Analysis and Design of Ultra-Wideband mm-Wave Injection-Locked Frequency Dividers Using Transformer-Based High-Order Resonators

A transformer-based high-order resonator is proposed to improve the locking range (LR) of the millimeter-wave injection-locked frequency dividers (ILFDs). The LR limitations on ILFDs are discussed, and the operating principles of the proposed high-order resonator are analyzed based on their flattened phase response. The inductive gain peaking technique and the tail current source requirement are further analyzed for low power considerations. Two chips are fabricated in a 65-nm CMOS process to implement the proposed techniques: the first one measures an LR of 62.9% from 27.9 to 53.5 GHz while consuming 5.8 mW from a 1-V power supply and the second chip achieves an LR of 62.7% from 32.4 to 61.9 GHz while consuming only 1.2 mW from a 0.42-V power supply. The best figure of merit can achieve up to 24.7 GHz/mW.