一种微波多工器的网络综合方法研究

在滤波器多项式综合基础上,将多项式综合技术在多工器上做了推广,将传统的多项式综合技术从传统的双端口网络拓展到多端口网络,并且给出综合实例。该方法是在归一化频率中综合考虑各路滤波器之间的相互影响,运用迭代算法综合得到多工器的的特征多项式。最终综合结果满足设计指标,同时也验证了这种方法的可行性。     

频变耦合双工器的快速综合方法

为了解决频变耦合双工器的快速综合问题，提出了一种耦合矩阵优化综合方法.该方法分通道滤波器综合和优化两个阶段.首先应用推导的双工器特征多项式迭代求解出各通道滤波器的特征多项式，并应用耦合矩阵综合法计算出各通道滤波器的规范耦合矩阵.然后，根据指定的频变耦合拓扑结构，优化逼近规范耦合矩阵.最后，反归一化双工器的频变耦合矩阵得到最终设计参数.电路仿真结果与理论综合结果一致，表明了所提方法的正确性和有效性.该频变耦合双工器快速综合方法保持了较好的通带等波纹特性，且可以根据设计需要，任意指定各通道滤波器的频变耦合拓扑结构.     

滤波器腔间耦合系数快速提取方法

传统基于优化理论的耦合系数提取方法依赖于繁琐的优化程序,耗时长且收敛效果无法保证。对此,提出一种快速的耦合系数提取方法。该方法从单端输入阻抗的零极点角度进行分析,推导出滤波器的特征多项式与谐振频率与零极点的函数关系,并采用Matlab语言编程实现了耦合系数提取算法。应用该算法对4阶切比雪夫滤波器的耦合系数进行了提取分析,提取结果与理论结果吻合良好,证明了该方法的正确性和有效性。     

频变耦合双通带滤波器的综合方法

为了解决频变耦合双通带滤波器缺少有效综合方法的问题,文中提出一种优化综合方法.该方法首先通过频率变换技术得到滤波器在归一化双通带域内的特征多项式,然后应用经典的耦合矩阵综合方法得到双通带滤波器的全规范耦合矩阵,进而以矩阵的特征值为趋近目标构造目标函数,最后应用梯度优化算法进行优化获得了双通带滤波器的频变耦合矩阵.文中对...     

同轴腔带通滤波器的一种设计方法

采用负阻线子网络…构造了多腔耦合的同轴带通滤波器电路模型，应用电路分析软件对滤波器进行了分析优化，得到腔体之间耦合系数和接入点位置。应用三维全波分析软件，分析了腔体结构参数与耦合系数和耦合窗的关系。以这种路和场的仿真、优化相结合的方法，得出了滤波器的耦合和输入输出结构参数。运用该方法设计的中心频率2．4GHz，通带100MHz的六腔滤波器的实际测试结果与仿真分析结果基本一致。     

频变交叉耦合带通滤波器的耦合矩阵综合研究

综合代表滤波器拓扑结构和特性的耦合矩阵是交叉耦合滤波器设计的重点。提出了一种基于广义特征值的优化综合方法,通过非线性最小二次求解,将耦合矩阵的广义特征值逼近至广义切比雪夫响应多项式传输函数零极值参考点,优化求解出带有频变交叉耦合带通滤波器的耦合矩阵。通过3个数值实例演示了该方法,并验证其有效性。这是对经典带通滤波器耦合矩阵综合方法的补充,为频变交叉耦合滤波器的设计建立了基础。     

一种微波三工器的电路网络综合方法

提出一种微波三工器电路网络综合的新方法,该方法同时考虑微波三工器中波导T型结电路模型和各通道滤波器相互之间的影响.与传统方法相比,该方法模型更接近实际模型.推导了含有波导T型结的微波三工器综合的公式,根据设计指标进行多项式迭代,获得微波三工器的传输及反射S参数,将多项式模型转换为电路模型,开展了仿真试验,电路项目响应与多项式响应吻合较好,证实该方法可行.     

