We describe a novel oscillator that converts continuous light energy into stable and spectrally pure microwave signals. This light-induced microwave oscillator (LIMO) consists of a pump laser and a feedback circuit, including an intensity modulator, an optical fiber delay line, a photodetector, an amplifier, and a filter. We develop a quasilinear theory and obtain expressions for the threshold ...

Measurements of the frequency stability of a far-infrared molecular laser have been made by mixing the harmonic of an ultrastable microwave source with a portion of the laser output signal in a terahertz (THz) Schottky diode balanced mixer. A 3 GHz difference-frequency signal was used in a frequency discriminator circuit to lock the laser to the microwave source. Comparisons of the short- and l...

In this paper, a novel 3D model is proposed to describe the temperature distribution of the thermoelectric microwave power sensor. In this 3D model, the heat flux density decreases from the upper surface to the lower surface of the GaAs substrate while it was supposed to be a constant in the 2D model. The power sensor is fabricated by a GaAs monolithic microwave integrated circuit (MMIC) proces...

Microwave testing has the advantage of detecting surface and sub-surface flaws and anomalies under coatings, paint or dirt. Thus, major application of microwave sensors is imaging to determine the shape, size, and location of buried flaws using scattered field measurements. A typical microwave system consists of transmitting and receiving antennas and requires that both sides of the material un...

Microwave heating processes involve electromagnetic and thermal effects coupled together through the local temperature dependence of the material dielectric properties. This paper presents a one-dimensional model for the coupled electromagnetic-thermal process and demonstrates its solutions for typical problems. The local temperature dependence of the lossy dielectric medium is taken into accou...

A localized and strong RF magnetic field, created by a magnetic write head, is used to examine the linear electrodynamic properties of a Nb superconducting film. The complex reflection coefficient of the write head held in close proximity to the films is measured as a function of sample temperature. A model combining a magnetic circuit (magnetic write head inductively coupled to the sample) and...

We present a compact single monolithic microwave integrated circuit (MMIC) transmitter module for four-channel RF/optical subcarrier multiplexed (OSCM) communication applications. The developed module consists of one fully monolithic four-channel OSCM transmitter integrated circuit (IC) and four coupled-line filters. The MMIC is designed and implemented in a commercial 0.6m GaAs MESFET process ...

The assessment of an alternative six-port circuit in terms of frequency behavior when used to measure complex voltage ratio is presented. A numerical comparison to commonly used and well-known six-port circuits is carried out. The presented results can help us to choose between different six-port configurations depending on the application, and show that the proposed circuit is the most suitabl...

The voltage oscillations which occur in an ideally current-biased Josephson junction were proposed to make a current standard for metrology. We demonstrate similar oscillations in a more complex Josephson circuit derived from the Cooper pair box: the quantronium. When a constant current I is injected in the gate capacitor of this device, oscillations develop at the frequency f(B)=I/2e, with e t...

In this paper a new design of a broadband microwave power limiter is presented and validated into simulation by using ADS software (Advanced Design System) from Agilent technologies. The final circuit is built on microstrip lines by using identical Zero Bias Schottky diodes. The power limiter is designed by Associating 3 stages Schottky diodes. The obtained simulation results permit to validate...