先进微波成像诊断技术中高通滤波板的优化设计

Optimization design of dichroic plate for the advanced technology in microwave imaging diagnostic

介绍了频率选择表面的理论模型和高通滤波板的模拟结果.通过在高通滤波板中规律性地加入介质,提高了高通滤波板高通上升沿的上升速度,并在模拟中证明了其可行性.论证了使用介质填充的方法可明显优化上升沿速度,并拓展通带带宽,拓展了高通滤波板的使用范围,提高了工作性能.为先进微波成像的高斯光束空间滤波提供了理想部件.

Taking theories and stimulation as the starting points, this paper gives the optimal design for dichroic plate in the advanced technology of imaging diagnostic. Dichroic plate is firstly analyzed theoretically, whose result shows that it is a wavelength-sensitive device, different from the traditional understanding of dichroic plate. In fact, a dichroic plate is a wavelength selective, and its outward manifestation is a frequency selective plate. There are two ways of putting medium into the dichroie plate. It can be seen that with the increase of the medium＇s semidiameter, the passband bandwidth increases obviously and the rising slope is sharper. When the medium is fully populated, the passband bandwidth reaches its maximum, the freguency increasing upto 12 GHz, and in the meanwhile the rising slope possessing the top speed. The other is to adopt the method of coating. If a hollow dielectric cylinder is filled to become a waveguide, it can also be seen that with the thickening of the wall of the dielectric cylinder, the passband bandwidth also increases obviously and the rising slope is sharper. When the medium is fully filled in the circular waveguide, the result is the same as that of the first method.