed at this research. We use a new topology for implementing the small phase shift steps and some circuits have been designed which their phase shifts can be adjusted after fabrication. All circuits are implemented with the 0.18µm CMOS technology. The research also explains all the necessary steps for measurement of fabricated circuits. The result of measurements shows good agreement with the...
Designing and Fabricating the Active Phase Shifter
, M.Sc. Thesis Sharif University of Technology ; Atarodi, Mojtaba (Supervisor)
Abstract
In this project, issues related to designing and fabricating active phase shifter blocks on the silicon substrate have been examined. Phase shifter circuits are designed in a way that have the most bandwidth and the less sensitivity to process characteristics changes and environmental conditions. The purpose of this research, is designing an active 6 bits phase shifter. The active phase shifter synthesizes the required phase using a phase interpolation process by adding quadrature phased input signals. It uses a new quadrature all-pass filter for quadrature signaling with a wide bandwidth. Also substitute structure has been suggested to this filter which is the main block in determining...
Design and Implementation of 7-10 GHz CMOS Phase Shifter
, M.Sc. Thesis Sharif University of Technology ; Medi, Ali (Supervisor)
Abstract
Phased array systems which are used for sending and receiving electromagnetic signals in mandatory directions are widely used in today’s wireless communication, satellite communication, and radar systems. Phased array systems are composed of units called transmitter/ receiver (TR) modules. These units are connected to antennas in one end and to the combiner/divider at the other end and are playing a major role in determining the quality of phased arrays. Transmitter/Receiver units include a phase shifting circuit for controlling the phase and an attenuator circuit for amplitude control of the signal being sent or received, solid state switches and a number of amplifiers. The aim of this...
Design and Implementation of a 15 dBm CMOS Power Amplifier
, M.Sc. Thesis Sharif University of Technology ; Medi, Ali (Supervisor)
Abstract
Today, phased array antennas have important role in wireless communication systems. Utilizing optimum channel capacity, having better signal to noise ratio and, high data rate are the most important features of these systems. These systems are composed of several thousands of separated transceivers which provide possibility of directional electromagnetic radiation by changing the phase and the amplitude of the signal in each transceiver independently. So, the main components of such a system are amplifiers, phase shifters and, amplitude controllers. Also a high resolution phased array military radar system is another vital applications of these systems at frequency band of 9-10 GHz. The...
Design of a Phase Shifter Based on Vector Summing
, M.Sc. Thesis Sharif University of Technology ; Atarodi, Mojtaba (Supervisor)
Abstract
Phase shifters are commonly used in the implementation of phased-array antenna systems.The function of these systems is highly dependent on the performance of phase shifters. In addition, phase shifter circuits are used in some applications such as antenna test and regulation, power amplifier linearization, and QAM modulator implementation, to name but a handful. In this project, design of phase shifter blocks, as well as limitations of fabrication on silicon substrate, is studied and these blocks are designed for maximum bandwidth and minimum sensitivity based on fabrication characteristics and environmental conditions. Design of a 6-bit phase shifter based on vector-sum method is the...
Design and Implementation of phase Locked Loop Using Low phase Noise Oscillator with Oversized Cavity Resonator
, M.Sc. Thesis Sharif University of Technology ; Banai, Ali (Supervisor)
Abstract
Phase noise is one of the most important parameters in communication systems especially in receivers. Implementation of low phase noise oscillators has always been important.One of the most important parameters in reducing the phase noise of the oscillator is the quality factor of the cavity used in its structure. As a result, increasing the quality factor of the cavity can reduce the oscillation phase noise. Cylindrical waveguides in higher order modes have a higher quality factor than the main modes of excitement. As a result, this property can be used to increase the quality factor of the cavity and reduce the phase noise of the oscillator. This will increase the size of the cavity. The...
Design of a Wide Band phase Shifter Based on Vector Summing
, M.Sc. Thesis Sharif University of Technology ; Atarodi, Mojtaba (Supervisor) ; Safarian, Amin Gasem (Co-Advisor)
Abstract
Phase shifters are commonly used in the implementation of phased-array antenna systems.The function of these systems is highly dependent on the performance of phase shifters. In addition, phase shifter circuits are used in some applications such as antenna test and regulation, power amplifier linearization, and QAM modulator implementation, to name but a handful. In this project, design of phase shifter blocks, as well as limitations of fabrication on silicon substrate, is studied and these blocks are designed for maximum bandwidth and minimum sensitivity based on fabrication characteristics and environmental conditions. Design of a 6-bit phase shifter based on vector-sum method is the...
