A fully integrated 24 GHz sub-harmonic image rejection mixer with quadrature coupler

In this paper, we demonstrated a 24-GHz SHIRM in a 0.15-mum GaAs pHEMT process. Since the proposed circuit with a symmetric layout provides good matches on amplitude and phase performances, the cancellation of the image signal can be accomplished easily. Therefore, the SHIRM has a greatest conversion loss of 13 dB and IRR of 19 dB under LO input power of 14.4 dBm, with all isolations better than 10 dB. According to the experimental results, this SHIRM with two quadrature couplers achieves good potentials in conversion loss, IRR, and compact size in the 24-GHz ISM band.