A Broadband Frequency Tunable Diamond-Shaped Metamaterial Resonator Using Varactor Diodes

This work proposes a broadband, diamond-shaped, frequency tunable and unique metamaterial resonator design featuring a ground frame and a feedline. Integration of varactor diodes to the design coupled with carefully engineered electric and magnetic field distributions of the resonator enable high frequency tunability as demonstrated by simulations and measurements. Furthermore, the proposed design enables the simpler measurements of the metamaterial resonator without the need for plane wave illuminations or additional waveguides. Measurements show a tunable frequency range over 0.82-2.04 GHz, which corresponds to 85.3% tunable bandwidth percentage with an almost constant Q-factor. Measured maximum insertion loss is 1.68 dB over this tunable band. Results indicate much better tunable bandwidth compared to similar works. Metamaterial properties are also demonstrated with permeability, permittivity, and transmission phase results. The designed tunable metamaterial resonator may be used to realize reconfigurable microwave circuits such as filters, antennas, sensors, absorbers, switches, and matching networks.