Harmonic control by photonic bandgap on microstrip patch antenna

In this letter, the single microstrip patch antenna having two-dimensional photonic handgap (PBG) in the ground has been demonstrated experimentally, and the effectiveness of the PEG structure is discussed for the suppression of the resonance at the harmonic frequencies of the antenna. Experimental results indicate that the radiation patterns at the harmonic frequencies ca n be drastically diminished comparing with the normal microstrip patch ante nna without the PEG structure, For instance, the radiation to the forward o f the PEG antenna is suppressed at more than 15 dB at the third harmonic fr equency.