高带外抑制特性S波段低损耗宽带高温超导滤波器研究

Wideband / ultra-wideband (UWB) filters recently have been well developed. Meanwhile, the design methods of wideband superconducting filters, with high out-of-band rejection and excellent performance, still remain as unsolved problems. The main focus of the proposed research is the study of the design of wideband / UWB superconducting filters, based on the study of multi-mode resonators. The design of multi poles wideband filters will be accomplished, with the study of the implementation of strong couplings between multi-mode resonators. The design of high Q multi-mode resonator will be attained, with the analysis of resonator topology model, reducing Insertion Loss(IL) of wideband superconducting filters. The design and fabrication of high accuracy wideband superconducting filters will be accomplished, with the study of reconfigurable multi-mode resonators. The improved out-of-band rejection of wideband filters will be designed, with the study of the distribution of harmonic resonant frequencies. S band low loss wideband HTS filters with high out-of-band rejection will be fabricated and tested. The S band HTS filters will be installed in the receive front-end of the radio astronomic telescope, improving the anti-interference ability and performance of the apparatus. The research achievements of this project will not only lead to solutions of the key problems of the S band wideband filter design, but also solve the long-term encountered interference problems of the radio astronomic telescopes. The research achievements will make an important contribution to the filter technology, especially to the development of wideband / UWB filters of China.

宽带/超宽带滤波器研究近年来在国内外获得了广泛的关注，而高性能宽带超导滤波器的理论和设计方法仍是亟待解决的难题。本项目主要基于多模谐振理论，研究高性能宽带/超宽带超导滤波器的设计方法。开展多模谐振器间强耦合实现方法研究，设计高节数的宽带超导滤波器；通过对谐振器拓扑模型的研究分析，设计具有高Q值特性的多模谐振器结构，降低宽带超导滤波器的通带损耗；开展可重构多模谐振器研究，设计高精度宽带超导滤波器；研究多模谐振器的谐频分布，改善宽带超导滤波器的带外抑制特性。以本项目滤波器设计方法为基础，研制具有高带外抑制特性的S波段低损耗宽带超导滤波器，并将其应用于射电天文望远镜接收机，提高望远镜的抗干扰能力和探测性能。通过本项目研究，将突破S波段高性能宽带滤波器设计的关键技术，解决射电天文望远镜长期遇到的干扰难题，为我国滤波器技术，特别是宽带/超宽带滤波器技术的发展做出重要贡献。

本项目开展了高带外抑制特性S波段低损耗宽带高温超导滤波器设计关键技术研究。包括基于多模谐振理论的高节数宽带滤波器设计，宽抑制滤波器设计，高性能超导滤波器及其他超导微波器件的制备封装技术等研究。本项目提出了通过级联U型微带线来构建多模谐振器的方法，分别构建了三模，四模，五模谐振器并以此为基础设计了超宽带滤波器。通过独立控制谐振器各个模式之间的耦合强度的方法，设计制作了三模三通带滤波器等器件。提出了窄带条件下使用频率变换、提取双模谐振器参数来直接设计双通带滤波器的设计流程。构建了多种具有高谐频特性的谐振器，包括埋地-类插指结构，加载插指结构的非对称阶跃阻抗结构，自嵌入非对称阶跃阻抗结构等。利用埋地-类插指结构设计的宽抑制滤波器，倍频高达7.2倍基频频率。开展了可重构多模谐振器研究，以减小仿真设计与实际制作的误差。开展了高Q值谐振器研究以及滤波器功率承受能力研究。本项目研制了具有不同带宽的S波段超导宽带超导滤波器，射电望远镜S波段接收机前端进行了应用试验。试验结果表明，加装超导滤波器后接收机的探测性能得到改善，通带外的干扰信号得到有效抑制。