One main obstacle that reduces the yield in RF MEMS technology is the variation of the residual stress resulting from
fabrication. Residual stress can occur across the wafer, from the wafer to another wafer, or from one batch of fabrication
to another one, and is more pronounced in cantilever bean type switches. For the present paper we have used new sets of
dimples to reduce the sensitivity of the structure to the stress level. The SEM pictures of the proposed configuration and
those of the conventional beam switch fabricated on the same wafer are analyzed sufficiently. The comparison amply
proves soundness of our method. The high actuation voltage is another main issue that requires considerable
investigation, and is generally higher in clamped-clamped beam type switches. In order to reduce the actuation voltage,
we have designed, fabricated and tested several configurations with different supporting beams. The actuation voltage of
as low as 10 volts is achieved and all switches exhibit excellent RF performance. At 40GHz the insertion loss of the
switches varies ranging from 0.35dB to 0.7dB. It is evident that at a lower frequency ranges this becomes even better. At
40GHz, the return loss for all switches measured -24dB. Lastly, isolation is better than 20dB to 30dB for all the
frequency band of interest.
This paper addresses the use of RF MEMS devices in wireless and satellite communication systems. It describes the MEMS actuators typically needed for such devices. Novel configurations are presented for MEMS variable capacitors, MEMS tunable inductors and RF MEMS mutiport switches. The tuning range of the variable capacitor was measured and found to be 280%, which far exceeds that of the traditional parallel plate MEMS variable capacitors. The MEMS tunable inductor is realized using MEMS fixed inductors, capacitors and a variable MEMS capacitor. The proposed MEMS multiport switch has demonstrated a superior RF performance up to 20 GHz.