Millimeter wave propagation in transmission lines with magnetized semiconductor element

Journal of Infrared, Millimeter, and Terahertz Waves - The peculiarities of electromagnetic wave propagation in transmission lines with a gyromagnetic semiconductor element are analysed....     

Phase-matched second harmonic generation and parametric mixing on nonlinear transmission lines

Phase-matched parametric coupling between forward and backward waves on a high frequency transmission line is achieved by periodic nonlinearity. An efficiency of more than 90% in the case of frequency doubling is experimentally observed as well as parametric mixing and parametric amplification with a gain of nearly 30 dB.     

GaAs nonlinear transmission lines for picosecond pulse generation and millimeter-wave sampling

The GaAs nonlinear transmission line (NLTL) is a monolithic millimeter-wave integrated circuit consisting of a high-impedance transmission line loaded by reverse-biased Schottky contacts. The engineering of functional monolithic NLTLs is considered. Through generation of shock waves on the NLTL, the authors have generated electrical step functions with approximately 5 V magnitude and less than 1.4 ps fall time. Diode sampling bridges strobed by NLTL shock-wave generators have attained bandwidths approaching 300 GHz and have applications in instruments for millimeter-wave waveform and network measurements. The authors discuss the circuit design and diode design requirements for picosecond NLTL shock-wave generators and NLTL-driven sampling circuits.<>     

Analysis of lumped-parameter nonlinear transmission lines

A lumped-parameter nonlinear transmission line is analysed rigorously. The method of analysis is applicable to travelling-wave harmonic generators, parametric amplifiers and nonlinear time-variable delay lines.     

Millimeter wave antennas

Major advances in millimeter-wave antennas have been made in recent years, in particular in two areas. A new class of leaky-wave antennas based on open millimeter waveguides has been proposed and investigated, and substantial progress has been achieved in integrated antennas where active and passive circuits, possibly in monolithic form, are combined with the radiating elements in one compact unit. Interesting developments have taken place also in a third group of millimeter-wave antennas, that of microstrip antennas and printed circuit antennas in general. An attempt is made to summarize these developments     

Millimetre-wave second harmonic generation on a nonlinear transmission line

Phase-matching between two forward waves on a monolithic nonlinear transmission line is achieved by alternating the length of the interconnecting transmission lines. With an input of 20 dBm at 50 GHz, amplitudes up to 1 V at 100 GHz have been measured by direct electro-optic sampling.<>     

Compact model generation for on-chip transmission lines

An approach for the fast and accurate generation of compact distributed circuit models for on-chip transmission lines on lossy silicon substrates is presented. Using a novel ABCD matrix partitioning procedure, accurate distributed circuit models are extracted from scattering parameters obtained from measurements and calibrated full-wave electromagnetic simulations for a small set of transmission-line geometries spanning ranges of design parameter values. A feedforward artificial neural network is trained using the extracted results, and applied to generate accurate compact models for arbitrary values within the bounds of the training ranges. Consequently, the model generation time is greatly reduced compared to conventional approaches by exploiting the interpolation capabilities of the neural network. The compact model generator is fully compatible with HSPICE and SPECTRE-RF and is easily incorporated into parasitic-aware RF circuit design and optimization tools.     

Standing wave oscillators utilizing wave-adaptive tapered transmission lines

In this paper, we introduce a novel standing wave oscillator (SWO) utilizing standing-wave-adaptive tapered transmission lines. This structure enhances Q and lowers phase noise through loss-reducing shaping of the transmission line, such that it is adapted to the position-dependent amplitudes of standing waves. Measurements validate the advantages of the proposed technique. The phase noise of a MOS SWO with the tapered line is 5-10 dB less than that of a uniform-line MOS SWO over a wide range of offset frequencies, centered about 15 GHz. Demonstrating a valuable exploitation of standing wave properties, the novel design concept boosts the potential for the emergence of standing wave oscillators as a useful alternative to the traditional lumped LC oscillator.     

