This paper aims to present some outcomes from a European Space Agency (ESA) Technology Research Programme (TRP) project on R&D of new design techniques, concepts, and filtering configurations for tunable IF (intermediate frequency) filters with a compact footprint, wide bandwidth tuning range (covering from 49 to 478 MHz at f0 = 1 GHz) as well as equivalent high-Q performance (i.e. low insertion loss variation and high selectivity by using low-Q resonators). In order to obtain a wide tuning range, the proposed filtering configuration utilizes a new tuning technique that only necessitates control of coupling values with simple DC control circuits, without the need of tuning the electrical length of resonators to avoid deviating the center frequency. Furthermore, in order to achieve the equivalent high-Q performance, a novel lossy technique by using a centrally resistor-loaded half-wavelength resonator is adopted. For the proof of concept, a six-pole prototype filter is designed, fabricated, and tested.

本文旨在介绍欧洲航天局 (ESA) 技术研究计划 (TRP) 项目的一些成果，该项目针对具有紧凑型、宽带宽调谐的可调谐 IF（中频）滤波器的新设计技术、概念和滤波配置进行研发范围（在f 0 = 1 GHz时覆盖 49 至 478 MHz ）以及等效的高Q性能（即低插入损耗变化和使用低Q的高选择性）谐振器）。为了获得较宽的调谐范围，所提出的滤波配置采用了一种新的调谐技术，该技术只需要通过简单的直流控制电路来控制耦合值，而无需调整谐振器的电气长度以避免偏离中心频率。此外，为了实现等效的高Q性能，采用了一种新的有损技术，即使用中央负载电阻的半波长谐振器。为了概念验证，设计、制造和测试了一个六极原型滤波器。