Comparative studies on (no)patterned ground shield (PGS) RF-CMOS transformers at different temperatures

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.