Design of Wideband Leaky-Wave Antenna with Fixed Beam and Switchable Beam Direction

A wideband leaky-wave antenna (LWA) with fixed beam and switchable beam direction is proposed. The antenna consists of a ridge gap waveguide (RGW) and nine groups of microstrip branches. The microstrip branches are used to compensate the feeding phase. Two rows of slots with different periods are used to couple energy to microstrip branches, and each group of microstrip branch has three sub-branches with different phase differences. By controlling the coupling slots with different periods and the sub-branches with different lengths using p-i-n diodes, the coupling and transmission path of energy to each antenna element can be controlled, so that six switchable beam angles can be realized. The simulated results show that the LWA can realize fixed beam switching between $\pm 30^{\circ}, \pm 18^{\circ}$ and ± 6° from 14 to $17 \mathbf{G H z}$ ($\mathbf{2 5 \%}$ bandwidth).