低损耗双模微带贴片带通滤波器研究

Study of Low Loss Dual-mode Microstrip Patch Bandpass Filters

首先提出了一种新颖、简单的带有两个切角的双模微带带通滤波器结构。该结构使用单个贴片谐振器并且没有耦合缝隙,通带两端各有一个衰减极点,可以有效减小滤波器的辐射损耗。对该滤波器结构进一步改进,又提出了一种中心频率1.8GHz相互正交槽线的新型双模微带带通滤波器结构。该滤波器在中心频率1.8GHz处,回波损耗达到31.65dB,通带内最小插损为0.01dB,3dB带宽为19.44%。研究结果表明该结构可以进一步减小辐射损耗,并且可以减小滤波器的体积,有利于小型化。

A novel simple dual-mode microstrip patch bandpass filter with double-corner cuts is proposed firstly. The proposed structure is to use one single patch resonator without coupling gaps, and has two attenuation poles on the both sides of the passband. The filter can provide a low loss. An improved new dual-mode microstrip patch passband filter using a pair of unequal crossed slots is also proposed, which operates at 1.8GHz. The return loss of the new filter is 31.65dB at the center frequency of 1.8GHz, the minimum insertion is 0.01dB in passband and the 3dB fractional bandwidth is 19.44%. The results show that the radiation loss and structure size can be significantly reduced simultaneously, and it is easy for miniaturization.