Abstract: A multi-frequency continuously adjustable reconfigurable filter antenna is designed. Firstly, two 1/4 wavelength SIR Bandpass filters loaded with varator diodes are integrated with 50 Ω microstrip transmission lines to obtain a reconfigurable filter feed network. By controlling the on-off state of six PIN diodes, the UWB and narrowband modes can be switched. In addition, a fractal ultra-wideband antenna whose operating frequency covers the passband range of the tunable filter is designed, and the two are integrated to realize the filter antenna. The design of the antenna is simulated and tested. The test results show that the antenna can work in WiMAX narrowband continuous tunable mode, WLAN narrowband continuous tunable mode and ultra-wideband mode, and all have good radiation characteristics, which can be widely used in multi-band wireless communication.