Title :
Micromachined branch line coupler in CMOS technology
Author :
Ozgur, M. ; Kozat, U.C. ; Zaghloul, M.E. ; Gaitan, M.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., George Washington Univ., Washington, DC, USA
Abstract :
An internally ground-equalized coplanar branch line coupler (BLC) is fabricated by post-processing 2poly/2metal analog CMOS chips. First level metallization is used to equalize the ground planes, hence to suppress the unwanted coupled-slot-line mode propagation. This addition necessitates additional compensation of signal lines to improve the return losses. Fabricated CMOS chips are post-processed with a two-step procedure. First, a thick polyimide film is screen-printed on the devices as a stress-compensation. Then, the silicon substrate is selectively removed underneath the devices. The measured responses show very good agreement with simulations. Fabricated devises exhibit return losses less than 10 dB and maximum of 1 dB amplitude difference in the frequency range of 25-30 GHz.
Keywords :
CMOS integrated circuits; coplanar waveguide components; field effect MMIC; integrated circuit metallisation; losses; waveguide couplers; 25 to 30 GHz; CMOS technology; coupled-slot-line mode propagation; first level metallization; internally ground-equalized coplanar branch line coupler; micromachined branch line coupler; polyimide film; return losses; screen-printing; stress-compensation; two-step procedure; CMOS technology; Coplanar waveguides; Educational institutions; Fabrication; Frequency; Impedance; Integrated circuit interconnections; Metallization; Polyimides; Silicon;
Conference_Titel :
Microwave Symposium Digest. 2000 IEEE MTT-S International
Conference_Location :
Boston, MA, USA
Print_ISBN :
0-7803-5687-X
DOI :
10.1109/MWSYM.2000.860983
