Design and Fabrication of Capacitive Mems Actuator Array on Spoof‐Surface‐Plasmon‐Polariton Waveguide for Active Microwave Modulation

Micro‐electro‐mechanical system (MEMS) actuator arrays integrated into the gap of split‐ring resonators (SRRs) that are capacitively coupled to a spoof‐surface‐plasmon‐polariton (SSPP) waveguide are numerically designed and experimentally fabricated. Owing to its compact size and lightweight structure, the microbridge exhibits high‐speed operation with a mechanical resonant frequency of 1.505 MHz in air. The microbridges are capacitively actuated by embedded lead electrodes and grounded microbridge arrays. When an alternating current (ac) voltage V ac of 30 V is applied, a maximum phase shift of 2.55° is achieved at 6.65 GHz, whereas a direct current (dc) voltage V dc of 140 V results in a maximum phase shift of 2.96° at 7.95 GHz. Theoretical analysis and numerical simulations reveal that the voltage‐induced deformation of the microbridge alters the dispersion properties of the SSPP waveguide and perturbs the local electric field beneath the bridge, thereby enabling phase modulation of the guided microwave signal. These findings demonstrate the capability of the device to function as an active phase modulator for integrated microwave circuits, with potential applications in 5 G/6 G communication systems and time‐varying metamaterials.