Planar Array of Electric- $LC$ Resonators With Broadband Tunability

A planar array of microwave electric- LC (ELC) resonators with broadband tunability of the resonance frequency is presented in this letter. An ELC resonator is typically composed of inductive loops and a capacitive gap, resonant at a wavelength much larger than its physical dimension. Here, the original resonator is modified to accommodate a varactor and its accompanying dc bias enabling resonance tunability. The wideband operation can be achieved through strategic placement of the varactor. The robustness of the response for a large array containing hundreds of the varactor-loaded resonators is considered via a sensitivity analysis. The numerical and experimental results show that the fabricated array possesses a wide tuning range of nearly 32% with no significant resonance broadening, despite the tolerance in varactor characteristics.