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。     

Dimensional synthesis for wide-band waveguide filters and diplexers

Broad-band waveguide filter and diplexer designs are widely used for telecommunications, space, and terrestrial applications. Fairly accurate design procedures giving equivalent-circuit information are well known for bandpass filters, but this data needs to be converted into physical dimensions, i.e., waveguide cavity lengths and iris dimensions. A novel procedure giving dimensions of bandpass filters directly for wide- and narrow-band applications is described. Iris network models are generated with the aid of electromagnetic simulators and used to derive correct iris dimensions and accurate susceptance slope parameters of the cavities, avoiding global optimization of the entire structure. The results demonstrate very good equiripple performance up to bandwidths of approximately 20% in frequency or 40% in terms of guide wavelength. A similar dimensional synthesis to design waveguide noncontiguous bandpass diplexers is also given. The method uses a fast and efficient optimization with a reduced number of variables, which is fixed and independent of the order of the two filters. The simplicity of the method leads to good return-loss levels and the derivation of the diplexer dimensions takes less than 10 min, including optimization.     

微波谐振腔湿度测量同轴环耦合设计与实现

基于微波谐振腔汽轮机内流动湿蒸汽湿度的测量原理,分析了微波谐振腔及同轴线小环耦合的场结构分布,设计出两端带栅网结构的湿度传感器.采用HFSS型微波软件对湿度传感器进行了建模仿真,由此得到场分布及S参数曲线图,以此设计出湿度传感器的结构尺寸.仿真结果表明,该微波谐振腔传感器工作在TE011模式下,谐振频率为9.58 GHz,其Q=1 198,适合作为测试流动湿蒸气的传感器.与采用矩形波导和谐振腔的孔耦合相比,这种新型同轴线耦合装置体积小,对汽轮机设备的开口也小,实用性也强.     

环形耦合谐振腔光波导的耦合率对光学延时线的影响

本文根据Bloch理论研究了耦合谐振腔光波导(CROW)的群速度、延迟时间及存储容量随耦合率的变化规律。结果表明,耦合谐振腔光波导(CROW)的群速度、延迟时间及存储容量随着耦合率的增大而降低,而色散随耦合率的增大而增大。还运用传输矩阵的方法,研究了环形耦合谐振腔透过率随耦合率的变化规律。在不考虑损耗的情况下,耦合率对透过率无影响,考虑损耗时,透过率则随耦合串的减小而减小。对衰减系数为0.995,耦合率为0,235情况下的CROW进行模拟。模拟结果显示,当CROW中含64个谐振腔时,延迟时间能达到100ps,透过率可达到-27dB,可以满足实际应用需要。     

Microstrip diplexers design with common resonator sections for compact size, but high isolation

High isolation and compact size microstrip diplexers designed with common resonator sections have been proposed. By exploiting the variable frequency response of the stepped-impedance resonator, resonators can be shared by the two filter channels of the desired diplexer if their fundamental and the first spurious resonant frequency are properly assigned. Size reduction are, therefore, achieved by introducing a few common resonator sections in the circuit. This concept has been verified by the experimental results of two diplexer circuits. One of the diplexers is composed of two three-pole parallel-coupled bandpass filters and the other is composed of two four-pole cross-coupled bandpass filters, which are formed by only five and six resonators, respectively. Both of them occupy extremely small areas while still keeping good isolations. Good agreements are also achieved between measurement and simulation.     

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.     

Design of single and coupled microwave meta-material resonators in microsystem technology

In this paper Coupled Triangular Resonators in coplanar waveguide have been studied for S (2–4 GHz) and C (4–8 GHz) Band microwave applications. The peculiarity of the triangular structure to exhibit multiple resonances is usually proposed for dual and three-band purposes, to obtain efficient unit cells for high performance microwave tunable oscillators. One more characteristic of the triangular shape is the meta-material behavior, which allows a significant size decrease of the device. Coupled resonating configurations are proposed in this contribution, to be manufactured in Microsystem Technology by using polymeric layers as spacers between individual resonators organized in a vertical stack. Electromagnetic simulations have been performed to study narrow-band filters characterized by reduced dimensions, low insertion loss and steep band edges. Lumped element models are presented which can be easily implemented in commercial circuital software packages for the design of networks using these resonators.     

Dual-tunable hybrid wave ferrite-ferroelectric microwave resonator

A novel electric and magnetic field tunable microwave resonator with a yttrium iron garnet and barium strontium titanate layered structure is investigated. The measured characteristics at 3.6 GHz, corresponding to the proximity of magnetic and dielectric resonance modes, show a broadband electrical tunability. A tuning range of 1.5% of the central resonance frequency is obtained for nominal electric fields.     

A GaInAsP-InP double-ring resonator coupled laser

A monolithic single-mode GaInAsP-InP double microring resonator coupled laser is demonstrated for the first time. The laser comprises two passive ring resonators, semiconductor optical amplifiers in the bus waveguides, and 3-dB codirectional couplers. The laser has an output power of 0.5 mW with a sidemode supression ratio of >35 dB. The tunability is demonstrated using integrated platinum resistors on top of the waveguides in the rings.     

