A 700-W peak ultra-wideband broadcast Doherty amplifier

A wideband high-power Doherty design technique enabling fractional bandwidths > 50% is described. It utilizes wideband impedance inversion, device output capacitance compensation and passive phase-optimized wideband input-signal splitting. As prove of concept a LDMOS based ultra-wideband broadcas...

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Bibliographic Details
Main Authors: Qureshi, J. H., Sneijers, W., Keenan, R., deVreede, L. C. N., van Rijs, F.
Format: Conference Proceeding
Language:English
Subjects:
Broadcast Amplifiers
Capacitance
Doherty
Impedance
Power amplifiers
Power generation
Transmission line measurements
Transmitters
Wideband
Wideband Amplifiers
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Description
Summary:A wideband high-power Doherty design technique enabling fractional bandwidths > 50% is described. It utilizes wideband impedance inversion, device output capacitance compensation and passive phase-optimized wideband input-signal splitting. As prove of concept a LDMOS based ultra-wideband broadcast Doherty amplifier is presented, which covers the UHF-TV 470MHz-803MHz (BW rel = 52%) band with average efficiencies between 38%-47% @P avg > 115W while maintaining peak power capability > 700W over the entire band. Predistortability is demonstrated by satisfying the digital TV linearity requirements (-38dBc) using a commercial DVB-T exciter. The proposed DPA is an excellent drop-in replacement for the low-efficiency wideband PA blocks currently in use in broadcast transmitters.
ISSN:0149-645X
2576-7216
DOI:10.1109/MWSYM.2014.6848495