Compact Dual-Mode Triple-Band Bandpass Filters Using Three Pairs of Degenerate Modes in a Ring Resonator
Compact Dual-Mode Triple-Band Bandpass Filters Using Three Pairs of Degenerate Modes in a Ring Resonator
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DOI：
10.1109/tmtt.2011.2123106
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发表时间：
2011-04
影响因子：
4.3
通讯作者：
S. Luo;Lei Zhu;Sheng Sun
中科院分区：
文献类型：
--
作者：
S. Luo;Lei Zhu;Sheng Sun
在本文中，提出了一类在环形谐振器中使用三对简并模式在每个通带中具有两个传输极点的三带带通滤波器。为了提供对谐振运动的物理洞察，首先开发了等效集总电路，其中可以根据端口分离角来清楚地跟踪第一和第三通带中的两个传输极点。在沿环选择 135° 和 45° 端口间隔的情况下，四个开路短截线沿环对称连接，并将它们视为扰动元件以分裂两个二阶简并模式，从而产生双极点第二通带。为了验证所提出的设计概念，最终设计、制造和测量了单个微带环谐振器上的两个滤波器原型。正如仿真和测量结果中所演示和验证的那样，在所有三个通带中均实现了三对传输极。
In this paper, a class of triple-band bandpass filters with two transmission poles in each passband is proposed using three pairs of degenerate modes in a ring resonator. In order to provide a physical insight into the resonance movements, the equivalent lumped circuits are firstly developed, where two transmission poles in the first and third passbands can be distinctly tracked as a function of port separation angle. Under the choice of 135° and 45° port separations along a ring, four open-circuited stubs are attached symmetrically along the ring and they are treated as perturbation elements to split the two second-order degenerate modes, resulting in a two-pole second passband. To verify the proposed design concept, two filter prototypes on a single microstrip ring resonator are finally designed, fabricated, and measured. The three pairs of transmission poles are achieved in all three passbands, as demonstrated and verified in simulated and measured results.