A Broadband Fixed-Beam Leaky-Wave Antenna With Switchable Beam Direction

A broadband fixed-beam leaky-wave antenna with switchable beam direction is designed. The ridge gap waveguide is used as the main transmission structure and a series of microstrip branches are used as the phase delay lines. By choosing the microstrip branch lengths appropriately, the main beam pointing to different directions can be realized. In this letter, each microstrip line branch has three switchable subbranches with different lengths, and the switching of subbranches is controlled by p-i-n diodes, so that three different phase delays can be realized by coding the diodes states and three switchable beam directions can be obtained. The antenna with beam angles switching among 0° and ±30° is designed as an example, and the main beam of the antenna is fixed to 0° and ±30° directions, respectively, in frequency band from 12 to 17 GHz (34% bandwidth). The proposed antenna shows the capability of adjusting the direction of fixed-beam flexibly, which is a candidate for broadband point-to-multipoint communication.