Wave Transmission Line Research Articles

Nonlinear suppression of microwave signals in a resonant magnetostatic wave transmission line

We have studied the phenomenon of suppression of a microwave signal in a magnetostatic wave (MSW) resonant transmission line comprising a microstrip resonator with a tangentially magnetized ferromagnetic film. Distinctions are revealed between the observed effects and those reported for a matched MSW line transmitting one microwave signal or two signals with different power levels.

Analysis of Method of Lines for a Novel Open Truncated Circular-Groove Guide

Groove guide is a millimeter wave and sub-millimeter wave transmission line. It has some characteristics that are superior to the other transmission lines such as simple structure, easy manufacture for its large size, low loss, low dispersion and wide bandwidth etc., when operational frequency is higher than 100 GHz. The groove guide with arbitrary cross-section is analyzed by using the method of lines in this paper. The correctness of the analytic model for solving this guide is demonstrated. A novel truncated circular-groove guide is presented and its transmission characteristics are numerically calculated and analyzed. It can be consulted for theoretical researching of groove guide and disposing electromagnetic field boundary value problems. The analytic method in this paper has some virtues such as easy formulation, less computation and universal application etc.

Monitoring of Filler Distribution in Resin with an Electromagnetic Wave Transmission Line

The authors previously presented a new method for monitoring resin flow and curing with a high-frequency electromagnetic wave transmission line constructed inside a structure. This method can provide information on discontinuities or distributions by using frequency characteristics or the time-domain response. In this paper, we applied our method for monitoring the defects in resin, such as uneven distribution of reinforcement or filler, voids or contamination, in the manufacturing process. The experimental results demonstrated the possibility of a transmission line as a monitoring tool and showed that the area with defects can be characterized by comparing with results of theoretical calculations.

OS09W0168 Health monitoring with electromagnetic wave transmission line

OS09W0168 Health monitoring with electromagnetic wave transmission line

Monitoring of resin flow and cure with an electromagnetic wave transmission line using carbon fiber as conductive elements

The authors previously presented a new method for monitoring resin flow and cure with a high-frequency electromagnetic wave transmission line constructed inside a structure, where information on discontinuity or distribution can be obtained by using frequency characteristics or time domain response. In this paper, we propose the use of carbon fiber for conductive elements constructing the transmission line, which were constructed from metal in the previous works, so as to use material reinforcements (i.e., carbon fiber) as sensing probes. The experimental results demonstrated the possibility of carbon fiber as transmission line elements.

Cutoff Characteristics of Modes in a Circular Waveguide Filled With Microwave Ferrite

This development starts from the deduction of the cutoff characteristics equations of the modes in the circular waveguide filled with microwave ferrite. Corresponding to different values of μr, the cutoff frequencies for several modes are calculated, the theoretical results of dominate mode and TM01 mode are proved to agree well with the experimental verification. The effects of μr on the cutoff characteristics of the device are also discussed. On the basis of depressing the TM modes, it is possible to develop the innovative low-loss millimeter wave transmission lines. On the other hand, when μr < 0.0, TM01 mode is converted into the lowest order mode in a circular waveguide, because of the symmetrical field distribution, its future application will be unmatched attractive.

Miniaturized Wilkinson power dividers utilizing capacitive loading

The authors report the miniaturization of a planar Wilkinson power divider by capacitive loading of the quarter wave transmission lines employed in conventional Wilkinson power dividers. Reduction of the transmission line segments from /spl lambda//4 to between /spl lambda//5 and /spl lambda//12 are reported here. The input and output lines at the three ports and the lines comprising the divider itself are coplanar waveguide (CPW) and asymmetric coplanar stripline (ACPS), respectively. The 10 GHz power dividers are fabricated on high resistivity silicon (HRS) and alumina wafers. These miniaturized dividers are 74% smaller than conventional Wilkinson power dividers, and have a return loss better than +30 dB and an insertion loss less than 0.55 dB. Design equations and a discussion about the effect of parasitic reactance on the isolation are presented for the first time.

