一种基于LTCC 的吸收式低通滤波器的设计

Design of LTCC-based Absorptive Low-Pass Filter

为了阻止阻带反射信号回到信号源,设计了一款LTCC半分布式吸收低通滤波器。该滤波器通过衰减电阻把阻带能量衰减掉,在不增加插入损耗的情况下达到吸收阻带反射信号的效果。仿真结果表明,该款滤波器的3 dB截止频fc=2.5 GHz,带内回波损耗大于20 dB,6fc处对反射信号的吸收大于12 dB,3.7 GHz处的带外抑制大于20 dB,模型尺寸仅为4.8 mm×3.6 mm×1.43 mm。

In order to prevent the stopband reflection signal from returning to the signal source,a LTCC semi-distributed absorption low-pass filter is designed.The filter attenuates the energy of the stopband through the attenuation resistor,and achieves the effect of absorbing the reflected signal of the stopband without increasing the insertion loss.Simulation results indicate that the 3 dB cut-off frequency of this filter is fc=2.5 GHz,the in-band return loss is greater than 20 dB,the reflected signal absorption at 6fc is greater than 12 dB,and the out-of-band rejection at 3.7 GHz is greater than 20 dB.The size of the model is only 4.8 mm×3.6 mm×1.43 mm.