Research On Broadband Patch Antenna And Filtering Patch Antenna Based On Mode Control

With the rapid development of modern wireless communication technology,increasingly demanding requirements on bandwidth and frequency selectivity of antennas have been put forward.Based on the multi-mode patch antenna,the radiation characteristics of each mode are analyzed,and then the mode control is realized by using the technology of loading perturbation structure,and the multi-mode broadband patch antenna and the filtering patch antenna with wide harmonic suppression are designed.The microstrip antenna designed based on the mode control method not only can achieve broadband and diversified functions,but also will not destroy the original advantages of the microstrip antenna such as simple structure and low profile.The following works are carried out in this paper:Firstly,the modes of patch antennas are analysed.Microstrip patch antennas are a common form of multimode antenna.In order to accurately excite or suppress a particular resonant mode,the resonant modes of a conventional rectangular patch antenna are investigated.Surface currents direction,field distributions and radiation patterns for each mode are analysed.The three types of commonly used harmonic suppression methods are analyzed and summarized.Secondly,broadband low-profile patch antenna is designed.Based on the multi-mode resonance method of microstrip patch antenna,a broadband low-profile microstrip antenna under quadruple-mode resonance is proposed.To effectively fusion of four resonant modes,enhance the bandwidth.,shorting pins and rectangular slots are loaded on the patch.At the same time,air gap is used to reduce the effective dielectric constant and further broaden the bandwidth.Compared with antennas using other broadband technologies,the antenna has a smaller profile and a simpler structure.The proposed wideband antenna achieves31.7% bandwidth and 9.8 d Bi average gain that the low-profile characteristics of the microstrip patch antenna are not destroyed.Thirdly,filtering patch antenna with wide harmonic suppression is designed.Based on a mode analysis method of microstrip patch antennas,a compact single-layer filtering patch antenna with wide harmonic suppression is proposed.The filtering patch antenna is derived from the conventional square patch antenna.To effectively eliminate harmonics,create an upper radiation null,and excite a new resonant mode near the operating band,two wide slots are etched on the patch,dividing the patch into three regions along the wide edge(y-axis).A shorting via is inserted near the central area of the patch to form a shorting stub,generating a lower radiation null and improving impedance matching.Combining these two methods,the proposed patch antenna features good filtering response,harmonic suppression,and broad operating band without size increasing,which satisfies the increasing demand of the integration of multifunctional devices.