【作者】 李逸；

【导师】 吴国安；

【作者基本信息】 华中科技大学 ， 微电子学与固体电子学， 2021， 硕士

【摘要】 滤波器在通信系统中的应用十分广泛。传统的滤波器是反射式滤波器,即将阻带信号反射回输入端口,使其无法通过。这些被反射的信号有时会对系统性能产生不利影响。例如,滤波器阻带处的反射信号进入混频器,会生成更多干扰产物;进入功率放大器,则可能使放大器的动态范围减小,甚至产生振荡。为了解决这些问题,无反射滤波器应运而生。本文介绍了无反射滤波器的技术发展概况,并根据应用场景和需求的不同,采用平面微带线结构,设计了两款无反射带通滤波器和两款无反射带阻滤波器,最后探讨了无反射滤波器的小型化途径——IPD无反射滤波器。具体包括:(1)基于耦合微带线窄带带通滤波器及带阻吸收结构,设计实现了一款选择性好、无反射范围大的无反射窄带带通滤波器,中心频率为1.92GHz,相对带宽为4.70%,插入损耗为1.84d B,回波损耗10d B的无反射范围为0.10-5.50GHz。利用环形谐振器优异的带阻特性,设计实现了一款通带平坦、无反射范围大的无反射宽带带通滤波器,中心频率为2.03GHz,相对带宽为57.14%,插入损耗为0.45d B,回波损耗10d B的无反射范围为0.10-4.10GHz。(2)利用慢波开口环谐振器的慢波效应和对称性,设计实现了一款双端口无反射窄带带阻滤波器,中心频率为1.746GHz,相对带宽为9.16%,陷波深度为29.10d B,回波损耗10d B的无反射范围为0.10-3.10GHz。基于内部自耦合传输线的宽阻带特性,设计实现了一款阻带范围大、结构简单的无反射宽带带阻滤波器,中心频率为3.15GHz,相对带宽为93.01%,陷波深度为36.61d B,回波损耗10d B的无反射范围为0.10-4.00GHz。(3)采用集成无源器件IPD工艺,仿真设计了中心频率为1.997GHz,通带带宽482MHz,回波损耗15d B的无反射带通滤波器芯片,版图大小为2.4mm×2.4mm。仿真结果显示出IPD无反射滤波器在小型化方面优势明显。更多还原

【Abstract】 Filters are widely used in communication systems.The traditional filter is a reflective filter,the stopband signal is reflected back to the input port,so that it cannot pass through.These reflected signals sometimes adversely affect the system performance.For example,when the reflected signal out of band enters into the mixer,more interference products will be generated;the reflected signal out of band entering into the power amplifier may decrease the dynamic range of the amplifier and even lead to oscillation.In order to solve these problems,reflectionless filters came into being.In this thesis,the technical development of reflectionless filters is introduced,and two reflectionless band-pass filters and two reflectionless band-stop filters are designed by using planar microstrip line structure,according to different application scenarios and requirements.Finally,the miniaturization approach of reflectionless filters-IPD reflectionless filters is discussed.The details are as follows:(1)Based on coupled microstrip the narrow band bandpass filter and bandstop absorptive structure,a reflectionless narrowband band-pass filter with good selectivity and large non-reflection range is designed.The center frequency is 1.92 GHz,the fractional bandwidth is 4.70%,the insertion loss is 1.84 d B,and the non-reflection range of 10 d B return loss is 0.10-5.50 GHz.By using the excellent band-stop characteristics of the ring resonator,a reflectionless broadband band-pass filter with flat passband and wide nonreflective range is designed.The center frequency is 2.03 GHz,the fractional bandwidth is 57.14%,the insertion loss is 0.45 d B,and the nonreflective range of 10 d B return loss is 0.10-4.10 GHz.(2)Based on the slow-wave effect and symmetry of the slow-wave split-ring resonator,a dual-port nonreflecting narrowband band-stop filter is designed.The center frequency is1.746 GHz,the fractional bandwidth is 9.16%,the notch depth is 29.10 d B,and the nonreflective range of 10 d B return loss is 0.10-3.10 GHz.Based on the wide stopband characteristics of self-coupling transmission lines,a reflectionless broadband band-stop filter with wide stopband range and simple structure is designed.The center frequency is3.15 GHz,the fractional bandwidth is 93.01%,the notch depth is 36.61 d B,and the nonreflective range of 10 d B return loss is 0.10-4.00 GHz.(3)Using IPD technology,a reflectionless bandpass filter chip with a center frequency of1.997 GHz,a passband bandwidth of 482 MHz and a return loss of 15 d B is designed,and the layout size is 2.4mm×2.4mm.The simulation results show that IPD antireflection filter has obvious advantages in miniaturization.更多还原