374~747 MHz数字可调谐微带滤波器

通过在微带开口谐振环加载数字可调电容，设计了一种新颖数字微带可调滤波器，同时提出了新型的非均匀开口谐振环混合耦合结构，使谐振器间耦合系数随谐振频率的降低而增大，实现恒定绝对带宽可调滤波器。接着对所提出的基于5 bit数字可调电容的数字可调微带滤波器进行了仿真和制作，测试表明，其通带中心频率可实现374~747 MHz可调，?3 dB绝对带宽在44~67 MHz之间变化，OIP3大于50 dBm。

374~747 MHz digital tunable microstrip filter

A novel digital microstrip tunable bandpass filter based on digitally tunable capacitor loading microstrip open ring resonators was proposed.The novel non-uniform open ring resonances with mixed coupling structure was used to make the coupling coefficient of the resonators increases with the decreasing of resonance frequency and achieve a con-stant absolute bandwidth tunable filter.Then the proposed digital tunable microstrip filters based on 5 bit digitally tunable capacitance was simulated and manufactured.The measurement shows that the ?3 dB absolute bandwidth varies from 44~67 MHz while the central frequency of the passband varying from 374~747 MHz,the OIP3 is greater than 50 dBm.