| Antenna is one of the most important parts of RF system.It undertakes the task of sending and receiving electromagnetic waves for the entire system.The performance and compatibility of the antenna have a great impact on the performance of RF system.Generally,a connector is set for the connection between the antenna and the upper-level circuit.Many problems,such as unnecessary losses and system impedance pulling,are caused by the bulky connector.In the low frequency band,the above problems are not very serious.However,with the emerging needs booming,high frequency and millimeter-wave antennas have become the focus of research.In the high frequency band,the problems of low space utilization and large loss cannot be ignored and heavily influence the performance and design of antennas.Therefore,it is necessary to design a new valuable architecture,so that the antenna can be easily integrated on the system circuit,and the adverse effects of connector can be fundamentally eliminated.Based on this background,the main contents and innovations of this thesis are summarized as follows:1.Considering the need for high-density integrated high-frequency antennas and array designs,how to achieve the character of high-performance and integrated has become a key issue.To solve this problem,this thesis studies aperture coupling feed technology to optimizes the coupling slot with a low discontinuity coupling slot with function curve transition,which is combined with a U-shaped feeding line to effectively improve the bandwidth and gain of the antenna to achieve good antenna performance.At the same time,this thesis focuses on the integrated feeding technology to proposes an adapter plate structure,which not only realizes the integrated feeding port transfer,but also provides chance for impedance matching.With the adapter plate and a specially designed vertical feeding structure,the unit can be directly packaged on the system board,which eliminates many adverse effects of the connector and realizes the integration of high-frequency antennas.Based on the research above,a K-band integrated stackable microstrip patch antenna element is designed.The proposed antenna element of which size is 7.2mm×7.2mm×4.37 mm achieves impedance bandwidth of 14%(18.7-21.5GHz)with maximum gain of 5.6d B.For the requirements of array application,based on a four-port feed network with high isolation,a 2 × 2 antenna array is formed to achieve impedance bandwidth of 14.3%(18.9-21.8GHz)with maximum gain of 10.8d B and minimum isolation of-15 d B between elements.2.With excellent characteristics,circularly polarized antennas are widely used.To meet the requirements,this thesis studies the characteristics of the radiating element with double circular patches,which effectively improves the axial ratio bandwidth.At the same time,the air cavity structure based on a 3D stacking structure of multi-layer PCB is added,which effectively reduces the dielectric loss and optimizes the gain.Finally,the dual feeding probes which are supplemented by a built-in 3d B coupler are studied to effectively provide the broadband equal-amplitude 90° phase difference feeding.Based on the research above,K-band integrated stackable microstrip patch antenna element is designed.The proposed antenna element of which size is 7.2mm×7.2mm×3.77 mm achieves impedance bandwidth of 19.5%(18.5-22.5GHz)and axial ratio bandwidth of 14.5%(18.8-21.7GHz)with maximum gain of 5.2d B.A 2×2 antenna array which is formed based on elements and a four-port feed network achieves impedance bandwidth of 14.3%(18.9-21.8GHz)with maximum gain of 10.8d B and minimum isolation of-15 d B between elements. |
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