【作者】 王学东；

【导师】 李英；

【作者基本信息】 上海大学 ， 无线电物理， 2004， 博士

【摘要】 近年来随着移动通信与个人通信业务的飞速发展和集成电路的高度集成化，作为无线通信系统必不可少的部件之一的滤波器正向小型化发展，同时，随着电子计算机的蓬勃发展，时域有限差分法(FDTD)正成为分析这类电磁问题的强有力工具。本论文提出了几种新颖的小型化，高性能微波滤波器设计，并用FDTD法做了分析和研究。论文主要包括以下内容： 首先，主要讨论了时域有限差分方法，基于波动方程基础的时域有限差分方法以及对这种方法的发展。提出的新方法需要的计算时间更少，计算效率更高。 其次，介绍了γ_g／4，γ_g／2和γ_gSIR的基本结构。随后，系统地讨论SIR的一些基本特性如：谐振条件、谐振长度、杂散谐振频率和等效电路等。 第三，提出一种抽头式阶梯阻抗带通滤波器，通过在谐振器开路端引入耦合电容，增强两个谐振器之间的耦合，使通带带宽变宽，通带衰减减小，在不改变体积的情况下，使滤波性能得到提高；提出一种新颖的采用阶梯阻抗抽头式带通滤波器，体积只是原来的60％左右，然而性能比以前好；设计出一种抑制寄生通带的多层陶瓷滤波器，这种滤波器采用短路阶梯阻抗谐振器，在减小体积、减小插入损耗的情况下，有效地抑制滤波器的寄生通带，加宽滤波器的阻带；提出一种小型化旋转对称阶梯阻抗滤波器，利用旋转对称结构，有效地消除了阻抗比对滤波器体积的影响。 最后，提出一种新颖、小型、简单的微带贴片带通滤波器结构。这种结构仅用一个谐振器实现了通带两端各有一个衰减极点，但体积是传统滤波器的1／2—1／3。这种结构中，没有耦合缝隙，可以减小制作过程中的不确定性：设计出一种结构新颖、简单的方形贴片双模滤波器。这种滤波器只有一个贴片，没有耦合缝隙，通过改变输入输出抽头的位置，可以使滤波器的通带任何一侧都有衰减极点；设计了一种不带耦合缝隙的双模椭圆函数滤波器。更多还原

【Abstract】 In recent years with the fast development of mobile communications, personal communications and the high integration of integrated circuits, microwave filter as one of the necessarily equipments in wireless communications systems, are becoming smaller and smaller. At the same time, with the fast development of computers, finite-difference time-domain (FDTD) method is becoming a powerful tool of analyzing these electromagnetic problems. In this dissertation, several novel miniaturized or high performance microwave filters are presented and FDTD analysis of some filters is studied. The dissertation is classified into four parts stated as follows.Firstly, introduces FDTD and presents a novel FDTD method. The FDTD formulation, based on wave equation, employs approximation techniques. The proposed algorithm uses much shorter time than the standard FDTD method. This method has much higher efficiency.Secondly, g / 4, g / 2 and g type transmission-line stepped impedance resonators (SIR’s) have been introduced, standardizes these three types of SIR’s and systematically summarizes their fundamental characteristics, such as resonance conditions, resonator length, spurious (higher order) responses, and equivalent circuits.Thirdly, a tapped bandpass filter composed of two coupled stepped-impedance resonators (SIR) is proposed . A coupling capacitor located at the end of resonators is introduced, by which strong coupling between them can be achieved, thus, a wider passband and lower insert loss can be realized. The performance is improved while the volume keeps no changes; A novel laminated bandpass filter composed of two SIR is proposed. The volume of proposed filter is about 60% of conventional filter while the performance is better than the former, describes the design of a compact stripline ceramic filter. Using short-circuit SIRs, this structure can restrain parasitical passband availably with decreasing volume and inserted losses of filter; A new compact SIR filter is proposed, in which impedance ratio has no impact on the volume. By reversing one of two resonators, the size of the filter is much smaller.Lastly, presents a new compact and simple microstrip patch bandpass filter structure using only one resonator. This filter has two transmission zeros on the both sides of the passband. The volume of this filter is about 1/3 or 1/2 of conventional filter. Without coupling gaps, the new filter can reduce uncertainty in fabrication; A class of new planar dual-mode filters using one square single patch without coupling gaps are proposed. Transmission zeros can be implemented on the either side of the passband by changing the locations of two feed lines. A novel dual-mode elliptic-function bandpass filter structure without coupling gaps is also proposed.更多还原