Importance and Measurement of Phase-Stiffness in RF Switching Amplifiers

Immunity of RF power amplifiers (PA) to reverse signal injection and changes in load reflection coefficients due to antenna mutual coupling in active phased arrays is essential for maintaining signal integrity and controllable radiation patterns. In conventional active phased-array radar, the amplifiers are protected from any reverse signal injection from the antenna by including isolators and/or circulators between the PA and the antenna [1-3].