In this paper, we present our progress toward designing a “smart” high-peak power microwave (HPM) tube. We use iterative learning-control (ILC) methodologies in order to control a repetitively pulsed high-power backward-wave oscillator (BWO). The learning-control algorithm is used to drive the error between the actual output and its desired value to zero. The desired output may be a given power...

This paper presents a set-up which enables the generation and the calibrated time domain measurements of complex envelopes of modulated signals at both ports of non linear microwave power amplifiers. The architecture of the characterization tool is given. Examples of error corrected time domain envelopes at the input / output RF ports of a 36 dBm output power – 30dB power gain L-band SSPA are s...

Future linear colliders will require a very high peak power per meter of accelerating structure at a relatively high frequency-greater than 10 GHz-but at a relatively short pulse length-less than 100 ns. One technique for generating the required peak power is to use a more or less conventional microwave power source, which produces power at a pulse length typically on the order of 1 ps, togethe...

the cost of drying carpet which is done toward the end of the manufacturing process, is quite high. the carpet industry has been using convection drying for many years. little attention has been given to quantifying the effect of microwave power during the drying of carpet. an experimental system was developed whereby air was introduced into the cavity of a domestic microwave oven. the results ...

Microwave radiation is widely used for heating tissues in hyperthermia or diathermy medical treatments. Usually, in such treatments, the tissue’s temperature is used as feedback for the microwave generator power control and consequently, for the control of the whole heating process. The temperature can be measured by contact, or non-contact (IR or MW radiometry), techniques. Unfortunately, in b...

The Doherty power amplifier (DPA) is one of the most popular power amplifier architectures for obtaining high average efficiency for modern communication signals with high peak-to-average power ratios (PAPR). However, the DPA suffers from often having narrowband performance which limits its capabilities in wideband and/or multi-standard microwave and radio frequency applications. In this thesis...

energy and mass transfer investigations in thermal processing of fruits serve as a breakthrough in the design and scale up of drying systems. diffusivity characteristics and specific energy consumption for drying of fig fruit in a laboratory scale microwave dryer were assessed. several intervals for microwave power intensity including 0.5, 1, 1.5, 2, and 2.5 w g-1, and 6 levels of power on-off ...

The GaN material parameters relevant to the negative di€erential resistance (NDR) devices are discussed, and their physical models based on the theoretical predictions and experimental device characteristics are introduced. Gunn diode design criteria were applied to design the GaN NDR diodes. A higher electrical strength of the GaN allowed operation with higher doping ( 10 cmÿ3) and at a higher...

High-output-power and high-bandwidth performances are usually two tradeoff parameters in the design of high-speed photodetectors. In this letter, we report high peak-output-voltage ~;20 V! and peak-output-current ~;400 mA, 50 V load! together with ultrahigh-speed performances ~1.5 ps, 220 GHz!, observed in low-temperature-grown-GaAs ~LTG-GaAs! based metal-semiconductor-metal ~MSM! traveling-wav...

Frequency multipliers based on superlattice (SL) devices as nonlinear elements have been developed as radiation sources for a terahertz (THz) laboratory spectrometer. Input frequencies of 100 and 250 GHz from backward wave oscillators have been multiplied up to the 11th harmonic, producing usable frequencies up to 2.7 THz. Even at these high frequencies the output power is sufficient for labora...