Ku to V-band 4-bit MEMS phase shifter bank using high isolation SP4T switches and DMTL structures

摘要

This work presents a micro-electro-mechanical system (MEMS) based on a wide-band 4-bit phase shifter using two back-to-back single-pole-four-throw (SP4T) switches and four different distributed MEMS transmission line (DMTL) structures that are implemented on 635 mu m alumina substrate using surface micromachining process. An SP4T switch is designed with a series-shunt configuration and it demonstrates an average return loss of > 17 dB, an insertion loss of < 1.97 dB and maximum isolation of > 28 dB up to 60 GHz. A maximum area of the SP4T switch is similar to 0.76 mm(2). Single-pole-single-throw and SP4T switches are capable of handling 1 W of radio frequency (RF) power up to > 100 million cycles at 25 degrees C; they can even sustained up to > 70 million cycles with 1 W at 85 degrees C. The proposed wide-band phase shifter works at 17 GHz (Ku-band), 25 GHz (K-band), 35 GHz (Ka-band) and 60 GHz (V-band) frequencies. Finally, a 4-bit phase shifter demonstrates an average insertion loss of < 6 dB, return loss of > 10 dB and maximum phase error of similar to 3.8 degrees at 60 GHz frequency over 500 MHz bandwidth. Total area of the fabricated device is similar to 11 mm(2). In addition, the proposed device works well up to > 10(7) cycles with 1 W of RF power. To the best of the author's knowledge, this is the best reported wide-band MEMS 4-bit phase shifter in the literature that works with a constant resolution.