A X-band switched-line 5-bit phase shifter with RF MEMS multithrow switches

In this paper, a 5-bit switched-line phase shifter is designed, processed and tested for X-band application, which is based on packaged RF MEMS single-pole double-throw(SPDT) and single-pole four-throw(SP4T) switches to get an compact structure. The design and optimization are carried out by analyzing the non-ideal performance of packaged RF MEMS switches and extracting their circuit model parameters. The effects of the bonding-wire connecting RF MEMS switches and peripheral circuits are also analyzed and modeled. The 5-bit phase shifter shows the average measured insertion loss of -3.1 dB, the average return loss of -21.1 dB, and the average absolute phase error of 2.2° at 10GHz. By comparison of simulations and measurements, this paper proposes that the main factors to effect the performances of phase shifters with packaged MEMS switches are parasitic inductances introduced by the bonding-wire and limited isolation of the used switches.