微带发夹型谐振器滤波器的实验研究

微带发夹型谐振器滤波器具有尺寸小、成本低、易于集成等优点,在微波平面电路的设计中有着良好的应用前景.此前已有一些文献对这类滤波器进行过研究,但一般都是只针对某一种特定的发夹型谐振器进行滤波器的分析设计,而没有对各种不同谐振器的性能指标与滤波器设计要求进行比较研究.本文使用几种不同的发夹型谐振器和不同耦合方式分别设计了三阶和四阶带通滤波器,通过实验对这几种谐振器滤波器进行了分析研究,得到了一些具有实际应用价值的结论.     

Slow-wave bandpass filters using ring or stepped-impedance hairpinresonators

This paper proposes a new class of slow-wave bandpass filters that uses a microstrip line periodically loaded with microstrip ring or stepped-impedance hairpin resonators. The new slow-wave periodic structures utilize the parallel and series resonance characteristics of the resonators to construct a bandpass filter. Unlike conventional slow-wave filters, the proposed bandpass filters are designed to produce a narrow passband at the fundamental mode of the resonators. The new filters provide lower insertion loss than that of parallel- or cross-coupled ring and stepped-impedance hairpin bandpass filters. The calculated frequency responses of the filters agree well with experiments     

Novel realization of monotonic Butterworth-type lowpass, highpass,and bandpass optical filters using phase-modulated fiber-opticinterferometers and ring resonators

A novel realization of monotonic Butterworth-type lowpass, highpass, and bandpass optical filters (from their electrical digital filter characteristics) by cascading the all-pole and all-zero resonators is presented. A graphical method for fast derivation of the transfer functions, quick inspection of the resonance effects, and important characteristics of any photonic circuits is described. It is shown that incorporation of the optical amplifiers and optical phase modulators into the delay lines of two basic optical resonators, whose pole and zero can be adjusted independently of each other, provides great design flexibility which would otherwise not possible using conventional passive optical resonators. Possible applications of these optical filters as optical pulse equalizers and receiver shaping filters in long-haul coherent lightwave transmission systems are discussed. Possible application of basic resonators comprising of optical phase modulators as tunable optical filters for spectrum analyzers is also considered     

Direct-coupled microwave filters with single and dual stopbands

This paper presents new ideas for the design and implementation of microwave filters with single and dual stopbands. They can be realized with waveguide, coaxial, dielectric resonators, or in a planar technology. The new methods represent an advance over present methods in that the resonators are direct coupled, thus avoiding the need for transmission line phase lengths between resonator stubs that tend to degrade performance due to their dispersion and are difficult to adjust during tuning. Three bandstop (BS) configurations are presented. The first will accommodate even or odd characteristics and also asymmetric responses, although some negative or diagonal cross-couplings will be needed. The second resembles the cul-de-sac configuration for bandpass filters and needs no diagonal or negative couplings even for asymmetric characteristics. The third is an application of the cul-de-sac synthesis technique to dual-band bandstop (DBBS) filters. All these BS designs are very similar to regular bandpass filters in their design and realization. The design of a DBBS filter is presented and compared with an equivalent bandpass filter to demonstrate its advantages. Finally, the simulated and measured results of a fourth-degree BS filter design in the novel cul-de-sac configuration are presented.     

Bandpass filters using dual-mode and quad-mode Mobius resonators

Compact bandpass filters are being developed using Mobius wire-loaded cavity resonators. Initial results on tuned filters indicate that excellent filter characteristics can be attained in devices that are significantly smaller than traditional wire-loaded cavity technologies. A novel quad-mode Mobius resonator is presented which occupies the same volume as a dual-mode Mobius resonator. A four-pole bandpass filter is demonstrated using a single quad-mode Mobius resonator. Precisely controlled dielectric loading of dual-mode Mobius wire resonators has been implemented to realize bandpass filters. Two-pole and four-pole bandpass filters are demonstrated using one and two dual-mode dielectric-loaded Mobius resonators, respectively     

A class of novel uniplanar series resonators and theirimplementation in original applications

