Design of a Low-Phase-Noise 70-/105-GHz Dual-Band VCO With Common Mode Resonance Expansion

This article presents the design of a CMOS-based voltage-controlled oscillator (VCO) operating in both <tex-math notation="LaTeX">V</tex-math> -and <tex-math notation="LaTeX">W</tex-math> -bands by fully utilizing the harmonics in Class-F <tex-math notation="LaTeX">₂₃</tex-math> tank. An auxiliary common mode (CM) resonance is introduced to Class-F <tex-math notation="LaTeX">₂₃</tex-math> structure via a transformer for CM resonance expansion. This transformer serves dual functions, also generating the second harmonic output, thereby enhancing the area efficiency. The proposed CM resonance expansion suppresses the flicker noise upconversion in a widehband without manual harmonic tuning. A Class-F <tex-math notation="LaTeX">₂₃</tex-math> VCO without CM expansion is designed and fabricated for comparison. Besides, the challenges in high-frequency harmonic extraction are highlighted and addressed. The proposed VCO is fabricated using 40-nm CMOS technology. The frequency can cover from 69.92 to 73.84 GHz and from 104.88 to 110.75 GHz with tuning ranges of 5.7%. The measured <tex-math notation="LaTeX">V</tex-math> -and <tex-math notation="LaTeX">W</tex-math> -band phase noises (PNs) are <tex-math notation="LaTeX">$-$</tex-math> 102.5 and <tex-math notation="LaTeX">$-$</tex-math> 92.35 dBc/Hz at 1-MHz offset with figures of merit of <tex-math notation="LaTeX">$-$</tex-math> 182.5 and <tex-math notation="LaTeX">$-$</tex-math> 176 dBc/Hz, respectively. The power consumption is 44 mW in an area of 0.36 mm <tex-math notation="LaTeX">²</tex-math> .