Design and Fabrication of Ultra-Wideband Baluns Embedded in Multilayer Liquid Crystal Polymer Flex

• Published in: IEEE transactions on advanced packaging Vol. 30; no. 3; pp. 533 - 540
• Main Authors: Chen, A.C., Chen, M.J., Anh-Vu Pham
• Format: Journal Article
• Language: English
• Published: Piscataway, NY IEEE 01.08.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Balun; Baluns; Circuit properties; Communication system control; Communication systems; Crystalline materials; Design engineering; Electric, optical and optoelectronic circuits; Electronic circuits; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; Fabrication; Impedance matching; Lamination; liquid crystal polymer (LCP); Liquid crystal polymers; microwave; Multilayers; Noise levels; Nonhomogeneous media; Printed circuits; Signal convertors; Stability; Thin films; thin-film; Ultra wideband technology; ultra-wideband (UWB); Performance evaluation; liquid crystal polymer (LCP); Multiple layer; Printed circuit board; Balun; ultra-wideband (UWB); Ultra wide band; Thin film; thin-film; Liquid crystal polymers; Insertion loss; Printed circuit; Signal converter; Impedance; microwave
• ISSN: 1521-3323; 1557-9980
• DOI: 10.1109/TADVP.2007.901577

In this paper, we present the design and fabrication of ultra-wideband (UWB) baluns embedded in multilayer liquid crystal polymer (LCP) flex. Fabrication techniques are demonstrated for processing these commercially available LCP thin-films by standard PCB equipments. Variations in the LCP thin-film thickness are characterized and compared before and after lamination. Results show good dimensional stability of the material, a critical factor in controlling the line impedances and performance of the balun. Electrical results of these baluns show bandwidths exceeding 3.1-10.6 GHz with less than 1 dB insertion loss, and amplitude and phase imbalance less than 1.2 dB and 2deg, respectively. These baluns are ideal for applications in UWB communication systems specified by the IEEE 802.15.3a standard.