A dual frequency retrodirective array with reduced surface waves

A one-dimensional, dual frequency, active retrodirective array is proposed. Microstrip circular patch antennas with four shorting pins are used as array elements to suppress surface waves. The proposed design eliminates undesired coupling between array elements due to surface waves present in conventional microstrip antenna arrays in order to improve array performance. The antenna array uses circularly polarized microstrip elements with higher gain than conventional microstrip antennas. The proposed retrodirective array operates at 2.4GHz for the interrogating signal and 5.8GHz for the retransmitted signal, using up-converting mixers. The Design procedure, simulation results and experimental measurements are presented.