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beam-forming-networks
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Performance analysis of an optical beam-forming network with custom microwave CAD tools
, Article Proceedings - 2010 18th Iranian Conference on Electrical Engineering, ICEE 2010, 11 May 2010 through 13 May 2010, Isfahan ; 2010 , Pages 100-104 ; 9781424467600 (ISBN) ; Akbari, M ; Sharif University of Technology
Abstract
Next generation wideband and ultra-wideband radar antenna arrays need efficient true-time delay networks for array control. Optical beam-forming networks have been considered as a promising solution in such arrays. Performance analysis of optical beam-formers is thus quiet necessary. In this paper signal to noise ratio and dynamic range of simple optical beam-forming structures are investigated with a custom microwave CAD tool. Two structures with optical and RF power combining methods are discussed. With the proposed devices' parameters, the optical combining method shows better performance for low and moderate optical powers
A figure of merit in a time-modulated array
, Article IEEE Antennas and Wireless Propagation Letters ; Volume 18, Issue 10 , 2019 , Pages 2086-2089 ; 15361225 (ISSN) ; Fakharzadeh, M ; Akbari, M ; Safavi Naeini, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this letter, we use G/T as a figure of merit to evaluate the performance of time-modulated arrays (TMA). The noise performance of a receiver, which is periodically switched on and off, is quite different from that of a conventional receiver. We analytically investigate the noise performance of a TMA. Based on this analysis, the figure of merit, G/T, of the TMA structure is investigated, including the details of the receiver hardware. Moreover, the G/T of the TMA is compared with that of a phased array. The comparison indicates that the TMA structure provides the same or even better performance compared to a phased array system, which demonstrates the capability of TMA in providing...
Sub-optimal beamforming for 3D cylindrical arrays of dipoles including the mutual coupling effects
, Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 1298-1302 ; 9781728115085 (ISBN) ; Poormohammad, S ; Farzaneh, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, an analytical and low cost computational antenna array beamforming method in the presence of mutual coupling has been proposed. Mutual coupling effects is taken under consideration through the induced EMF method and the concept of active element pattern. After establishing the corresponding optimization problem, the desired beamformer is obtained through solving a convex optimization. At the end, the 3D arrays of half-wave dipole elements, of different geometries are compared based on the SIR criterion
A novel algorithm in a linear phased array system for side lobe and grating lobe level reduction with large element spacing
, Article Analog Integrated Circuits and Signal Processing ; Volume 104, Issue 3 , 13 March , 2020 , Pages 265-275 ; Ranjbar, J ; Karami, P ; Sharif University of Technology
Springer
2020
Abstract
Phased array antennas are generally used for the inherent flexibility to beamforming and null-steering electronically. In the phased arrays the side lobes level (SLL) level is main problem which causes waste of energy or saturation of the receiver in the case of presence of the strong spatial blockers. In this paper, a weighting method was first used to reduce the level of SLL. However, this method increased the beam width and reduced resolution, which is not suitable for track applications. In next step hoping to increase the resolution, the distance between the antennas increased. But in this way, grating lobes appeared in the final beam. In fact, the main idea of the article is to solve...
Modeling beacon period length of the UWB and 60-GHz mmWave WPANs based on ECMA-368 and ECMA-387 standards
, Article IEEE Transactions on Mobile Computing ; Volume 12, Issue 6 , 2013 , Pages 1201-1213 ; 15361233 (ISSN) ; Manzuri Shalmani, M. T ; Sharif University of Technology
2013
Abstract
To evaluate the performance of the distributed medium access control layer of the emerging ultrawideband and 60-GHz millimeter wave (mmWave) wireless personal area networks based on ECMA-368 and ECMA-387 standards, the first step is to determine the beacon period length (BPL) of the superframe in a given network. In this paper, we provide an analytical model for the probability mass function (PMF) of the BPL as a function of the network dimensions, number of beaconing devices, antenna beamwidth, and the transmission range of the devices. To enable devices with steerable directional antennas in the ECMA-387 standard to have simultaneous communications with neighbors in their different antenna...
