Graphical design of millimeter-wave finline bandpass filters

A very simple yet accurate design procedure for the finline bandpass filters at millimeter wavelengths is presented. The technique enables the geometry of finline bandpass filters to be obtained accurately from simple closed-form equations and curves. Using this graphical approach, various millimeter-wave finline bandpass filters have been designed. Results in V-band (50 to 75 GHz) and W-band (75 to 110 GHz) are presented and indicate a good agreement between the calculated and measured performances.     

A finline PSK modulator for W-band

A 90° phase switch in finline technique has been developed for application in a W-band homodyne network analyzer. It is realized on a 0.127 mm fibre reinforced teflon substrate in a standard WR 10-waveguide. It employs two low capacitance beam-lead PIN diodes mounted in series to the finline. The waveguides are connected via Dolph-Chebyshev tapers.The analysis of this circuit shows that the diode junction capacitance imposes certain constraints for the wave impedances which must be realized. They can only be met with overlapping antipodal finlines. There are several analytical solutions with different lengths and wave impedances of the transmission line sections. The choice has been taken with respect to bandwidth in the limits imposed by the range of wave impedances which can be realized. Between 90 and 105 GHz, the phase error of the realized modulator is below ±2.5°, and the amplitude imbalance is less than 0.5 dB.     

Knowledge-Based Artificial Neural Network Models for Finline

Finline plays an important role in millimeter-wave integrated-circuit design. In this paper, a knowledge-based artifcial neural network is used to model the finline. Using prior knowledge input method and Bayesian regularization technique make the neural network models for finline reduce the amount of training data needed and prevent overfitting in neural network training. The neural network is electromagnetically developed with a set of training data that are produced by the fnite element method, which is robust both from the angle of time of computation and accuracy.     

Design and performance of millimeter-wave end-coupled bandpass filters

The design and performance of millimeter-wave microstrip/suspended-stripline end-coupled bandpass filters are presented. Filters in Ka-band (26.5 to 40 GHz) and W-band (75 to 110 GHz) using suspended-stripline and microstrip have been designed. Good agreement between the experimental results and those predicted theoretically was observed. Measured passband insertion losses of less than 1 and 0.5 dB have been achieved in W- and Ka-band, respectively. An extremely wideband waveguide-to-microstrip transition with an insertion loss of 0.25 dB over the full W-band is also presented.     

High Unloaded Qs MM Wave WDR Filters Designing

The designing results of original high unloaded-Q waveguide-dielectric filters (WDFs), are discussed. The basic physical ideas, underlying the unique design of both narrow- and wide-band filters with a widened region of suppression up to a doubled working frequency and higher, with low losses (0.2-0.5 dB), are set forth; some of their parameters in the frequency range from 8 GHz up to 80 GHz, are brought forward. The distinctive features of a WDFs are observed and the perspective directions of their development and application are predicted.     

利用准谐频叉指换能器实现GHz高频SAW滤波器

本文利用准谐频设计方法,在常规光刻工艺水平上,成功地实现了ＧＨＺ级声表面波（ＳＡＷ）器件,准谐频叉指换能器（ＱＨＩＤＴ）的优点为：其指条宽与指间隙可以比一般的单指换能器宽,克服了单指换能器内指间的多次反射,并且又较好地解决了普通谐频叉指换能器基频抑制不好的缺点,本文给出了制作在ＳＴ石英基片上,工作频率１１２８ＭＨＺ的声表面波滤波器的实验结果。     

Neural Network Models for Finline Discontinuities

The radial basis network is used as the finline discontinuities electromagnetic artifical neural network(EMANN) models. EM software analysis is employed to characterize finline discontinuities. EMANN models are then trained using physical parameters and frequency as inputs and equivalent electric circuit element parameters of finline discontinuities as outputs. Once trained , the EMANN models can simulate equivalent electric circuit element parameters of finline step, notch and strip very fast and efficiently.     