A class of novel millimetric uniplanar series resonators are presented, which can be used in monolithic and hybrid uniplanar microwave integrated circuits (MIC's). The proposed structures are able to demonstrate low radiation and compactness characteristics, which are attractive for passive and active monolithic and hybrid integrated circuits. A principle of achieving these high-quality circuits is described and also confirmed by experimental and theoretical results, which are in good agreement up to 50 GHz. To illustrate the features of the proposed series resonators and demonstrate their effectiveness, two classes of miniature coplanar waveguide (CPW) filters (namely, low-pass and bandpass) are designed using these resonators. The developed low-pass filter has some important advantages such as low insertion loss in passband, very wide stopband, high cutoff rates, small size, low number of elements, and an effective control of spurious signals. On the other hand, the newly developed bandpass filter provides an alternative, yet compact, structure to classical filters. Obviously, many other classes of filters or passive components can also be designed     

An L-Band MIC Front End for an IFF Receiver

A microwave integrated circuit (MIC) front end which satisfies stringent environmental and filtering requirements has been developed; the design objectives were based on the requirements typical of an L-band receiver for an identification friend or foe (IFF) transponder. The front end includes a preselector, a balanced mixer, and a multiplier for providing the local oscillator (LO) signal. A compact low-loss design has been achieved for the bandpass filter portion of the preselector through the use of "hairpin" resonators. Use of a semilumped 3-dB coupler has resulted in a significant reduction in the size of the mixer. The front-end noise figure was measured to be 10.4 dB at room temperature, with a maximum of 14.0 dB at 125/spl deg/C. All spurious responses were measured to be more than 80 dB down, and LO reradiation was -67 dBm. Dynamic range was greater than 70 dB.     

基于3-D打印技术的新型微波/毫米波无源波导器件

综述了近年来基于多种3-D打印工艺的微波直至太赫兹频段无源波导器件的发展研究现状,并介绍了作者所在小组研制的多个基于立体光刻3-D打印工艺的滤波器(包括基于新型高Q值单模和双模球形腔体谐振器的X频段带通滤波器以及基于裂缝波导和紧凑片上结构的W频段带通滤波器).这些滤波器射频性能的测量与仿真结果吻合良好.与相同形状的铜制器件相比,采用非金属材料的3-D打印器件的重量减轻了80%以上,并保持了优良的射频性能.     

Coplanar stripline resonators modeling and applications to filters

This paper presents coplanar stripline (CPS) resonators and their practical implementations to filters. Five types of CPS resonator are built using open and short-ended strips. Lumped-element equivalent circuits are presented for each resonator. Their performances are investigated and compared in terms of Q factor or bandwidth. Two types of bandpass filter are developed with the resonators. The bandpass filters have low-passband insertion losses and wide-stopband suppression bandwidths. Lumped-element equivalent circuits are presented for the bandpass filters. A wide-band CPS-to-microstrip transition is developed for the measurements. The back-to-back transition has an insertion loss of less than 3 dB and a return loss of better than 10 dB for the frequency range from 1.3 to 13.3 GHz (1:10.2)     

Stripline combline filters on substrates designed on high-permittivity ceramic materials

Stripline bandpass combline filters designed on high-permittivity ceramic materials are analyzed. In order to form coupling between codirectional quarter-wave resonators, they are connected in the regions of their short-circuited ends by a stripline conductor. Features of the characteristics of such filters are revealed and compared with the parameters of other ceramic microwave filters. Experimental characteristics of a stripline filter designed on a ceramics with permittivity ?_r = 38 are presented. The experimental results are in good agreement with results of computer simulation.     

Application of Dielectric Resonators in Microwave Components

Dielectric resonators are being used in microwave filters and oscillators now that high-dielectric-constant, high-Q, temperature-stable ceramics have been developed. This paper reviews dielectric resonators with emphasis on applications, contains tutorial material, deseribes new 2-, 4-, and 6GHz bandpass filters, and presents several examples of oscillator applications. A complete blbliography to English language publications on dielectric resonators is included.     

