scholarly journals Broadband beamforming and direction finding using concentric ring array

2005 ◽  
Author(s):  
◽  
Yunhong Li
Keyword(s):  
Sensor Arrays ◽  
Direction Finding ◽  
Side Lobe ◽  
Ring Structure ◽  
Concentric Ring ◽  
Pattern Synthesis ◽  
Element Space ◽  
Broadband Beamforming ◽  
Array Pattern ◽  
Beamformer Design

Sensor arrays have been used widely in applications including radar, sonar, seismology, biomedicine, communications and imaging. A very popular type of sensor array is circular array, which has almost invariant array pattern in azimuthal plane. This dissertation considers beamformer design and direction finding for a broadband source using concentric ring array (CRA) that contains many concentric rings of different radii. The multi-ring structure of a CRA has several advantages including the flexibility in array pattern synthesis and adaptive array design. We first proposed three CRA array pattern synthesis techniques, which can be used to control the side lobe and/or main lobe width of the array pattern of a deterministic broadband beamformer. We then proposed a flexible partially adaptive broadband beamformer design based on element-space approach. Finally, we proposed an efficient direction finding technique for broadband source using CRA. The proposed design techniques are corroborated by experiments from simulated as well as measured data.

scholarly journals Exploiting Array Pattern Synthesis for Physical Layer Security in Millimeter Wave Channels

Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 745 ◽  
Author(s):  
Jong-Ho Lee ◽  
Jeongsik Choi ◽  
Woong-Hee Lee ◽  
Jiho Song
Keyword(s):  
Millimeter Wave ◽  
Channel State Information ◽  
Physical Layer Security ◽  
Physical Layer ◽  
Channel State ◽  
Pattern Synthesis ◽  
State Information ◽  
Array Pattern ◽  
Beamformer Design ◽  
Partial Channel

In this paper, we propose a beamformer design scheme for wireless physical layer security using partial channel state information (CSI) in millimeter wave channels. The partial CSI used in this work is the range of angle-of-departure (AOD). Assuming that the AOD range of each node is available, we design a transmit beamformer using semidefinite programming based on array pattern synthesis. Numerical results are presented to verify the secrecy rates achieved by the proposed scheme.

scholarly journals Design of Concentric Ring Antenna Arrays Based on Subarrays to Simplify the Feeding System

Symmetry ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 970
Author(s):  
Elizvan Juárez ◽  
Marco A. Panduro ◽  
Alberto Reyna ◽  
David H. Covarrubias ◽  
Aldo Mendez ◽  
...  
Keyword(s):  
Antenna Arrays ◽  
Side Lobe ◽  
Phase Shifters ◽  
Side Lobe Level ◽  
Antenna Element ◽  
Feeding System ◽  
Concentric Ring ◽  
Array Pattern ◽  
Ring Antenna ◽  
Symmetry Problem

The global synthesis for antenna arrays that produce a desired radiation pattern is a scientific symmetry problem. This paper deals with the design of concentric ring antenna arrays to simplify the feeding system using a cophasal subarray configuration. This simplification in the feeding network is achieved by the reduction of phase shifters via a proper clustering of radiators applying one amplitude and one phase excitation by subarray in the array system. The array design for this geometry considers an optimization process based in differential evolution to reduce the side-lobe level, resulting in simplification of the feeding network. Simulation results based on CST Microwave Studio and HFSS are provided to verify the accuracy of the array model and to take mutual coupling into account. These simulations are provided using a circular patch as antenna element to generate a scannable array pattern over the elevation plane. Furthermore, an analysis of the manufacturing tolerances was made to verify the reliability of our design.

scholarly journals An Improved Gravity Search Algorithm and Its Application in Planar Array Synthesis

2020 ◽  
Vol 38 (5) ◽  
pp. 1018-1024
Author(s):  
Cuizhen Sun ◽  
Jun Ding ◽  
Chenjiang Guo
Keyword(s):  
Search Algorithm ◽  
Cumulative Effect ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Concentric Ring ◽  
Pattern Synthesis ◽  
Fitness Value ◽  
Planar Array ◽  
Evolutionary Speed ◽  
Improved Algorithm

An improved gravity search algorithm, adaptive gravity search algorithm (AGSA), is proposed to solve the problem that the gravity neutralization caused by the cumulative effect of particle inertia mass at the end of iteration, which will affect the optimization performance. An adaptive decay factor is designed, which can produce different gravitation values at different iteration stages of the algorithm and accelerate the mining ability of the algorithm at the later iteration stage. In order to enhance the memory ability of the algorithm, the influence of elite particles is added to the realization of the speed to expand the exploration ability. The improved algorithm is used to optimize uniform concentric ring array, the main lobe width optimized by the AGSA is 6.7°narrower and the side lobe level is 5.1 dB and 1.8 dB lower than the algorithm in the literature. It is clear that the pattern obtained by AGSA meets the desired pattern very well. Moreover, when the number of iterations is 2 000, the fitness value of the improved algorithm is increased by 30%. It can be seen that AGSA outperforms the algorithm in the literature in evolutionary speed and accuracy. Sparse concentric ring array also has the same optimization results. The effectiveness of the proposed improved algorithm in solving the array pattern synthesis is proved.

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