TY - GEN
T1 - 60 GHz Optimised Nickel-free Gold-plated Enclosed Coplanar Waveguide Liquid Crystal Phase Shifter
AU - Li, Jinfeng
N1 - Publisher Copyright:
© 2020 IEEE.
PY - 2020/7
Y1 - 2020/7
N2 - A novel nickel-free gold-plated enclosed coplanar waveguide is experimentally demonstrated for a liquid crystal tunable delay line phase shifter at 60 GHz. By numerical investigations, we find that conventional surface impedance model (without meshing inside metals) fails to accurately characterise the effect of gold-plating thickness on conductor loss, especially when the plating thickness is smaller than 4 times of the gold's skin depth. To address this, adaptive meshing inside metals is performed for accurate modelling of the device. The gold-plating thickness is then experimentally optimised and tailored for the liquid crystal-based device-making procedures, i.e. taking into account the accelerated copper migration into gold problem during the alignment agent baking process at 200°C. Measurement results of assembled phase shifters at 60 GHz verify that a direct gold plating of 2μm on Cu can reduce the insertion loss by 1.79 dB and 2.85 dB as compared with that with a thinner plating of 50 nm, and no plating, respectively. The maximum insertion loss of -2.996 dB demonstrated at 60 GHz for the 0-π phase shifter delivers a figure-of-merit of 60°/dB, an improvement of 42°/dB as compared with up-to-date literature.
AB - A novel nickel-free gold-plated enclosed coplanar waveguide is experimentally demonstrated for a liquid crystal tunable delay line phase shifter at 60 GHz. By numerical investigations, we find that conventional surface impedance model (without meshing inside metals) fails to accurately characterise the effect of gold-plating thickness on conductor loss, especially when the plating thickness is smaller than 4 times of the gold's skin depth. To address this, adaptive meshing inside metals is performed for accurate modelling of the device. The gold-plating thickness is then experimentally optimised and tailored for the liquid crystal-based device-making procedures, i.e. taking into account the accelerated copper migration into gold problem during the alignment agent baking process at 200°C. Measurement results of assembled phase shifters at 60 GHz verify that a direct gold plating of 2μm on Cu can reduce the insertion loss by 1.79 dB and 2.85 dB as compared with that with a thinner plating of 50 nm, and no plating, respectively. The maximum insertion loss of -2.996 dB demonstrated at 60 GHz for the 0-π phase shifter delivers a figure-of-merit of 60°/dB, an improvement of 42°/dB as compared with up-to-date literature.
KW - enclosed coplanar waveguide
KW - gold plating
KW - insertion loss
KW - liquid crystal
KW - millimetre wave
KW - phased array
KW - tunable delay line
UR - http://www.scopus.com/inward/record.url?scp=85089616347&partnerID=8YFLogxK
U2 - 10.1109/IMWS-AMP49156.2020.9199680
DO - 10.1109/IMWS-AMP49156.2020.9199680
M3 - Conference contribution
AN - SCOPUS:85089616347
T3 - 2020 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications, IMWS-AMP 2020 - Proceedings
BT - 2020 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications, IMWS-AMP 2020 - Proceedings
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2020 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications, IMWS-AMP 2020
Y2 - 29 July 2020 through 31 July 2020
ER -