Design of filtering microstrip antenna using filter synthesis approach

Design, simulation, and measurement of a compact filtering microstrip antenna is presented. A feed line, two hairpin resonators, and a rectangular patch are integrated to form the filtering antenna. The elements together function as a third order bandpass filter with Chebyshev equal ripple response of 0.043 dB at midband frequency of 2.0 GHz. The rectangular patch acts not only as a radiating element, but also as the last resonator of the bandpass filter. The proposed filtering antenna exhibits good out-of- band gain suppression, flat in-band gain response, good selectivity at the band edges, and well-shaped radiation pattern.