一种微波带通滤波器的快速设计及仿真

介绍一种快速简便的微波带通滤波器的设计方法。通过计算几个典型的带通滤波器的归一化杆径和归一化间距，给制出分别以相对带宽为横坐标，归一化杆径和归一化间距为纵坐标的快速简便的微波带通滤波器的设计曲线，用ANSOFT-HFSS仿真软件对微波带通滤波器进行结构仿真和优化，得到满意的滤波器结构设计尺寸。     

一种抽头式交指带通滤波器的设计及实现

传统的交指带通滤波器设计采用公式计算归一化自电容和互电容,并通过查表计算得到滤波器的参数,该方法计算繁琐,且计算误差较大.文中介绍了一种根据谐振器的直接耦合原理,利用两终端的外部品质因数Q和谐振器间的耦合系数K设计抽头式交指型带通滤波器的方法.据此,设计了一种用于微波选频的交指滤波器,借助ADS软件对滤波器进行仿真和优化.通过仿真及实测结果的分析对比,进一步给出了设计改进方案.     

波导带通滤波器的精确设计和快速优化

介绍了采用三维微波电磁场仿真软件快速提取直接耦合波导带通滤波器耦合窗口参数的方法,并提出了优化最终模型的快速扫描技术.全波仿真及实验结果表明,该方法能满足波导带通滤波器快速精确设计的要求.     

硅衬底上射频无源低通滤波器的设计及版图实现

文章系统地研究了微波无源低通滤波器的设计原理及其设计方法。根据网络综合法，设计出了一个—3dB截止频率为1．2GHz的2阶低通无源滤波器，其器件参数C1、L1、C2分别为2．56pF、13．252nH和2．56pF。采用自行设计的算法，编制了相应的Matlab程序，计算出滤波嚣的版图结构参数。最后，用ADS软件对该滤波器进行了版图级的模拟验证。结果表明，该微波无源滤波器的散射参数曲线与理想元件所组成的滤波器的散射曲线相吻合，且性能好，能够满足实际应用的需要。     

小体积微波滤波器的设计

微波滤波器广泛运用在各种通信系统中。如何设计体积小重量轻,功率容量大,电气性能指标好的微波滤波器成为工程师们最关注的问题。这里设计了中心频率为1 675 MHz的小体积窄带圆杆梳状线带通滤波器。设计过程中采用了等效电路原理方法计算滤波器尺寸的初值,并用CST软件进行了耦合系数的计算和S参数的优化,提高了设计的速度和准确度。由于采用了较大电容加载,所设计的滤波器体积小,结构紧凑;由于采用圆杆结构因此加工方便,做到了一次加工成型,成本非常低廉。将滤波器的仿真曲线和实测曲线进行了比较,两者基本吻合,实测曲线完全满足电气指标要求。     

园杆梳状线微波带通滤波器的研制

给出了一种中心频率为1.675GHz园杆梳状线微波带通滤波器的设计过程.设计方法采用等效电路原理,并用HFSS软件仿真优化.所设计滤波器采用园杆梳状线结构,其结构紧凑,体积小,便于加工.文中将实测曲线和仿真曲线进行了比较,二者吻合很好.     

微带带通滤波器CAD仿真

论述了应用Ansoft公司的designer微波仿真软件来设计微波带通滤波器的方法,给出了通过增加四个90°拐角来使微带带通滤波器结构更加紧凑,并使其保持良好性能的实现方案。仿真结果表明,利用此软件结果设计出的滤波器具有良好的滤波性能,而且一致性好。     

一种UHF带通滤波器的设计

为了掌握微波滤波器的制作原理及设计方法,实现一种UHF波段带通滤波器的设计和制作。该设计采用了既定指标确定滤波器的形式（椭圆函数LC带通滤波器）,以椭圆函数为理论基础,通过软件仿真、版图制作、加工,并通过矢量网络分析仪进行调试、测试,从而制作成功满足指标的UHF波段带通滤波器。要设计一个滤波器,首先要分析滤波器的技术指标,选择合适的滤波器形式,确定滤波器的级数,分析滤波器的带外特性以及通带特性,估算滤波器中心衰减和带外抑制的大小,对滤波器进行合理的设计与计算,最后要对滤波器进行仿真优化,直至达到满意的技术指标。     

