小型化SIR同轴腔体双通带滤波器研究

基于频率变换技术的双通带滤波器综合理论,应用阶跃阻抗谐振器(SIR)的基本原理,在双通带滤波器设计中引入λg/4型SIR同轴腔体谐振单元,设计了一种交叉耦合型拓扑结构的小型化同轴腔体双通带滤波器,相比于实际长度λg/4的传统滤波器,尺寸压缩了约50%。仿真结果显示,两个通带内回波损耗均大于20 dB,插入损耗小于0.1 dB,通带之间的阻带衰减特性良好。该滤波器的两个传输零点提高了阻带抑制度,满足了通信系统对滤波器小型化、低插损、高选择性的要求,能够广泛应用于双频带通信系统。     

阶跃阻抗滤波器及其倍频应用

阶跃阻抗谐振结构(SIR)是一种新型微带线结构,它具有小型化,尺寸易调整,寄生谐振频率可调等优势.本文利用一种半波长阶跃阻抗谐振结构设计了两个不同尺寸发卡形滤波器,获得同样优秀的性能指标.而后利用此类滤波器完成了一个倍频电路的设计并且达到预期要求.     

Miniaturized thick-film RC-active filters for PCM application

This paper presents thick-film RC-active filters developed for use in pulse-code modulation (PCM) systems. Filters for PCM telephone transmission systems are required to be small in size and low cost in production, and they must have good performance. The filters presented have a twelve-lead single in-line package configuration. Dimensions are 5-mm thick, 10-mm high, and 30-mm wide. They meet the D3-Channel Bank requirements. The transmitting filter is a seventh-order bandpass filter (BPF). The receiving filter is a fifth-order low-pass filter (LPF) with an input RC stage which acts as a lossy sample and hold circuit. To achieve miniaturization, thick-film resistors are printed on one side of alumina substrate. On the other side, one chip of quad op-amps and monolithic ceramic-chip capacitors are assembled. Considering economical production, these filters are designed with the following features: 1) only one type of equal-valued capacitors is used; 2) to get good yields, a multiple-feedback configuration having low sensitivity to circuit elements is adopted; 3) a fast deterministic trimming method is used with computer-controlled laser-trim equipment.     

Surface-acoustic-wave resonator filters

This paper presents an overview of surface-acoustic-wave (SAW) resonator filter technology. Given the current state of the art, these filters promise reproducible low-loss (≲6 dB) narrow-bandwidth (500 ≲ f/Δf ≲ 50 000) responses in the VHF and UHF ranges. Devices that contain one or a number of sections, each consisting of a resonant cavity between two grating reflectors and an input and output coupling mechanism, are considered. The initial discussion describes the layout, theoretical characteristics, and typical experimental responses of singlesection two-port filters. The subsequent discussion focuses on multisection devices using any of various intercavity coupling techniques. A generalized analysis and design formalism based on wave-scattering theory is reviewed, and experimental results from a number of device prototypes are given. Finally, practical design and fabrication trade-offs and performance ranges are summarized for a number of configurations.     

Double-sided MICs and their applications

The basic concept and features are presented of double-sided microwave integrated circuits (double-sided MICs), which effectively utilize various kinds of transmission lines on both sides of a substrate. The fundamental circuits such as 180° hybrids (magic Ts) and many application circuits described here are very useful in developing microwave and millimeter-wave band equipment. The concept of the double-sided MIC technique is also suitable for application to monolithic MICs     

Conductor-loss limited stripline resonator and filters

We report on stripline resonators on thin dielectric membranes that show dispersion-free, conductor-loss limited performance at 13.5 GHz, 27.3 GHz, and 39.6 GHz. The unloaded-Q (Q_u) of the resonators increases as √f with frequency and is measured to be 386 at 27 GHz. The measured results agree well with a new conformal mapping analysis. The stripline resonators are used in a micromachined state-of-the-art planar interdigitated bandpass filter at K-band frequencies. Excellent agreement has been achieved between the microwave model at 850 MHz and the 20 GHz filter. The micromachined filter exhibits a passband return loss better than -15 dB and a conductor-loss limited 1.7 dB port-to-port insertion loss (including input/output CPW line loss) at 20.3 GHz     

Electrically cascaded surface-acoustic-wave resonator filters

Three nearly identical surface-acoustic-wave resonator filters at ? 35 MHz have been fabricated with aluminium metallisation on yz LiNbO3 substrates. The filters are electrically cascaded to yield a combined frequency response that exhibits 80 dB sidelobe suppression, Q ? 3000, no spurious responses in the range 1?500 MHz and an insertion loss in a 50 ? system of only 13 dB.     

Microring resonator channel dropping filters

Microring resonators side coupled to signal waveguides provide compact, narrow band, and large free spectral range optical channel dropping filters. Higher order filters with improved passband characteristics and larger out-of-band signal rejection are realized through the coupling of multiple rings. The analysis of these devices is approached by the novel method of coupling of modes in time. The response of filters comprised of an arbitrarily large dumber of resonators may be written down by inspection, as a continued fraction. This approach simplifies both the analysis and filter synthesis aspects of these devices     

New dual-mode dielectric resonator filters

The paper presents a new design of dual-mode dielectric-loaded rectangular cavity filters. The response of the filter is mainly controlled by the location and orientation of the coupling apertures with no intra-cavity coupling. Each dual-mode dielectric-loaded cavity generates and controls one transmission zero which can be placed on either side of the passband. Example filters which demonstrate the soundness of the design technique are presented.     

