新颖高温超导紧凑型双CT结构带通滤波器

A Novel HTS Compact Dual CT Structure Bandpass Filter

设计了一种新颖的平面单螺旋菱形谐振器,采用平面单螺旋菱形谐振器设计滤波器时易于构成无交叉耦合线的紧凑型CT单元。利用CT单元在通带边缘产生传输零点,提高滤波器的边带抑制性能,实现滤波器整体结构的小型化设计,整个电路在视觉上具有立体感的美观效果。结合自拟的带通滤波器耦合矩阵,在面积为13.5 mm×3.8 mm、厚度为0.5 mm、介电常数为24.1的YBCO/La AlO_3/YBCO双面高温超导薄膜上,设计了通带为2 850~3 000 MHz的六阶新颖高温超导紧凑型双CT结构带通滤波器,该结构的带通滤波器可以实现两个传输零点、边带抑制度大于45 d B/MHz;同时二倍频通带在6 GHz处,实现了宽阻带。实物测试结果与理论设计能很好地吻合。

In this paper, a novel planar single spiral diamond resonator is designed, which is convenient to achieve the compact CT unit without the cross-coupling line for the filter design. By using this kind of CT unit, transmission zeros can be generated for improving the filter＇s selectivity and realize a miniaturized size, and also present an artistic three-dimensional sense. A 6-order novel high temperature superconducting（HTS） compact CT structure filter with passband covering 2 850-3 000 MHz is fabricated on the double-sided YBCO/La AlO3/YBCO thin film with the size of 13.5 mm × 3.8 mm, the thickness of 0.5 mm and the dielectric constant of 24.1. The measured results show that there are two transmission zeros; the out-of-band rejection is greater than 45 d B/MHz; and the second-harmonic passband is located at 6 GHz, which means the filter possesses a wide stopband. The measured results agree rather well with the simulated ones.