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    A compact microstrip combline filter for microwave S-band

    , Article 29th Iranian Conference on Electrical Engineering, ICEE 2021, 18 May 2021 through 20 May 2021 ; 2021 , Pages 891-894 ; 9781665433655 (ISBN) Rezaee, S ; Memarian, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    In this paper, a wideband coupled-resonator microstrip bandpass filter is designed and experimentally demonstrated in the S-Band. The filter is comprised of quarter-wavelength hair-pin resonators, reducing resonator and filter footprint compared to conventional hairpin designs. Additionally, it is considerably forgiving to fabrication tolerances and yields remarkably close matched results between theory, simulation, and measured results. One demonstration presented has minimal insertion loss ${(< 1{dB})}$ for the entire wide bandwidth of 3.4 GHz to 4.2 GHz. Wider bandwidths up to 60% are also observed using the design. The proposed filter is an attractive solution when space is a critical... 

    A broad-band tunable cmos channel-select filter for a low-if wireless receiver

    , Article IEEE Journal of Solid-State Circuits ; Volume 35, Issue 4 , 2000 , Pages 476-488 ; 00189200 (ISSN) Behbahani, F ; Tan, W ; Karimi Sanjaani, A ; Roithmeier, A ; Abidi, A. A ; Sharif University of Technology
    2000
    Abstract
    This paper presents a broad-band bandpass filter (BPF) designed as a channel-select filter for wireless applications. It is implemented as a low-pass filter (LPF) in series with a high-pass filter (HPF) for lower power consumption compared to true BPF. Semiscaling of the filter nodes is superior in the wireless receiver over traditional full scaling. The HPF is built with low-pass feedback of an amplifier. The bandwidth is selectable from 625 kHz, 2.5 MHz, or 10 MHz. The filter stopband loss is more than 50 dB extending beyond 100 MHz, and passband ripple less than 2.5 dB. Fabricated in a 0.6-μm CMOS process, it provides a minimum input noise of 16 nV/√Hz noise with 22.5-dBm out-of-band... 

    Analysis and design of 4-path filter using gyrator based complex impedance

    , Article AEU - International Journal of Electronics and Communications ; Volume 70, Issue 11 , 2016 , Pages 1532-1542 ; 14348411 (ISSN) Karami, P ; Behmanesh, B ; Atarodi, S. M ; Sharif University of Technology
    Elsevier GmbH 
    Abstract
    A novel N-path filter using a complex impedance is designed to replace the frontend SAW filters in receivers with on-chip bandpass filters. It is demonstrated that the center frequency of the filter can be tuned solely by changing the value of some capacitances without the need to change the clock frequency. In addition, thanks to the use of smaller capacitors, the silicon area is reduced compared to similar designs. The high-Q bandpass filter is realized utilizing two gyrators and an arrangement of four baseband capacitors with NMOS switches, driven by 4-phase 25% duty cycle clock signals. This paper also analyzes the performance of the proposed filter against imperfections such as thermal... 

    Design and Implementation of Complex Multi-Path Filters

    , M.Sc. Thesis Sharif University of Technology Karami, Poorya (Author) ; Atarodi, Mojtaba (Supervisor)
    Abstract
    In most radio receivers like superheterodyne receivers, a weak desired incoming signal is accompanied with many interferer signals that are much more powerful than the desired signal itself. These interferers, also called blockers, can cause a great disturbance in the functionality of the receiver. Due to gain compression and an increase in the noise figure (NF) of the receiver, the blockers should be filtered before the arrival at the output of the LNA. Because of the low quality factors of the available on chip inductors and in order to eliminate the out of band interferer signals and image frequency (in superheterodyne receivers), usually an external surface acoustic wave (SAW) filter is... 

    Attitude estimation and sensor identification utilizing nonlinear filters based on a low-cost MEMS magnetometer and sun sensor

    , Article IEEE Aerospace and Electronic Systems Magazine ; Volume 30, Issue 12 , December , 2015 , Pages 20-33 ; 08858985 (ISSN) Mirzaei Teshnizi, M ; Shirazi, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    A combination of low-cost micro-electoro-mechanical sensors (MEMSs) and nonlinear attitude estimation algorithm techniques can provide an inexpensive and accurate system for navigation and attitude determination. The features of MEMSs are their light weight and small size; hence, the MEMSs have found significant attention in low-cost navigation and control systems [1]. A common disadvantage of these sensors is the significant errors that accompany the corresponding measurements. The accuracy obtained using MEMSs depends on a number of factors, such as scale factor, bias, and random noise corrections [2]. However, these low-cost sensors suffer from large noise and errors, making calibration... 

