United States Patent Number: 7,135,931, November 14, 2006. 15 pages. Also available from the United States Patent and Trademark Office. Website: http://www.uspto.gov.
NOTE: At the time of publication, the author Vladimir Prodanov was not yet affiliated with Cal Poly.
Power amplifiers are disclosed that demonstrate improved linearity and efficiency in applications requiring significant peak-to-average ratios (PAR). A power amplifier in accordance with the present invention comprises a first transistor in an input stage that converts DC power into AC power; and a second transistor in a negative conductance stage that has a current-voltage characteristic with at least two slopes. The at least two slopes of the current-voltage characteristic are separated by a break point that may be controlled. The power amplifier may also include a non-dissipative two-port device that has two AC ports. The non-dissipative two-port device has a Z matrix with two zero-valued diagonal elements and two complex valued off-diagonal elements having a same sign and only imaginary parts for an operating frequency. In one implementation, the diagonal entries of the Z matrix are small at twice the operating frequency.
Electrical and Computer Engineering