Design of a 90.9% Locking Range Injection-Locked Frequency Divider with Device Ratio Optimization in 90-nm CMOS

A 12-32 GHz divide-by-2 (D2) injection-locked frequency divider (ILFD) is presented in this paper. First, the device ratio of the injection mixer and cross-coupled pair is optimized to achieve a wide locking range (LR). Then, the inductive peaking and forward-body-bias techniques are applied to the injection mixer to boost its transconductance and to enhance injection efficiency for further extension of the LR. Finally, the harmonic suppression technique is introduced to reduce the output harmonics. Using the aforementioned approaches, we successfully demonstrate a D2 ILFD implemented in the 90-nm low-power CMOS technology with a maximum LR of 90.9% at an injection power of 0 dBm. Even with the injection power as low as-10 dBm, the proposed ILFD maintains an LR of 32.9%. This ILFD consumes 2.4 mW with a supply voltage of 0.6 V in a chip size of 0.45 mm².