Title :
Equal-gain loci and stability of a microwave GaAs MESFET gate mixer
Author :
Shimizu, Masahiko ; Daido, Yoshimasa
Author_Institution :
Fujitsu Lab. Ltd., Kawasaki, Japan
fDate :
1/1/1991 12:00:00 AM
Abstract :
The performance of a microwave GaAs MESFET gate mixer is theoretically investigated to clarify the existence of a conditionally stable RF frequency range as well as an unconditionally stable frequency range in which maximum available conversion gain (MACG) can be defined. For the unconditionally stable range, the MACG and load and source impedances are calculated as functions of RF frequency. For the conditionally stable range, the stability circle and equal gain loci are shown for source RF and load IF impedances. The conditionally stable region of the GaAs MESFET mixer appears around FT of the MESFET. Higher conversion gain is easily obtained by choosing a MESFET for which the FT is close to the RF frequency
Keywords :
III-V semiconductors; Schottky gate field effect transistors; gallium arsenide; mixers (circuits); solid-state microwave circuits; stability; GaAs; MACG; MESFET gate mixer; conditionally stable RF frequency range; equal gain loci; functions of RF frequency; load impedances; maximum available conversion gain; semiconductors; source impedances; stability; stability circle; unconditionally stable frequency range; Circuit noise; Circuit stability; Frequency conversion; Gallium arsenide; Impedance; MESFETs; Mixers; Radio frequency; Scattering; Sparse matrices;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