一种S波段窄带带通滤波器的设计和优化

本文应用Serenade8.71微波仿真软件,设计和优化了一种中心频率为3GHz、带宽20%的S波段耦合微带线带通滤波器。结果表明,利用该软件设计出的滤波器完全符合设计要求,而且方便、快速,适用于工程设计。     

吸收型准高斯带通滤波器的研制

在数字及高速率信号传输系统中,经常采用Bessel或Gaussian函数滤波器,该类滤波器只有在中心频率(带通滤波器)或DC处(低通滤波器)才有良好的匹配特性,在其他频点都有很大的反射,在微波电路的级联中会产生杂波和干扰。为了解决该问题,设计了一种在通带和阻带内都有很小反射的滤波器,即吸收型(匹配型)准高斯类带通滤波器。介绍了其设计过程及方法,并设计了一种中心频率为100 MHz的吸收型准高斯带通滤波器,给出了仿真结果和实测曲线,实测结果与仿真结果吻合得很好。     

变容管电调微波带通滤波器

本文叙述采用梳状线结构的变容管电调微波带通滤波器的设计理论和方法。推导出梳状线带通滤波器的输入、输出耦合网络的参数条件,以补偿带通滤波器的谐振器之间电磁耦合随不同调谐频率的变化;并给出使带通滤波器的绝对带宽或通带回波损耗在调谐频率范围内变化最小时,梳状线谐振器的电长度应满足的相应条件,由此来保证电调带通滤波器在较宽的调谐频率范围内具有较高的通带回波损耗,且保持带通滤波器的响应形状和绝对带宽基本不变。此外,还讨论了由电调变容管的Q值引起的带通滤波器的通带有功损耗问题。文中给出了具体的设计公式。最后,给出了一个L波段变容管电调带通滤波器的研制实例和测试结果。     

Analysis and Composition of a New Microwave Filter Configuration with Inhomogeneous Dielectric Medium

A theoretical study has been undertaken to solve inter-resonator coupling problems, and to design a new structure of microwave bandpass filter. This filter is composed of quarter-wavelength resonators arranged in a housing with the same ends short-circuited. This arrangement of resonators has never been utilized to compose bandpass filters because of the small inter-resonator coupling. The coupling coefficient of TEM resonant lines has been derived theoretically and expressed with capacitive parameters of the coupled lines. The accurate values of capacitances of the lines were obtained by the numerical analysis of the TEM field. By a simple method to make the medium inhomogeneous through removing the dielectric partially, a simplified structure of filter has first been realized based on the theory. Through numerical analysis by the finite difference method, this structure is also shown to have higher unloaded Q of resonator than conventional dielectric-filled coaxial filters to minimize the volume of filters.     

The Half-Wave Stepped Digital Elliptic Filter

A design procedure for narrow-band bandpass TEM-line elliptic-function filters is presented. The proposed realization is in the form of a stepped-impedance digital n-wire line which is one-half of a wavelength long at midband and short circuited to ground at both ends, where the digital line is stepped in impedance along any arbitrary prescribed plane in the filter. Due to its physical form and mode of electrical operation, the filter has been termed the half-wave stepped digital elliptic filter. A detailed design procedure for the construction of the two characteristic admittance matrices which describe the digital n-wire line from the low-pass prototype element values is presented. It is also shown that the normalized impedance values of the elements in the filter are all of the order of unity and independent of the actual bandwidth of the falter except for the input and output transformer elements. A numerical example and experimental results on a seventh-degree 1-percent bandwidth filter with a center frequency at 3.7 GHz are given, demonstrating the significant improvements which may be obtained from the half-wave stepped digital elliptic filter over most other known form of microwave TEM-line narrow-band bandpass filter.     