Shunt stub line impedance matching: a wave reflection analysis tutorial

This paper presents a detailed transmission-line wave reflection analysis for the situation where an antenna's feed-point impedance is matched to the transmission-line characteristic impedance through the use of a shunt stub line. In most engineering texts, the steady-state solution to the shunt-stub-line impedance-matching problem is presented in detail. However, the solution in terms of a wave reflection analysis is generally not presented, since the steady-state solution is sufficient for most practical applications. This article is presented as a tutorial review of both the steady-state solution and the solution as determined through a detailed wave reflection analysis. It is conceptually and mathematically demonstrated that the wave reflections created at the antenna and at the stub-line termination do not cancel one another at the stub-line connection point, and they do not stay separate from one another. It is demonstrated that the steady-state impedance match is achieved when the wave reflections created at the antenna and at the stub-line termination combine at the connection point to cancel the initial wave reflections created at the connection point. The analysis and resulting formulas presented are derived for the general problem of a stub line being connected in parallel to a transmission line at any point, and are therefore valid independently of an impedance match being established at the connection point. The analysis and formulas are valid for any combination of transmission-line length, transmission-line properties, antenna impedance, stub line length, and stub line termination impedance.

Application of Genetic Algorithm for Computer-Aided Design and Optimisation of Microwave Circuits

The application of genetic algorithm for computer-aided design and optimisation of microwave circuits is presented using the example of three section Quarter wave transmission line transformers. The circuit chosen In this paper is a classic example to compare different optimisation algorithms[1]. Two different optimisation methods gradient search algorithm and genetic algorithm have been used for the optimisation. It has been found that the optimisation method based on genetic algorithm is very robust for the optimisation of microwave circuits.

Polarizers with non-rectangular grooves for high power millimeter waves

Polarizers with non-rectangular grooves are studied in high power millimeter wave transmission lines for electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD) of fusion plasmas. The groove shape is important for determining the polarization parameters and avoiding arc breakdown in the system. A low-power measurement has been carried out for several polarizers with different groove depths. The polarization characteristics experimentally measured are in good agreement with numerical results in which the actual groove shape is taken into account. The polarizers are designed and applied to different frequencies of ECH/ECCD systems. Favorable results have been obtained in high-power transmission up to 500 kW, 0.2 s.

Localized Electrochemical Deposition of Copper Microstructures

This work demonstrates the electrodeposition of micrometer‐scale copper structures using a simple instrument based on the scanning electrochemical microscope (SECM). Copper columns of 25 μm width up to about 2 mm high were deposited on different substrates and interconnects were grown within an integrated circuit package. In the present instrument electrodeposition is localized by applying a voltage between a closely spaced glass insulated Pt disk ultramicroelectrode, ca. 25 μm diam, and a substrate, all immersed in a solution of acidified . The potential, the concentration of the , and the presence of organic additives were all found to affect the microstructure of the deposits and control the efficiency of the deposition. To demonstrate some of the possible applications of this technique, copper lines were grown between pads in an integrated circuit package and an antenna about 2 cm long was grown on a millimeter wave transmission line cantilever. © 2000 The Electrochemical Society. All rights reserved.

Cure Monitoring of Matrix Resin with High-Frequency Electromagnetic Wave Transmission Line

A new monitoring method for the curing process of matrix resin is proposed. In this method, a high-frequency electromagnetic wave transmission line is constructed inside or on the surface of a material and changes in the characteristics of the line during the curing process are measured. The use of a high-frequency electromagnetic wave mainly aims at getting information on the position of the discontinuity or distribution of material properties, making use of its short wavelength. As the first step of the investigations, an experimental setup of a microstrip line and a parallel-wire line was constructed, and changes in the frequency characteristics of reflectance from each of the lines were monitored during the curing of epoxy resin between the pair of conductors of the line. Changes in the characteristics when the resin is partly filled were also investigated to examine the possibility of detecting local distributions or discontinuities. The experimental results are successfully explained by theoretical calculations. Results obtained in this study suggest the potential of the transmission line of a high-frequency electromagnetic wave as a tool for in-situ monitoring of curing and other properties.

Measurement, filtering and control in quantum open dynamical systems

A Markovian model for a quantum automata, i.e. an open quantum dynamical system with input and output channels and a feedback is described. A multi-stage version of the theory of quantum measurement and statistical decisions applied to the optimal control problem for quantum dynamical discrete-time objects is developed. Quantum analogies of Stratonovich nonstationary filtering and Bellman quantum dynamical programming for the discrete time are obtained. The Gaussian case of quantum one-dimensional linear Markovian dynamical system with a quantum linear transmission line is studied. The optimal quantum multi-stage decision rule consisting of the classical linear optimal control strategy and quantum optimal filtering procedure is found. The latter contains the optimal quantum coherent measurement on the output of the line and the recursive processing by Kalman-Busy filter. All the results are illustrated by an example of the optimal control problem for a quantum open oscillator at the input of a quantum wave transmission line.

