General Coupling Matrix Synthesis Method for Microwave Resonator Filters of Arbitrary Topology

This letter presents a new approach to synthesize the resonator filters of an arbitrary topology. This method employs an optimization method based on the relation between the polynomial coefficients of the transfer function and those of the S₂₁ from the coupling matrix. Therefore, this new method can also be applied to self‐equalized filters that were not considered in the conventional optimization methods. Two microwave filters, a symmetric 4‐pole filter with four transmission zeros (TZs) and an asymmetric 8‐pole filter with seven TZs, are synthesized using the present method for validation. Excellent agreement between the response of the transfer function and that of the synthesized S₂₁ from the coupling matrix is shown.     

Synthesis of Optical Filters Using Sagnac Interferometer in Ring Resonator

We propose a new synthesis method for the implementation of infinite impulse response filters, using a Sagnac interferometer within a ring resonator. This structure permits the synthesis of second-order optical functions per stage. We present the parameters of the structure, which are related to the poles position, radial and azimuthal, and the design procedure, with an example of an autorregresive filter.     

基于嵌套缺陷地谐振器的紧凑型多通带滤波器*

根据双模缺陷地谐振器(DDGSR)在结构上易于嵌套实现多通带滤波器的独特优势,以及通过馈线中加上枝节线引入传输零点改善高频阻带特性的方法,提出了一种新颖的具有较陡边带和较宽高阻带特性的四通带滤波器。一节DDGSR 包含一个槽线谐振器(SLR)和一个缺陷地阶跃阻抗谐振器(DSIR),运用具有四节双模缺陷地谐振器的嵌套双模缺陷地谐振器结构,并通过仿真软件优化结构参数设计并制作了GPS(1.57GHz)、DCS(1.8GHz)、WLAN(2.4GHz)、WiMAX(3. 5GHz)频段的四通带滤波器。测试结果表明,四个通带中心频率分别为1. 58/1.8/2.42/3.58GHz,3dB 带宽为8.2/5/5.4/6.7%,带内插损最小值为1.2/1.6/1.6/2.6dB。设计与测试结果良好的一致性验证了理论的准确性。     

Design of Real FIR Filters With Arbitrary Magnitude and Phase Specifications Using a Neural-Based Approach

An efficient and yet simple neural-based approach is utilized to design real finite-impulse response filters with arbitrary complex frequency responses in the least-squares sense. The proposed approach establishes the quadratic error difference of the filter optimization in the frequency domain as the Lyapunov energy function. Consequently, the optimal filter coefficients are obtained with good performance and fast convergence speed. To achieve good convergences for large filter lengths, a cooling process of simulated annealing is used for the neural activation function. Several examples and comparisons to the existing methods are presented to illustrate the effectiveness and flexibility of the neural-based method     

Programmable Photonic Microwave Filters With Arbitrary Ultra-Wideband Phase Response

We present a coherent optical signal-processing approach for synthesis of programmable microwave phase filters over an ultra-wideband. Our scheme relies on a programmable optical phase filter implemented in a pulse-shaping geometry incorporating a spatial light modulator and hyperfine (~600-MHz spectral resolution) optical spectral disperser. The user-defined optical phase filter is directly transferred to the electrical domain through heterodyne conversion, and the overall system response is characterized via vector network analyzer measurements. We illustrate our approach by synthesizing linear, quadratic, and cubic spectral phase functions over a 20-GHz band. To our best knowledge, this is the first realization of programmable arbitrary microwave phase filters over such a bandwidth     

微型化Ka波段环形带线谐振腔LTCC带通滤波器

提出了一种微型化Ka频段带线带通滤波器设计方案.采用带有调谐枝节的环形谐振腔和带线耦合结构,利用低温共烧陶瓷(LTCC)技术设计并研制了一个相对带宽约10.4%的Ka频段带通滤波器,典型性能为在中心频率26.99 GHz处插入损耗小于1.3 dB,带内驻波比小于1.20:1,损耗起伏小于0.30 dB,滤波器的尺寸为4...     

Design of Microwave Filters With Arbitrary Frequency Response Based on Digital Methods

This letter presents a novel general technique for the design of microwave filters with arbitrary frequency response. It is based on the translation of the microwave specifications to the digital domain, where the well known and readily available digital filter design techniques are applied. By means of these digital techniques, the method provides a straightforward procedure to calculate the poles and zeros corresponding to the analog frequency response that satisfies the target specifications. From the poles and zeros, the microwave filter can be readily obtained using conventional techniques. As an example to demonstrate the proposed technique, a filter with user-defined specifications over two independent passbands has been implemented and successfully tested in microstrip technology.     

Multitap Photonic Microwave Filters With Arbitrary Positive and Negative Coefficients Using a Polarization Modulator and an Optical Polarizer

A novel multitap photonic microwave filter with arbitrary positive and negative coefficients implemented using an electrooptic polarization modulator (PolM) and an optical polarizer is proposed and experimentally demonstrated. In the proposed filter, the optical polarizer is connected at the output of the PolM with its transmission axis aligned at an angle of 45 to one principal axis of the PolM. By adjusting the polarization direction of the input lightwave to be 45 or 135 to one principal axis of the PolM, an inverted or noninverted intensity-modulated optical microwave signal is obtained at the output of the optical polarizer, which leads to the generation of a negative or positive coefficient. A time delay difference between adjacent taps is generated by using a wavelength-dependent delay line. A five-tap photonic microwave filter with arbitrary positive and negative coefficients is demonstrated. The reconfigurability of the filter is also investigated.     

