Title: STOCHASTIC ELECTRON TRAJECTORIES AND WAVE INTERACTION IN RELATIVISTIC GYRO-TRAVELING-WAVE AMPLIFIERS. Roland Ngogang, Master of Science, 2005 Directed By: Professor Victor L. Granatstein, Department of Electrical Engineering Gyro-traveling-wave amplifiers (gyro-TWAs) are types of gyrodevices, which take advantage of the cyclotron maser instability to produce coherent electromagnetic (EM)...

Typically two configurations are used for energy harvesting with different advantages: piezoelastic and piezomagnetoelastic. Best performance of the piezoelastic configuration is when the excitation frequency is close to the resonance frequency. If the input frequency slightly deviates from the natural frequency, the generated power is severely decreased. To tackle the problem, the piezomagneto...

In this study, snapshots of operating frequency profiles of domestic microwave ovens were collected to reveal the extent of microwave frequency variations under different operation conditions. A computer simulation model was developed based on the finite difference time domain method to analyze the influence of the shifting frequency on heating patterns of foods in a microwave oven. The results...

1. We measured spatial and temporal sensitivity of 81 X-cells and 46 Y-cells in the lateral geniculate nucleus of cats by determining contrast thresholds of single cells to counterphased, sine-wave gratings. The plots of contrast sensitivity (reciprocal of the contrast threshold) as a function of spatial or temporal frequency of the sine-wave grating represent the contrast sensitivity functions...

2014 The analysis of possible phenomena in the superconductor-constriction-superconductor (S-c-S) junctions inserted into microwave circuits is carried out. The results of experiments in which properties of the junctions making them different in comparison with usual nonlinear microwave elements were studied are discussed. The characteristics of receiving devices such as amplifiers, detectors a...

There has recently been considerable interest in the possibility, both theoretical and practical, of invisibility (or “cloaking”) from observation by electromagnetic (EM) waves. Here, we prove invisibility with respect to solutions of the Helmholtz and Maxwell’s equations, for several constructions of cloaking devices. The basic idea, as in the papers [GLU2, GLU3, Le, PSS1], is to use a singula...

Articles you may be interested in High efficiency coupling of radio frequency beams from the dual frequency gyrotron with a corrugated waveguide transmission system Rev. Dual cylindrical metallic grating-cladding polymer hollow waveguide for terahertz transmission with low loss Appl. Magnetic metal cladding gives better attenuation in small waveguides operating at high microwave frequencies tha...

Inductive powering for implanted medical devices, such as implantable biosensors, is a safe and effective technique that allows power to be delivered to implants wirelessly, avoiding the use of transcutaneous wires or implanted batteries. Wireless powering is very sensitive to a number of link parameters, including coil distance, alignment, shape, and load conditions. The optimum drive frequenc...

We demonstrate heterodyne mixing of a 94 GHz millimetre wave photonic signal, supplied by a Gunn diode oscillator, with coherent acoustic waves of frequency ~100 GHz, generated by pulsed laser excitation of a semiconductor surface. The mixing takes place in a millimetre wave Schottky diode, and the intermediate frequency electrical signal is in the 1-12 GHz range. The mixing process preserves a...

Polarization-control devices have attracted considerable interest, however, most of the polarization converters operating at lower frequencies a heavy design and narrow bandwidth which limits their practical applications. Here we report simple an ultra-wideband lightweight converter for applications in S- C-bands. The proposed is designed based on metasurface structure with dielectric layer mod...