【作者】 杨瑾屏；

【导师】 吴文；

【作者基本信息】 南京理工大学 ， 通信与信息系统， 2009， 博士

【摘要】 局域电磁带隙结构单元具有显著的慢波效应和谐振带隙特性,并采用非周期形式排布,已被广泛应用于各种微波电路和微波通信系统,是目前国内外微波技术领域的研究热点之一。本文重点对缺陷接地结构和谐振加载耦合线单元这两类局域电磁带隙结构的理论分析及其在低通滤波器、带通滤波器和功分器等电路设计中的应用进行研究,具体研究内容包括如下几个方面:1.建立了螺旋型缺陷接地结构的四阶等效电路模型和易于综合的三阶等效电路模型,从而提高螺旋型缺陷接地结构的设计效率;利用奇偶模方法分析并建立了加载了缺陷接地结构的耦合微带线的奇偶模等效电路模型,为缺陷接地结构在多端口电路设计中的应用奠定了基础。2.在切比雪夫原型滤波器基础上引入衰减极点来获得准椭圆低通滤波器的集总参数电路,并分别采用哑铃型和螺旋型缺陷接地结构实现其串联支路电感和高外Q值LC并联谐振电路,再采用加宽微带线实现其并联支路电容,从而获得了整体结构紧凑,具有良好的频率选择性及宽阻带特性的准椭圆低通滤波器。3、通过在耦合微带线功分器中加载缺陷接地结构和集总电容实现了具有谐波抑制功能的小型化功分器设计,同时该功分器还具有非π/2的相移特性;在多节阻抗变换器基础上嵌入螺旋型缺陷地结构以满足功分器所需阻抗和相位条件,从而实现了在两个任选的工作频率上同时具有良好功率传输、匹配和隔离特性的双频功分器设计。4.建立了开路短截线加载耦合微带线单元的奇偶模等效电路模型,并利用等效电路模型分析了该结构的电磁带隙特性。在此基础上采用开路短截线加载耦合微带线单元设计巴特沃斯和切比雪夫响应低通滤波器。仿真和测试结果表明该滤波器具有良好的选频特性和较宽的阻带。5.采用开路和短路短截线加载耦合微带线单元设计窄带带通滤波器。该滤波器可以同时抑制三个高次谐波。更多还原

【Abstract】 In recent years, Localized electromagnetic band-gap structures (LEBGs) have been widely used in research and application fields of communication because of their remarkable slow wave effect, resonant bandgap characteristics, and non-periodic structures. This dissertation focuses on two kinds of LEBGs: Defected Ground Structure (DGS) and Resonator Loaded Coupled-Line Cell (RCLC). Main works include modeling of LEBGs and their applications to the filters, power dividers (PDs) and harmonic suppressing:First, a four-order equivalent circuit model of the spiral shaped defected ground structures (SP-DGS) and a simplified three-order equivalent circuit model of SP-DGS are developed, which can be applied directly to improve designs of microwave circuits. An even-/odd- mode equivalent circuit model of the coupled-lines on a defected ground is also investigated, which is important to develop multi-port network applications based on DGSs.Second, a compact Quasi-Elliptic lowpass filter (QE-LPF) is proposed, whose lumped topology is derived from the Chebyshev prototype circuits by introducing an attenuation pole. Inductances in series branch circuits of QE-LPF are realized by dumb-bell shaped defected ground structures (DB-DGSs), while the high external quality factor of LC parallel resonance circuits in series branch circuits are achieved by SP-DGSs. And shunt capacitances are implemented by broadened microstrip lines.Then, a novel compact coupled microstrip PD with harmonic suppression is designed, which consists of a pair of coupled-lines on a defected ground. Two outputs of the PD are connected by a resistor and a capacitor. The non-π/2 phase-shifts between the input and outputs are also discussed. A novel dual-band PD is further developed, which consists of a multi-section impedance transformer integrated with a SP-DGS. By properly utilizing SP-DGS, a PD has been implemented with desirable characteristics such as an equal power split, impedance matching at all ports, and a good isolation between output ports at two arbitrary given frequencies simultaneously.Furthermore, an even-/odd- mode equivalent circuit model of the Open Stub Resonator Loaded Coupled-Line Cell (OS-RCLC) is proposed and used to analyze the bandgap effect of OS-RCLC. Utilizing this configuration, Butterworth response and Chebyshev response LPFs are designed.Finally, a compact narrow band-pass filter using OS-RCLC and short stubs is presented. The passbands are determined by the short stubs, and the multi-harmonic suppression is achieved with introducing transmission zeros of OS-RCLC.更多还原