An antenna system including a retro-directive adaptive phased array antenna, comprised of a group of antenna modules. There is a phasing cell in each antenna module that adds a certain amount of phase shift to the wireless transmit and receive signals in order to generate a pair of retro-directive radiation beams, such that the wireless transmit and receive beams are aligned to each other. Each phasing cell synthesizes the phase shift values for the transmit and receive beams using only one phase shifter. Therefore, as a beam forming algorithm changes the receive beam forming coefficients (i.e. the phase shifters values) to steer the receiving beam, the transmit beam will be automatically aligned to that of receive beam for arbitrary transmit and receive frequencies.