    Modification of unscented kalman filter using a set of scaling parameters

    , Article IET Signal Processing ; Volume 12, Issue 4 , 2018 , Pages 471-480 ; 17519675 (ISSN) Zarei Jalalabadi, M ; Malaek, M. B ; Sharif University of Technology
    Institution of Engineering and Technology  2018
    Abstract
    This work, based on the standard unscented Kalman filter (UKF), proposes a modified UKF for highly non-linear stochastic systems, assuming that the associated probability distributions are normal. In the standard UKF with 2n + 1 sample points, the estimated mean and covariance match the true mean and covariance up to the third order, besides, there exists a scaling parameter that plays a crucial role in minimising the fourth-order errors. The proposed method consists of a computationally efficient formulation of the unscented transform that incorporates N - 1, N ≥ 2, constant parameters to scale 2n(N - 1) + 1 sample points such that the 2Nth order errors are minimised. The scaling parameters... 

    Fast design of relatively wide band fractional delay all-pass filters

    , Article Signal Processing ; Volume 88, Issue 3 , 2008 , Pages 612-623 ; 01651684 (ISSN) Jahani Yekta, M. M ; Sharif University of Technology
    Elsevier  2008
    Abstract
    A fast and simple procedure for designing relatively wide band fractional delay (FD) all-pass filters is proposed and filters designed based on it are compared to those designed using Thiran's method, which is one of the simplest, fastest and widely used approaches in designing FD all-pass filters. It is shown that filters designed using the introduced method have wider fractional group delay (fgpd) bandwidths compared to those obtained via Thiran's technique, as well as some other desired properties. The designed filters are also demonstrated to be stable for several pairs of filter orders and fgpd values. © 2007 Elsevier B.V. All rights reserved  

    An n-path enhanced-q tunable filter with reduced harmonic fold back effects

    , Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 60, Issue 11 , 2013 , Pages 2867-2877 ; 15498328 (ISSN) Mohammadpour, A ; Behmanesh, B ; Atarodi, S. M ; Sharif University of Technology
    2013
    Abstract
    A high-Q, tunable, bandpass filtered amplifier structure is proposed which is based on a novel Q enhancement technique in N-path filters. Using Fourier series analysis, frequency response of an N-path filter as well as the aliasing effects which are present in it are derived. Frequency translation of unwanted contents at higher frequencies to the center frequency of the bandpass filter is called harmonic fold back (HFB). It is shown that using an additional N-path filter with the same clock frequency but different clock phases can reduce the HFB. The required conditions for fold back elimination are derived fromFourier series expansion analysis. In order to achieve HFB reduction as well as... 

    A tunable-Q 4-path bandpass filter with Gm-C second-order baseband impedances

    , Article 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 244-248 ; 9781509059638 (ISBN) Rezvanitabar, A ; Babamir, S. M ; Behmanesh, B ; Atarodi, S. M ; Sharif University of Technology
    Abstract
    An active switched-capacitor 4-path bandpass filter suitable for multi-standard applications in ultra-high frequency (UHF) band with different channel bandwidths is designed and simulated in 0.18 μm CMOS technology. The baseband impedance of the filter is implemented as a second-order Gm-C low-pass filter which can be used to tune the channel bandwidth as well as the quality factor (Q) of the RF filter. The center frequency of the filter can be tuned from 100 MHz up to 1.5 GHz by changing the clock frequency applied to the filter while its bandwidth can be tuned by tuning impedance parameters in any center frequency. To do so, the baseband impedance utilizes a frequency dependent negative... 

    Tunable low-Jitter low-drift spurious-free transposed-frequency optoelectronic oscillator

    , Article IEEE Transactions on Microwave Theory and Techniques ; Volume 65, Issue 7 , 2017 , Pages 2625-2635 ; 00189480 (ISSN) Hosseini, S. E ; Banai, A ; Kartner, F. X ; Sharif University of Technology
    Abstract
    We propose and theoretically and experimentally demonstrate a novel tunable spurious-free single-loop optoelectronic oscillator (OEO) with low drift and low-phase noise. In the proposed transposed-frequency OEO (TF-OEO), a nonreciprocal bias unit and an optical phase modulator in a fiber Sagnac interferometer function jointly as an intrinsically drift-free intensity modulator, which improves the long-term drift. Besides, a transposed-frequency low-noise filtered amplifier is used which replaces the conventional radio frequency (RF) bandpass filter (BPF) and RF amplifier with an intermediate frequency (IF) BPF, an ultralow phase noise IF amplifier, and a tunable local oscillator, to attain... 

