刘新红

(北京信息职业技术学院，北京100015)



支节加载双模带通滤波器设计

刘新红

(北京信息职业技术学院，北京100015)

摘要阶梯阻抗谐振器高低阻抗微带线直线连接，实现输入输出强耦合需要减小和方形环双模谐振器之间的耦合距离，距离过小会造成实物加工困难。为此，提出了高低阻抗微带线垂直连接且在连接处输入输出的方式，使高低阻抗微带线都能与方形环谐振器耦合，且输入和输出也能耦合，加大了阶梯阻抗谐振器和方形环谐振器的耦合以及输入和输出的直接耦合。仿真结果表明，该方法在提高滤波器性能的同时减小了电路尺寸。

关键词双模带通滤波器；方形环谐振器；支节加载；阶梯阻抗谐振器

Dual-mode Bandpass Filter Using Stub-Loaded Resonator

LIU Xin-hong

(BeijingInformationTechnologyCollege,Beijing100015,China)

AbstractHigh and low impedance microstrip lines of stepped impedance resonator are connected,and the input and output strong couplings need to reduce the coupling distance to square ring dual-mode resonator,but the circuit board production is difficult if the distance is too short.It is proposed that high and low impedance microstrip lines are connected vertically and the input and output are at the connection,so that the high and low impedance microstrip lines can couple with the square ring resonator,and the input and output can also be coupled.The coupling between stepped impedance resonator and square ring resonator and direct coupling between input and output both are enhanced.The simulation results show that the circuit size is reduced while the performance of filter is improved.

Key wordsdual-mode bandpass filter;square ring resonator;stub load;stepped impedance resonator

0引言

双模微带滤波器通过在谐振器中增加微扰的方式激励起2个简并模，用一个谐振器实现2个谐振器的功能，在减少滤波器尺寸的同时，降低损耗，并且由于结构简单、成本低和容易设计等优点，被广泛应用于卫星通信和无线通信中[1-3]。

方形环谐振器容易实现级联耦合，并且方形环谐振器是闭合式的，其辐射损耗比半开环谐振器小。采用在方形环谐振器中心加载开路支节的微扰方式，能够在保持奇模频率不变的基础上，通过调节开路支节的尺寸来调节偶模频率，带宽调节更加方便[4,5]。滤波器输入/输出与谐振器之间采用间隙耦合的馈电方式[6]，很难实现强耦合，通常滤波器的相对带宽都较窄。采用阶梯阻抗微带线结构实现输入/输出与双模谐振器之间的强耦合[7,8]，可实现较大带宽的滤波器。……