High performance lumped component Wilkinson power combiner distributed amplifier design
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Date
2010-01
Authors
Pragash Sangaran
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Abstract
The development of broadband power amplifier is critical for future radio technology.
Conventional broadband power amplifier has gain-bandwidth product limitation based
on transistor used. Distributed amplifier (DA) overcomes this limitation by combining
output power from several transistors in additive fashion. However, conventional
distributed amplifier has limitation in bandwidth as well. Adding devices beyond
optimum number will increase gate and drain line attenuation and will degrade the
power performance. Moreover, conventional distributed amplifier also exhibits low
power and efficiency due to the drain line reverse wave. In this project, lumped
component Wilkinson power combiner and splitter is used at the input and output of the
distributed amplifier respectively to increase the bandwidth, efficiency and output
power of a distributed amplifier. A lumped component Wilkinson combiner distributed
amplifier and a conventional distributed amplifier have been designed. The measured
performance of this novel lumped component Wilkinson combiner distributed amplifier
had been compared with the conventional distributed amplifier using the same number
of devices, layout and dc supply. These amplifiers have frequency range from 100 MHz
up to 610 MHz and from 100 MHz to 520 MHz with output power of 26.25 dBm to
29.56 dBm and 24.11 dBm to 28.51 dBm respectively. PAE ofLC Wilkinson combiner
DA is varies from 26.2 % to 36 % whereas P AE of conv.entional DA is varies from 20.5
% to 26.5 %. The amplifier had been fabricated ln a 14-mil thick printed circuit board
(PCB) with a dielectric constant of 4.5. Measured results of the fabricated board have
been found to be comparable to simulation results.
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Keywords
Conventional broadband power amplifier has gain-bandwidth product , limitation based on transistor used.