MEMS-Based Frequency-Tunable Reflect-Line Phase Shifter

This paper presents a reflect-line phase shifter with a frequency reconfigurable behaviour. The proposed design approach uses Metal-Insulator-Metal (MIM) capacitors as loads of a branch-line coupler. The reconfigurability is obtained by means of RF-MEMS switches. Results referring to a 90° differential phase shifter able to work at two different frequencies (7.7 GHz and 9.76 GHz) are reported and discussed. It will be shown that the use of RF-MEMS switches combined with MIM capacitors results in compact dimensions and good performance in terms of bandwidth, thus demonstrating that the proposed approach is an optimum candidate for designing frequency reconfigurable phase shifters.