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A colinear Second-Harmonic Orthogonal Polarized (SHOP) interferometer diagnostic capable of making electron areal density measurements of plasmas formed in Magnetically Insulated Transmission Lines (MITLs) has been developed.
New low-noise cryogenic input transmission lines have been developed for the Deep Space Network (DSN) at 1.668 GHz for cryogenically cooled Field Effect Transistors (FET) and High Electron Mobility Transistor (HEMT) amplifiers. These amplifiers exhibit very low noise temperatures of 5 K to 15 K, making the requirements for a low-noise input transmission line critical. Noise contribution to the total amplifier system from the low-noise line is less than 0.5 K for both the 1.668-GHz and 2.25-GHz FET systems. The 1.668-GHz input line was installed in six FET systems which were implemented in the DSN for the Venus Balloon Experiment. The 2.25-GHz input line has been implemented in three FET systems for the DSN 34-m HEF antennas, and the design is currently being considered for use at higher frequencies.
Power system reliability requirements necessitate the development of measurement systems to monitor the operational state of critical transmission lines. Here in this article, a novel noncontact method for monitoring overhead transmission lines is proposed. The method is based on measuring the amplitude and relative phase of the transmission line's space potential at two or more strategically located points in space along with the use of passive phase shifters to enhance the sensitivity of the measurements. Applications of voltage unbalance and conductor sag measurements are demonstrated along with the results of conductor sag measurements on an operating 230-kV transmission line. It is shown that using enhanced relative phase measurements can significantly improve the sensitivity of the measurements.
Computer model of fluid transmission line using digital technique to simulate transport delay associated with pressure wave propagation along fluid line
A highly accurate transmission line fault locator based on the traveling-wave principle was developed and successfully operated within B.C. Hydro. A transmission line fault produces a fast-risetime traveling wave at the fault point which propagates along the transmission line. This fault locator system consists of traveling wave detectors located at key substations which detect and time tag the leading edge of the fault-generated traveling wave as if passes through. A master station gathers the time-tagged information from the remote detectors and determines the location of the fault. Precise time is a key element to the success of this system. This fault locator system derives its timing from the Global Positioning System (GPS) satellites. System tests confirmed the accuracy of locating faults to within the design objective of +/-300 meters.
Lightweight cable forms balanced transmission line and replaces costlier coaxial cables for multiplex-signal transmission. Cable is fabricated with carefully-controlled electrical characteristics and functions without tuning networks at frequencies up to 10 MHz.
Proposed optoelectronic coupling circuit used to insert signal in transmission line and to isolate transmission line from ground of circuit in which signal originates. Made from commercially available components, reduces susceptibility to interference along transmission path.
Multipacting breakdown in coaxial transmission lines at frequencies above 150 MHz, noting validity of scaling laws
The sources for electrical power on a lunar base are said to include solar/chemical, nuclear (static conversion), and nuclear (dynamic conversion). The transmission of power via transmission lines is more practical than power beaming or superconducting because of its low cost and reliable, proven technology. Transmission lines must have minimum mass, maximum efficiency, and the ability to operate reliably in the lunar environment. The transmission line design includes conductor material, insulator material, conductor geometry, conductor configuration, line location, waveform, phase selection, and frequency. This presentation oulines the design. Liquid and gaseous dielectrics are undesirable for long term use in the lunar vacuum due to a high probability of loss. Thus, insulation for high voltage transmission line will most likely be solid dielectric or vacuum insulation.
Technologies pertaining to a power supply that includes a nonlinear transmission line are described herein. In an embodiment, a DC power supply comprises a pulsing circuit that receives a DC input and outputs a first plurality of pulses having a first frequency to a nonlinear transmission line. The nonlinear transmission line receives the first plurality of pulses and outputs a second plurality of pulses having a second frequency that is greater than the first frequency. The second plurality of pulses is then received at an amplifier/rectifier circuit that amplifies the second pulses to increase a voltage amplitude of the pulses, and rectifies the pulses to provide a substantially constant DC output.
The 'transmission-line' model is an approximation that is frequently used to relate the electric and magnetic fields radiated during lightning discharges to the currents that produce those fields. A principal prediction of this model is that the distant (radiation) fields are directly proportional to the current propagating along the lightning channel, multiplied by the velocity of propagation. This paper examines the derivation of this relationship and its implications in some detail. It is shown that the formulas commonly used to describe the transmission-line model cannot be correctly applied to many lightning processes. A correction factor is required that is significant when the channel is not oriented perpendicular to the line of sight to the observer, unless the propagation velocity is only a small fraction of the speed of light. An important implication of this more general version of the model is that the current and velocity decouple so that they could be separately determined by suitable, multistation measurements.
A method for modeling discontinuities in a coaxial transmission line is presented. The methodology involves the use of a nonlinear least-squares fit program to optimize the fit between theoretical data (from the model) and experimental data. When this method was applied to modeling discontinuities in a slightly damaged Galileo spacecraft S-band (2.295-GHz) antenna cable, excellent agreement between theory and experiment was obtained over a frequency range of 1.70-2.85 GHz. The same technique can be applied for diagnostics and locating unknown discontinuities in other types of microwave transmission lines, such as rectangular, circular, and beam waveguides.
The datasets contain wildfire risk probabilities for transmission lines in the Western Interconnect, identified only by the HIFLD dataset identifier. The dataset is generated using PNNL's WREST Tool (https://www.pnnl.gov/projects/wildfire-risk-resilience/tools/wrest). The input dataset includes HIFLD datasets on transmission lines and wildfire burn potentials and flame lengths from the PNNL RADR-FIRE Tool for 2025.
Current distribution in thin film superconducting strip transmission line by Fredholm equation
We report on resistivity and chemical stability of Cr/Au bilayers deposited by sputtering on three kinds of substrates: alumina, aluminum nitride and aluminum nitride coated alumina. The insertion loss of Cr/Au microstrip lines fabricated on these three substrates was low and stable after 100 cycles in the -65 degree C to 125 degree C temperature range.
We have measured the dispersion in phase velocity of a Nb-SiO(x)-Nb microstrip transmission line resonator over a frequency range from 50 GHz to 800 GHz. A submicron Nb/Al-AlO(x)/Nb Josephson junction was used as a voltage-controlled oscillator to excite the high order modes in the resonator. The same junction is used as a direct detector resulting in a series of step-like structures in the DC current-voltage characteristic at the position of each mode frequency. The transmission line is dispersionless up to about 500 GHz where the phase velocity begins to decrease. This is well below the gap frequency f(sub g) approx. equals 700 GHz. Results agree qualitatively with the expected theoretical behavior near f(sub g). This onset of dispersion and loss in Nb transmission lines will have a significant impact on the design of submillimeter wave RF circuits.
Current distribution in thin film superconducting strip transmission line
A reference signal of RF frequency modulates a 0.85 micrometer wavelength optical transmitter. The output of which passes through a first optical filter and a voltage-controller phase shifter. The output of the phase shifter is provided to the fiber optic transmission line. At the receiving end of the transmission line, the signal is demodulated and used to modulate a 1.06 micrometer optical transmitter. The signal from the transmitter is provided to the fiber optic transmission line and passes through the voltage-controlled phase shifter to a phase error detector. The phase of the modulation of the 1.06 micrometer wavelength signal is compared to the phase of the reference signal by the phase error detector. A phase control signal related to the phase difference is provided to the voltage controlled phase shifter which alters the phase of both optical signals until a predetermined phase relationship between modulation on the 1.06 micrometer signal and the reference signal is obtained.