Dual-band bandpass filters using equal-length coupled-serial-shunted lines and Z-transform technique

A synthesizing method is presented to design and implement digital dual-band filters in the microwave frequency range. A dual-band filter consists of a bandstop filter and a wide-band bandpass filter in a cascade connection, wherein the transfer functions of both the bandpass filter and bandstop filter are expressed in the Z domain. The bandstop filter is implemented by using a coupled-serial-shunted line structure, while the wide-band bandpass filter is constructed by using a serial-shunted line configuration. In particular, the bandwidth of each passband of the dual-band filter is controllable by adjusting the characteristics of both the bandpass filter and bandstop filter. By neglecting the dispersion effect between microstrip lines of different widths over a wide bandwidth, a dual-band filter is realized in the form of microstrip lines and its frequency responses are measured to validate this method.     

A New Approach to Computing Distortion of an FM Single-Tone Modulated Signal Due to Ideal Filtering

By factorizing a finite sum of harmonics, an expression is obtained for an FM demodulator output when the modulating signal is a simple sinusoid and the RF filter is an ideal bandpass filter. Using this result, harmonic distortions and the signal-to-distortion ratio are defined and computed; several curves are drawn to show the variation of these quantities in terms of the modulation index and the normalized bandwidth.     

A new compact microstrip two-layer bandpass filter using aperture-coupled SIR-hairpin resonators with transmission zeros

A new design of a compact two-layer bandpass filter using aperture-coupled microstrip stepped-impedance hairpin resonators is proposed and investigated in this paper. The proposed filter is composed of four stepped-impedance hairpin resonators located on two stacked microstrip layers, and the couplings between the resonators on the upper layer and those on the lower one are obtained by using three coupling apertures etched on a common ground plane placed between the two layers. In addition, the use of tapped input/output couplings allow this bandpass filter to generate two independent transmission zeros. A full-wave simulator is used to design the proposed structure and calculate the aperture coupling coefficients. With this two-layer configuration, the proposed filter becomes very compact and occupies a small space. To demonstrate the proposed design, a four-order bandpass-filter prototype was designed, fabricated, and tested at 2.14 GHz. Furthermore, a single-layer filter prototype was also designed and fabricated at the same frequency band and then compared to the first one. As a result, a significant reduction of approximately 50% was achieved. These features make the proposed structure suitable for compact and high-performance circuit component designs in microwave circuits.     

MNG传输线带通滤波器设计

为了以更简单的结构、更少的电路元件实现更好的左手媒质特性,设计了一种新型磁负介质传输线（MNG）。该传输线具有负的磁导率和正的介电常数,是对传统混合左右手（CRLH）传输线理论上的扩展和设计上的改进。采用该MNG传输线设计了一个切比雪夫带通滤渡器,获得任意可调的双频带特性,其仿真和测量结果吻合很好,验证了MNG传输线的设计理论。该MNG传输线所具有的非线性相位响应特性,可以实现耦合器、滤波器、双模天线等多种新颖的可调双频带微波器件的设计。     

一种设计小型滤波器的方法

体积更小、性能更高、成本更低且更易于大量生产是现在滤波器发展的趋势。体积的减小,使得滤波器的内部耦合的情况更加复杂和难以设计。提出一种设计小型滤波器的新方法,并设计了一个小型的微带环行阶跃阻抗(SIR)带通滤波器。这种方法就是先根据经验公式估算出了环行SIR单元的尺寸和抽头线位置;对Ansoft HFSS软件进行二次开发,利用遗传算法控制多台计算机上的Ansoft HFSS软件并行优化SIR单元的尺寸和抽头线位置。优化后的滤波器,满足设计指标,加工后进行实测,实测结果与仿真结果几乎完全一致。实验结果表明所提出的方法能准确、高效地设计一种设计小型滤波器。     

Reflective Amplified Recirculating Delay Line Bandpass Filter

A new microwave photonic filter structure that can achieve a high factor, high stopband rejection, and high skirt selectivity bandpass filter response simultaneously is presented. It is based on reflecting the signal back into a single amplified optical recirculating delay line and comprises coherent summation of the multiple signals that constitute each tap and incoherent summation of the successive taps. This introduces a new class of filter operation and effectively enables the realization of a higher order bandpass filter characteristic in a very simple structure. Experimental results are presented that demonstrate a multiple-tap high- bandpass filter response that also displays high stopband rejection level and high skirt selectivity.