An investigation on the performance of receiving optical beam-forming networks
, Article Final Program and Book of Abstracts - iWAT 2010: 2010 International Workshop on Antenna Technology: Small Antennas, Innovative Structures and Materials, 1 March 2010 through 3 March 2010 ; March , 2010 ; 9781424448845 (ISBN) ; Akbari, M ; Sharif University of Technology
2010
Abstract
Next generation wideband and ultra-wideband radar antenna arrays need efficient true-time delay networks for array control. Following the great interest for optical control of antenna array beam steering, performance analysis of optical beam-formers is a must. In this paper signal to noise ratio and dynamic range of simple optical beamforming structures with components off the shelf are investigated theoretically. Especially the effects of certain power combining components such as arrayed wave guide gratings, broadband passive optical combiners and microwave combiners inspected. It turns up that an efficient microwave combiner would surpass the optical combiners in both SNR and dynamic...
A mm-Wave MIMO transmitter with a digital beam steering capability using CMOS all-digital phase-locked loop chips
, Article 2018 IEEE MTT-S International Microwave Workshop Series on 5G Hardware and System Technologies, IMWS-5G 2018, 30 August 2018 through 31 August 2018 ; 2018 ; 9781538611975 (ISBN) ; Bogdan Staszewski, R ; Farzaneh, F ; Sharif University of Technology
Abstract
In this paper, we propose a mm-wave transmitter architecture intended for radar and 5G MIMO applications with beam steering over 57-63 GHz frequency band. Each transmitter chain comprises an all-digital phase-locked loop (ADPLL) CMOS IC chip intended to be dictated to a single antenna unit within an array. For demonstration purposes, each IC is embedded on a printed circuit board (PCB) to provide beam steering using highly accurate digital approach. The overall transmitter is connected to an antenna array with half wavelength spaced elements to maximize the beam scanning coverage. The ADPLL boards are fabricated and a calibration technique is carried out to align amplitude-phase of all...
Beamforming, null-steering, and simultaneous spatial and frequency domain filtering in integrated phased array systems
, Article AEU - International Journal of Electronics and Communications ; Volume 110 , 2019 ; 14348411 (ISSN) ; Atarodi, S. M ; Sharif University of Technology
Elsevier GmbH
2019
Abstract
In the case that phased array systems are not capable of attenuating interferences, Radio Frequency (RF) front-ends and Analog Digital Converters (ADCs) with a large dynamic range are required to avoid saturation of the receiver. This leads to a higher power consumption. In this paper, employing N-path circuits in Mixer-First receivers, a novel method is introduced in which spatial and frequency blockers are eliminated right before entering the system on the antennas input. In fact using this technique, adjustable spatial notch filter and band-pass frequency filter are implemented to suppress spatial and frequency interferences. The proposed method enhances the robustness and effectiveness...
Asymmetrical 4×4 butler matrix and its application for single layer 8×8 butler matrix
, Article IEEE Transactions on Antennas and Propagation ; Volume 67, Issue 8 , 2019 , Pages 5372-5379 ; 0018926X (ISSN) ; Shafiei Alavijeh, A ; Fakharzadeh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
The design procedure and measured results of a novel 4 × 4 Butler matrix are presented in this paper. This asymmetrical structure provides fairly flexible phase outputs; therefore, the array radiation pattern can be rotated around the array normal axis. The structure of this modified Butler matrix is discussed in detail, and the explicit design formulas are derived to achieve the arbitrary main beams direction. Using the proposed design procedure, the Butler matrix can provide even broadside and endfire beams. In addition, this structure is employed to design two Butler matrices, which generate similar patterns as a conventional 8 × 8 Butler matrix, using only single layer circuits with...
