A compact duplex filtering antenna using a T-shape probe-fed patch and hairpin resonators

A compact duplex filtering antenna using a T-shape probe-fed patch and hairpin resonators is proposed. First, the T-shape probe-fed patch is designed as a dual-band radiation element by connecting a microstrip line to the patch. Then the dual-band radiation element is coupled to two bandpass filters based on half-wavelength hairpin resonators directly to construct the duplex filtering antenna. The two modes of the dual-band radiation element function as last stage resonators, improving the selectivity of both the transmitting band and the receiving band, increasing the bandwidths, and enhancing the isolation. A prototype antenna is fabricated and measured. The measured results agree well with the simulated results.