IEEE S.F. Bay Area Council e-GRID's
BayAreaTech

THURSDAY March 8, 2012
SCV Microwave Theory and Techniques Chapter
Speaker: Dr. George Vendelin
Time: Networking and snacks at 6:00 PM; Presentation at 6:30 PM
Cost: none
Place: Agilent Technologies, 5301 Stevens Creek Boulevard, Santa Clara
RSVP: not required
Web: www.e-grid.net/calendar.html

There are three different microwave amplifiers which benefit from lossless feedback:
(1) High Gain – Mason 1954 – where we achieve |S12| = 0 and the two-port gain is:
U = 1/2 |S21/S12 – 1 |^2 / k(S21/S12 – Re(S21/S12)
(2) Low Noise – Vendelin 1975 – where we achieve NFmin and |S11′| = 0 simultaneously, usually using an inductor in the emitter/source
(3) High Power – Zuo-Min Tsai et.al. April 2006 – where we achieve P1dBcmax and |S22′| = 0 simultaneously, usually using a capacitor in the emitter/source
Notice that (2) and (3) are duals of each other.
All of these designs are fairly narrow band (>5%) which is sufficient for many applications.? Only linear S-parameters are needed.? Nonlinear models should predict the same performance.