Design and fabrication of Cherenkov flux-flow oscillator

The Josephson Flux-Flow Oscillator (FFO) has been used as an on chip local oscillator at frequencies up to 650 GHz. The FFO linewidth of about 1 MHz was measured in the resonant regime V<915 /spl mu/V for niobium-aluminum oxide-niobium tunnel junctions, while considerably larger values were reported at higher voltages. To overcome this fundamental linewidth broadening we propose a novel on chip Cherenkov radiation flux-flow oscillator (CRFFO). It consists of a long Josephson junction and a superconducting slow wave transmission line that modifies essentially the junction dispersion relation. Two SIS detectors are connected both to the long Josephson junction and the transmission line to evaluate available microwave power. The output power coming both from the long junction and the transmission line is estimated at different bias conditions.

Microwave bistability in a magnetostatic wave interferometer with external feedback

Microwave bistability has been obtained for the first time in a magnetostatic wave (MSW) interferometer with external magnetic field feedback. The interferometer contained a magnetostatic surface wave transmission line with a 7.5-/spl mu/m thick epitaxial film of yttrium iron garnet magnetized with an external static magnetic field of 1048 Oe, a variable attenuator in a parallel reference channel, and external feedback in the form of an additional static field derived from the line output. Bistable and multistable output power versus input power responses are derived from the frequency dependence of the interferometer transmission and the MSW wave number dependence on the static magnetic field. Typical bistable and multistable output versus input power hysteresis loops were obtained under constant frequency operation in the range 4.9 to 5.2 GHz, and for input powers from -30 to +10 dBm. The bistable response depends on the frequency of the microwave signal, the attenuation in the reference channel, and the gain of the feedback loop. An analysis based on linear MSW theory agreed with experiment. Applications of MSW microwave bistability include power limiter devices and basic microwave logic elements.

Influence of thermal velocity distribution on electron beam - backward electromagnetic wave interaction

One—dimensional linear theory of interaction between electron beam and backward electromagnetic wave in transmission line is presented taking into account arbitrary velocity distribution of electrons and allowing correct consideration of finite length of interaction region. Influence of electron velocity spread оn start oscillation regime of low— voltage backward—wave oscillator is analysed. Calculations are carried out for rectangular, Lorentz and Maxwell distributions.

POLARIZER WITH NONRECTANGULAR GROOVES IN THE HE11 MODE TRANSMISSION LINE

This paper presents experimental results on polarizers with nonrectangular grooves to be used in high power millimeter wave transmission lines for electron cyclotron heating (ECH) of fusion plasmas. A low-power test at a frequency of 106.4 GHz has been carried out for several polarizers with different groove depths. The polarization characteristics experimentally measured are in good agreement with numerical results in which the actual groove shape functions are taken into account. This confirms the design optimization for future polarizer. Favorable results have also been obtained in a 400 kW-level high-power test for the polarizer installed in an ECH transmission line of the Heliotron-E plasma device.

On-off intermittency observed in a system of coupled sine-Gordon solitons

On-off intermittency is numerically observed in a coupled sine-Gordon soliton system. In the present system two solitons are pinned at impurities and couple through inter-chain interaction. The distributions of the burst amplitude and the laminar duration time show a −1 power law and a −3 2 power law, respectively. These power laws agree with the proper statistical features of on-off intermittency. The present type of model is realized in soliton systems such as charge density wave (CDW) and Josephson transmission line ones in which the on-off intermittency can be hopefully observed.

A computer-aided modelling analogue for lattice dynamics

A useful methodology to study lattice dynamics is presented in this paper. Our method is based on the analogous behaviour of electromagnetic waves in transmission lines. The parameters analysed include the optical and acoustical branches and the frequency gap. The electrical circuit is solved using commercial software (MicroCap ); therefore, our methodology would be easily implemented on different systems.Resumen. En este trabajo se presenta una metodología útil para estudiar dinámica de redes. Nuestro método se basa en el comportamiento análogo de las ondas electromagnéticas en las líneas de transmición. Los parámetros analizados incluyen las ramas óptica y acústica y el gap de frecuencia. El circuito eléctrico es resuelto utlizando un software comercial (MicroCap ); por lo que nuestra metodologiá puede ser fácilmente implementada en diferentes sistemas.

Transmission characteristics of several kinds of closed groove waveguides for millimeter waves

An advantage of closed groove guide over open groove guide is attended. In this paper, the several kinds of closed groove guides including the trapezoidal-, elliptic- and parabolic-groove guides as new types of millimeter wave transmission lines are presented. Their dispersion and cut-off characteristics of the dominant mode are analysed and compared with ones of the closed V-and circular- groove guides by using the equivalent network method. The obtained results have important meaning in theoretical studies and actual applications of groove waveguides.