Filtering antenna with radiation and filtering functions for wireless applications

This manuscript presents, a new 5th order Chebyshev band pass filter with 2.45 GHz center frequency and 0.1 dB equal-ripple filtering antenna are proposed. The design is based on the synthesis approach of the filter, which uses antenna radiator as the last-stage resonator of the filter. This new compact design acts as a multi-function module performing filtering and radiation simultaneously. The 4 resonators are provided by the parallel coupled half-wavelength microstrip lines and the last resonator is provided by the antenna. Without additional circuit area, the proposed geometry provides good design accuracy and filter selectivity as compared to the filter simply cascade with antenna and a band pass filter of the same order. The measured results agree well with the designed ones.