Prorogation Characteristics of CMOS Synthetic Transmission Line and Slow-Wave Inductor on the Complementary Spiral-Shaped Electromagnetic Bandgap (EBG) Shielding Ground Plane

A complementary spiral-shaped electromagnetic bandgap (CSS-EBG) structure based on 0.18 mum 1P6M CMOS technology is presented. The CSS-EBG structure, which is operated below its stop-band frequency, forms a uniform shielding ground plane for the CMOS transmission line (TL) and spiral inductor designs. Measurements show that the characteristic impedance (Z
_c
) and slow-wave factor (SWF) of the CSS-EBG transmission line (TL) are 71.4 ohm and 2.33 at 5.0 GHz, revealing 20% and 35% higher than that of conventional thin-film microstrip (TFMS) with the same line width and material parameters. On the other hand, the slow-wave inductor on the CSS-EBG shielding ground plane has the maximum Q-factor of 10.5 at 37.8 GHz, showing 12% higher than that of the conventional spiral inductor without shielding ground plane. The electromagnetic coupling between the two slow-wave inductors with edge-to-edge spacing of 90.0 mum is 55.0-to-60.0 dB from 0.1 GHz to 5.0 GHz, indicating 30.0-to-35.0 dB improvement against conventional spiral inductors without shield.