A Ka-band wide locking range frequency divider with high injection sensitivity

This paper proposes a direct injection-locked frequency divider（ILFD） with a wide locking range in the Ka-band. A complementary cross-coupled architecture is used to enhance the overdriving voltage of the switch transistor so that the divider locking range is extended efficiently. New insights into the locking range and output power are proposed. A new method to analyze and optimize the injection sensitivity is presented and a layout technique to reduce the parasitics of the cross-coupled transistors is applied to decrease the frequency shift and the locking range degradation. The circuit is designed in a standard 90-nm CMOS process. The total locking range of the ILFD is 43.8% at 34.5 GHz with an incident power of –3.5 dBm. The divider IC consumes 3.6 mW of power at the supply voltage of 1.2 V. The chip area including the pads is 0.50.5 mm2.