微波平面多通带滤波器的研究

发布时间：2018-09-09 12:00

【摘要】：无线通信技术的不断发展,使有限的频谱资源更加拥挤。在这种情况下,能够同时工作在多个频段的通信设备已经成为研究的热点。由于现代通信系统中的微波电路更加复杂,器件和模块的集成度不断提高,传统的器件结构和模块正面临着“转型”和“升级”的挑战。作为多频接收机前端的重要器件之一,多通带滤波器的选频特性直接影响整个通信系统的性能。微波平面多通带滤波器不仅能够同时提取带内信号和抑制杂散、干扰信号,还能够和平面电路集成,极大地降低通信设备的体积和成本,逐渐获得众多专家学者的关注。阶梯阻抗谐振器(SIR)不仅可以通过调节阻抗比和电长度控制谐振频率,而且可以和四分之一波长谐振器(QWR),缺陷地结构(DGS),加载短路枝节谐振器(SSLR)和加载开路枝节谐振器(OSLR)集成在一起,为多频带滤波器的综合和设计提供了广阔的舞台。本文根据SIR的谐振特性,研究了其在多频带滤波器中的应用。本文首先研究了双节SIR的谐振特性,将双节SIR的输入导纳表达为几个因式相乘的形式;还研究了三节SIR和三节SIR加载开路枝节的谐振特性,以及广义切比雪夫函数和准带通节的相关理论;同时研究了其应用于多通带滤波器的实现方式。通过在三节阶梯阻抗谐振器上加载开路枝节,综合并设计了双通带滤波器,在此基础上,通过微调阻抗比,改进馈电方式,设计了宽阻带的双带通滤波器,进一步研究发现,在地表面蚀刻缺陷地结构实现了超宽带外抑制的双通带滤波器。然后,利用双节SIR和QWR构成两路交叉耦合路径,同时,利用DGS结构精准控制耦合系数设计了三通带滤波器,产生了8个传输零点,获得了高频率选择特性和带外抑制。最后,利用准带通节级联设计了高选择性可重构双通带滤波器,利用NRN之间的耦合取代传统的谐振器之间的耦合,提高了滤波器的调频范围,滤波器的中心频率和传输零点都可以通过调节可调薄膜电容调节。通过测量,滤波器的带外抑制超过60dB,在部分工作状态下,带外抑制度甚至能够达到78dB。本文采用EM仿真软件进行滤波器的设计,同时采用标准PCB工艺加工滤波器,最后用HP8510B矢量网络分析仪进行测试。测试数据与仿真结果很好的吻合,证明了本文提出的设计方案的合理性和可行性。
[Abstract]:With the development of wireless communication technology, the limited spectrum resources become more crowded. In this case, the communication equipment that can work simultaneously in multiple frequency bands has become a hot research topic. As the microwave circuits in modern communication systems are more complex and the integration of devices and modules is increasing, the traditional device structures and modules are facing the challenge of "transformation" and "upgrading". As one of the most important devices in the front end of multi-frequency receiver, the frequency-selecting characteristics of multi-band filter directly affect the performance of the whole communication system. Microwave planar multiband filter can not only extract in-band signals and suppress stray and interference signals simultaneously, but also integrate with planar circuits, which greatly reduces the volume and cost of communication equipment, and gradually attracts the attention of many experts and scholars. The step impedance resonator (SIR) can not only control the resonant frequency by adjusting the impedance ratio and electric length. Moreover, it can be integrated with the (DGS), loaded short-circuit branch resonator (SSLR) and the open-circuit branch resonator (OSLR), which provides a broad stage for the synthesis and design of the multi-band filter. According to the resonance characteristic of SIR, the application of SIR in multi-band filter is studied in this paper. In this paper, we first study the resonant characteristics of the two-section SIR, and express the input admittance of the two-section SIR as several factorial multiplications, and study the resonant characteristics of the three-section SIR and the three-section SIR loaded open branch. The theory of the generalized Chebyshev function and the quasi-band-pass joint is also discussed, and the realization of the multi-pass filter is also studied. By loading open branch section on three step impedance resonators, a double pass band filter is synthesized and designed. On the basis of this, a wide stopband double band filter is designed by fine-tuning impedance ratio and improving the feed mode. A double pass band filter with UWB external suppression is realized by etching the defective ground structure on the ground surface. Then, two cross-coupling paths are constructed by using two-section SIR and QWR. At the same time, the three-way band filter is designed by using the DGS structure to control the coupling coefficient accurately. Eight transmission zeros are generated, and the high frequency selection characteristics and out-of-band suppression are obtained. Finally, a highly selective reconfigurable double pass band filter is designed by using the quasi band-pass node cascade. The coupling between the NRN and the traditional resonator is used instead of the coupling between the traditional resonators, which improves the frequency modulation range of the filter. The center frequency and transmission zero of the filter can be adjusted by adjusting the tunable film capacitance. The out-of-band suppression of the filter is more than 60 dB, and in some cases, the suppression degree can even reach 78 dB. In this paper, EM simulation software is used to design the filter, and the standard PCB process is used to process the filter. Finally, HP8510B vector network analyzer is used to test the filter. The test data are in good agreement with the simulation results, which proves the rationality and feasibility of the design scheme proposed in this paper.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN713

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