Wave Transmission Line Research Articles

Design, Modeling & Simulation of Analysis of coupling to Cables due to Electromagnetic Pulse (EMP)

This paper is to analyze the EMP coupling to cables using 3D EM Modeling and Simulation Analysis. Bounded wave transmission line structure as per MIL-STD 461, RS105 EMP requirement in terms of peak electric field of 50KV/m with rise time-2.3ns and pulse width-25ns was developed. Single conductor cable, RF Coaxial cable were modeled. EMP Coupling to cables was carried out by placing the cable under generated EMP field in terms of induced voltage and currents due to EMP fields. EMP coupling to active line with matched termination also analyzed.

A dual‐band branch line coupler for LTE 0.7 GHz and LTE 2.6 GHz frequencies

In this paper, a dual-band branch line coupler (BLC) for Long Term Evolution (LTE) 0.7 GHz and LTE 2.6 GHz frequencies is designed and developed. A dual-band quarter wave transmission line (DBQWTL) capable to perform dual band operation for frequency ratio >3 is also proposed. The dual band BLC is designed by replacing the quarter wave transmission line of the conventional single band BLC with the proposed DBQWTL. By means of even and odd mode analysis, the closed form design equations of the proposed DBQWTL are obtained. Considering the implementation viewpoint of the proposed BLC, the circuit parameter analysis is carried out. The proposed BLC performs dual band operation with maximum amplitude imbalance of 0.26 dB and phase deviation of 3.07°. It is found in the comparative analysis that the proposed BLC has novelty in terms of its operating frequency ratio range.

Experimental Study of Wave Attenuation in Trapezoidal Floating Breakwaters

A comprehensive experimental study was carried out on the regular wave attenuation with a trapezoidal pontoontype floating breakwater (FB) in deep water. The functionalities of two simple FB geometries consist of a rectangle and a trapezoid with the slope of 60° were investigated under the wave attack. A two-dimensional wave flume was used in the experiment; the incident, transmitted waves, mooring line forces and motion responses of the floating breakwaters were measured. Also the influence of the sea state conditions (incident wave height and wave period) and structural parameters (draught of the structure) were investigated using the trapezoidal FB. Our experimental results indicated that the trapezoidal FB significantly reduced the wave transmission and mooring line force when compared with rectangular FBs. A new formula was developed in order to predict the value of the transmission coefficient in trapezoidal FBs with the slope of 60°. Experimental data showed to be consistent with the results of the formula.

A Dual Band Branch Line Coupler With Wide Frequency Ratio

A dual-band quadrature branch line coupler (BLC) with wide frequency ratio has been proposed in this paper. A dual-band quarter wave ( $\lambda $ /4) transmission line structure with wide frequency ratio operation has also been presented here with closed-form design equations. An analysis for the BLC’s circuit parameters variations versus frequency ratio in the view of the implementation has been carried out as well. In order to the experimental verification, a dual-band BLC has been designed, implemented, and analyzed then tested for long term evolution (LTE) 0.7GHz and public safety band (PSB) 4.9GHz. The novelty of the proposed design is the wide frequency ratio of its dual-band operation, which can reach up to 11.8.

Full Modeling, Loss Reduction, and Mutual Coupling Control of Spoof Surface Plasmon-Based Meander Slow Wave Transmission Lines

The full models of meander spoof surface plasmon (SSP) cells are presented for the design of slow wave transmission lines (SW-TLs) with the minimum loss and controllable mutual coupling (MC). In addition to the modeling of dispersion curve and characteristic impedance, the proposed circuit model based on geometrical parameters calculates the ohmic loss of the SW-TLs composed of meander SSP cells. Being verified with the full-wave analysis, the model provides a clear understanding of the mechanism of the SSP-based SW-TLs and a new way to design with other circuits at a system level. The model is applied to minimize the ohmic loss in the meander SW-TLs up to at least 10 dB per 10 wavelengths lower than that of conventional TLs. The MC of the SW-TLs can be controlled either up to three orders of magnitude lower or one order of magnitude higher than that of the conventional TLs. This paper proposes methods to decrease the ohmic loss of single-layered meander SW-TLs and also controls MC between them. The proposed methods open new avenues for complex and compact circuit designs.

Транспорт электроэнергии переменного тока на сверхдальние расстояния

There are two different ways to transmit the AC electric power for a long distance: a compensated, the half-wave and tuned to half-wave transmissions. The compensation of the wave length is an effective way to increase the distance and the capacity of the transmission line. Through the wave length compensation it might to give to a long distance line the properties of the short line (except the active power losses). But with the distance and capacity increasing also increases a capacity of the compensation devices. Therefore, usage of the half wave and tuned to a half wave transmission lines to transmit an AC electric power for a long distances is more effective because there is no need to additional expenses to reactive power compensation by the stability conditions. The boundary length of the tuning to a half-wave is defined in article. The advisability of the tuning to a half-wave is arises when the length of the line more than 1500 km. Otherwise it recommended to tune the line to a «zero length».

