非接触式低无源互调波导滤波器

无源互调（passive intermodulation, PIM）是微波部件及系统中一种常见的非线性干扰，对卫星及地面通信均有着普遍影响。不良金属电接触所导致的接触非线性是PIM的主要根源。将间隙波导技术原理与PIM问题相结合，提出通过非接触电磁屏蔽消除微波部件中的金属接触，实现了稳定高效的PIM抑制效果。首先以槽间隙波导为例，开展了非接触式波导传输线的PIM实验研究，进一步采用串联短路枝节结构，设计研制了一种Ku频段非接触式波导低通滤波器。实测结果显示，非接触式滤波器在具有优秀电磁传输性能的同时，其PIM电平基本保持在测试系统残余PIM电平附近，且不受表面处理及连接力矩影响，获得了稳定的低PIM特性。该工作可为低PIM微波毫米波部件及系统设计实现提供一种新的思路。

Contactless low passive intermodulation waveguide filter

Passive intermodulation (PIM) is a kind of interference generated in microwave components and systems, which has harmful impact on satellite and ground communication. Contact nonlinearity caused by non-ideal metallic contact is the main source of PIM. In this work, gap waveguide technology is adopted to solve the PIM problem, and the metal contact in microwave components is eliminated by contactless electromagnetic shielding, thus achieving a stable and efficient PIM suppression. The PIM performance of contactless waveguide is first experimentally studied with groove gap waveguide as an example, and a Ku band contactless waveguide low pass filter with series short-circuited stubs is successfully designed and fabricated. The measurement results shows that the contactless filter obtains excellent electromagnetic transmission performance, while its PIM level maintains near to the residual PIM level of the test system, and is not affected by surface treatment or connection torque, achieving a stable low PIM performance. This work provides a new idea and reference for low PIM design of microwave and millimeter-wave components and systems.