信道数目可拓展的新型微带多工器设计

提出了一种新型结构的多工器,能够任意拓展信道数目,同时具有较小的体积,弥补了传统结构的微带多工器信道数目较小的缺陷。该结构利用一条馈线作为输入端,各信道滤波器通过与该馈线的耦合合并在一起。信道合并时所带来的相互干扰可以通过调节各信道部分参数来弥补,不需要额外的补偿电路,缩减了多工器的尺寸;而且当输入馈线被延长时,可以添加更多的信道。提出了新的多工器综合方法及空间映射法,基于此方法设计并制作了一个微带六工器,中心频率3.97 GHz,各信道均为3阶切比雪夫滤波器,带宽80 MHz,信道间隔100MHz,实物测试的插入损耗约为3.6 d B,回波损耗约为14 d B。实验结果验证了本文提出的设计方法。     

广义耦合矩阵在多工器设计中的应用

介绍一种新型的适用于耦合谐振器网络的多端口耦合矩阵,它是对过去的双端口网络耦合矩阵的推广。应用多端口网络耦合矩阵可以方便地优化综合多工器,这样得到的多工器由于没有额外的消抗网络,相比过去的设计方案要小型而紧凑得多。通过仿真试验,验证了其有效性,及与理论的一致性。     

Ku波段交叉耦合波导滤波器的精确设计

针对软件优化法设计交叉耦合波导滤波器的耗时性,利用矩形波导设计了Ku波段折叠型交叉耦合滤波器。采用S参数的多项式综合和矩阵消零的方法提取耦合矩阵,设计过程将全波建模和电路模型分析相结合,利用微波CAD软件HFSS分步骤对每个谐振单元及耦合结构进行仿真,以确定其尺寸,避免了对滤波器的软件优化,所得仿真结果与理论值吻合较好。     

Scattering matrix approach for the design of microwave filters

A synthesis procedure, based on a distributed parameter model, for the design of microwave filters is presented in this paper. The frequency response of the filter is described in terms of the characteristic polynomial T₂₁=S₁₁/S₂₁ where S₁₁ and S₂₁ are the scattering parameters of the filter. Starting from the desired polynomial T₂₁, the design scheme directly yields the scattering parameters of the various junctions, which can be realized by any kind of discontinuity. The capability of synthesizing an arbitrary frequency response allows one to introduce the concept of a “predistorted” characteristic polynomial in order to compensate for the degradations caused by multimodal interactions, frequency dispersion, etc. Comparison with measured data of a Chebyshev-like eight-pole E-plane filter confirms the validity of the method also in the presence of losses     

Microwave Networks with Equiripple Delay Characteristics

The problem of finding a characteristic polynomial to provide equiripple delay characteristics in commensurate TEM microwave networks is solved numerically. These polynomials enable the synthesis of such filters in the form of cascaded transmission lines or in the form of stub filters to be undertaken. Results for the orders 2 through 6 are presented. The synthesis of constant delay all-pass networks can also be performed and the method for doing so is presented. The attenuation characteristic corresponding to the equiripple delay filter does not, of course, possess a sharp cutoff, since these filters are of the minimum phase type.     

内嵌光栅微环型三维立体功分/波分器

基于消逝场耦合原理、微环谐振原理和光栅反射原理,设计了一种内嵌光栅微环型三维立体功分/波分器结构。该结构采用以内嵌光栅的微环滤波层为中间层,上下两层输出波导层关于中间层对称的三维立体集成结构,使得器件同时具有滤波和功分的功能,提高了器件的集成度,级联光栅的嵌入则提高了器件的滤波特性。理论分析结果表明,该器件结构具有良好的滤波特性,并且能实现3种不同功率光信号输出。     