Miniaturized design of rat-race coupler by utilizing T-shape stubs

Nowadays, demands for fully integrated and miniaturized Radio Frequency Integrated Circuits have increased in wireless microwave communication system. Passive components such as coupler, divider and filters are always fabricated in outside of Integrated Circuits, which have been a great barrier to a realization of a fully integrated design. To solve this problem, miniaturization of passive components is one of the big issues at the present time. This paper shows the development of important microwave passive component, rat-race hybrid coupler 180° for LTE higher (1.7 - 2.7 GHz) frequency band, which is obtained by replacing (3λ/4)-wave transmission line of a conventional coupler by their equivalent T-shape line section, resulting in significant size reduction. The miniaturized Rat-Race Hybrid Coupler 180° (RRHC) is designed on a low cost material using a substrate material of FR-4 with dielectric constant (4.3), substrate thickness (h = 1.570mm). The design and simulated results are validated by Method of Momentum using the Advance Design System (ADS) tool from Agilent technologies. The size of the implemented rat-race coupler is 76.11x37.24 mm², which is 28% compared to the conventional couplers for higher frequency band. Also, the reflection coefficient, the isolation and the phase difference between two output ports are as good as conventional one and coupling procedure is similar or better than it.

High-Gain and Wideband Antenna Arrays: Introducing Three Patch Antenna Arrays to Show the Advantages of SPPWs Used in a Feed Network

Spoof planar plasmonic waveguides (SPPWs) are a new type of low-loss surface wave transmission line whose modes are tightly confined near the SPPWs. Spoof surface plasmon polaritons (SPPs) propagating in the SPPW can be efficiently converted into free-space radiation by high-efficiency antennas. In this article, three patch antenna arrays are introduced to show the advantages of SPPWs used in a feed network, such as low-insertion loss. The first patch antenna array is designed to illustrate the feeding mechanism by the SPPW. The second antenna array is designed directly based on the first for high-gain purpose; it is also fed by the SPPW. For comparison, the third one is a stacked patch array fed by the SPPW to improve bandwidth. All of the antenna arrays are operated in the K-band, and the experimental results validate the simulations of the proposed arrays. This idea provides a simple way to design high-gain antenna arrays and an avenue to extend the bandwidth of antenna arrays excited by SPPWs.

Microwave dynamics of high aspect ratio superconducting nanowires studied using self-resonance

We study the microwave impedance of extremely high aspect ratio (length/width ≈ 5000) superconducting niobium nitride nanowires. The nanowires are fabricated in a compact meander geometry that is in series with the center conductor of a 50 Ω coplanar waveguide transmission line. The transmission coefficient of the sample is measured up to 20 GHz. At high frequency, a peak in the transmission coefficient is seen. Numerical simulations show that this is a half-wave resonance along the length of the nanowire, where the nanowire acts as a high impedance, slow wave transmission line. This resonance sets the upper frequency limit for these nanowires as inductive elements. Fitting simulations to the measured resonance enables a precise determination of the nanowire's complex sheet impedance at the resonance frequency. The real part is a measure of dissipation, while the imaginary part is dominated by kinetic inductance. We characterize the dependence of the sheet resistance and sheet inductance on both temperature and current and compare the results to recent theoretical predictions for disordered superconductors. These results can aid in the understanding of high frequency devices based on superconducting nanowires. They may also lead to the development of novel superconducting devices such as ultra-compact resonators and slow-wave structures.

Dubanton's and Wait's Approximations of the Earth Return Impedance Used for Evaluating Transmission-Line Wave Propagation Parameters

In this letter, a new theoretical support of the well-known Dubanton's approximation widely used in the evaluation of the earth return impedance of transmission lines is provided. For that purpose, the electromagnetic-wave theory of guided cylindrical waves along an axial conductor inside a circular tunnel, developed by J. Wait, is utilized, considering that the tunnel radius is very large and that only the fundamental quasi-transverse electric-magnetic mode propagates.

A Two-Way Wilkinson Power Divider Realized Using One Eighth Wave Transmission Line for GSM Application

A Two-Way Wilkinson Power Divider Realized Using One Eighth Wave Transmission Line for GSM Application

Dipole Nantennas Terminated by Traveling Wave Rectifiers for Ambient Thermal Energy Harvesting

In this paper, rectennas formed from nanodipole antennas terminated by plasmonic metal–insulator–metal (MIM) travelling wave transmission line rectifiers are developed for ambient thermal energy harvesting at 30 THz. The transmission lines are formed from two strips coupled either vertically or laterally. A systematic design approach is presented, that shows how different components can be integrated with each other with maximum radiation receiving nantenna efficiency, maximum coupling efficiency between nantenna and rectifier, and maximum MIM diode rectifier efficiency. The tunneling current of the rectifier is calculated using the transfer matrix method and the nonequilibrium Green's function. A detailed parametric study of the coupled strips plasmonic transmission lines is presented and thoroughly discussed. The overall efficiencies of the proposed travelling wave rectennas are fully expressed and compared.