Design and Implementation of a Passive Ku band phase Shifter in 0.18µm CMOS Process
, M.Sc. Thesis Sharif University of Technology ; Medi, Ali (Supervisor)
Abstract
In this project, a “Ku” band (16.3GHz-17.3GHz) 6-bit phase shifter for realizing a phase array T/R module is designed, implemented and measured in CMOS 0.18μm technology. Design specifications for this block were: RMS phase error should be less than 2.5 degree in bandwidth, better than 12dB loss and better than 16dBm input 1dB compression point. High-pass/low-pass filter structure is used to implement this phase shifter. In order to decrease phase shift error in process and temperature corners, a new structure for one of bits was introduced. This structure is less sensitive to process and temperature corners and furthermore it conSumes less area in layout, but it has more loss variation...
Design and Implementation of C band Vector- Sum phase Shifter for WLAN Applications
, M.Sc. Thesis Sharif University of Technology ; Akbari, Mohmoud (Supervisor) ; Fakharzadeh Jahromi, Mohammad (Supervisor)
Abstract
On the demand of higher directivity, higher throughput and less interference, phased array systems and MIMO have become attractive to reach these goals. The advantages of phased array systems include the ability to perform electronic beam steering and arbitrary pattern synthesis. Phase shifters and variable gain amplifiers are used to reach these advantages. In this thesis, a ‘’ C‘’ band (4.8 GHz-6.2 GHz) vector-sum phase shifter using HMIC technology for realizing a phased array receiver is designed. This phase shifter can change the signal phase and amplitude. The main blocks of this phase shifter are low-insertion phase and low-noise variable gain amplifier, which consists of current...
Design of a Low-IF Phased-Array Receiver for 5G Applications
, M.Sc. Thesis Sharif University of Technology ; Fakharzadeh, Mohammad (Supervisor)
Abstract
The most important feature of the fifth generation of mobile telecommunications is the increase of information transfer rate and together with it the increase of the capacity of telecommunication channels in comparison with the previous generation. One solution is to increase the frequency toward millimeter-wave frequencies. Currently, the most suitable option for the millimeter-wave frequency band is the 28 GHz band, which has received a lot of attention due to its availability and the possibility of implementing cheap integrated circuits using CMOS technology in this band. In addition to the features that this frequency band has; This band has limitations such as high emission losses and...
Phase Shifter Response Compensation in Microwave Band
, M.Sc. Thesis Sharif University of Technology ; Khavasi, Amin (Supervisor) ; Fakharzadeh, Mohammad (Co-Supervisor)
Abstract
A phase shifter is a microwave element that changes the phase of the input signal at a specific center frequency and bandwidth and, ideally, produces a signal with the same amplitude and a modified phase at the output. In practice, this phase change in the passive phase shifter is accompanied by a decrease in amplitude due to different factors. Various use cases can be described for phase shifters in telecommunication circuits, but its most important application is in regulating the relative phase of each antenna in a phased array system, which is the most common method of beam steering and forming. A phased array system is one of the leading solutions to achieve beamforming and high...
Clock and Data Recovery based on Phase Shifting and Accordion Oscillator
, M.Sc. Thesis Sharif University of Technology ; Fotowat Ahmady, Ali (Supervisor) ; Akbar, Fatemeh (Supervisor)
Abstract
The continuous growth of network traffic and people's demand for higher data rates, have driven wireline communication systems towards higher data rates. In these systems, the power consumption of these transmitters and receivers is a crucial and influential factor. This paper presents two different solutions to reduce the power consumption and area of these systems. In the first solution, a low-power phase shifter with variable phase and amplitude control is introduced. The changes in these parameters are mutually orthogonal, ensuring that a change in one characteristic does not affect the others. This phase shifter can be used to generate clock pulses with different phases in wireline...
Beamforming for 5G Wireless Communication Systems using Machine Learning Methods
, M.Sc. Thesis Sharif University of Technology ; Behroozi, Hamid (Supervisor) ; Fakharzadeh, Mohammad (Supervisor)
Abstract
The significant growth in wireless data traffic over the past few years has necessitated the use of new frequency bands for wireless communications. With the advent of the fifth-generation mobile network (5G), millimeter wave band will be widely employed for the purpose of wireless data transmission, increasing in channel bandwidth and data rate. Due to high propagation loss, severe vulnerability to blockage and poor reflection in millimeter wave frequencies, beamforming for antenna arrays is being considered a key enabler for millimeter wave applications in 5G. Beamforming contributes significantly to maintaining channel stability and capacity through enhancing Signal-to-Noise-Ratio (SNR)...
