高性能小型化有耗滤波器设计及其功率容量研究

Multifunctional integration has been one of the important trends of modern electronic information technology, which requires the microwave filter, one of the key components in communication systems, keep the rapid developments of high performance and miniaturization. A lossy filter can be designed with low-Q resonators to achieve flat in-band response, steep band transition and sharp zeros as a high-Q filter, only at the expense of its limited insertion loss. Therefore, it has become one of the most attractive solutions for miniaturized passives. Based on the investigations on electro-thermal fields and power handling capabilities of miniaturized passive components in the applicant’s Youth Science Foundation, this project is mainly focused on the systematical investigations on the design methods, 3D realizations and power handling capabilities of lossy filters, especially including: 1) the synthesis and optimization methods of lossy filters combined with several promising techniques, such as predistortion, lossy synthesis and non-uniform Q-factor; 2) the 3D integration schemes of high-performance miniaturized lossy filters, based on hybrid structure, high-Q dielectric loading and embedded passives, etc.; 3) the effective methods for diagnosing and tuning lossy filters, to extract their coupling matrices and circuit models from the simulated and measured results and to further obtain the quantitative relationships between the critical parameters and performances; 4) the multi-physical mechanisms of electro-thermal coupling and passive intermodulation in lossy filters, and the prediction of their power handling capabilities. By this project, we intend to build up a complete technology for the design, implementation, diagnosis and verification of high-performance miniaturized lossy filters, where the requirement on power handling capability will also be incorporated with the design procedure, so as to achieve the collaborative optimization for all the concerns.

多功能集成是当前电子信息技术的重要趋势，这要求通讯系统关键部件微波滤波器不断向高性能和小型化方向飞速发展。有耗滤波器可用较低Q值谐振器以牺牲有限的插损为代价实现高Q滤波器的带内平坦、边带陡峭和零点尖锐特性，是小型化无源元件的首选方案之一。本项目拟在青年基金小型化无源元件电热分析与功率容量研究基础上，系统探究有耗滤波器的设计与三维实现方法及其功率容量问题。具体包括：1）研究结合预失真、有耗综合、非一致Q值等技术的有耗滤波器综合和优化方法；2）研究基于混合结构、高Q介质加载、嵌入元件的高性能小型化有耗滤波器三维集成方案；3）研究从仿测结果提取有耗滤波器耦合矩阵和电路模型并确定其参数化定量关系的有效诊断和调试技术；4）研究有耗滤波器中电热耦合和无源交调的多物理机理，预测其功率容量。本项目拟提供高性能小型化有耗滤波器设计、实现、诊断和验证的整套技术，将功率容量要求结合到设计中实现性能的协同优化。

为满足当前电子系统多功能、小型化、集成化的紧迫需求，小型化微波滤波器的研发工作正在不断推进。然而，小型化会引起损耗增加、Q值降低、功率密度升高等问题，这使得滤波器的边带变圆滑、通带不平坦、频率选择性降低、功率容量降级。为此，本项目系统研究了用低Q谐振器以有限额外插损为代价实现高性能有耗滤波器的综合设计方法、诊断调试技术和功率容量特性。本项目取得的主要成果包括：1）提出了结合预失真、阻性和复耦合系数、非一致Q值、灵敏度分析等技术的有耗滤波器综合方法，采用双模/多模微带、基片集成波导等混合结构实现，获得了具有平坦通带特性的高性能有耗带通滤波器；2）通过人为调控滤波器中的损耗分布，解析设计出具有负群时延特性的吸收式带阻滤波器、具有稳定插入损耗的电可调负群时延电路，并利用阻性交叉耦合改善了多端口滤波网络的端口隔离特性，基于频变耦合设计了高频率选择性四路滤波功分器；3）针对有耗滤波器Q值低、耦合系数多为复数、拓扑结构复杂的特点，提出了从其仿真和测试结果提取有耗耦合矩阵和电路模型并确定其参数定量关系的诊断和调试技术，满足因果性、无源性、可实现性等，编制了多款通用软件；4）研究了有耗滤波器的电热耦合机理，提出了电阻和谐振器上热耗散的紧凑模型，预测其带外功率容量，给出全波电热仿真结果进行验证，进而分析各种典型有耗滤波器所适合的不同功率等级应用场景；5）基于多层PCB和LTCC工艺，实现了多款三维混合结构的小型化有耗滤波器。基于本项目成果已发表和录用论文25篇，申请专利6项，登记软件著作权5项，培养研究生7名。综上所述，本项目已形成了一整套高性能小型化有耗滤波器设计、实现、诊断、验证、功率容量评估的方法。