Approximate evaluation of the wave propagation parameters of MF TL communication systems for mine tunnels using image theory

Mine tunnel communications are migrating to wireless; however, medium frequency (MF) communications based on conductor-to-wall transmission line (TL) structures still exist and can be used as emergency or backup systems. This research, addressing MF TL communication systems, is aimed at the finding of simple approximated expressions of the wave propagation parameters characterizing the transmission properties of such systems: attenuation, phase velocity, and characteristic impedance. Bearing in mind the variety of tunnels’ geometries and the lack of rigorous information about the surrounding soil electromagnetic properties, it turns clear that general accurate solutions of the problem are out of reach in a general formulation. In this work, a tunnel model with an equivalent circular cross section and a homogeneous soil with average conductivity is adopted and analyzed. The novelty of the analysis is its intrinsic simplicity due to the employment of image theories, which are applied not only to obtain the capacitance and external inductance of the TL but also to obtain the soil return impedance. Closed-form approximate expressions of the MF TL wave propagation parameters are offered and discussed, their dependence on the frequency and on the position of the signal carrying conductor located inside the tunnel being disclosed.

Study of transmission line attenuation in broad band millimeter wave frequency range

Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmospheric water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively.

An Investigation of High Frequency Wide Band Low Noise Amplifier for Antenna Testing System

A design of wide band low noise amplifier for a typical antenna system is investigated here. This utilizes a wide frequency band from 1-6 GHz .The design objective is to achieve minimum Noise Figure at reasonable gain throughout the entire band. The transistor model used is ATF58143, An e pHEMTfamily member offering the best noise performance. After simulations a NF below 1db is achieved from 1-3.6 GHz band along with a gain above 10 dB. While below 2 dB noise figure is achieved between 3.6 -5.6GHz but at this the gain achieved is above 7dB. The input and output matching networks for the circuit are designed using micro wave transmission lines and PCB used is PTFE board.

Dissipative Soliton Oscillator With a Nonlinear Spin Wave Transmission Line and a Signal-to-Noise Enhancer in the Feedback Loop

This study reports on a dissipative soliton oscillator utilizing two nonlinear magnetostatic spin wave (MSW) devices in a feedback loop. Both nonlinear MSW devices [a spin wave transmission line (TL) and a signal-to-noise enhancer (SNE)] operate in the frequency band where three-wave parametric processes are allowed. Self-generation of a complex-modulated MW signal is caused by nonlinearity of the spin wave TL. The SNE carries out a passive locking of the spin wave self-modulation frequencies and forms the dissipative soliton trains. It is shown, that electronic control of a repetition interval and pulse ratio of dissipative solitons is realized by the change of a klystron beam current.

HIGH PERFORMANCE V-BAND GAAS LOW NOISE AMPLIFIER WITH MODIFIED COPLANAR WAVEGUIDE EBG TRANSMISSION LINES TECHNOLOGY

This paper presents an integrated millimeter-wave (mmW) low noise amplifler (LNA) which is implemented by using 0.15-m baseline GaAs pHEMT technology. The design utilized mod- ifled co-planar waveguide (CPW) to perform a slow wave transmission line (TLine) with electromagnetic band gap (EBG) ground structures for the input/output matching networks. The low noise V-band LNA chip size was hence reduced by adopting the new EBG transmission lines. The developed amplifler exhibited a noise flgure of 6.21dB, and a peak gain of 17.3dB at 66GHz. Additionally, the amplifler has linear characteristics and its measured third-order intercept (IIP3) point is greater than i0:5dBm under a dc power consumption of 75mW.

The Design and Test of HEMP Simulator Based on Coaxial Peaking Technology

A HEMP Simulator was constructed based on coaxial peaking technology. The experimental results show that: a HEMP field matching the MIL-STD-464A standard is generated under the bounded wave transmission line when the parameters are selected reasonably; the variation coefficient of output wave parameters such as peaking filed strength, rise time and half time show that the repeatability of the HEMP simulator are very good; there is linear relation between the peaking field strength and the charging voltage of the Marx generator.

Branch line coupler using hybrid T‐model structure

AbstractA reduced size branch line coupler (BLC), which does not use bonding wires, lumped elements, or via holes, is reported in this article. The technique presented uses T‐model approach, which is a combination of low‐impedance and high‐impedance quarter wave transmission lines for realizing the proposed structure. The coupler's operating frequency bandwidth is between 2.1 and 2.67 GHz, and its size has been reduced by almost 75.31% compared with the conventional BLC. The S‐parameters and the phase difference between the output ports are simulated using CST microwave studio, and the simulation results have been compared with the measurements. The BLC has been designed to operate at 2.5 GHz and fabricated on flame resistance board (FR4 Board). The study shows that there is good agreement between the simulated and measured results. The proposed coupler has promising potentials for beam‐forming network applications such as butler matrix due to its smaller size. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:237–240, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26476

High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system

High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20°-40° from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system.