Integrated 3-bit RF MEMS phase shifter with constant phase shift for active phased array antennas in satellite broadcasting systems

In this paper, integrated 3-bit RF MEMS phase shifters with low insertion loss, narrow frequency band, and constant phase shift independent to the operating frequency are proposed for active phased array antenna in mobile satellite broadcasting systems. The proposed 3-bit RF MEMS phase shifter is comprised of 3 different 1-bit phase shifters with 11.25/spl deg//22.5/spl deg//45/spl deg/stub-loaded line phase shifters and 90/spl deg//180/spl deg/ reflection type phase shifters are also investigated for 5-bit RF MEMS phase shifter. These 1-bit phase shifters are comprised of RF MEMS capacitive shunt switches, CPW overlay couplers (for 90/spl deg//180/spl deg/ phase shifters), open/short stubs, air-bridges, MIM capacitors, and resistors for dc bias. The fabricated 3-bit phase shifter has insertion loss of avg. -2.0 dB, return loss of -10 dB, phase error of avg. 2.0/spl deg/ at the frequency ranged 10.7 from 12.75 GHz, and a size of 5 mm /spl times/ 5 mm, respectively. 15 volts of actuation voltage are the lowest value in the reported RF MEMS phase shifters.