Millimeter-wave Ka-band H-plane diplexers and multiplexers

Millimeter-wave H-plane diplexers/multiplexers are designed using modified H-plane waveguide T-junctions and modified inductive window bandpass filters. Modeling of the diplexers/multiplexers are performed using the full-wave mode-matching method to obtain the generalized scattering matrices of the building blocks and by the cascading procedure to provide the overall frequency response. A complete systematic optimization procedure leads to the desired diplexer/multiplexer design. The validity of employing the modified H-plane T-junctions in the diplexer/multiplexer configurations are demonstrated by the design examples. A millimeter-wave Ka upper band diplexer based on the simulated results was built and tested. Without any tuning, excellent experimental results are obtained, which verified the full-wave mode-matching-based precise design     

Temperature compensated sapphire-rutile microwave whisperinggallery mode resonator

A 2 μm-thick film of rutile (TiO₂) was deposited on a sapphire disk using a sol-gel method to realise a temperature compensated microwave resonator operating in whispering gallery mode configuration. The resonator, though not yet completely optimised, shows turnover temperatures ranging from 40 to 60 K depending on the mode azimutal number. For the WGH_7,0,0 mode at 9.4 GHz, the Q-factor is of the order of 1.5×10⁶ at 46 K. The technique appears easy to implement and can be used for the design of a high-frequency stability microwave source     

Vertically coupled glass microring resonator channel droppingfilters

Air-clad glass microring resonators vertically coupled to buried channel waveguides are experimentally investigated. Ring radii of 10 μm, and channel drop bandwidths of 5 nm are reported. Vertical coupling eliminates the need for the etching of fine features, and relaxes the alignment of the resonator with respect to the input and output bus waveguides     

Directly coupled multiple resonator wide-band microstrip antennas

Three new configurations for increasing the impedance bandwidth of the microstrip patch antennas are described. In these configurations, additional resonators are directly coupled through short sections of microstrip line to the radiating edges, nonradiating edges, and all the four edges of the rectangular patch antennas, respectively. Green's function approach and segmentation method are used for the analysis. The experimental results are in reasonable agreement with the analysis and impedance bandwidths of 548 MHz, 605 MHz, and 810 MHz are obtained for these three configurations, respectively inS-band (substrate thickness = 0.318 cm andepsilon_{r} = 2.55). The variation in the radiation pattern over this impedance bandwidth is discussed.     

Dual-band bandpass filter using coupled resonator pairs

This letter proposes and fabricates a novel dual-band bandpass filter topology. The proposed topology facilitates the split resonating frequencies of coupled resonator pairs in realizing the dual-band response and introduces transmission zeros for improving the stopband attenuation. The semi-lumped prototype enables the integration of the filter in a multilayer circuit for miniaturized implementation. Finally, a design example fabricated with low temperature co-fired ceramic (LTCC) technology is presented for validating the filter configuration.     

Wide tunable double ring resonator coupled lasers

A double ring resonator coupled laser (DR-RCL) is proposed and analyzed in this letter. Benefiting from the uniform peak transmission, narrow bandwidth and other superior characteristics of traveling wave supported high-Q resonators, DR-RCLs offers many promising advantages over the conventional tunable lasers, including ultra wide wavelength tuning range, high side mode suppression ratio, uniform threshold and efficiency, narrow linewidth, low frequency chirp, and simple fabrication. A DR-RCL with a moderate optical loss ~10 dB/cm in the ring resonators can achieve a wavelength tuning enhancement of ~50. With such a large tuning leverage, DR-RCLs could utilize the electrooptic effects to achieve ultrafast tuning speed with a wide tuning range covering the material gain bandwidth     

Stochastic instability of oscillator with coupled stabilising resonator

The influence of regular periodic perturbations on behaviour of an oscillator with an additional stabilising resonator is studied. It is shown that, under certain conditions, chaotic oscillations appear in the system.<>     

Comments on "The dielectric microwave resonator"

Equations are given from which the resonant frequencies of a rectangular anisotropic dielectric resonator can be calculated. The limitation of the validity of these equations is also discussed.     

Quasi-lumped suspended stripline filters and diplexers

This paper demonstrates a general concept and different types of filters and a diplexer realized in suspended stripline using quasi-lumped elements. Very small low-pass, bandpass, and high-pass filters with typically low loss are designed, fabricated, and tested; even transmission zeroes can easily be included into the design by additional coupling structures. Finally, a low-pass and high-pass filter are combined to form a diplexer of very small size.     

Observation of crosspolar effects using a microwave open resonator

The occurrence of a crosspolar resonant field, generated from the interaction of a particle and the normal fundamental mode of a microwave open resonator, is reported. Results are presented for the cases where the scatterers are a short length of wire and simulated melting hailstones.