Abstract
This thesis is a comprehensive study of how harmonic terminations can greatly increase a power amplifier's efficiency (PAE). To show this improvement, the PHEMT amplifier is biased in the low noise region of operation (L, = 20 mA, Vd, = 3 V) and operated at a frequency of 2.2 GHz. An attempt is made to generate a working model which characterizes the amplifier's performance with and without harmonic termination. Both measured and modeled data are compared in order to verify the model's performance. Once a working model is realized, the designing of an amplifier can be done by simulation without the cumbersome task of taking measurements. The measured data is obtained using an electronic load pull system which is capable of rapid data acquisition. This study shows that when harmonic termination is used, the PAE can improve in some cases by about 15 % depending upon the operating conditions of the device. This improved PA-E can result in longer operational lifetimes of devices such as cellular phones and reduce the size of these units. Longer lifetimes are extremely important especially for space applications where replacement of power supplies is very costly. Power measurements as well as relevant intermodulation distortion measurements are also done for Class A and Class B operation in order to show the advantages and disadvantages of each.
Strassner, Bernd Herbert (1997). Nonlinear harmonic modeling of phemt devices for increased power amplifier efficiencies. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1997 -THESIS -S765.