Design of IIR Notch Filter with Approximately Linear Phase

A method for design of linear phase notch IIR filters is presented in this paper. The filter is realized in the form of a?parallel connection of two all-pass sub-filters. In order to achieve the resulting filter with an approximately linear phase in the pass-band, the applied all-pass sub-filters should be also with a?linear phase. The desired amplitude characteristic of a?resulting filter is obtained by all-pass sub-filter phase approximation. It can be achieved by applying either a?pure delay or an IIR all-pass filter in one branch. If a?pure delay is positioned in one branch, equiripple phase of all-pass sub-filter from the other branch is guaranteed for an equiripple amplitude characteristic of the resulting filter. Efficiency of the proposed algorithm is demonstrated on a?few examples. The algorithm exhibits a?fast convergence and an easy determination of initial values. In the case where IIR all-pass sub-filters are placed in both branches, the resulting amplitude characteristic satisfies all the prescribed demands, but the amplitude characteristic is not equiripple even when both all-pass sub-filters have equiripple phase.     

A Direct Synthesis Approach for Microwave Filters With a Complex Load and Its Application to Direct Diplexer Design

This paper presents a direct synthesis approach for general Chebyshev filters terminated with a complex load. The new approach is based on the fact that the polynomial functions for synthesizing the filters are composed for any matched loads. By normalizing the polynomial functions with assumed complex matched load impedance by a real reference load impedance using power waves normalization, a set of new polynomial functions for the same filter, but with real load impedance, can be formulated, from which the coupling matrix for the physical filter design can be obtained using a standard direct filter synthesis approach. This new direct synthesis approach can find many applications. A practical application is the direct diplexer design with a realistic junction model being taken into account. With the diplexer design is concerned, a fast-converged iterative scheme is proposed. The effectiveness and the validation of the proposed scheme are demonstrated by two design examples     

一种数字全通滤波器的设计方法研究

研究了一种数字全通滤波器的设计方法.对于一个平稳的全通滤波器,其分母多项式一定具有最小相位.该方法是基于最小相位滤波器的复倒谱系数和其群迟延函数以及其系统函数之间的关系,通过一个非线性的递归方程求解分母多项式的系数.由全通滤波器的特性已知,分母系数可以完全决定全通滤波器的传递函数.仿真结果表明这种方法能够使所设计滤波器的群延迟特性在整个频率范围内以近似理想的群延迟特性存在.并结合实现提出了一种用FIR逼近IIR的方法.     

Synthesis of Wideband Linear-Phase FIR Filters with a Piecewise-Polynomial-Sinusoidal Impulse Response

A method is presented to synthesize wideband linear-phase finite-impulse-response (FIR) filters with a piecewise-polynomial-sinusoidal impulse response. The method is based on merging the earlier synthesis scheme proposed by the authors to design piecewise-polynomial filters with the method proposed by Chu and Burrus. The method uses an arbitrary number of separately generated center coefficients instead of only one or none as used in the method by Chu–Burrus. The desired impulse response is created by using a parallel connection of several filter branches and by adding an arbitrary number of center coefficients to form it. This method is especially effective for designing Hilbert transformers by using Type 4 linear-phase FIR filters, where only real-valued multipliers are needed in the implementation. The arithmetic complexity is proportional to the number of branches, the common polynomial order for each branch, and the number of separate center coefficients. For other linear-phase FIR filter types the arithmetic complexity depends additionally on the number of complex multipliers. Examples are given to illustrate the benefits of this method compared to the frequency-response masking (FRM) technique with regard to reducing the number of coefficients as well as arithmetic complexity.     

微波双工器电路综合

近年微波滤波器多项式综合技被广泛用于微波滤波器的设计,将此技术由双端口网络推广至三端口网络可以实现微波双工器的综合。根据微波网络技术,可以推导得到微波双工器电路等效y参数与S参数的关系,进而得到微波双工器散射参数s11,s21,s31与两个通道单通带微波滤波器散射参数s11,s21的关系。应用推广后的微波双工器电路综合技术可以实现微波双工器的精确、快速综合。经过对比发现,微波双工器多项式综合结果与微波双工器电路建模仿真响应吻合度很好。