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 8 dB 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 8 dBi at the S‐band and measured bandwidth of 10.5% and gain of 11.5 dBi at the X‐band. This antenna can be used for satellite applications.