An 8.4-to-10.89 GHz Dual-Core Wideband Inverse-Class-F VCO Using Quad-Coupled LC Tanks with a 187-dBc/Hz FoM

This paper presents a wideband, dual-core balanced inverse-class-F (class-F-1) VCO. The class-F-1 topology achieves a wideband impedance at the second harmonic frequency by constructing the proposed qual-coupled LC tanks, obtaining a 25.8% tuning range from 8.4-to-10.89 GHz. In addition, amplitude balancing is achieved by cross-linking the cores. Prototyped with 110-nm CMOS process, the VCO dissipates 20 mW with 1.2-V supply and achieves phase noise of -119 / -139 dBc/Hz at 1- / 10-MHz offset from 10-GHz carrier. The core area is 0.14 mm(2).