Research on the development of dielectric-loaded super-high-efficiency small planar antennas by injection compression molding approach

采用注射压缩成型方法制备了介质球。这些介质材料，然后加载到一个原型的微波平面天线的表面上，以提高天线增益的目的。本次测试的原型天线是X波段波导天线，为了实现高增益天线，必须认识到阻抗匹配的重要性。在本研究中，我们首先尝试了波导与单槽的匹配，然后尝试了单槽与介质球的匹配，然后将这种结构推广到多槽波导阵列，考虑了两种波导天线。一种是蛇形波导馈电天线，其中馈电波导在正方形平面天线中的天线壁处左右弯曲。这种类型的天线的特点是，天线可以被构造为单层低剖面天线，辐射无线电波，同时在波导中传播。在这种天线中，匹配过程变得复杂。另一种类型的天线是平行波导馈电天线。在这种类型的天线中，匹配过程可以独立地为馈电分支和辐射结构完成，使得匹配过程相对容易。原型蛇形波导馈电天线的辐射方向图测量在f=12 GHz的“紧凑范围”内进行。“研究发现，通过在辐射槽表面加载介质材料，天线的前端增益得到了改善，但远角旁瓣电平有所增加。通过确定适当的介质材料参数，使天线的孔径效率最大化，这还有待进一步研究。

By using injection compression molding approach, dielectric spheres were fabricated. These dielectric materials were then loaded on the surface of a prototype microwave planar antenna for the purpose of enhancing the antenna gain. The prototype antenna tested this time is an X-band waveguide antenna.To realize a high-gain antenna, we must recognize that an impedance matching plays an important role. In this study, we first tried a matching of a waveguide with single slot, and next a single slot with a dielectric sphere.Then this structure was extended to a multi-slot waveguide arrays.Two types of waveguide antennas were considered. One is a snake-waveguide-fed antenna, where a feed waveguide is bent right and left at the antenna walls in a square planar antenna. The feature of this type of antenna is that the antenna can be constructed as one-layer low-profile antenna, radiating radio waves while propagating in the waveguide. In this antenna, however, the matching procedure becomes complex.The other type of antenna is a parallel-waveguide-fed antenna.In this type of antenna, the matching procedure can be done independently for the feed branch and for the radiating structures, enabling relatively easy matching procedures.Radiation pattern measurements of the prototype snake-waveguide-fed antenna were conducted at f=12 GHz in the "compact range." It has been found that the front gain of the antenna is improved by loading dielectric materials on the radiating slot surfaces, though some far-angle side-lobe levels were increased.Further studies are left for maximizing the aperture efficiency by determining the proper parameters of the dielectric materials.