CMOS shielded multi-conductor spiral inductor incorporating synthetic edge-coupled transmission lines

In this paper, the CMOS shielded multi-conductor spiral inductor using synthetic edge-coupled transmission lines is proposed. The synthetic edge-coupled transmission lines, which are operated in the even-mode, can assist in maintaining the quality factor (Q-factor) and providing spiral inductor with shielding for silicon integration, simultaneously. The prototype is fabricated by using the standard 0.18-¿m 1P6M CMOS technology. The measured results show that the proposed inductor has the maximum Q-factor of 6.5 at 24.0 GHz, which is the same with that of conventional design without shielding ground plane. The prototypes with edge-to-edge spacing of 80.0 ¿m show coupling characteristics of approximately 50.0-to-60.0 dB improvement below 20.0 GHz and 50.0 dB improvements at 24.0 GHz against conventional spiral inductor.