DocumentCode :
531223
Title :
Liquid crystal based phase shifters in 60 GHz band
Author :
Bulja, S. ; Mirshekar-Syahkal, D. ; Yazdanpanahi, M. ; James, R. ; Day, S.E. ; Fernández, F.A.
Author_Institution :
Sch. of Comput. Sci. & Electron. Eng., Univ. of Essex, Colchester, UK
fYear :
2010
fDate :
27-28 Sept. 2010
Firstpage :
37
Lastpage :
40
Abstract :
Preliminary structures and performance results of two different 60 GHz band planar phase shifters using liquid crystal (LC) are presented. The first phase shifter is based on a meandered microstrip line structure with the conductor pattern exposed to a layer of a nematic LC, while the second phase shifter is based on the reflection type microstrip line phase shifter structure whose tunable reflective loads are formed on a nematic LC substrate. The LC used in these two phase shifters is E7 with a low temperature coefficient over a wide range of temperatures. In both phase shifters, the LC is biased through a variable low voltage external source allowing for the control of the dielectric constant of the LC. To facilitate the on-wafer measurement and the application of the electric field to the LC, a broadband transition from the microstrip line to the CPW is developed and used in both phase shifters. The best figure of merit of the meandered line phase shifter, 20.8°/dB, occurs at 60.7 GHz coinciding with a differential phase shift of 243 degrees, while the RTPS achieves a maximum figure of merit, 12.3°/dB, at 61.31 GHz corresponding to a differential phase shift of 170 degrees.
Keywords :
liquid crystals; microstrip lines; phase shifters; band planar phase shifter; conductor pattern; dielectric constant; differential phase shift; frequency 60 GHz; frequency 60.7 GHz; frequency 61.31 GHz; liquid crystal based phase shifter; meandered microstrip line phase shifter structure; temperature coefficient; tunable reflective load; Dielectric constant; Frequency measurement; Insertion loss; Microstrip; Phase measurement; Phase shifters; Voltage measurement; Dielectric anisotropy; liquid crystal (LC); meandered inverted microstrip line phase shifter; reflection type phase shifter (RTPS);
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Wireless Technology Conference (EuWIT), 2010 European
Conference_Location :
Paris
ISSN :
2153-3644
Print_ISBN :
978-1-4244-7233-8
Type :
conf
Filename :
5615198
Link To Document :
بازگشت