Design of a 28GHz Phased Array Receiver Front-end for 5G Applications
, M.Sc. Thesis Sharif University of Technology ; Fakharzadeh Jahromi, Mohammad (Supervisor)
Abstract
Design of a 28GHz phased array receiver front-end for 5G applications in CMOS 0.18um technology in the frequency band from 27.5 to 28.3 GHz is presented in this thesis. We use an RF phase shifting structure which consists of a low-noise amplifier, a phase shifter and a power combiner. The low-noise amplifier is designed using common-source cascode topology with a transformer-based gm-boosting technique in order to enhance the power gain and reduce the noise figure. A vector sum phase shifter is then designed to further enhance the gain. A Wilkinson power combiner with lumped elements is designed as the power combiner. The results of simulating a single RX chain shows a maximum of 15 dB...
A Novel Simultaneous Frequency and Spatial Filtering Methodology for Beam-forming and Null-steering in Integrated Phased-Array Systems Using N-path technique
, Ph.D. Dissertation Sharif University of Technology ; Atarodi, Mojtaba (Supervisor)
Abstract
In the communication systems, there are two types of blockers: in-band and out-of-band. High frequency pre-filters and band-pass filters can be used to suppress the out-of band blockers. However, using these methods does not affect the in-band interferers. Spatial filtering by means of phased array antennas and using frequency filtering can suppress both types of interferers. In a typical phased array receiver, all of the received signals pass through active blocks (such as LNAs, active phase shifters, driver amplifiers, etc.) that amplify the interferers before canceling them. Therefore, because of the high strength of the interferers, the dynamic range of the front-end blocks preceding...
An S-Band CMOS 6-Bit vector-sum phase shifter with low RMS phase error using frequency-to-voltage converter feedforward loop
, Article Journal of Circuits, Systems and Computers ; Volume 29, Issue 3 , 2020 ; Safarian, A ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2020
Abstract
In this paper, a wideband full-360o phase shifter with 6 bits of accuracy has been designed and simulated with minimal root mean square (RMS) phase error. The proposed phase shifter deployed a feed forward path including a frequency-to-voltage converter (FVC) to minimize the mismatch in quadrature generation to eventually reduce the RMS phase error for S-band (2-4GHz) applications. The designed phase shifter in 180nm CMOS technology achieves an RMS phase error in the range of 0.607-1.18? with -50dBm input signal over 2-4GHz frequency band. With lower input signal of -75dBm, the RMS phase error is 0.621-1.34? for 2-4GHz input frequency. The proposed phase shifter shows an RMS amplitude error...
An isolated bidirectional integrated plug-in hybrid electric vehicle battery charger with resonant converters
, Article Electric Power Components and Systems ; Volume 44, Issue 12 , 2016 , Pages 1371-1383 ; 15325008 (ISSN) ; Akbari, R ; Tahami, F ; Oraee, H ; Sharif University of Technology
Taylor and Francis Inc
2016
Abstract
Plug-in hybrid electric vehicles draw electricity from the electrical grid and store energy in their batteries. To increase charge availability for plug-in hybrid electric vehicles, on-board chargers can be used, which should be small in size and lightweight. In this article, an on-board bidirectional soft-switched battery charger is proposed that utilizes a phase-shift-controlled dual-bridge series resonant converter with isolation. The bidirectional characteristic of proposed charger makes it suitable for vehicle-to-grid operation (i.e., injecting power from the vehicle to the grid) in smart grids. A switching control scheme is also proposed to provide soft-switching operation for all...
A fast converging integrated implementation of zero-knowledge beamforming algorithm for phased-array receivers
, Article Analog Integrated Circuits and Signal Processing ; 2019 ; 09251030 (ISSN) ; Atarodi, M ; Sharif University of Technology
Springer New York LLC
2019
Abstract
This paper presents a new implementation of adaptive beamforming algorithm that can be fully implemented on chip. It does not require the knowledge of the incoming signal direction or phase shifter characteristics. Besides, it eliminates the need for the ADC to convert the analog output signal to digital values for the microprocessor and the DAC to apply the calculated values to the control voltages of the analog phase shifters. Thus, it exhibits better convergence speed. In addition, the need for the complex and power-hungry processor is eliminated. Therefore, this implementation consumes less power. Analytical equations and constraints on system design parameters are derived, and the...
A fast converging integrated implementation of zero-knowledge beamforming algorithm for phased-array receivers
, Article Analog Integrated Circuits and Signal Processing ; 2019 ; 09251030 (ISSN) ; Atarodi, S. M ; Sharif University of Technology
Springer New York LLC
2019
Abstract
This paper presents a new implementation of adaptive beamforming algorithm that can be fully implemented on chip. It does not require the knowledge of the incoming signal direction or phase shifter characteristics. Besides, it eliminates the need for the ADC to convert the analog output signal to digital values for the microprocessor and the DAC to apply the calculated values to the control voltages of the analog phase shifters. Thus, it exhibits better convergence speed. In addition, the need for the complex and power-hungry processor is eliminated. Therefore, this implementation consumes less power. Analytical equations and constraints on system design parameters are derived, and the...