Low cross-polarized integrated mixer/phase shifter patch antenna for beamforming applications

This paper describes a demonstration of the IF beamforming potential of an integrated mixer active patch antenna. A compact microstrip patch radiator circuit, consisting of an integrated mixer and injection-locked VCO, is described. Computations and measurements show that such a circuit not only provides frequency down-conversion but also can perform phase control through injection locking. The active element has good far-field radiation pattern characteristics and exhibits low cross-polarization. A measurement scheme is described to confirm the circuit's usefulness as a building block in electronically steerable IF beam-forming antenna array applications.