Synthesis and design of a wideband and reconfigurable filtering slot antenna (FSA) is presented in this letter. This is achieved by using an open/short-ended interdigital E-shaped resonator through two integrated PIN diodes within its structure. A rectangular slot antenna with M-shaped radiating stub is excited by the resonator via an inset coupling structure. The slot antenna also performs the filter last stage, and the inset structure can be acted in the filter as the admittance inverter. The circuit model of the structure is analyzed, and the synthesis process is discussed using design curves and formulation. The reconfigurable FSA is designed at center frequencies of 5.2/5.5 GHz with 6%/17% fractional bandwidth and Butterworth broadside antenna gain response when both diodes are on/off, respectively. Compared to the conventional antenna, the filtering antenna obtains good frequency skirt selectivity, flatter passband responses, and wider bandwidth.