HFSS的2.4GHz微带带通滤波器设计

摘要随着无线通信技术的发展，系统对射频收发端提出了越来越高的要求。而微波滤波器作为关键部件，它的好坏直接影响整个系统的优劣。采用阶梯阻抗谐振器（SIR）的微带滤波器具有易于集成、尺寸小、成本低和远寄生通带等优点，在微波通信系统中得到了广泛的应用。尤其是伪交指型结构，相比于传统的平行耦合线在一个方向上级联，其尺寸更加小型化、结构更加紧凑。
本毕业论文介绍了SIR微带滤波器的基本理论和设计方法，并在此理论基础上设计了一个伪交指型SIR微带带通滤波器。结合HFSS软件对该滤波器进行了精确的研究和设计，用该软件所特有的本征模仿真功能对单个谐振单元的尺寸进行参数扫描，绘制出外部品质因数与抽头位置的曲线以及耦合系数与级间距离的曲线等，再对结构参数进行优化使其更加符合工程要求，并给出了仿真结果。最终设计出的滤波器中心频率为2.4GHz，带宽0.2GHz，频率在2.1GHz和2.7GHz带外抑制分别为30dB和30.2dB（大于30dB），带内插损0.9dB（小于3dB），整体尺寸为23mm*25mm。该滤波器采用阶梯阻抗谐振器和嵌套耦合的方式，使得滤波器尺寸很小，同时独特的结构使得在滤波器通带两侧有两个明显的传输零点，且寄生通带远大于中心频率，阻带特性良好。为了获得更好的带外抑制和陡峭的边缘特性，在馈线上引入马刺线，使得阻带抑制和通带选择性更加优良。最后，本文用HFSS软件对马刺线的各项尺寸进行参数扫描，比较其对滤波器网络的（即阻带抑制）的影响，从而对滤波器再次进行优化。19169
关键词阶跃阻抗谐振器伪交指微带带通滤波器 HFSS 阻带抑制
毕业设计说明书（论文）外文摘要
Title    A Design of 2.4GHz Microstrip Bandpass Filter
Abstract
With the development of wireless communication technology , the system presents the ever-increasing demands of the RF transceiver. As a key component, the microwave filter directly impact the entire system. Microstrip filters which are using the Step Impedance Resonator (SIR) have many advantages. They are easy to integrate, have a small size, cost lower, and have a further spurious passband. They have been widely used in microwave communication systems. Especially pseudo interdigitated structure. Compared to the conventional parallel-coupled lines cascaded in one direction, they have a smaller size and a more compact structure.
    This paper introduces the design methods and basic theory of an SIR microstrip filter, and designs a SIR pseudo interdigital microstrip bandpass filter on the basis of the theory above. Combined with HFSS software, the filter is precisely researched and designed.
    The size of the single resonator unit is simulated by the unique function of HFSS--the parameter sweep in eigen mode. And then, the curves of the relationship between coupling coefficients and interstage distance and the relationship between the external quality factor and tap position are drawn. Last, this design optimizes the parameters of the structure to make it more in line with the project requirements, and the simulation results very well. The center frequency of this filter is 2.4GHz, the bandwidth is 0.2GHz, stopband rejections at 2.1GHz and 2.7GHz were 30.5dB and 31dB ( greater than 30dB), in-band insertion loss is 0.8dB ( less than 3dB), the overall size is less than 23mm * 25mm. The filter uses stepped impedance resonators and nested coupling manner, so that the size of the filter is small. While a such unique structure make two distinct transmission zeros on the two sides of the passband, and the parasitic passband is much further than center frequency. The characteristic of stopband is good . To get a better stopband rejection characteristic and steep edges , this design introduced the spurlines which make stop-band rejection and selectivity of passband more excellent. Finally, parameters of the size of spurlines are swept by HFSS. And the influences over the (i.e., stop-band rejection) in the filter network are researched, in order to optimize the filter again . HFSS的2.4GHz微带带通滤波器设计:http://www.751com.cn/tongxin/lunwen_10431.html