GaAs Schottky varactor diode optimization for high-performance nonlinear transmission lines

Nonlinear transmission lines (NLTLs) using Schottky diodes as varactor loads provide significant performance and efficiency advantages for both frequency multiplication and phase shifting applications that will benefit comb generator and phased array applications, respectively. Prior NLTL optimization has been limited only to analytical studies of specific diode profiles. This paper describes, for the first time, the optimization of NLTL performance through the design, simulation, and fabrication of five different experimental GaAs diode doping profiles. Fabricated device and circuit data from the different wafers are presented and compared. To the knowledge of the authors, these NLTLs demonstrate the least conversion loss for any comb generators driven at 1 GHz.