Harmonic Suppression for Microstrip Antennas with Complementary Split Ring Resonators

A method of harmonic suppression for microstrip patch antennas with complementary split ring resonators is presented.Lower transmission zero can be realized by loading a pair of narrow slots in the gap of the ring.An equivalent circuit model of the structure is given,and the model is verified by the simulation results.And the decline of the transmission zero is analyzed from the equivalent circuit model.With the units of different resonant frequencies in series,suppression of the hamonics can be realized for the microstrip antenna.The antenna is fabricated and measured.It is in good agreement between simulations and measurements,which verify the correction of the design.The structure is compact and the method is simple.