Two different interfaces for optical confinement in GaAs resonators (air/GaAs/air, air/GaAs/AlOx) are compared in cylindrical microstructures with 10 μm diameter. The AlOx is obtained by the lateral oxidation of AlGaAs layers. The spectrum of the resonators is obtained using a tapered fiber system in the wavelength range of 1470nm to 1610nm. The modal separation agrees with our simulation. The quality factor for cylindrical microstructures with air/GaAs/air interface is almost twice the case with AlOx interface. Since it is expected that surface recombination velocity is reduced by a factor of ten for this last case, these structures are shown to be suitable for active resonators.
This paper presents the bandwidth enhancement of a Planar Inverted F-Antenna (PIFA) up to 1.55 GHz as results of adding slots in the radiator element of the structure. The S-Parameters, gain, and radiation pattern after analyzed were used for comparison purpose with a published PIFA model. The simulations were made using the commercial software CST Design Studio. As result, a bandwidth enhancement of approximately 53% was achieved.
This paper presents the modeling and control design of an isolated full-bridge boost converter fed by a photovoltaic (PV) device. The converter and PV device are modeled using the method of average state variables and the controller is designed with the state-space feedback control technique, using concepts of characteristic polynomial, controllability and Ackerman's matrix. The dynamic model of the converter is obtained and the voltage controller is designed in order to achieve the regulation of the input voltage of the boost converter, thus allowing the direct control of the PV voltage, which brings advantages when this system is compared to traditional control strategies for grid-tie PV converters. Streszczenie. W artykule zaprezentowano modelowanie i projekt sterowania izolowanym pełnomostkowym, przekształtnikiem typu boost zasilanym przez ogniwo fotowoltaiczne. Zbadano właściwości dynamiczne. Układ sterowania jest tak zaprojektowany żeby osiągać prawidłowy poziom napięcia. Pełnomostkowy przekształtnik typu boost sterowany sprzężeniem zwrotnym typu state-space stosowany do współpracy z ogniwem fotowoltaicznym.
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