Comparative Studies on (No) Patterned Ground Shield (PGS) RF-CMOS Transformers at Different Temperatures
ABSTRACT Extensively comparative studies are carried out on the performance of on-chip CMOS transformers in the presence and absence of patterned ground shields (PGS) at temperatures of 253 K, 298 K, 333 K, and 373 K. These transformers were fabricated using 0.18 micron CMOS processes and designed to be interleaved and center-tapped interleaved geometries, respectively, but with the same inner dimension, metal track width, track spacing and substrate properties. Based on the two-port S-parameters measured at different temperatures, all performance indicators, such as maximum available gain Gmax, Q-factor of the primary or secondary coil, power loss, and minimum noise figure of these transformers are extracted and compared with each other.
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ABSTRACT: In the current trend of technologic products is light, small and high-speed, so electronic products widely applied in high frequency. Due to high frequency, the parasitic effects and more noise are generated. To solve this problem, we used to add the band-pass filters behind the signal line to enhance signal integrity (SI) and reduce noise. But this method required to increase size of the circuit. In this study, microstrip is reference plane, a novel EBG structure enable the microstrip become bandpass filter. This new structure is still a transmission line. A section of transmission line embeded EBG in the bottom of transmission lines.EBG combine with ground plane of transmission lines to enable the signal which is not in the pass band will not have return path. The section of microstrip which combine with EBG possess band-pass filter characteristics. The purposes not only reduce the area effectively, but also decrease the cost. This study designs a 4GHz and 2.4GHz bandpass filter structure. The feature in this specifications correspond with provisions of the current range of wireless communication frequency (2.4GHz), and broadcasting TV (4GHz), and in the future there will be more application development.