A Comparative Investigation on Effect of Coupling in Aperture Coupled Microstrip Antennas

This paper investigates the electromagnetic coupling from various aperture shapes in aperture coupled suspended rectangular microstrip antennas. The proposed study involves various shapes of coupling aperture such as “rectangle”, “H”, “bowtie”, and “hourglass” with a single-layer aperture coupled suspended rectangular microstrip antenna. Among the various shapes, “hourglass” shaped aperture yields maximum coupling leading to maximum bandwidth. For the validation aperture coupled suspended rectangular microstrip antenna with “hourglass-shaped” aperture is fabricated, and measurements were carried out. The measured fractional impedance bandwidth (FBW) with “hourglass” aperture is more than 30% at 1.06 GHz. Measured peak gain and front-to-back (F/B) ratio of aperture coupled suspended microstrip antenna with “hourglass” at 1.06 GHz are 8.5 dBi and greater than 11.2 dB, respectively. The influence on the antenna’s performance parameters such as realized gain, impedance bandwidth, and F/B ratio due to metallic mounting surface is also investigated. The simulated and measured performances of the antenna are in agreement. The proposed investigation is very useful for various applications, when broadband antenna is mounted on a metallic body. © 2022, Electromagnetics Academy. All rights reserved.