Research And Design Of Filtering Antenna With High Selectivity

Nowadays,integrating RF front-end passive components such as filters,power dividers,and antennas is research focus the design method not only reduces the overall size of the communication system,but also realizes that one device has multiple functional characteristics.The filtering antenna is one of the most popular research directions,in order to improve the selectivity of filtering antenna,it is necessary to introduce radiation nulls on sides of the passband.At present,the method of generating radiation nulls is basically a separate design through the filter circuit part or the antenna part.For the filtering antenna working in the dual band,there have been few reports that the dual band have high selectivity at the same time.In view of the above problems,single band and dualband filtering antennas with high selectivity are researched and designed in this paper.The specific contents of the paper are as follows:1)A high selectivity filtering antenna based on the cross-coupling theory is designed.By adopting the structure of double-layer substrate,the rectangular patch and the quarter-wavelength resonator are etched on the top and bottom surfaces of the double-layer dielectric.The middle common ground is shared.A H-shaped gap is etched on the ground to realize the coupling between the quarter-wavelength resonator and the rectangular patch,In addition,another H-slot is introduced to realize the coupling between the feedline and the antenna.Due to the addition of a new coupling path,radiation nulls are generated on both sides of the passband,which achieve a high selectivity filtering antenna.2)A high selectivity dualband filtering antenna based on a multi-mode resonator is designed.By loading two identical open stubs symmetrically in a hairpin resonator,the resonator has the characteristics of dual band and multi-mode.By coupling with a monopole dual band antenna,a dualband filtering antenna is achieved.Since there are two signal propagation pathsfrom the input to the output,which caused multiple transmission nulls.So,the dual band filtering antenna is realized with high frequency selectivity.3)An omnidirectional dualband filtering antenna is designed without additional filter circuits.By adopting multi-layer structure and central feeding structure,a dual band filtering antenna with omnidirectional radiation characteristics is achieved.In addition,by introducing short-circuit probes and etching gaps on the patches,radiation nulls on both sides of the passband was introduced,and then a dualband omnidirectional filtering antenna is achieved with the character of low profile and hign selectivity.