An Octave Tuning-Range Frequency Generator Integrating a Quad-Core VCO Using Quad-Mode Coupled Dual-Path Inductor With a Wideband ILFD

Abstract

This article presents an octave frequency generator that integrates a quad-core voltage-controlled oscillator (VCO) using a quad-mode resonator with a wideband injection locked-frequency divider (ILFD). The quad-core VCO incorporates a resonator based on a quad-mode coupled dual-path inductor (CDPI), enabling wide frequency operation without additional switch loss. This design improves phase noise (PN) performance and supports four distinct inductor mode operations through mode switching between the cores. The VCO is followed by a wide locking range (LR) ILFD which can divide all the VCO output frequencies. The ILFD employs techniques for frequency tracking and inductive peaking to achieve a wide LR. Both the VCO and ILFD are fabricated using a 28-nm CMOS technology. The VCO exhibits a measured tuning range (TR) of 72.6%, spanning from 17 to 36.4 GHz, and consumes 9.7–13.3 mW at a 0.6-V supply voltage. With a compact core area of 0.065 mm2, the VCO achieves peak figure of merit for tuning (FoMT) and FoM for tuning and area (FoMTA) of 196.3 and 208.1 dBc/Hz, respectively. The ILFD achieves an LR of 90.2%, spanning from 14 to 37 GHz, and consumes 3 mW at a 0.6-V supply voltage. Finally, a prototype octave-TR frequency generator, integrating the proposed quad-core VCO and wideband ILFD, is demonstrated. This frequency generator exhibits octave TR performance and shows promising potential for PLL integration.