A novel aperture isolation circuit for use in phased array systems

A novel electronically controlled matching network has been demonstrated as an aperture isolation circuit. This approach offers smaller size, lower weight, and potentially lower cost than circulators. An X-band MMIC (monolithic microwave integrated circuit) realization of this circuit has comparable loss to a circulator. An S-band hybrid realization demonstrated reductions in insertion loss of up to 2.3 dB for antenna VSWRs (voltage standing wave ratios) of up to 5:1 lying within a 100° sector on the Smith chart. One disadvantage of this approach is that it increases the complexity of controlling and calibrating the module