Cross-coupled microstrip hairpin-resonator filters

A new class of cross-coupled planar microwave filters using microstrip hairpin resonators is introduced. The realization of bath the canonical and the cascaded quadruplet (CQ) filters is feasible. Coupling characteristics of four basic coupling structures encountered in this class of filters are investigated in the light of full-wave electromagnetic (EM) simulations. A four-pole cross-coupled filter of this type is designed and fabricated. Both the theoretical and experimental performance is presented     

Distortion Mechanisms in Varactor Diode-Tuned Microwave Filters

This paper examines the broadband distortion behavior in flexible filters employing varactor-diode tuning elements. Series- and parallel-resonant varactor-loaded transmission-lines, both commonly used in bandpass and bandstop microwave filters, are analyzed. Nonlinear Volterra-series analysis is employed to determine the second- and third-order distortion ratios dependent on the frequencies of the incident signals. It is shown that in a bandpass filter (employing parallel tuned resonators), maximum distortion occurs in the passband, while in a bandstop filter (employing series tuned resonators), minimum distortion occurs at the minimum-loss passband. The analysis is verified by practical measurement of filters employing the two modes of resonators.     

Mixed Mode Filters (Short Papers)

Mixed mode bandpass filters are described which utilize alternating TE/sub 011//spl deg/ and TE/sub n11//spl deg/ circular waveguide cavity modes. This novel filter configuration exhibits both excellent unloaded Q and spurious mode response characteristics. The use of mixed resonant modes makes possible the design of microwave filters for both in-line side wall connected cylindrical resonators as well as folded planar filter configurations, whereby cross-coupling between selected resonators can be realized.     

Novel Centrally Loaded Resonators and Their Applications to Bandpass Filters

This paper presents several novel centrally loaded resonators and their applications to various types of bandpass filters. Based on the theoretical analysis, it is found that the even- mode resonance of the proposed resonators can be conveniently controlled without affecting the responses at the odd-mode resonant frequencies. Benefiting from this feature, the resonator can be utilized to design not only harmonic-suppressed bandpass filters and dual-band bandpass filters but also tunable bandpass filters. The tunable filter offers a fixed passband and a tunable one. The center frequency of the upper passband can be electrically tuned, whereas the performance of the lower one is maintained constant. To demonstrate these applications, four filters using the proposed resonators are implemented. The experiments verify the theoretical predictions and simulations.     

高选择性发夹型带通滤波器的设计

微带发夹型带通滤波器具有尺寸小、结构简单、性能稳定等优点,在射频微波领域有着广泛的应用。 本文使用ADS 软件设计仿真了一种高选择性抽头式发夹型带通滤波器。与一般发夹型滤波器相比,该滤波器在输 入输出端并联四分之一波长开路微带线,通过在寄生通带增加传输零点的方法提高滤波器的带外抑制性能。另外, 在该滤波器的谐振单元上增加并联阶跃阻抗枝节,在通带两侧产生一对传输零点,来提高该发夹型带通滤波器的选 择性。最后对这种高选择性发夹型带通滤波器进行实物加工,测试结果证实了该带通滤波器的良好选择性能。     

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.     

Dual-mode filters with conductor-loaded dielectric resonators

In this paper, a new class of dual-mode microwave filters is presented. These devices use conductor-loaded dielectric resonators with unloaded Q-factors of 2000-8000 achievable in half the physical size of TEM filters and with good spurious performance. The basic properties of this resonator have been examined with the aid of a finite-element field-analysis package. Fundamental design rules for bandpass filters have been developed. A design example of a transmit filter for a ground-signal-metal cellular-radio base station is demonstrated     

New Design Equations for a Class of Microwave Filters (Correspondence)

New approximate design equations for a class of microwave bandpass filters are presented. The filters are 1) dual forms of half-wave parallel-coupled resonator filters, 2) one form of interdigital filter, and 3) dual forms of direct-coupled stub filters. The advantages derived from using the new equations are 1) exact realization of the specified design bandwidth and 2) improved pass-band voltage standing-wave ratio (VSWR) response in the vicinity of band edge. Experiments data are presented for a trial filter design having 7 resonators, 40-percent bandwidth, and passband VSWR of 1.2.     

Miniaturized Hexagonal Stepped-Impedance Resonators and Their Applications to Filters

Miniaturized hexagonal stepped-impedance resonators and their applications to bandpass filters are presented. Based on the odd- and even-mode equivalent circuits, the resonance characteristics of these resonators are investigated. A series of circuit configurations, including the third-order Chebyshev, trisection, and fifth-order cascaded trisection filters, are constructed by the proposed resonators. These filters are very compact and have good stopband responses. Measured results validate the analysis and theoretical prediction with good agreement.