A Gain-Reconfigurable Reflector Antenna With Surface-Mounted Field-Induced Artificial Magnetic Conductor for Adaptive HIRF Prevention

This article presents a gain-reconfigurable reflector antenna that could adaptively focus or defocus to adjust gain, thereby preventing the high-intensity radiation fields (HIRFs). The reflector’s surface is partially covered by the field-induced artificial magnetic conductor (F-AMC). According to the status of diodes loaded in F-AMC, the reflection characteristics could be switched between electric and magnetic conductors. When field intensity is low, the diodes are off-state, and the reflection phase is about 180°, performing as an electric conductor; once the diodes are triggered into on-state by the high-intensity field, the reflection phase would switch to nearly 0° and perform as a magnetic conductor. Through nonperiodically arranging and optimizing the number of F-AMC unit cells on the reflector surface, the phase distribution of the wavefront would remain uniform in a low-intensity environment and be messed under HIRF. The messed phase of the wavefront could defocus the radiation beam and reduce the gain to prevent the high-intensity fields from being received. After simulation and measurement, the proposed reflector antenna was demonstrated to decrease its gain by more than 20 dB under HIRF. The gain difference from loading the F-AMC was less than 1 dB in the band from 8.4 to 9.8 GHz in the low-intensity environment.