Sun, 06 Jul 2008 11:01:33 BST CiteULike: dcastros Hanington http://www.citeulike.org/user/dcastro/author/Hanington CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/2762226 <i>Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 1 (1998), pp. 327-330 vol.1.</i><br /><br />This paper presents several power amplifier approaches that promise to significantly improve efficiency, while meeting the linearity requirements of advanced, spectrally efficient wireless systems. The approaches include: a) use of active integrated antenna structures that provide harmonic terminations for high efficiency Class F amplifiers; b) integrated dc-dc converters for power conditioning and envelope restoration; c) switching mode amplifiers based on bipolar transistors with controlled saturation; and d) the use of band-pass delta-sigma modulators to tailor input signals Device and circuit approaches for improved linearity and efficiency in microwave transmitters PM Asbeck T Itoh Y Qian MF Chang L Milstein G Hanington PF Chen V Schultz DW Lee DW Lee J Arun A10 doi:10.1109/MWSYM.1998.689385 Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 1 (1998), pp. 327-330 vol.1. 2008-05-06T18:30:58-00:00 1998 Microwave Symposium Digest, 1998 IEEE MTT-S International 1 327 330 vol.1 efficiency microwave transmitter http://www.citeulike.org/user/dcastro/article/2762148 <i>Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 2 (1998), pp. 589-592 vol.2.</i><br /><br />This paper presents a technique for raising power efficiency in portable wireless transmitters by integrating a variable voltage output DC-DC converter together with a MESFET RF power amplifier. Significant increases in power efficiency are obtainable over a large range of output power levels. The system includes an envelope detector, a closed feedback loop, and a pulse width modulator operating at 10 MHz. A 300 mW transmitter is shown for which battery life can be extended by over 1.4 times Microwave power amplifier efficiency improvement with a 10 MHz HBT DC-DC converter G Hanington PF Chen V Radisic T Itoh PM Asbeck doi:10.1109/MWSYM.1998.705062 Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 2 (1998), pp. 589-592 vol.2. 2008-05-06T17:42:50-00:00 1998 Microwave Symposium Digest, 1998 IEEE MTT-S International 2 589 592 vol.2 amplifier power