In-Band RCS Reduction of a U-Slot Microstrip Patch Antenna

Abstract

A systematic method for reducing the in-band radar cross-section (RCS) of a U-slot microstrip patch antenna is developed. The U-slot microstrip patch antenna is designed based on an empirical design technique and then analyzed using the theory of characteristic modes (TCM). The radiation modes and scattering modes of the U-slot patch antenna are distinguished by examining the CM indicators, including modal significances, modal currents, and modal fields. According to the designated frequency band and angular range for RCS reduction, a specific scattering mode is selected and loaded with lumped elements. Values of the lumped elements can be calculated theoretically in this method and a maximum RCS reduction of 20 dB is obtained.