Interdigitated Low-Loss Ohmic RF-MEMS Switches

R. Gaddi, M. Bellei, A. Gnudi, B. Margesin and F. Giacomozzi
ARCES - University of Bologna, IT

Keywords: rf-mems, switch, ohmic, low-loss, model

Abstract:
An interdigitated design for MEMS RF-switches is applied to both a shunt and a series ohmic contact configuration. Interdigitated Al-Ti-TiN RF-signal paths and poly actuation electrodes are arranged underneath an electrodeposited gold plate, suspended by four thinner gold beam springs. Ohmic contact occurs at pull-in between the gold plate and the RF-signal elecrodes only. Measurements show insertion loss better than 0.8 dB and isolation better than 20 dB up to 13 GHz. Extracted lumped element equivalent circuits show intrinsic contact resistances of 1.6 Ohm in the shunt and 4.5 Ohm in the series switch. The interdigitated topology of RF-signal and actuation electrodes results in uniform contact pressure distribution and consistently low contact resistance.

Nanotech 2004 Conference Technical Program Abstract