Wideband Low Reflection Transmission Lines for Bare Chip on Multilayer PCB
2011 (English)In: ETRI Journal, ISSN 1225-6463, Vol. 33, no 3, 335-343 p.Article in journal (Refereed) Published
The pad pitch of modern RF ICs is in order of few tens of micrometers. Connecting the large number of high speed I/Os to outside world with good signal fidelity and low cost is extremely challenging. To cope with this requirement, we need reflection-free transmission lines from on-chip pad to on-board SMA connectors. Such a transmission line is very hard to design due to the difference in on-chip and on-board feature size and the requirement for extremely large bandwidth. In this paper, we propose the use of narrow tracks close to chip and wide tracks away from the chip. This narrow to wide transition in width results in impedance discontinuity. A step change in substrate thickness is utilized to cancel the effect of the width discontinuity, thus achieving a reflection-free microstrip. To verify the concept several microstrips were designed on multilayer FR4 PCB without any additional manufacturing steps. The TDR measurements reveal that impedance variation is less then 3Ω for 50Ω microstrip when the width changes from 165μm to 940μm and substrate thickness changes from 100μm to 500μm. The Sparameter measurement on same microstrip shows S11 better then -9dB for the frequency range 1-6GHz.
Place, publisher, year, edition, pages
Daejeon, Korea: Electronics and Telecommunications Research Institute , 2011. Vol. 33, no 3, 335-343 p.
Bare chip mounting, RF testing, microstrip discontinuities, microstrip transitions.
National CategoryEngineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-18203DOI: 10.4218/etrij.11.0110.0386OAI: oai:DiVA.org:liu-18203DiVA: diva2:216709
The original status of this article was: Manuscript.2009-05-112009-05-112014-04-01Bibliographically approved