In this paper, a novel high isolation and high-capacitance-ratio radio-frequency micro-electromechanical systems (RF MEMS) switch working at Ka-band is designed, fabricated, measured and analyzed. The proposed RF MEMS switch mainly consists of a MEMS metallic beam, coplanar waveguide (CPW) transmission line, dielectric layer and metal–insulator–metal (MIM) fixed capacitors. The measured results indicate that the insertion loss is better than 0.5 dB at 32 GHz, and the isolation is more than 35 dB at the resonant frequency. From the fitted results, the capacitance ratio is 246.3. Compared with traditional MEMS capacitive switches, this proposed MEMS switch exhibits a high capacitance ratio and provides a wonderful solution for cutting-edge performance in 5G and other high-performance applications.

A Ka-band CPW-Slot-Couple (CSC) fed microstrip antenna with enhanced bandwidth and gain is presented in this paper. To simplify the feed network, the matching slots are designed at the end of the CPW. Consequently, the patch antenna is designed with a low profile, which has a size of 7.2 × 32.6 × 0.508 mm³. Characteristic mode analysis (CMA) is applied to illustrate the principle of the enhancement of the band with the form characteristic mode point of view. A slot based on inductive loading is employed on the parasitic patch to move the resonant frequency of CM3 to the resonant frequency of CM2 for enhanced bandwidth, which avoids introducing additional impedance matching networks. The measured results show that the bandwidth of the proposed monolayer antenna is 14.18% from 24.84 to 28.6 GHz and the peak gain is 7.9 dBi. Due to its attractive properties of low profile, compact configuration, wide band, and high gain, the proposed antenna could be applied to miniaturized millimeter-wave applications.

This paper presents a novel radio frequency micro-electro-mechanical systems (RF MEMS) switch fabricated on a high resistivity silicon substrate. Slots, like square interleaved slots and split-ring slots, are used in the transmission-line to get better RF performance. Comparing three switch structures with different slot cells, the switch with square interleaved slots is suitable at Ka-band (26 ~ 40GHz), but the switch with split-ring slots can be applied to RF circuits at 10-60GHz. The switch with split-ring slots is optimal for the switching mechanism in diverse 5G RF circuitry. When it works at 30GHz, it shows a low insertion loss better than − 0.256dB, a low re-turn loss better than − 22dB, and the isolation is observed below − 39dB. Its “pull-down” voltage is 6.5V. Due to its outstanding performance, the proposed RF MEMS switch is suitable for various applications.