Abstract
A compact quadrature coupler — using intertwined mutual inductors by the proposed GaAs integrated passive device (IPD) process — is developed by considering the quality factor of inductor and minimum insertion loss for the long term evolution (LTE) applications. At the center frequency of LTE bands 5 and 8, the quadrature coupler achieved -3.45 dB of insertion loss S21 and -3.43 dB of coupling S41 with less than 0.65 degrees of phase error over the frequency range. The reflection coefficient S11 and the isolation S31 are -24.32 dB and -23.45 dB, respectively. This coupler can be usable for a compact quadrature 3-dB divider/combiner as partial component of a balanced power amplifier.
