In order to develop a microstrip antenna which is suitable for wireless communication system and has the characteristics of antenna radiation and filter out-of-band suppression. A filter antenna consisting of four halfwave open-loop resonators

one-segment transmission coupling line and one-type microstrip antenna was designed and fabricated by the filter integrated design method. The antenna integrates with the fourth-order resonator of the filter as the coupling line of the admittance converter

and acts as the fifth-order resonator of the filter to realize the filtering function. The simulation and test results show that the impedance bandwidth of the filter antenna is 2. 39～2. 49 GHz

the maximum gain is 3. 71 d B

the maximum gain deviation within the band does not exceed 0. 43 d B

and the gain at 100 MHz outside the band quickly drops to-5 d B and tends to be stable. The filter antenna has simple structure and thin substrate. It optimizes the overall size of the filter and antenna and reduces the transmission loss between them. It can be applied to the RF front-end of wireless communication system.