Miniaturized microwave tunable bandpass filters on high-k LTCC with integrated resistive vias as bias-T

Summary form only given, as follows. This paper describes a MEMS tunable bandpass filter operating in the S band region and featuring a low insertion loss of −2.3 dB and small size of 3.7 mm by 4.1 mm. The tunable filter is based on MEMS-varactors-loaded microstrip resonators and has been directly constructed on a high-k low-temperature-co-fired-ceramics (LTCC) wiring wafer whose dielectric constant is 50. The RF signal paths are isolated from the MEMS driving paths by built-in high resistivity-vias, leading to low insertion loss.