POLARIZATION-DIVERSITY PHASE-ENCODED PATCH-ANTENNA TRANSPONDER

Application of phase encoding to a received RF signal, and retransmiss ion of the signal phase encoded at the same frequency using polarisati on diversity, is used to design a simple two-port microstrip patch ant enna which will permit single-frequency polarisation-diversity operati on. The antenna is characterised in terms of its far-field radiation p attern and its two-port parameters. An injection-locked is coupled to an adapted passive quasicirculator to perform the phase-encoding funct ion. Here control of the direct tuning voltage to the injection-locked oscillator effects the degree of phase change obtained. The operation of this circuit is discussed and its inclusion with the dual-port pat ch antenna to form a phase-encoding transponder is described.