Broadband 2-6 GHz polarization circuit for dual polarized phased array antenna

Modem phased array antennas need polarization diversity for much improved performance. In this report, an active polarization circuit for circular polarization of a broadband antenna array in the frequency band 2-6 GHz has been investigated and designed. The polarization circuit makes use of an active power splitter and two 90° phase shifters to provide an independent control of the amplitude and phase of the signal at each antenna element. These circuits were simulated using software Libra from Agilent Corp. and designed using a specific fabrication process from OMMIC foundry (ED02ah). The phase error was less than ±10°.