Axions in the microeV mass range are a plausible cold dark-matter candidate and may be detected by their conversion into microwave photons in a resonant cavity immersed in a static magnetic field. We report the first result from such an axion search using a superconducting first-stage amplifier (SQUID) replacing a conventional GaAs field-effect transistor amplifier. This experiment excludes KSV...

A layer-encoded interactive evolutionary algorithm (IEA) for optimization of design parameters of a monolithic microwave integrated circuit (MMIC) low noise amplifier is presented. The IEA comprises a combination of the genetic algorithm (GA) and the particle swarm optimization (PSO) technique. The layer-encoding structure allows human intervention in order to accelerate the process of evolutio...

A ferroelectric cathode is employed for the first time as the electron-beam source in a microwave amplifier tube. A PLZT 12/65/35 ferroelectric ceramic with a high dielectric constant ( 4000) is used in a form of a hollow cathode. The tube is operated in poor vacuum conditions (2 10 Torr) at room temperature, in a mechanism of a cyclotron-resonance maser amplifier. The device operates near the ...

We present a method for the measurement of the noise of microwave amplifiers operating at the single photon level. It is based on the shot noise produced by a nanowire resistor in the hot electron regime. This noise source is simply controlled by a dc current and offers the advantage of being self-calibrating. After testing the noise source with a cryogenic high electron mobility transistor amp...

Formulas for the noise figure, and the minimum uoisefigure of a multi-link distributed amplifier have been developed. In addition, a relatively simple approximation formula has been devised that predicts the minimum noise figure of a practicaf amplifier design with good accuracy np to frequencies of 9 GHz. Finafly, after the dependence of the noise characteristics on the circnit parameters is d...

High Frequency Current Mode Class-D Amplifiers With High Output Power and Efficiency By Anthony Lawrence Long A 13 watt Current Mode Class-D (CMCD) with 60% efficiency is presented. This amplifier is the highest power switch mode microwave power amplifier reported to date. The CMCD architecture is an improvement over the Voltage Mode Class-D in that the parasitic reactance in the active device ...

ETRI Journal, Volume 30, Number 1, February 2008 ABSTRACT⎯A highly linear and efficient GaN HEMT Doherty amplifier for wideband code division multiple access (WCDMA) repeaters is presented. For better performance, the adaptive gate bias control of the peaking amplifier using the power tracking circuit and the shunt capacitors is employed. The measured one-carrier WCDMA results show an adjacent ...

This paper is focused on a model for the power amplifier considering the memory effects in short terms, this work was developed for periodic signals through Matlab software and was implemented in Simulink. This model for the power amplifier implements a Memory-Polynomial models. Memorypolynomials prove to be both accurate and easy to implement and was compared with Ghorbani and Saleh quasi-memo...

We have performed spectroscopic measurements of a superconducting qubit dispersively coupled to a nonlinear resonator driven by a pump microwave field. Measurements of the qubit frequency shift provide a sensitive probe of the intracavity field, yielding a precise characterization of the resonator nonlinearity. The qubit linewidth has a complex dependence on the pump frequency and amplitude, wh...