Abstract: Based on the Yagi antenna principle, a reconfigurable four-arm helical antenna with a liquid metal reflector as its directional diagram has been proposed in this paper. The antenna is composed of a four-arm helical antenna, which serves as the main radiating unit, and a hollow column acting as a reflector for directional diagram switching. The directional diagram can be reconstructed by injecting liquid metal into different hollow columns. The mechanism of the reflection process has been theoretically studied and experimentally verified. The final designed antenna achieves beam switching at 5 radiation angles within a 360 ° coverage range, with an increased antenna directivity. The radiation frequency range covers the B1 frequency band of the BeiDou satellite and the L1 frequency band of GPS, ranging from 1.5 to 1.64 GHz.

Key words: beam control, liquid metal, pattern reconfigurable antenna, four arm spiral antenna, satellite navigation