×

Output universality in maximum efficiency linear power amplifiers. (English) Zbl 1026.94553

Summary: A general linear passive termination is considered for a typical field effect power transistor such that the first \(m\) odd harmonics, excluding the fundamental frequency, are open circuited with the remaining harmonics short-circuited. Under this termination, with the appropriate resistive termination at the fundamental frequency, it is shown that an optimum maximum efficiency of \[ {\eta}=\frac {\pi}{2(m+1)}\cot \Biggl[\frac {\pi}{2(m+1)} \Biggr] \] is universally achieved independent of nonlinearities in the transistor. Furthermore, where higher ordered harmonics are terminated in finite reactive impedances, which is the case with any realizable network, it is shown that the same maximum efficiency is obtained with the correct complex termination at the fundamental frequency.
A prototype network is then defined including the output capacitance of the transistor and synthesized in a lowpass form which, when terminated in a shunt resonant circuit and load resistor, will provide the correct impedances at the fundamental and all of the harmonics. Remarkably, this optimum network has a simple formula for the element values in the general \((2m+1)\)th degree network, and a rigorous proof is presented in the appendix.

MSC:

94C05 Analytic circuit theory
PDFBibTeX XMLCite
Full Text: DOI

References:

[1] RF Power Amplifiers for Wireless Communications. Artech House, 1999; ISBN 0-89006-989-1.
[2] Raab, IEEE Transactions of MTT 49 pp 1162– (2001)
[3] Raab, IEEE Transactions on MTT 49 pp 1462– (2001)
[4] Raab, IEEE Transactions of MTT 45 pp 2007– (1997)
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.