2D and 3D beam synthesis from different antenna array arrangements are investigated in this paper. Planar sunflower, conformal cylinderical and spherical helical array arrangements are studied. The particle swarm optimization (PSO) technique is used to predict the phase distribution on the array elements. The beam synthesis is achieved by comparing the array factor with a predetermined mask with both upper and lower limits according to the intented application requirements. Different 2D and 3D masks are used in beam synthesis as pencil, flat-top, and cosecant single beam are predicted. The planar sunflower antenna array is investigated due to its high gain, low side-lobe level (SLL) below ??20 dB and its compact size. The phase distribution of sunflower array is estimated using PSO to radiate dual-beams in different planes. Dual-beam with pencil, flat-top, and cosecant beams are obtained with different half-power beam widths. 3D conformal antenna arrays of cylindrical and spherical helical arrangements are studied. Each 3D conformal array consists of four arms shifted in position by 90° orintation angle. Each arm is designed to radiate single beam in a specific direction. Four-beams are considered to radiate in the directions of θ1,2,3,4?=?30°, and ?1?=?0°, ?2?=?90°, ?3?=?180°, and ?4?=?270° with SLL optimized below ??17 dB. The array arrangements analysis is based on the array theory formulation, through the implemention of the estimiated equation using a home programmed MATLAB code.
相似文献In this paper, dual-band wearable microstrip patch antenna printed on FR4-substrate is designed and fabricated for wearable wireless communications. A star-shaped monopole Ω antenna connected to 50 Ω transmission line, backed by partial ground plane is used. The antenna dimensions are optimized for wideband radiation characteristics. Different types of dielectric substrates are investigated for wideband wearable applications. The proposed antenna printed on jeans textile substrate introduces an impedance matching bandwidth of 7.3 GHz with maximum gain of 5 dBi. The effect of mutual coupling between two parallel patches, two opposite patches and two orthogonal patches on their radiation characteristics are investigated. High isolation is achieved for two orthogonal patches placed away from each other by 0.3λ with a rectangular strip etched between them and cutting in the ground plane. The isolation is below ? 29 dB within the frequency band. The structure achieves impedance matching bandwidth of 1.8 GHz in 1st-band and 4.8 GHz in 2nd-band with maximum gains of 8.5 dBi and 5.3 dBi, respectively. A prototype element is fabricated, measured and the radiation characteristics coincide with the simulated results. The structure is simple, light-weight, and is suitable for WAN applications in the frequency band from 2 GHz to 7 GHz. The effect of human body tissue on the radiation characteristics of the antenna array is investigated.
相似文献Reconfigurable sensing antennas (RSA) play a significant role in modern internet-of-things (IOT) applications. The RSAs are capable of transmiting and receiving electromagnetic waves besides sensing different enviroment parameters. This paper introduces a reconfigurable sensing microstrip patch antenna desinged to sense high temperature variations in harsh environment. The indium antimonide (InSb) semiconductor material is a temperature sensitive material employed in RSA designs in the Terahertz (THz) frequency band. An investigation of the temperature dependency of the electrical properties of the InSb-material is introduced. The proposed sensing antenna introduces high sensitivity of 1.588 GHz shift in resonance frequency per unit change in temperature (Kelvin). The resonance frequency of the InSb sensor antenna is changed according to the surrounding environment temperature from 264 GHz to 502.2 GHz with a broadband tuning range of 90.2%. The InSb patch sensor have temperature sensing range of 150 K starting from 250 up-to 400 K. At 300 K the InSb sensor antenna proposes a peak gain of 6.4 dBi with impedance matching bandwidth of 9.57%. An equivalent circuit consists of five lumped elements is estimated for the InSb sensor antenna using particle swarm optimization (PSO) technique at different temperatures. At T?=?250 K the maximum radiation efficiency is 2.5% and is increased up to 86.3% at T?=?400 K.
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