Novel high gain air gap directive antenna for X-band satellite to earth downlink applications

Abstract

In this paper, a compact air gap microstrip patch antenna with high gain and directivity for satellite and mobile communication has been proposed. The proposed antenna has been designed using Flame Retardant 4 (FR4) as substrate having dielectric constant εr of 4.4 sandwiched in between patch and ground plane made up of copper. The power from coaxial connector is fed to the designed antenna via microstrip feedline and impedance of the antenna is perfectly matched with 50Ω impedance of the connector so as to minimize the back reflections from the antenna. The performance of the air gap antenna has been scrutinized for different antenna parameters such as return loss (S11), directivity, gain, bandwidth, VSWR etc. The proposed antenna has been designed and simulated using CST Microwave Studio 2014. It has been observed that the antenna is resonant at 11.5 GHz with an impedance bandwidth of 528 MHz and an operating frequency range of 11.532 GHz–12.06 GHz. The proposed antenna has return loss (S11) of −43.48 dB at resonant frequency of 11.5 GHz. The antenna has gain of 8.58 dB and directivity of 1 0.29 dBi. The designed antenna has applications in X-band for fixed satellite to earth downlink applications (11.7GHz–12GHz) and can be suitably employed for mobile satellite to earth downlink (11.7GHz–12GHz) applications. The proposed antenna has been practically fabricated and tested using E5071C network analyzer and anechoic chamber and it has been observed that the practical results closely match with the simulated results.