Quadrature direct conversion receiver integrated with planar quasi-Yagi antenna

A compact receiver front-end comprised of subharmonic direct conversion mixers integrated with a planar quasi-Yagi antenna is presented. The front-end generates I and Q baseband outputs, using the quasi-Yagi antenna as a circuit element to split the incoming signal into an I and Q component. Furthermore, the subharmonic design cancels even mixing products, thereby improving even-order distortion. Downconversion and demodulation of a QPSK modulated RF carrier signal is demonstrated successfully with a C-band prototype.