MICROWAVE TRANSISTORS.

An analysis of the S- and C-band performance specifications is presented. Epitaxial structures of n on n and p on n on n have been grown. A spreading resistance probe has been assembled for evaluation of p- on n-type germanium epitaxial deposits. Planar bases have been successfully formed by both arsenic and antimony isolation diffusion in epitaxial and diffused layers. A heavy-doping approach to base and emitter formation was initiated. Several contact systems were investigated as n-type contacts. Epitaxial-base, planar germanium transistors have been characterized in detail. An improved equivalent circuit has been developed. A new ceramic package, called the Texas Instruments C-band transistor package, has been designed and is being fabricated. Techniques for measuring 50-ohms S-parameters of microwave transistors in the 1-4 GHz range were perfected. A tuning range of 763 MHz has been obtained in Teflon-Fiberglass series tuned circuit 1.811 to 2.574 GHz. Comparison of theoretical and experimental results has been good. A more complete and accurate set of design curves has been obtained. Masks for a modified ceramic parallel tuned circuit are being made. Both Si and GaAs Schottky barrier diodes have been evaluated satisfactorily as broad-band S-band mixers. The silicon diodes, when operated with only 0.2 mW of LO power, give noise figures of less than 7dB over the desired S-band frequency range. The stub lengths and characteristic impedances for a 3-stage preamplifier 1.7 to 2.4 GHz have been determined using chip L-148 S-parameters. Author