Stochastic geometry modeling and analysis of finite millimeter wave wireless networks
, Article IEEE Transactions on Vehicular Technology ; Volume 68, Issue 2 , 2019 , Pages 1378-1393 ; 00189545 (ISSN) ; Makki, B ; Nasiri Kenari, M ; Svensson, T ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
This paper develops a stochastic geometry-based approach for the modeling and analysis of finite millimeter wave (mmWave) wireless networks where a random number of transmitters and receivers are randomly located inside a finite region. We consider a selection strategy to serve a reference receiver by the transmitter providing the maximum average received power among all transmitters. In our system model, we employ the unique features of mmWave communications such as directional transmit and receive beamforming and different channels for line-of-sight (LOS) and non-line-of-sight (NLOS) links. Accordingly, deploying a blockage process suitable for mmWave networks, we study the coverage...
Proposed 2D and 3D geometries intended for smart antenna applications, including direction finding and beamforming implementation
, Article IET Radar, Sonar and Navigation ; Volume 13, Issue 5 , 2019 , Pages 673-681 ; 17518784 (ISSN) ; Farzaneh, F ; Sharif University of Technology
Institution of Engineering and Technology
2019
Abstract
Novel two-dimensional (2D) and three-dimensional (3D) antenna array geometries for smart antenna application are introduced. Minimum mean square error beamforming algorithm, using these arrays, in presence of signal, noise and interferences is implemented. Beamforming approach is used for every type of array assuming uniform and log-normal distributions for the interference amplitudes. Equal volume cylindrical or prism type arrays with circular, hexagonal, triangular, square and star cross-sections with equal number of elements are considered. Novel geometries consisting of rotated cross-sections are studied as well. In each case, the relative signal-to-interference ratios (SIRs) are...
Proposed 2D and 3D geometries intended for smart antenna applications, including direction finding and beamforming implementation
, Article IET Radar, Sonar and Navigation ; Volume 13, Issue 5 , 2019 , Pages 673-681 ; 17518784 (ISSN) ; Farzaneh, F ; Sharif University of Technology
Institution of Engineering and Technology
2019
Abstract
Novel two-dimensional (2D) and three-dimensional (3D) antenna array geometries for smart antenna application are introduced. Minimum mean square error beamforming algorithm, using these arrays, in presence of signal, noise and interferences is implemented. Beamforming approach is used for every type of array assuming uniform and log-normal distributions for the interference amplitudes. Equal volume cylindrical or prism type arrays with circular, hexagonal, triangular, square and star cross-sections with equal number of elements are considered. Novel geometries consisting of rotated cross-sections are studied as well. In each case, the relative signal-to-interference ratios (SIRs) are...
Smart antennas for OFDM-WLANs based on a spatial-temporal multi-scenario channel model
, Article Iranian Journal of Electrical and Computer Engineering ; Volume 7, Issue 2 , 2008 , Pages 107-114 ; 16820053 (ISSN) ; Dadashzadeh, G ; Shishegar, A. A ; Hojjat, N ; Sharif University of Technology
Jahad Daneshgahi
2008
Abstract
combination of smart antenna techniques and OFDM could be considered as a promising solution for improving the performance and enhancing the data rates of next generation wireless communication systems operating in frequency selective fading environments. There are different design parameters which could affect the application of adaptive arrays in OFDM-based systems. Various beam-forming methods in frequency or time domain, different array architectures and various number of array elements are important factors which are able to change the performance and complexity of the system. These parameters may show different effects in different channel conditions. In this paper we implemented a new...
Direction finding and beamforming using cylindrical array of dipole antennas in the presence of cylindrical scatterer/reflector including the mutual coupling effect
, Article IET Microwaves, Antennas and Propagation ; Volume 15, Issue 5 , 2021 , Pages 521-528 ; 17518725 (ISSN) ; Farzaneh, F ; Banai, A ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
Three-dimensional dipole arrays are normally used at the proximity of a reflective structure. Filamentary short-circuited dipoles are proposed to model the effect of the reflector structure. The computational burden is significantly reduced by using mutual impedance matrices. An analytical method of modelling the effect of the cylindrical reflector in a three-dimensional cylindrical geometry of dipole antenna arrays is introduced both for direction finding and beamforming applications in the presence of mutual coupling. The results of the implementation of the MUSIC (multiple signal classification) direction-finding algorithm show that the proposed model for accounting the cylindrical...