Gain enhancement of rectangular microstrip patch antenna using air gap at 2.4 GHz

Abstract

This project is carried out to design two antennas; one of them is a basic rectangular microstrip patch antenna and the other is the rectangular microstrip patch antenna added with an air gap technique for the main purpose of gain enhancement. Both antennas have been designed using RT5880 substrate because of its low dielectric constant at 2.2 and the permittivity of 0.0009. The proposed antennas were analysed and simulated at the frequency of 2.4GHz for WLAN application using the Computer Simulation Technology (CST) software. In order to increase the antenna’s gain performance, a 3 mm air gap thickness was added in between the radiating patch element and the ground layer. From the simulation results, it was realized that the antenna’s gain was enhanced from 6.907 dB (basic antenna) to 9.179 dB (antenna with 3 mm air gap) with 32.9% improvement, while the frequency is maintained at 2.4 GHz. Meanwhile, from the measurement results the gain improved 11.4% from 7.1 dB (basic antenna) to 7.91 dB (antenna with 3 mm air gap). However, the bandwidth decreased from 111.07 MHz (basic antenna) to 72.873 MHz (antenna with 3 mm air gap) from the simulation results. Both antennas prototype has been fabricated to validate the performance of the antennas. The simulated and measured results in terms of reflection coefficient, S11, gain and VSWR are presented.