Miniaturized Dual-Band Hybrid Couplers With Arbitrary Power Division Ratios

Branch-line and rat-race couplers are designed to have dual-band operation with arbitrary power division ratios. An elementary two-port is proposed to imitate the 90^deg section at the two designated frequencies with different characteristic impedances. The two-port consists of a stepped-impedance section with open stubs attached to its two ends, and its circuit parameters are determined by the transmission line theory. The use of the stepped-impedance sections also leads to circuit miniaturization. By the standard microstrip technology, investigated also includes the realizable power division ratios and circuit bandwidths in the two bands, the upper limit of the ratio of the two designated frequencies and the miniaturization factor of the proposed circuit. Hybrid couplers operating at 2.45/5.2 GHz with various power division ratios are designed, fabricated and tested. Experiment results are compared with the theory and simulation.     

波导微环共振滤波器的滤波特性分析

根据波导耦合模理论详细研究了微环共振滤波器的滤波特性,分析了单环、串联双环、串联三环结构等波导微环共振滤波器的滤波特点。通过模拟计算发现,滤波带宽平坦化程度和信道串扰大小主要依赖于由波导构成的各方向耦合器之间的功率耦合比k,同时微环波导的损耗是器件滤波特性劣化的重要原因。在一定优化参数条件下,多环结构的滤波效果优于传统单环结构,并且各方向耦合器功率耦合比k值的优化取值范围扩大,降低了器件工艺实现难度。     

任意阶正则线性相位小波滤波器的特征滤波器设计方法

小波滤波器的设计是小波分析的关键，本文给出了任意阶正则线性相位近正交小波滤波器的特征滤波器设计方法。     

Synthesis of Combline and Capacitively Loaded Interdigital Bandpass Filters of Arbitrary Bandwidth

Synthesis procedures are presented for commensurate linelength combline and capacitively loaded interdigital filters. A simple modification for using lumped capacitors is given and is found to yield excellent results for any practical bandwidth. The synthesis procedures for both filter types follow directly from the classical bandpass filter design approach using a transformed frequency variable. Two design examples are given to illustrate the design procedures and experimental results are presented for a 40 percent bandwidth combline filter. The problems of network sensitivity, use of network equivalents, and extension to other filter types are also discussed.     

一种任意阵的方向图综合方法

该文提出一种新的基于优化理论的方向图综合算法。该方法先利用与相位无关的约束得到期望主瓣,再利用优化方法求解残余权矢量获得期望旁瓣,使残余权矢量对主瓣的影响控制在一定范围内,优化问题可看作是二次锥规划(SOCP)。与传统的对模值和相位均进行约束的综合方法相比,该方法要求综合期望方向图的模值,不仅能够有效地获取期望方向图,而且主瓣控制机制与参考点的选取无关。对多种任意阵的仿真结果证明该方法的有效性和正确性。     

Design of Defected Ground Structure Band Stop/Band Pass Filters Using Dielectric Resonator

Wireless Personal Communications - MultiACK-Slotted Floor Acquisition Multiple Access (MultiACK-SFAMA) is a medium access control (MAC) protocol that has been proposed for underwater acoustic...     

任意型一维FIR数字滤波器设计新方法

本文介绍了一种设计任意型（宽带、窄带、低阶、高阶、低通、高通、带通、带阻）一维FIR数字滤波器新方法．给出设计不同类型滤波器的统一方法。各种类型滤波器脉冲响应的设计公式简单、计算方便。该方法消除了Gibbs现象．不仅克服了优化设计中收敛速度、设计精度及初值选取等问题，而且减少设计高阶滤波器的时间。最后，本文给出了各种类型滤波器设计的仿真结果。     

任意阶CCCII-C多功能滤波器的设计

提出了一种基于电流控制传送器(CCCII)任意阶多功能滤波器的设计方法。该方法导出的滤波器具有最少的元件,n阶滤波器仅需n个CCCIIs和n个电容,且所有的电容均接地,便于集成且与VLSI工艺兼容。完成了2阶多功能滤波器和6阶带通滤波器的PSpice仿真,理论分析和计算机仿真表明所提电路方案正确可行。     

任意阶OTA-C多功能滤波器的设计。

提出了一种新的任意阶运算跨导放大器——电容(OTA-C)多功能滤波器的设计方法。通过将n阶传递函数分解为n+1个一阶传递函数,导出了任意阶传递函数OTA-C实现电路。适当选择各输入端电压,可实现低通、高通、带通、带阻、全通等滤波功能。文中给出了6阶滤波器设计实例,PSPICE仿真结果与理论分析相吻合,验证了设计方法的可行性。     

聚合物微环谐振滤波器特性的研究

利用耦合模理论,计算了聚合物微环谐振滤波器的通路和下话路的传输函数,分析了耦合系数和损耗对传输函数的影响,并推导出了谐振滤波器的谐振波长、自由光谱范围、腔的品质因子、半峰全宽和精细度等特性参数,分析了不同的滤波器结构参数(如环形半径和有效折射率)对滤波特性的影响.     

Design of Optical Circuit Devices Using Topology Optimization Method With Function-Expansion- Based Refractive Index Distribution

We propose a design method for optical waveguide devices based on topology optimization with alternative expression of refractive index distribution. In our approach, a refractive index distribution in a design region is expressed by an expansion with some analytical functions and gray area, which has intermediate refractive index between usable materials, does not appear. We can obtain better results in the optimization of waveguide bends and branches, compared with the widely used density method.