Designs of K-Band Divide-by-2 and Divide-by-3 Injection-Locked Frequency Divider with Darlington Topology

Kuan Hsiu Chien, Jian Ying Chen, Hwann Kaeo Chiou

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


This paper presents divide-by-2 and divide-by-3 injection-locked frequency dividers (ILFDs) using a Darlington cell in a TSMC 0.18-m CMOS process. The Darlington cell has higher transconductance than the traditional cross-coupled common source cell for free-running oscillator that reduces the power consumption of ILFDs. Besides, an LC resonance technique is used in the proposed divide-by-2 ILFD to achieve lower power consumption and wide locking range. This work provides an analytic method to choose the injector size for widening the locking range and lowering the power consumption. The measured locking range of the proposed divide-by-2 ILFD is from 20.5 to 22.9 GHz. The measured operation range of the divide-by-3 ILFD is from 24.71 to 28 GHz. The measured phase noises of two dividers under locked condition are 138.3 and dBc/Hz at an offset of 1 MHz when the input referred signals have phase noises of 132.54 and 131.5 dBc/Hz, respectively. Meanwhile, both phase noise differences with respect to injection signal are 5.76 and 8.85 dBc, which are close to the theoretical values of 6 and 9.5 dBc. The core power consumptions are 1.73 and 5.13 mW with the supply voltages of 1.2 and 1.45 V, and the chip sizes are 0.8 ×.75 mm and 0.77 ×.79 mm , respectively.

Original languageEnglish
Article number7159090
Pages (from-to)2877-2888
Number of pages12
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number9
StatePublished - 1 Sep 2015


  • CMOS process
  • Darlington cell
  • LC resonance technique
  • injection-locked frequency divider (ILFD)
  • single and differential injectors


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