A wide locking range and low DC power injection-locked frequency tripler for K-band application

This paper presents a wide locking range and low DC power injection-locked frequency tripler for K-band frequency synthesizers application. The proposed ILFT employs a variable current source to decouple the injection signal path and the bias current so that the third harmonic of the injection signal can be maximized to enlarge the locking range. Meanwhile, a 2-bit digital control capacity array is used to further increase the output frequency locking range. It is implemented in a 130-nm CMOS process and occupies a chip area of 0.7 × 0.8 mm² without pads. The measured results show that the proposed ILFT can achieve a whole locking range from 18 to 21 GHz under the input signal of 4 dBm and the core circuit dissipates only 4 mW of DC power from a 0.8 V supply voltage. The measured phase noise degradation from that of the injection signal is only 10 dB at 1 MHz offset. (semiconductor integrated circuits)