Frequency tuning in electromagnetic bandgap nonlinear transmission lines

Frequency tuning in stopband filters based on nonlinear transmission lines is demonstrated for the first time. The structure is an electromagnetic bandgap (EBG) coplanar waveguide reflector periodically loaded with varactor diodes, acting as tuning elements. By varying the capacitance of the diodes the phase velocity can be tailored, the result being a wide tuning range for the central frequency of the rejected band. It was also found that the EBG-based reflector is able to inhibit harmonic generation under large-signal driving conditions.     

Pulse propagation along certain lumped nonlinear transmission lines

A lumped RGC transmission line having a switch in series with G (switch open for voltages greater than some fixed threshold; switch closed otherwise) and a shunt battery-resistor combination in each section is considered. It is shown that, although there exist two distinct resting states for each section, it is not always possible to switch the entire line from one state to the other, and it is never possible to propagate a pulse along such a line. Modifications are suggested in order to obtain pulse propagation.     

Millimeter wave microstrip circulator

A new and unique microstrip “drop-in” type Y-junction circulator has been designed and developed for operation in the millimeter wave frequency region. This device utilizes NiZn ferrite as the gyromagnetic material which is mounted on a duroid substrate.     

Millimeter wave self-mixing oscillators

Self-oscillating mixers in both dielectric and waveguide cavities have veen investigated in the 60 GHz frequency range. The deveces consist of negative resistance diodes of GaAs and InP material coupled to waveguide cavities or high resistivity dielectric cavities such as silicon or Al₂O₃. Experimental measurements show that these devices have a sensitivity in the order of ?80 dBm with the intermediate frequency at 60 MHz and an IF bandwidth of 120 MHz. Applications are suggested based on minimum detectable signal and RF power capabilities for systems requiring small size and low cost.     

端接非线性负载的非均匀传输线瞬态分析

在均匀多导体传输线的时域有限差分法(FDTD)基础上,对非均匀多导体传输线及端接非线性负载的情况进行了分析。结果表明：对于非均匀多导体传输线,采用FDTD法进行瞬态分析极为方便,并且可以处理端接非线性负载的情况;同时,还可获得线上各点的电压、电流波过程。通过实例验证了所提出的FDTD算法的有效性,可用于传输线波过程的研究。     

Wave propagation in nonlinear transmission lines with simple losses

Heaviside's condition for distortionless wave propagation in linear transmission lines with losses is generalised to cover nonlinear transmission lines. Analytical expressions are given for voltage and current in these lines.     

Millimeter/submillimeter nonlinear spectroscopy

The techniques of coherent transient spectroscopy have been successfully applied to the microwave and optical regions of the spectrum, but lack of suitable sources has prevented convenient extension to the millimeter/submillimeter region where several strong molecular transitions occur. Analysis of the experimental requirements and theory for such experiments considering several molecules including H₂O and CH₃Cl indicates how such experiments can be performed employing recently developed oscillators with increased power.     

Millimeter wave QWITT diode oscillator

The quantum well injection transit time (QWITT) diode charecteristics, small signal and large signal device models are used. A peak output power density of 35–5 KW/Cm² in the frequency range of 5–8 GHZ hasx been obtained from a planar QWITT Oscillator     

Millimeter wave imaging lens antenna

The factors which influence the design of lenses suitable for imaging at millimetre wavelengths are discussed. Examples are given of optical designs for a military tracking application, firstly for use with an open ended waveguide array, and secondly for use with monolithic arrays, each covering a field of view of ±20°.     

Capacitance free generation and detection of subpicosecondelectrical pulses on coplanar transmission lines

By reanalyzing an earlier experiment to generate subpicosecond pulses using photoconductive switches (M.B. Ketchen, et al., Appl. Phys. Lett., vol.48, pp.751-753, 1986), it is shown that to first order, the sliding-contact generation site has no capacitance. This conclusion is further supported by a double sliding-contact experiment where, to first order, neither the generation nor the detection site has any capacitance. This result removes the parasitic capacitance of the electrical circuit as one of the major difficulties to short electrical pulse generation using photoconductive switches