Continuous Scan of Radiation Beam from a Half-Width Microstrip Leaky-Wave Antenna at a Fixed Operating Frequency

A leaky-wave antenna (LWA) that can scan a beam continuously at a fixed operating frequency is presented in this paper. A half-width (HW) microstrip LWA is considered as the main radiating element in which one edge of the microstrip is shorted to the ground plane, and the other edge is open. Periodic gap capacitors are loaded at the open edge of the microstrip, each created by placing a small patch close to the microstrip edge, leaving a gap. A via and a varactor diode connect the small patch to the ground plane. In the simulation, lumped capacitors with different capacitance values that are available from a commercial varactor diode are used to replicate the characteristics of a varactor.