A 700-W peak ultra-wideband broadcast Doherty amplifier

Author

Qureshi, J.H. ; Sneijers, W. ; Keenan, R. ; deVreede, L.C.N. ; van Rijs, F.

Author_Institution

NXP Semicond. Nijmegen, Nijmegen, Netherlands

fYear

2014

fDate

1-6 June 2014

Firstpage

1

Lastpage

4

Abstract

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.

Keywords

UHF power amplifiers; digital video broadcasting; radio broadcasting; radio transmitters; LDMOS; broadcast transmitter; digital TV linearity; frequency 470 MHz to 803 MHz; high power Doherty design technique; optimized wideband input signal splitting; output capacitance compensation; passive phase input signal splitting; power 700 W; ultrawideband broadcast Doherty amplifier; wideband impedance inversion; Capacitance; Impedance; Power amplifiers; Power generation; Transmission line measurements; Transmitters; Wideband; Broadcast Amplifiers; Doherty; Power Amplifiers; Wideband Amplifiers;

fLanguage

English

Publisher

ieee

Conference_Titel

Microwave Symposium (IMS), 2014 IEEE MTT-S International

Conference_Location

Tampa, FL

Type

conf

DOI

10.1109/MWSYM.2014.6848495

Filename

6848495