High-order subharmonically pumped mixers using phased local oscillators

A high-order subharmonically pumped mixer architecture that utilizes multiple pairs of antiparallel diodes is described. A key component of the mixer architecture is a K-way power-divider/phase shifter that divides the local oscillator (LO) to multiple ports with equal magnitude and prescribed phase shifts. Undesired mixing products are eliminated through phase cancellation by symmetry rather than relying on intermediate idler circuits. As a proof-of-principle demonstration, an eighth-order mixer is implemented based on this approach and has shown a measured conversion loss of 8 dB at 8 GHz. The mixer architecture is suitable for applications in the millimeter and submillimeter-wave regions where high-frequency LOs are difficult to implement.