Integrated RF MEMS phase shifters with constant phase shift

In this paper, fully integrated RF MEMS phase shifters with low insertion loss, narrow frequency band, and constant phase shift are designed, fabricated, and characterized for mobile satellite broadcasting/communication systems. The fabricated phase shifters are comprised of CPW lines, short/open ended-stubs, and RF MEMS capacitive shunt switches. The constant phase shift can be obtained by optimizing the length of the open-ended stub and the short-ended stub. The fabricated 3-bit phase shifter has insertion loss of avg. -2.0 dB, return loss of min. -10 dB, and phase error of avg. 2.0/spl deg/, respectively. The utilized RF MEMS switches are operated at between 15 and 20 volts.