Leaky-Wave Antennas Based on Capacitively Tuned Modulated Reactance Surfaces

The performance of a leaky-wave antenna that utilizes a sinusoidally modulated reactance surface is numerically investigated. In contrast to previously reported design methodologies, the sinusoidal reactance fluctuation is introduced in the structure by using lumped capacitors that load a frequency selective surface composed of simple uniformly distributed metallic strips. A key advantage of the approach presented herein is that it provides a pathway to realizing a reconfigurable surface impedance by allowing the lumped elements to be tunable. Using a 2-port network representation of the sub-unit-cell, the required capacitance-to-reactance map, necessary to determine the capacitor values that yield the desired sinusoidal reactance profile, can be rapidly extracted.