HIGH EFFICIENCY pHEMT BALANCED POWER AMPLIFIER DESIGN USING LOAD PULL TECHNIQUE
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Date
2011-01
Authors
VIJAYAKUMARAN, LOKESH ANAND
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Abstract
A rapid increase in transmission capacity is required to meet the needs of the multimedia
society. In broadband power amplifier design, a key element is maintaining flat gain
across band while providing good efficiency and high output power. Commonly this is
addressed using the single stage amplifier design. But in reality, to achieve high
efficiency while maintaining good output power usually not practical with a single stage
amplifier design. Alternatively, few stages of amplifier can achieve this and this is the
point where balanced amplifier design comes into picture. Implementation of the push
pull configuration using uniplanar technology is very desirable for microwave as it can
create a high performance low cost compact amplifier. This thesis provides suitable
design method to achieve high efficiency of single balanced amplifier based on load pull
techniq:Je. The device technology is using pseudomorphic High Mobility Electron
Transistor (pHEMT) having gate-width of 6400-J..tm. Wideband baluns were used to
achieve balance to unbalanced characteristics. A test board with FR-4 material having
dielectric of 4.5 and thickness of 14 mils was fabricated. Power-aided-efficiency (PAE)
of more than 50 %, output power of 1 W and gain of 14 dB for the entire range 1-
1.5 GHz is achieved at measurement level. These results show the feasibility of the
balanced pHEMT amplifier configuration using load pull technique for micro'vave
applications. This high efficiency design is favorable candidate for two way portable
radios where the radio is required to operate over a large number of channels for long
period from a small size battery.
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HIGH EFFICIENCY pHEMT BALANCED POWER AMPLIFIER