A Multi-tap-transformer Based Quad-core Dual-mode VCO Achieving 213.1dBc/Hz FoMTA@100kHz and Wideband 1/f3 Noise Suppression

This work proposes a multi-tap transformer-based quad-core dual-mode voltage-controlled oscillator (VCO) with wideband 1/f3 noise suppression. The design integrates enhanced electromagnetic (E-M) mixed-coupling and harmonic-free-like techniques, achieving a high drain-to-gate voltage gain and generating a non-shaping balanced impulse sensitivity function (ISF). This approach effectively mitigates both thermal and flicker noise in the VCO across a wide bandwidth. Furthermore, a wide frequency tuning range (FTR) is realized by employing two identical orthogonally stacked dual-core multi-tap transformer VCOs combined with mode switches that define two distinct resonant modes. The proposed VCO demonstrates an impressive FTR of 62.8% (4.54–8.7 GHz), phase noise (PN) of -103.2 dBc/Hz and -146.9 dBc/Hz at 100 kHz and 10 MHz offsets from a 4.8 GHz carrier, and a 1/f3 PN corner frequency spanning 70 to 250 kHz. Additionally, it achieves a peak figure of merit with tuning FoMTA of 213.1 dBc/Hz at 100 kHz offsets, respectively.