Design Of Filter Antennas Based On The Coupled Patch Array

Wireless communication is severely limited by the channel capacity of the system when facing huge communication traffic.The multi-beam antenna is a common solution to this problem from the perspective of the RF devices.At the same time,with design requirements of compact structures and low insertion loss of the communication system,the design size of the RF devices is continuously reduced;the fusion design of the filter antenna as a solution can enhance the frequency selection ability of the antenna with a smaller structure and reduce insertion loss.The thesis mainly focuses on the antenna structure of the coupled patch array.Based on the lossy mutual coupling between the antennas,the traditional lowpass prototype coupling matrix and the frequency dependent network matrix are used to study the controllable multi-beam filter traveling-wave antenna.The main work and contributions include the following two aspects:1.Based on the synthesis of the lossy filter,the thesis extracts and studies the mutual coupling equivalent circuit of the patch antenna,and regards the mutual coupling of the antenna as a lossy J/K converter,and uses the frequency response of the lossy filter for the goal,the low-pass prototype lossy coupling matrix when multiple antennas are cascaded is obtained by numerical optimization.At the same time,the elements of the coupling matrix corresponded to the actual structure of the antenna,and a calculation example of six-order filtering traveling wave antenna is obtained.The results of the fullwave simulation are basically consistent with the theoretical results,and the maximum gain of the antenna is about 8.82 d Bi.2.According to the complex frequency conversion of the lowpass prototype coupling matrix,insufficient bandwidth,and poor radiation performance,the cascade of the coupled patch array is directly designed based on the frequency-dependent network matrix,and a method that can accurately extract the circuit parameters is proposed.Based on the mapping relationship between the resonant equivalent circuit of the linear topology and the physical structure,two calculation examples are given,which are basically consistent with the results of the full-wave simulation.At the same time,there is a deviation between the frequency response of the optimized calculation example during the synchronous tuning of the resonator network and the full-wave simulation.Based on the actual extraction results,the radiating element of the antenna is regarded as an asynchronously tuned resonator.The improved calculation example is compared with the full-wave simulation and processing results are very consistent.The antenna has a gain of about 10 d Bi in the 2.4–2.6 GHz range.Every port of the antenna finally realized beam scanning of 12°–34° in the ? direction.At the same time,the maximum gain of the antenna is relatively high filtering characteristics.In summary,this thesis starts from the coupled-patch series-fed array antenna structure,transforms it into a lossy filter equivalent network,and controls the coupling between adjacent patches and the complex impedance matching antenna's port to make it natural the filtering characteristics of the antenna,and the antenna radiation achieves a controllable multi-beam,which provides an idea for antenna design.At the same time,the modeling ideas,extraction,and design methods in this article can be extended to the research and design of other antenna structures,broadening the antenna design theory.