Micromachined RF-Coupled Cantilever Inverted-Microstrip Millimeter-Wave Filters

This paper introduces a new concept for implementing millimeter-wave filters intended for monolithic integration. The approach uses silicon micromachining and wafer bonding techniques to create inverted-microstrip transmission lines in air and radio frequency (RF)-coupled cantilevers. A third-order filter demonstrated a measured insertion loss of only 0.54 dB at 76.5 GHz. Simple MEMS tuning of 60-GHz coupled-line resonators has also been demonstrated for the first time. This paper could form the basis for a new type of low-loss tunable distributed-element RF microelectromechanical system filter technology for millimeter-wave applications.