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Analysis and design of a DC to 18 GHz 6-bit attenuator with simultaneous phase and gain error correction
, Article AEU - International Journal of Electronics and Communications ; Volume 110 , 2019 ; 14348411 (ISSN) ; Karami, P ; Atarodi, S. M ; Sharif University of Technology
Elsevier GmbH
2019
Abstract
In this paper the design of a digital step attenuator with simultaneous low phase and gain error characteristics is investigated. First, the loading effect of the consecutive blocks of an N-bit attenuator on the precision of the attenuation levels is analyzed. Then a modified structure to decrease the loading effect as well as the phase error of the attenuator blocks is presented. A comprehensive analysis of the circuit is performed and some design guidelines have described. Finally, a 6-bit attenuator with attenuation range of 0.5–31.5 dB and resolution of 0.5 dB is implemented in 0.18 µm complementary metal–oxide-semiconductor (CMOS) technology. The root mean square (RMS) gain error and...
On the error in phase transition computations for compressed sensing
, Article IEEE Transactions on Information Theory ; Volume 65, Issue 10 , 2019 , Pages 6620-6632 ; 00189448 (ISSN) ; Haddadi, F ; Amini, A ; Lotz, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Evaluating the statistical dimension is a common tool to determine the asymptotic phase transition in compressed sensing problems with Gaussian ensemble. Unfortunately, the exact evaluation of the statistical dimension is very difficult and it has become standard to replace it with an upper-bound. To ensure that this technique is suitable, [1] has introduced an upper-bound on the gap between the statistical dimension and its approximation. In this work, we first show that the error bound in [1] in some low-dimensional models such as total variation and ell _{1} analysis minimization becomes poorly large. Next, we develop a new error bound which significantly improves the estimation gap...
A 6-Bit CMOS phase shifter for S - Band
, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 58, Issue 12 PART 1 , 2010 , Pages 3519-3526 ; 00189480 (ISSN) ; Azizi, M ; Kiani, M ; Medi, A ; Atarodi, M ; Sharif University of Technology
Abstract
A 6-bit passive phase shifter for 2.5- to 3.2-GHz frequency band has been designed and implemented in a standard 0.18- μm CMOS technology. A new switched-network topology has been proposed for implementing the 5.625 ° phase shift step. The insertion loss of the circuit is compensated with an on-chip bidirectional amplifier. The measured return losses of the circuit are better than 8 dB with output 1-dB compression point of +9.5 dBm in the transmit mode and noise figure of 7.1 dB in the receive mode. The fabricated phase shifter demonstrates an average rms phase error of less than 2° over the entire operation bandwidth, which makes it suitable for high-precision applications
Off-resonance oscillation, phase retention, and orthogonality modeling in quadrature oscillators
, Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 63, Issue 6 , 2016 , Pages 883-894 ; 15498328 (ISSN) ; Kananian, S ; Fotowat Ahmady, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
Two important drawbacks of parallel coupled LC quadrature oscillators (P-QOSC) which have not heretofore been addressed thoroughly in the literature are obviated simultaneously in this paper. The first, has to do with the inevitable off-tune operation of the tank which results in quality factor (Q) degradation, and hence, phase noise deterioration. The other, stems from process, voltage, and temperature (PVT) variations which exacerbate quadrature accuracy. Here, a feedback loop is presented which generates a control signal by mixing the quadrature outputs and tunes the injection strength in the coupled oscillators autonomously. A complex coupling factor is implemented which compensates 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...
A 6-bit active digital phase shifter
, Article IEICE Electronics Express ; Volume 8, Issue 3 , 2011 , Pages 121-128 ; 13492543 (ISSN) ; Atarodi, M ; Sharif University of Technology
2011
Abstract
This paper presents the design of a 6-bit active digital phase shifter in 0.18-μm CMOS technology. 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 and low phase error. The phase shifter has simulated RMS phase error of <0.85° at 2.4-5 GHz. The average voltage gain ranges from 1.7 dB at 2.4GHz to -0.14 dB at 5 GHz. Input P1 dB is typically 1.3±0.9 dBm at 3.5 GHz for overall phase states
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...
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 Simulation of Bioimpedance Chip for Monitoring Heart Failure
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
Cardiovascular disease is one of the leading causes of death and mortality. among these diseases, heart muscle inability, especially acute decompensated heart failure is very common. There are several methods to diagnose and monitor this disease, but a method that is accurate, non-invasive, portable and easy to access and easy to measure without multiple visits to the clinic; Priority for use. Early detection and continuous monitoring of fluid status by measuring the bio-impedance (Bio-Z) measurement of thoracic magnitude or phase is critical in reducing the mortality of chronic heart failure (CHF) patients. In this dissertation, for monitoring chronic heart failure, bio-impedance chips with...
A full 360° vector-sum phase shifter with very low rms phase error over a wide bandwidth
, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 60, Issue 6 PART 1 , 2012 , Pages 1626-1634 ; 00189480 (ISSN) ; Atarodi, M ; Sharif University of Technology
2012
Abstract
An innovative vector-sum phase shifter with a full 360° variable phase-shift range in 0.18-μm CMOS technology is proposed and experimentally demonstrated in this paper. It employs an I/Q network with high I/Q accuracy over a wide bandwidth to generate two quadrature basis vector differential signals. The fabricated chip operates in the 2.3-4.8 GHz range. The root-mean-square gain error and phase error are less than 1.1 dB and 1.4° over the measured frequency span, respectively. The total current consumption is 10.6 mA (phase shifter core: ∼2.6 mA) from a 1.8 V supply voltage and overall chip size is 0.87 × 0.75 mm 2. To the best of the authors' knowledge, this circuit is the first...