Single-layer design of microstrip patch Electrically-Steerable Parasitic Array Radiator (ESPAR) with integrated DC isolation

A microstrip patch ESPAR with reactive mutual coupling control is presented as a single-layer design for the first time. A prototype 3-element 1-GHz array without phase shifters and employing tunable reactive loading is fabricated and measured to be in excellent agreement with full-wave simulation. The prototype greatly simplifies the microstrip patch ESPAR design method while maintaining the established high performance, incorporating innovative DC biasing solutions while simultaneously reducing losses. This allows extension of the microstrip ESPAR technique to conformal, high frequency designs while mitigating fabrication risks.