Design and investigation of a novel variable reactance-based capacitive RF-MEMS switch with multifrequency operation for mmWave applications

This paper presents the design and investigation of a variable reactance-based RF-MEMS capacitive switch operating on multiple frequency bands in millimetre wave ranges used for B5G applications. The proposed switch has a built-in band switching capability to cover multiple frequency bands in FR-II mmWave band which can provide an inspirational and optimistic platform to tackle 5G and beyond challenges. The novel design utilizes lateral deflections to make and break the device's connection and results in a very low pull-in voltage of < 3 V. The switch operates in different modes maximum up to 9 and switches between multiple frequencies by varying the reactance of the electromechanical structure. These modes are tuned to cover all the bands from n257 to n261, primarily used to provide 5G/B5G services in various countries. The RF performance, voltage requirement, and switching speed of the proposed device are as per the guidelines of the 5G/B5G communication system. The insertion losses are < 0.5 dB, and isolation is > 20 dB over the tuned frequency range (FR-II mmWave) with optimum isolation peaks at 12.1 GHz, 12.9 GHz, 21.2 GHz, 22.2 GHz, 23.5 GHz, 24.8 GHz, 26.1 GHz, and 39.5 GHz. The proposed device features a significant improvement in electromechanical and electromagnetic performance over a wide bandwidth with different structural configurations and thus can be used as an efficient IoT (Internet of Things) frequency reconfigurable device.