介质陶瓷滤波器的可调性研究

Tuning Properties of Dielectric Ceramic Filters

为了降低介质陶瓷滤波器的磨加工精度和提高产品合格率,提出在滤波器的开路端面涂覆银层的技术。研究这种开路端有银层的介质陶瓷滤波器的可调性。仿真结果表明这银层不仅能够有效地降低介质陶瓷谐振器和滤波器的频率而且可以增大或减小耦合系数。用介电常数为74的介质陶瓷制作了滤波器样品并测量其性能,测量结果表明滤波器的中心频率可以从1.219 GHz下调至1.081 GHz,滤波器的通带带宽可以从9 MHz变化到30 MHz。

In order to reduce grinding precision and improve the qualified rate of dielectric ceramic filters, a technology by which a silver layer is plated at the open-circuited end of the filters is proposed. This paper studies the tuning properties of dielectric ceramic filters with a silver layer at the open-circuited end. The simulated results show that the plating at the open-end not only effectively lowers the resonant frequency of dielectric ceramic resonators and filters, but also increases or decreases the coupling coefficient. The filters made of dielectric ceramics with permittivity of 74 are fabricated and measured, the centre frequencies of the filters are tuned from 1.219 GHz to 1.081 GHz, and the bandwidths of the filters can vary from 9 MHz to 30 MHz.