Research of the active antenna fed by coplanar waveguide for satellite communication

近年来，共面波导(CPW)的普及率显著提高。共面波导的优点是带宽更宽，相邻两条线路之间的相互耦合更小，更容易与固体有源器件集成。在过去的几年里，人们对共面波导馈电的线极化天线进行了大量的研究，如贴片天线、环形天线和缝隙天线，但实现共面波导馈电的圆极化天线的尝试还很少。本文提出了一种新型的共面波导馈电的圆极化印刷天线的结构，并对这种天线进行了数值模拟和测量分析。此外，最近还研究了用于移动卫星通信的各种带有电自动跟踪机制的车载天线。这样的天线需要移相器或开关来形成所需的波束。在本研究中，我们还提出了一种通过改进CPW馈电的圆极化天线来实现中等增益波束切换的天线阵，并以一个由四个单元组成的天线阵为例，给出了12 GHz频段的一些仿真结果。该阵列应该有四个1比特(180度)移相器或开关来跟踪卫星。结果表明，低成本、小尺寸的波束切换阵列是可行的。最后，对与微波开关电路集成的天线进行了研究。

The popularity of coplanar waveguide, (CPW) has increased significantly in recent years. The advantages of CPW are wider bandwidth, smaller mutual coupling between two adjacent lines and easier integration with solid active devices. Over the past few years a considerable number of studies have been carried out on the linearly polarized antenna fed by CPW such as patch antennas, loop antennas and slot antennas, but only a few attempts have so far been made at realizing a circularly polarized antenna fed by CPW.In this study, we proposed a new structure of the circularly polarized printed antenna fed by CPW and analyze this antenna fed by using both a numerical simulation and measurement.Moreover, various types of vehicle antennas with, an electrically auto-tracking mechanism have been studied for mobile satellite communications recently. Such antennas require phase shifters or switches to form a desired beam. In this study, we also proposed a medium-gain beam-switching antenna array by modifying the circularly polarized antenna fed by.CPW.As an example, an array composed of four elements is demonstrated with some simulated results at 12 GHz band. The array is supposed to have four 1-bit (180-degree) phase-shifter or switches to track the satellite. The results show the possibility of a low-cost and small-size beam-switching array.Finally, the antenna integrated with the microwave switching circuits was also investigated.