高温超导双工器综合与设计

介绍了一种高温超导双工器的设计方法.双工器包含一个公共节点和两个带通滤波器.作者使用开环半波长谐振器作为公共节点用于合并两信道滤波器,同时作为消纳网络消除滤波器之间的影响.各信道滤波器均包含了六个带折叠耦合线的发卡型谐振器,利用跨线引入交叉耦合.该高温超导双工器工作在c波段,仿真结果与理论计算结果相一致,说明了该设计方...     

Investigation of frequency-selective devices based on a microstrip 2D photonic crystal

The frequency-selective properties of structures based on a 2D microstrip photonic crystal have been investigated theoretically and experimentally. It is shown that various microwave devices, including diplexers, bandpass filters, and double bandpass filters, can be designed based on these structures.     

Gaussian beam-mode optics and the design of millimetre-wave Martin-Puplett instruments

The Martin-Puplett Interferometer is a polarising version of the Michelson two-beam interferometer. Optical systems of this type are widely used in the millimetre-wave spectral region. This paper details some ways in which the techniques of Gaussian beam-mode optics may be employed to assist in the design of compact, high performance systems for use as spectrometers, diplexers, filters, or general four-port networks.     

DWDM VSB modulation-format optical transmission: Effects of optical filtering and electrical equalization

The transmission of 40 Gb/s wavelength multiplexed channels under vestigial single side band modulation format is transmitted over long haul optically amplified fiber systems. Bit-error-rate (BER) of 10⁻¹² or better can be achieved across all channels. Optical filters are designed with asymmetric roll-off bands. Simulations of the transmission performance, BER versus receiver sensitivity are demonstrated with wavelength channel spacing of 20–40 GHz. An optical filter, whose passband is 28 GHz and 20 dB cut-off band, performs best for 40 Gb/s bit rate due to optimum filtering and minimum noise contribution. Furthermore the single-sideband property of VSB format can assist linear equalization by electronic processing. The transmission performance is accurately evaluated based on the eye opening using a fast statistical method based on an equivalent Gaussian probability density distribution (pdf) which is derived from multiple peaks pdf of distorted eye diagram.     

Rigorous analysis of novel dielectric resonator filters with printed tuning septum

This paper describes the analysis of dielectric resonator filters with printed tuning septum in waveguide sections operating below cutoff. In this design approach a thick dielectric slab of high permittivity is placed longitudinally in the waveguide. A bilateral ladder-shaped metallization determines the resonator and coupling sections (modified finline filter). In contrast to conventional dielectric resonator filters, this approach provides better passband separation and increased stopband attenuation. Furthermore, due to the bilateral tuning septum, the resonator and coupling sections can be manufactured accurately with photolithographic techniques rather than by expensive machining.     

高温超导膜微波表面电阻Rs对微波滤波器插入损耗的贡献

利用微波电路仿真软件，分析高温超导膜微波表面电阻Rs对各种频率、各种级数的滤波器插入损耗的影响.结果给出:对于级数较少、频率较低的滤波器，使用Rs较高的薄膜或厚膜就可以得到很低的插入损耗;对于频率较高(高于6GHz),或极数较多（超过8极）的滤波器，就必须采用高质量的高温超导薄膜（Rs<1mΩ）. 关键词： 高温超导膜 微波滤波器 微波表面电阻 插入损耗     

Amplitude and phase characteristics of metal meshes—The elements of submillimeter interference filters

The direct measurements of the amplitude and phase characteristics of the capacitive and inductive meshes of different pattern, used as the elements in the submillimeter interference filters, are presented. The measurements were produced vith the submillimeter spectrometer «EPSILON» in the frequency range 250–550 GHz, which allowed to investigate the amplitude and phase characteristics of the meshes in the range of the relative frequencies=G/=0.2–1.5, whereG is a mesh constant and is the wavelength. The mathematical models of the amplitude and phase frequency dependences of the meshes, which allow to calculate correctly the spectral characteristics of the interference filters, constructed from the meshes, are presented.     

