Dual-frequency microstrip antenna at S and X bands with higher-order mode suppression technique

In this study, a higher-order mode suppression technique in single- and dual-frequency microstrip antennas is proposed. The technique integrates a microstrip filter within the microstrip antenna, thereby simplifying the transmitter/receiver chain by eliminating the need of a separate filter. This technique gives higher-order mode suppression of 8dB using a low-pass microstrip filter without any effect on the resonance frequency and the gain of the antenna. A dual-frequency antenna for S and X bands is designed using this technique to obtain measured bandwidth of 7% and gain of 8dBi at the S-band and measured bandwidth of 10.5% and gain of 11.5dBi at the X-band. This antenna can be used for satellite applications.