Three-stage bandpass filters implemented in silicon IPD technology using magnetic coupling between resonators

Thin-film technologies most commonly use capacitors or inductors to couple resonator stages for the implementation of band-pass filters. The use of mutual inductance (referred to as magnetically coupled, to distinguish it from conventional inductive coupling) has some inherent advantages, especially for ESD robustness and DC isolation. Furthermore, this method is naturally suited for the implementation of balanced filters. This paper describes the design and characterization of some example bandpass filters for wireless LAN applications in silicon IPD technology using capacitively-loaded ring resonators coupled by mutual inductance.