Divide-by-2 Injection-Locked Frequency Dividers Using the Electric-Field Coupling Dual-Resonance Resonator

This article designs and analyzes LC injection-locked frequency dividers (ILFDs) using dual-resonance LC resonator. The ILFD consists of two single-resonance LC-tank capacitive cross-coupled sub-ILFDs operating at 3.7 and 5.1 GHz, respectively, and the two sub-ILFDs are coupled by the electric field through a pair of metal-insulator-metal (MIM) capacitors. The die area in the Taiwan Semiconductor Manufacturing Corporation (TSMC) 0.18-μm CMOS is 0.65 × 1.023 mm². By controlling the gate voltages of the switching transistors, the ILFD has three different operational modes-high-band dominant mode, low-band dominant mode, and concurrent oscillation mode. Overlapped locking range is demonstrated for the first time in the designed electric-field coupling resonator ILFD. Non-overlapped locking range is found for the ILFD manifesting an effect of the dual-resonance resonator.