Title :
A monolithic broadband doubly balanced EHF HBT star mixer with novel microstrip baluns
Author :
Ryu, Y.I. ; Kobayashi, K.W. ; Oki, A.K.
Author_Institution :
RF Product Center, TRW Inc., Redondo Beach, CA, USA
Abstract :
This paper describes a planar MMIC HBT Schottky diode mixer utilizing novel baluns fabricated on a 4 mil thick GaAs substrate. The balun is based on the Marchand balun structure and is implemented in a microstrip environment. The balun structure consists of 7 closely coupled microstrip lines and backside vias. Four 10/spl times/10 /spl mu/m/sup 2/ HBT Schottky diodes in a star configuration provide the mixing function. The HBT diodes have cut-off frequencies in excess of 750 GHz. The mixer achieves 8-10 dB conversion loss and very low spurious responses over a 26-40 GHz RF and LO bandwidth and DC-11 GHz IF. This IF bandwidth is broader than a previously demonstrated CPW star mixer using InGaAs HEMT technology, and easier to integrate into an assembly due to its microstrip implementation.<>
Keywords :
III-V semiconductors; MMIC mixers; baluns; bipolar MMIC; gallium arsenide; heterojunction bipolar transistors; microstrip circuits; 26 to 40 GHz; 4 mil; 8 to 10 dB; GaAs; HBT Schottky diode mixer; IF bandwidth; Marchand balun structure; backside vias; closely coupled microstrip lines; cut-off frequencies; doubly balanced EHF HBT star mixer; microstrip baluns; microstrip environment; planar MMIC; spurious responses; star configuration; Bandwidth; Cutoff frequency; Gallium arsenide; Heterojunction bipolar transistors; Impedance matching; MMICs; Microstrip; Mixers; Radio frequency; Schottky diodes;
Conference_Titel :
Microwave Symposium Digest, 1995., IEEE MTT-S International
Conference_Location :
Orlando, FL, USA
Print_ISBN :
0-7803-2581-8
DOI :
10.1109/MWSYM.1995.406084
