Integrated 3-bit RF MEMS phase shifter with constant pahse 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 11.25degrees/22.5degrees/45degrees stub-loaded line phase shifters and 90degrees/180degrees 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 90degrees/180degrees 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 min. -10dB, phase error of avg. 2.0degrees at the frequency ranged 10.7 from 12.75GHz, and a size of 5mm x 5mm, respectively. 15 volts of actuation voltage are the lowest value in the reported RF MEMS phase shifters.