Fixed-Frequency Beam-Steering Leaky-Wave Antenna With Switchable Beam Number

This letter presents a fixed-frequency beam-steering leaky-wave antenna (LWA) with switchable beam number. The proposed LWA consists of an impedance modulation surface (IMS) and dc bias circuit. A three-strip structure is designed as the unit cell of the IMS. In this design, varactor diodes are inserted in the unit cell and the impedance characteristics of every unit cell can be controlled independently. Both average reactance and modulation periodicity of the IMS can be tuned for leaky-wave radiation with different beam angle. The proposed LWA can be configured to work in single-beam mode or dual-beam mode. A prototype of the proposed LWA operating at 8 GHz is fabricated and measured. By controlling the dc voltages of varactor diodes, a scanning range of 118° can be achieved.