OPTIMIZATION OF ACTIVE MICROWAVE FREQUENCY-MULTIPLIER PERFORMANCE UTILIZING HARMONIC TERMINATING IMPEDANCES

A primary factor affecting optimum performance of microwave multiplier s employing nonlinear devices is the proper termination of the fundame ntal and other harmonic frequency components. The objective of this pa per is to present a quantitative analysis leading to the assessment of optimum terminating impedances in the design of active frequency mult ipliers with special attention given to harmonics other than those des ired, The analysis includes computer modeled HEMT data and supporting measured data for corresponding circuit realizations. Circuit designs are presented utilizing HEMT transistors as the active element to veri fy modeled results. Based on available literature, the results demonst rate, for the first time, the quantitative effects of harmonic termina tion on active multiplier conversion gain and fundamental and higher h armonic suppression. An experimental design reveals an improvement in multiplier gain of 124% over the conventional approach and data is pre sented which quantitatively illustrates the advantages of impedance te rmination considerations under optimal bias conditions.