Miniaturized 3 GHz cross-coupled planar microwave filters

Cross-coupled planar microwave filters were fabricated using YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// superconducting thin films deposited on both sides of a LaAlO/sub 3/ single crystal substrate by pulsed laser deposition. The hairpin resonator geometry allows one to miniaturize the 3-GHz filters by compacting the entire filter onto a substrate with dimensions 0.5 cm /spl times/ 1 cm. By adjusting the relative spacing among the resonators to establish adequate couplings, filters with very sharp rejection skirt and extremely small insertion loss in passband were obtained.     

Finite elements for microwave device simulation: application tomicrowave dielectric resonator filters

The two-dimensional (2-D) and three-dimensional (3-D) finite element methods (FEMs) are applied to compute the exact scattering parameters (taking into account the transmission lines) of dielectric resonator (DR) filters. These filters act in TM or hybrid modes. A sensitivity analysis is also performed to predict the influence of the geometrical parameters on the devices responses. Examples of one, two, and three DR filters are given. Experimental results are in good agreement with theoretical ones     

Compact lowpass filter using stepped impedance hairpin resonator

A novel microwave lowpass filter using a microstrip stepped impedance hairpin resonator is proposed. This filter has the advantages of compact size, easy fabrication, and sharp cutoff frequency response. The filter is useful for many microwave system applications     

Dielectric resonator filters with wide stopbands

Dielectric resonators used in filter networks present a model spectrum with undesired, or spurious, resonances in close proximity to the desired one. Through the use of evanescent mode bandpass irises tuned to the filter center frequency, the resonator spurious modes are suppressed, resulting in N-section filters with stopbands clean to at least (N-1) times the individual iris stopband levels. The problem of achieving a wide stopband is reduced to the problems of realizing the resonating capacitance required in an evanescent bandpass filter and computing the junction susceptance occurring at the interface between a larger evanescent section (the resonator enclosure) and the smaller iris opening. The technique results in high-Q resonator filters with stopbands clean to at least -55 dBc, out to at least 1.7 times the filter center frequency     

A novel CMOS hairpin resonator using slow-wave structure

A novel hairpin resonator incorporating a defective uniplanar compact photonic bandgap (D-UCPBG) slow-wave structure has been developed using monolithic silicon-based CMOS technology and the impact of the D-UCPBG slow wave feature on the hairpin resonator performance is presented. Two stepped impedance hairpin resonators of equal dimensions, one with a solid ground plane and another with a D-UCPBG structure, were implemented in the TSMC 0.25 /spl mu/m RF-mixed signal fabrication process. The D-UCPBG incorporated hairpin resonator resonates at 4.5 GHz, a significant frequency reduction from 10.2 GHz, the resonant frequency of the solid ground plane based hairpin resonator. The loaded Q of the resonator also increases from 5.8 for the solid ground plane resonator to 13 for the D-UCPBG structure.     

Automated CAD of coupled resonator filters

A gradient-based optimization technique along with a new definition of cost function is applied to the CAD of coupled resonator filters. The topology of the structure is enforced at each step of optimization and its physical dimensions are used as optimization variables. The cost function is defined using location of zeros and poles of the filter's transfer and reflection functions. Numerical tests show that with the new definition of the cost function, the optimization process converges from an arbitrarily selected starting point. This allows one to design filters even without a rough microwave synthesis which usually provides initial dimensions.     

Miniature high-Q double-spiral slot-line resonator filters

A new class of low insertion-loss miniaturized filters using slot-line resonators is proposed. Miniaturization is achieved by terminating the slot line with a double-spiral inductive termination at both ends. Using this miniaturized resonator, both positive and negative couplings may be realized, and therefore, both standard coupled-line and cross-coupled quasi-elliptic filters are realizable. The unloaded Q of these slot-line filters is considerably higher than that of miniaturized microstrip filters of comparable dimensions due to the inherent higher Q of the slot line. To demonstrate the validity of the design procedures and the performance characteristics, two different types of filters were fabricated and tested. One is a four-pole Chebyshev filter and the other is a quasi-elliptic filter where, in each case, the full-wave simulations show very good agreement with measurements.     

Two-path cutoff waveguide dielectric resonator filters

The authors propose an evanescent-mode wave-guide filter consisting of two parallel cutoff waveguide paths with dielectric resonators. They introduce an accurate design method incorporating both the full-wave analytical method and the impedance inverter method. The specified overall characteristic is then synthesized with the help of a computer-aided design method. Measurements on several kinds of filters modeled at X-band show excellent agreement with the designed characteristics     

Direct-coupled resonator filters with improved selectivity

A method is outlined whereby a narrow-band direct-coupled resonator filter may be derived from an elliptic-function low-pass prototype. The construction and performance of a three-resonator waveguide cavity filter designed on this basis is described.     

Electronically tunable ring resonator microstrip and suspended-substrate filters

Electronically tunable ring resonator microstrip and suspended substrate microwave filters with high tuning speed are presented. The filters are realised using two coupled ring resonators with GaAs varactors as the tuning elements. Computer optimised circuits are used at the input and the output to obtain better than 10 dB return loss across the tuning band. Tuning ranges of 1.075-2.25 GHz for the microstrip filter and 1.35-2.075 GHz for the narrower suspended substrate filter are predicted by computer simulation.<>     

Miniaturized microstrip bandpass filter designed using rectangular dual spiral resonator

A miniaturized microstrip bandpass filter based on a rectangular dual spiral resonator (DSR) is proposed in this paper. The rectangular DSR bandpass filter is centered at 3.65 GHz to suit for Wireless LAN (IEEE802.11y) application. The proposed filter offers transmission zero at the high side of out-of-band response. Across the bandwidth, the measured minimum insertion loss is about 1.7 dB, while the measured return loss is better than 19 dB. Measurement results are good agreement and closed to the simulated ones. The total circuit size of the miniaturized bandpass filter is about 0.145λ_g by 0.135λ_g, where λ_g is the guided wavelength at 3.65 GHz.