Frequency shifting in free-electron laser (FEL) oscillators and amplifiers is investigated theoretically and numerically. The analysis includes frequency shifts from the resonant FEL interaction and the nonresonant beam dielectric. Expressions for the frequency shift in a microwave amplifier with time-dependent beam energy and current are derived and found to be in good agreement with experimen...

Worldwide Interoperability for Microwave Access (WiMAX) is currently one of the hottest technologies in wireless; it’s a standard-based on the IEEE 802.16 wireless technology that provides high throughput broadband connections over long distance. The Worldwide Interoperability of Microwave Access (WiMAX) technology becomes popular and receives growing acceptance as a Broadband Wireless Access (...

This paper is written in response to many inquiries about 10 μ Free-Space Optics (FSO) performance compared to shorter wavelengths. The increasing interest in better understanding FSO weather effects is the result of carrier requests as well as recent progress in analyzing fog effects on FSO signal propagation. Extensive studies in modeling fog and simulating FSO attenuations revealed the compl...

It has recently been pointed out that generic models of quantum gravity must contend with severe phenomenological constraints imposed by gravitational Čerenkov radiation, neutrino oscillations and the cosmic microwave background radiation. We show how the non-critical Liouvillestring model of quantum gravity we have proposed escapes these constraints. It gives energetic particles subluminal vel...

Abstract Bessel, Bessel-Gauss, and Gaussian beams have widely been investigated in optics the paraxial approximation, under frame of a scalar wave theory. Such approximations can hardly be applied microwave/millimeter-wave range, where vectorial nature electromagnetic fields cannot neglected, experimental realizations for some these appeared only recently. In this work, we discuss generation th...