Radio -over-Fiber (RoF) technology is an integration of microwave and optical networks [1]. RoF technology uses optical fiber as a backend technology due to the enormous advantages offered by it. SCM-WDM RoF systems (Subcarrier based Wavelength division multiplexing RoF system) improves spectral efficiency with high dispersion tolerance [7]. The data to be transmitted is electrically modulated with an IF (Intermediate frequency)or a RF (Radio frequency) carrier and electrically multiplexed using a multiplexer these signals are further optically modulated using an optical modulator and multiplexed using WDM to exploit the high bandwidth offered by the optical fiber. A comparison between IF over fiber and RF over has been analyzed in terms of quality factor and BER (Bit error rate) in a RoF system. In which the IF over fiber shows better performance than RF over fiber in terms of BER and Quality factor. IF signals are up-converted using HBT (Hetero-junction bipolar transistor) electronic mixer in the remote antenna units to the RF frequencies with the help of LO (local oscillator) and transmitted wirelessly [27].
General TermsWireless communication systems, Optical fiber communication, Subcarrier multiplexing, Wavelength division multiplexing, Radio-over fiber systems.
Microwave power transistors play key role in today's wireless communication, necessary for virtually all major aspects of human activities from entertainment, business to military. HEMT is widely used due to its high speed and power amplification capabilities. The paper deals with comparison of Shockley's Model and the New Model of HEMT to evaluate its sensitivity to illumination to find its application in optical monolithic microwave integrated circuits(OMMIC).
Solar energy is an important part of life and has been in use since the beginning of time. Increasingly, man is learning how to yoke this important resource and use it to replace traditional energy sources. Solar cells are the development to store the solar energy and reproduce electricity. But the amount of energy converted is very less, that is the efficiency of conversion is poor. The main challenge is to improve the efficiency so that the losses can be minimized. The Maximum Power Points are found and the Fill Factor is calculated. Â The comparative study of silicon solar cell and panels with different sizes is done in this paper using MATLAB and SIMULINK model. The simulated results are compared with practically tested solar cell at Standard Test Conditions (STC).
In this paper the effect of an intensity-modulated Optical Signal on the Y parameters of a MESFET is studied theoretically. It shows that at a constant gate voltage the drain current of the device can be controlled by the intensity of incident optical power density and the frequency of the modulating signal frequency because the Y parameters of the device change with the intensity of incident optical power density and the frequency of the modulating signal .
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