High-Q, tunable, photonic microwave single passband filter based on stimulated Brillouin scattering and fiber Bragg grating filtering

We experimentally demonstrate a single passband, photonic microwave bandpass filter scheme based on stimulated Brillouin scattering (SBS) in optical fiber. A single side band (SSB)-modulated probe and a single frequency, tunable pump beam that have been produced by the combination of conventional Mach-Zehnder modulators and fiber Bragg grating filters, are used for the generation of SBS phenomenon in a 1-km long highly nonlinear dispersion-shifted optical fiber. Using the proposed scheme a single microwave passband with a ∼26 MHz bandwidth is readily achieved over a radio frequency tuning range from 1.3 to 9.3 GHz. The maximum Q-factor is measured to be ∼360.     

Stable all-fiber photonic temporal differentiator using a long-period fiber grating interferometer

A novel configuration of all-fiber photonic temporal differentiator optimized for tens-of-gigahertz processing bandwidth is suggested and experimentally demonstrated. This device covers the gap in terms of processing bandwidth between the two previously-demonstrated all-fiber designs, namely the fiber Bragg grating-based differentiator (<20 GHz) and that based on a uniform long-period fiber grating (>100-200 GHz).     

Ideals and Filters in Pseudo-Effect Algebras

In this paper, we show that the filters and local filters are equivalent in pseudo-effect algebras. Ideals and local ideals and generalized ideals are equivalent in the pseudo-effect algebras, too.     

Construction of high-quality narrow-band holographic filters

We have studied the factors limiting the quality of holographic notch filters. We have employed a novel recording scheme in which the sample is translated during exposure, eliminating flare due to reflections at the boundaries, and simultaneously reducing the scatter of the final hologram. We have also refined a gravity-settling dichromated gelatine (DCG) deposition technique and incorporated hardening of the DCG layers during the drying stage. With this, we have produced high optical quality, uniform, flare-free DCG filters with an optical density, OD > 5, bandwidth < 20 nm and scatter almost as low as that for state of the art dielectric notch filters.     

Chebychev Response of Thin Film Optical Filters

The power reflection coefficient (reflectance) of linear, periodically homogenous, isotropic, nonabsorbing stack filters is derived using full wave analysis. The well-known ABCD characteristic matrix is used to assess the spectral response of the stack filters. Adopting this method requires a huge number of matrix multiplications as the number of layers increases. An alternative approach of evaluating the whole matrix is suggested which is shown to save computational time. Band reject response far from ideal characteristics, due to the presence of unwanted ripples surrounding the stopband, is obtained. Equating these ripples without changing the length of the structure is undertaken by varying some design parameters related to the layers constituting the filter. Namely, the index of refraction and the physical thickness of individual layers are used as optimization variables. This process requires evaluating the derivative of the reflectance with respect to each design variable while leaving other parameters unchanged. The sensitivity of the derivatives to various design parameters is also addressed, which is sometimes required in manufacturing multilayered dielectric thin films.     

A Novel LO Power Injection Method for SIS Mixers

We propose a novel LO power injection method developed for SIS mixers in this paper. Based on the feature of extremely small LO power requirements of SIS quantum mixing, the new method fulfills SIS pumping through a DC/IF route based built-in LO path, which is composed of an additional LO waveguide and the existing microstrip choke filter on the junction substrate. With the new method, traditional external LO diplexers(e.g., crossguide-couplers or beamsplitters) become unnecessary, resulting in a lower loss, compact, and stable receiver system. Experiments at 110- and 230 GHz bands have shown that the present method is efficient in coupling sufficient pumping power to SIS junctions from general LO sources, and the receiver sensitivities have a further improvement of about 10 K. We expect this method is also able to be applied into submillimeter wave band for SIS mixers.