A Dual-Band Injection-Locked Frequency Quadrupler for 5G Multiband Applications

This article proposes a 24.2–29-/36.8–44-GHz dual-band injection-locked frequency quadrupler (ILFQ) with high harmonic rejection for 5G multiband applications. By introducing two parallel reconfigurable amplifiers that switch between low-band mode and high-band mode, the proposed ILFQ supports dual-band operation with only one harmonic generator. These reconfigurable amplifiers can also purify and enhance the 4th harmonic of the injection current, thereby widening the locking range and improving the harmonic rejection ration. In addition, an embedded notch filter is designed to further improve harmonic rejection ratio (HRR). Fabricated in a 65-nm CMOS, the proposed ILFQ achieves more than 44.9-/36.3-dBc 1st HRR and more than 35.5-/27.2-dBc 2nd HRR within the locking range of 24.2–29/36.8–44 GHz. The measured maximum dc power consumption is 15.4/16.3 mW in two modes, with a chip area of 0.49 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>.