Broad Coverage Impedance Tuner Using the Field-Programmable Microwave Substrate

This letter presents the study of the field-programmable microwave substrate (FPMS) used as an impedance tuning device. FPMS metamaterial technology allows several degrees of freedom to synthesize the desired impedance, leading to many different possible configurations. Unit cells of the matrix can be turned on or off independently, and the bias voltage of each can be varied continuously from 0 to 25 V. Different impedance values are synthesized at 1.5, 1.8, 2, and 2.4 GHz via effective waveguide modifications by varying the bias voltage of the unit cells’ varactor diodes. Measurements of over 1000 different configurations show very broad coverage of the Smith chart.