Spring 2014 IAB & Research Review
March 5 - 6

Plenary 11:
Mehmet Akgul

High Rejection True RF Channel-Select Filter

The introduction of 39nm capacitive actuation gaps, voltage-controlled frequency tuning, and a stress relieving coupled array design has enabled a 0.09% bandwidth 223.4-MHz channel-select filter with only 2.7dB of in-band insertion loss and 50dB of out-of-channel interferer rejection, marking 25dB improvement over previous generation capacitive-gap transduced filters. It also comes in tandem with a 20dB shape factor of 2.7 realized by a hierarchical mechanical circuit design utilizing 206 micromechanical circuit elements, all contained in an area footprint (sans bond pads) of only 600um420um. The key to such low insertion loss for this tiny percent bandwidth is Qs >8,800 supplied by capacitive-gap transduced polysilicon disk resonators employing for the first time gaps small enough to generate coupling strengths on the order of (Cx/Co) ~0.1%, which is a 10 improvement over previous efforts. This filter is the first demonstrated that truly offers low insertion loss and high rejection channel-selection for ultra-low power communication front-ends targeted for autonomous sensor networks.