摘要
微带滤波器由于其轻便,体积小和易于制造等优异的特点而得到了广泛的应用。但是经过Richards变换和黑田规则得到的低通滤波器由于变换函数的周期性在高频段出现了严重的寄生通带,且采用的切比雪夫模型在过渡带的性能可以得到进一步的改进。本文采取高低阻抗变换得到的椭圆函数低通滤波器,加入叉指结构的谐振单元后相比于以前的滤波器有更好的过渡带性能和高频段的寄生通带的寄生能力,三倍频处的正向电压传播系数仍抑制在-40d B以下,且其匹配性能在通带内的驻波比最大为1.5,基本符合滤波器设计要求。
Microstrip filter has been widely used due to its outstanding characteristics such as lightweight,small size,easiness to manufacture and so on.But the lowpass filter gotten by Richards transformation and Kuroda rule has serious parasitic passband due to the periodic character of transform function.Furthermore,transition band of filters transformed from Chebyshev model can be further improved.This article focuses on the elliptic lowpass filter gotten by high and low impedance transformation,which has better performance of transition band and restraint capacity for parasitic passband at higher frequency after adding pectinate resonant unit.Forward voltage transmission coefficient at three times frequency can be still restrained under-40dB,with standing wave ratio within passband up to 1.6 which indicates good matching performance.It can be concluded that the design requirement of filter have been basically fulfilled.
出处
《科技风》
2018年第24期238-238,共1页
关键词
宽阻带
椭圆函数
高低阻抗
叉指结构
Wide stopband
elliptic function
high and low impedance
pectinate structure
