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ANTENNA ACCESSORIES 147
ANTENNA ACCESSORIES
Attenuator
PLINIO R. G. ALVES LEONARDO R. A. X. MENEZES PAULO H. P. CARVALHO FRANKLIN C. SILVA
University of Brasilia Brasilia, DF, Brazil
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1. ATTENUATORS Attenuators are circuits designed to introduce a wellknown loss between input and output ports [1]. The power ratio, expressed in decibels, between input and output represents the loss in these circuits. The main use of attenuators is in measurement of the standing-wave ratio (SWR) in antennas and of the transmission coefcient. In the case of the SWR measurement [2], a variable-loss attenuator is used between the generator and the slotline. One adjusts the attenuation value to maintain equal outputs in the stationary wave detector at the maximum and minimum p
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