Performance enhancement of nested hexagonal ring-shaped compact multiband integrated wideband fractal antennas for wireless applications

摘要

In this paper, nested hexagonal ring-shaped fractal antennas are designed andinvestigated which are different from each other in patch orientation. Initially,the multiband integrated wideband hexagonal nested ring antenna is designed(antenna-Ⅰ). To improve the multiband/wideband behavior, the patch orientationof antenna-Ⅰ is changed to −60°/60° (antenna-Ⅱ), −120°/120° (antenna-Ⅲ), and−180°/180° (antenna-Ⅳ). Antennas are designed on low cost FR-4 glass epoxysubstrate with relative permittivity of 4.4 and overall dimension 30 × 30 ×1.6 mm3. Comparison among antennas have been made and found that theantennas with negative orientation exhibit better results in terms of bandwidth,impedance matching, number of frequency bands, and gain. Designed antennashave been comparedwith each other and found that antennas-Ⅱ and Ⅲ are betterin performance as compared to antennas-Ⅰ and Ⅳ. Antenna-Ⅱ exhibits widerbandwidth of 1.26 (2.52-3.78 GHz), 2.75 (4.03-6.78 GHz), and 6.1 GHz(7.82-13.92 GHz) with maximum gain of 7.14 dB. Similarly; antenna-Ⅲ exhibitsthe bandwidth of 340 MHz (1.92-2.26 GHz), 820 MHz (3.04-3.86 GHz), 4230 MHz(5.38-9.61 GHz), and 3040 MHz (10.41-13.45 GHz) with a maximum gain of6.19 dB. Prototype of the designed antennas with satisfactory orientations are fabricatedand tested for the validation of results. Simulated and measured results arealso juxtaposed and observed in good agreement with each other. Antennasexhibit bidirectional and omnidirectional pattern in E-plane and H-plane, respectively,also the radiation efficiency of antennas are in acceptable range from 75%to 95%. Due to the wider bandwidth of designed antennas, they can be used for differentwireless standards such as Advance Wireless Services AWS-1, AWS-2,AWS-3, Wi-MAX, WLAN, X-band satellite communication, point-to-point wirelessapplications, ITU band, military satellite communication, television broadcasting,andmilitary land and airborne systems.