$K$ -Band 4-Bit Phase Shifter Using Two Back to Back MEMS SP16T Switching Networks

This paper presents a
K
-band 4-bit phase shifter using micro-electromechanical system-based dc contact single-pole-sixteen-throw (SP16T) switching networks. The circuit is fabricated on 635-μm alumina substrate using surface micro-machining process. Compact circular type SP16T switch is the primary functional building block of the 4-bit phase shifter. SP16T switch demonstrates an average insertion loss of ~1.9 dB, isolation of better than 14 dB and average return loss of better than 14 dB in the 18-26-GHz band. Total area of the fabricated SP16T switch is only ~2.5 mm
²
. Finally, two SP16T switches are cascaded with different delay lines to develop the complete 4-bit phase shifter. The 4-bit phase shifter demonstrates an average insertion loss of 3.47 dB in the 19.75-20.25-GHz band with a return loss of better than 14 dB and average phase error is less than ~1.77° at 20 GHz. Total area of the fabricated 4-bit phase shifter is ~13.5 mm
²
. The reliability of the SPST and SP16T switches show more than 1 billion (B) cycles with an RF power of 0.1-1 W. Finally, device demonstrates >1 B cycles with cold switched and >~600 million cycles with hot switched conditions. To the best of our knowledge, this is the first reported high reliable and more compact MEMS 4-bit phase shifter in the literature that has undergone extensive measurement stages with minimum number of switching elements per phase state. [2018-0014].