    Single-channel high-transmission optical band-pass filter based on plasmonic nanocavities

    , Article Journal of the Optical Society of America B: Optical Physics ; Volume 37, Issue 8 , 1 August , 2020 , Pages 2329-2337 Najafabadi, M. M ; Vahidi, S ; Ghafoorifard, H ; Valizadeh, M ; Sharif University of Technology
    OSA - The Optical Society  2020
    Abstract
    This paper is concerned with the investigation of an optical band-pass filter based on subwavelength surface plasmon polaritons. The transmission characteristics are numerically analyzed by the finite-difference time-domain method, and simulation results reveal that the structure has a band-pass filtering characteristic. The metal–insulator–metal plasmonic nanostructure is implemented by several vertical rectangular cavities across an optical waveguide. The metal and dielectric materials utilized for the realization of the filter are silver and air, respectively. Furthermore, the performance can be efficiently modified by tuning the geometric parameters such as the cavities’ length and width... 

    Design of Tunable, Multi-Mode, Multi-Path Filters

    , Ph.D. Dissertation Sharif University of Technology Behmanesh, Baktash (Author) ; Atarodi, Mojtaba (Supervisor)
    Abstract
    In this dissertation a special category of RF filters known as multi-path filters are introduced, chracterized and implemented. The center frequency of the multi-path filters can be tuned by changing the frequency of the clocks applied to the filter, which makes them attractive for use in multi-standard receivers. In this thesis, different types of multi-path filters are studied and by proposing different circuits, their various applications are covered. First, the concept of multi-path filters and their chracteristics are studied. Then a novel technique to analyze these filters based on Fourier analysis is proposed and then, based on this analysis, a new circuit architecture with reduced... 

    Design of an N-Path Tunable Bandpass Filter for RF Range

    , M.Sc. Thesis Sharif University of Technology Mohammadpour Darzinaghibi, Amin (Author) ; Atarodi, Mojtaba (Supervisor) ; Sadughi, Sirous (Supervisor)
    Abstract
    A high-Q tunable bandpass filtered amplifier structure is proposed which is based on N-path Q enhancement. Using Fourier series analysis, frequency response of an N-path filter and aliasing effect of this filter is achieved. This effect is caused by frequency translation to bandpass frequency as harmonic fold back (HFB). It is shown that using an additional N-path filter with the same clock frequency but different clock phase HFB is reduced. The conditions for fold back elimination are derived from Fourier series expansions for switched signals. In order to realize HFB reduction and increasing stop-band rejection and Q factor, an LNA associated with N-path filter is added to each of the... 

    Analytical distributed non-linear model for symmetric and asymmetric superconducting parallel-coupled microstrip lines

    , Article IET Microwaves, Antennas and Propagation ; Vol. 8, Issue. 6 , 2014 , pp. 429-436 ; ISSN: 1751-8725 Javadzadeh, S. M. H ; Farzaneh, F ; Fardmanesh, M ; Sharif University of Technology
    Abstract
    Superconducting materials are known to produce intermodulation distortion and other non-linear effects. In microstrip structures, the non-linearity depends on the current distribution on the strip which is mainly determined by the geometrical structure of the device. The current distribution in superconducting parallel-coupled microstrip lines is computed by a numerical approach based on a three-dimensional finite element method. This computed current distribution is used to produce a non-linear circuit model for parallel-coupled superconducting lines. A numerical technique based on the harmonic balance approach is used for non-linear analysis of the proposed equivalent circuit. To validate... 

    Design and implementation of a high dynamic range C band down-converter

    , Article Progress in Electromagnetics Research Letters ; Volume 31 , 2012 , Pages 25-33 ; 19376480 (ISSN) Saatchi, V ; Tavakoli, Z ; Sharif University ot Technology
    PIER Letters  2012
    Abstract
    A technique that expands dynamic range (DR) of frequency down-converters in the C band frequency is presented. Primary characteristics of down-converter are evaluated to confirm that it can be used in microwave receivers. The C band down-converter is carried out by the combination of RF mixers, band pass interdigital filter, and X band combline filter which are designed entirely for this project. Attainment of the perfect receiver is the final purpose of this paper, and a method that causes 72 dB dynamic range, high tangential signal sensitivity and fine gain flatness is used for achieving the mentioned purpose. These efforts improve the dynamic range about 19 dB and gain flatness about 3.07... 

