A Cassegrain Antenna With Field-Controlled Reconfigurable Subreflector for HIRF Protection

This paper proposed a Cassegrain antenna with a field-controlled reconfigurable subreflector for high-intensity radiation fields (HIRF) protection. By replacing the rotating hyperboloid subreflector with a field-controlled reconfigurable metasurface, the antenna can adaptively change its gain based on the incident electromagnetic field intensity. The proposed reconfigurable metasurface consists of 97 unit cells, each unit cell with a thickness of 4 mm and equipped with four diodes. The simulation and measurement have demonstrated that under low-intensity fields, the gain of the proposed antenna reaches 27.4 dBi at 9.3 GHz, which is only 0.3 dB less than the normal hyperboloid subreflector antenna. In HIRF, the gain of the proposed antenna decreases to 8.9 dBi, below the level of the feed.