Design of Compact Filtering Antenna Based on Stepped Impendence Resonator

Modern communication systems are developing towards miniaturization and integration. Filters and antennas are two important components in the front end of the system. The integrated design of these hvo parts is of great significance to the overall integration of the system. Firstly, the characteristics and basic structure of Sir resonator are introduced. On this basis, a quarter-wavelength resonator is selected as the basic resonant unit. Successfully introduce two transmission zero points by adding short-circuit vias. Realize the function of band pass filter. In this paper, a single band-pass filter with simple structure and small size is designed. Then, one port of the filter is opened, and the inverted L-shaped antenna working in the same frequency band is cascaded directly. Finally, the parameters are fine tuned to achieve the impedance matching behveen the filter and the antenna. Conclusion The center frequency of the filter antenna is 5.25GHz, the maximum gain is 4.37dB, the cut-off frequency is 5.0GHz and 5.38GHz, and the bandwidth is 380MHz. That is, the passband range of -10dB in the passband is 5.0-5.38GHz, and the relative bandwidth is 7.2%, the minimum reflection coefficient in the passband is -27dB.