    Analysis of imperfections in N-phase high-Q band-pass filters

    , Article IEEE International Symposium on Circuits and Systems, ISCAS 2015, 24 May 2015 through 27 May 2015 ; Volume 2015-July , May , 2015 , Pages 273-276 ; 02714310 (ISSN) ; 9781479983919 (ISBN) Nikoofard, A ; Kananian, S ; Behmanesh, B ; Atarodi, S. M ; Fotowat Ahmady, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    The effect of clock skew and duty-cycle on the performance of high-Q N-phase band-pass filters (BPFs) have been examined in this paper. Following a mathematical approach and using the analytical derivations carried out, the effects of such non-idealities as clock skew and duty-cycle error are determined in an N-path filter. It is analytically proved that image signals from all integer multiples of the clock signal, rather than just those at (1 ± kN) multiples of the clock signal, land atop the wanted RF spectrum. In a real world clock generator, with non-idealities in effect, filtering property and proper behavior of the filter is adversely affected. Finally, system level simulation along... 

    Applying Contour Integral method for analysis of substrate integrated waveguide filters

    , Article 2010 10th Mediterranean Microwave Symposium, MMS 2010, 25 August 2010 through 27 August 2010 ; August , 2010 , Pages 418-421 ; 9781424472437 (ISBN) Shahvirdi, T ; Banai, A ; Sharif University of Technology
    2010
    Abstract
    In this paper the Contour Integral (CI) method is applied to the design and analysis of substrate integrated waveguide (SIW) filters. This method is used for planar structures and is based upon the discretization of the boundary of the structure and needs less memory than full wave methods. For decreasing the computation time, circular vias replaced by square ones. A four pole Chebyshev X band dual inductive post substrate integrated waveguide filter is designed using this technique and the results are compared with measurements and simulation software Ansoft HFSS. Good agreement is seen between the results  

    A switching decentralized and distributed extended Kalman filter for pressure swing adsorption processes

    , Article International Journal of Hydrogen Energy ; Volume 41, Issue 48 , 2016 , Pages 23042-23056 ; 03603199 (ISSN) Fakhroleslam, M ; Fatemi, S ; Bozorgmehry Boozarjomehry, R ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    A continuous-discrete Distributed and Decentralized Switching Kalman Filter (DDSKF) is designed for estimation of spatial profiles in Pressure Swing Adsorption (PSA) processes. The introduced observer is an integral part of the control strategy of hybrid systems in general and PSA systems in particular. A reduced order model is developed based on the mechanistic model of the process. The sensors are optimally located and observability of the process is studied. The proposed observer is used to estimate the spatial profiles of various states of a two-bed, six-step PSA system used for production of pure H2 from a H2–CH4 gas mixture. The spatial profiles of the system have been estimated using... 

    Parallel-plate waveguide integrated filters and lenses realized by metallic posts for terahertz applications

    , Article International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz, 25 September 2016 through 30 September 2016 ; Volume 2016-November , 2016 ; 21622027 (ISSN) ; 9781467384858 (ISBN) Ahmadi Boroujeni, M ; Sharif University of Technology
    IEEE Computer Society  2016
    Abstract
    In this paper, we report on the design and analysis of filters and lenses realized by an array of metallic posts integrated in a parallel-plate waveguide (PPWG). The design methodology of these components is inferred from the modal analysis of a spoof surface plasmonic waveguide composed of metallic posts arranged in a 1D periodic structure inside PPWG. Samples of the proposed devices are analyzed using a full-wave analysis method and their performance is assessed. We show that the mentioned structure can be used to realize all-metallic band-pass filters and lenses for mm-wave and terahertz applications  

    Optimized kalman filter based on second momentum and triple rectangular for cell tracking on sequential microscopic images

    , Article 22nd Iranian Conference on Biomedical Engineering, 25 November 2015 through 28 November 2015 ; 2015 , Pages 251-256 ; 9781467393515 (ISBN) Khodadadi, V ; Fatemizadeh, E ; Setarehdan, S. K ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc 
    Abstract
    Cell dynamics and motion stages are very important issues in the biological cell investigation in this novel method, we propose a novel method based on Kalman filter and second momentum for tracking cells on Sequential Microscopic Images. In proposed manner at first, we select a cell and cut covering rectangle. in the next step, we predict rectangle center of the cell in Next frame based on a modeling of velocity-acceleration using Kalman filter. The rectangle with triple covering area of previous cell rectangle and predicting center by Kalman filter is considered as a searching area. So, if all objects in the search areas have second momentum error less than threshold, it is selected as a...