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The design and experiment of an upgraded W-band gyrotron travelling wave amplifier (gyro-TWA) based on a helically corrugated interaction region is presented. The upgrade of the input coupler, output window, corrugated output mode converter enabled a measured output power of a few kWs from the gyro-TWA with an unsaturated gain of up to 40 dB and a 3 dB frequency bandwidth of at least 5.5 GHz.
This paper reports the development and evaluation of a ultra-small and ultra-light wireless sensor node for real time monitoring of biological information of animals. Power consumption of the sensor node was decreased dramatically by improving efficiency of the MCU and irradiation power of the RFIC, which enables a few months life time when using SR416SW batteries. Various configurations of the antenna...
In this paper, quasi-optics and its application in millimeter waves and THz bands are introduced. Firstly, a quasi-optical monopulse antennas are illuminated, one is combination of lenses and quasi optical sum difference network; another consists of beam guide and quasi optical sum difference network. The simulations and experimental results are presented. Then, quasi optical beam power combining...
This paper presents the development of an implantable wireless sensor node for bio-logical information monitoring of animals. Power consumption was evaluated and then decreased dramatically by improving the efficiency of the MCU, which enables >4 months lifetime when using CR1220 battery for body temperature monitoring. Various configuration of the antenna were investigated for the pursuit of small...
Latest experimental developments of W-band gyro-devices with helically corrugated waveguides and a cusp electron gun are presented. The cusp generated a 40 keV, 1.5 A axis-encircling electron beam. Helical corrugated waveguides have ideal dispersive properties which improve the frequency tuning range of a gyrotron backward wave oscillator (gyro-BWO) whilst maintaining the already good efficiency of...
In this work, we investigated the failure behavior of a commercial chip size packaging (CSP) under coupling fields of electrical current and thermal cycles. The failure process was real-time monitored through the response resistance change. Under the coupling condition, the lifetime was much shorter than that in single thermal cycle condition. Instead of the void accumulation mechanism, the excessive...
Devices based on wide-band gap semiconductors such as SiC, GaN allow high power densities, size reduction, high integration and elevated operating temperatures. In this study, we present solutions for high temperature power packages based on finite element simulations and experimental approach. Analytical methods are used to investigate the best choice among the different selected materials for the...
We have studied Co60 ionizing radiation effect on the characteristics of Type IA fiber Bragg gratings. A record Bragg peak shift of 190 pm was observed for a grating written in Fibercore PS-1250/1500 photosensitive fiber at a radiation dose of 116 kGy. Type IA and Type I gratings show different kinetics under radiation and during post-radiation annealing, which can be used for the design of a grating...
The electric-field control of magnetization has many potential applications in magnetic memory storage, sensors, and spintronics. A new multiferroic spin-valve (SV) heterostructure was grown by combining a multiferroic (BFO) and a spin valve on /Si substrate. Through the magnetoelectric...
This paper presents a mathematical model-based approach for tracking maximum power point of photovoltaic array. The array voltage corresponding to the maximum power point is directly calculated from measurements of irradiance and cell temperature. The proposed method is suitable for small stand-alone photovoltaic systems with using limited computing power. This scheme not only operates in high performance,...
Cooling was a very effective way to eliminate the bow of Silicon solar cell. In this paper, by a series of experiments, we found that during the cooling, the electrical characteristics and internal or external quantum efficiency nearly stayed the same, and the lifetime of minority carriers as well. The cooling was a available way to apply in industrial process.
The I-V characteristics of ZnO-based varistor ceramics were investigated in a wide temperature range of 93 K-373 K. From the relationship between overall conductance and temperature, individual conductance component having different temperature dependence can be separated and analyzed. In addition, the equivalent circuits can be developed as well. As to ZnO-Bi2O3 system, the overall conductance is...
The silicide growth over the spacers (bridging) in the conventional self-aligned silicide process using titanium disilicide is dominated by the lateral diffusion of Si atoms from the gate and source/drain areas. A TiN cap layer, which has been suggested to minimize the bridging problem was studied. The influence of such a capping layer on the reaction between Ti and Si, on the lateral diffusion of...
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