A methodology for measurement and characterization of substrate noise in high frequency circuits

A method is proposed in this paper to measure and characterize substrate noise in high-frequency circuits. Since substrate coupled signals are small quantities, special precautions must be taken to isolate these signals to avoid contamination by signals coupled through the package and the board. The method proposed is based on sensing and down-converting substrate signals on-chip to lower frequencies for measurement. As an illustration of this general method, we measure the noise injected by an on-chip Voltage Controlled Oscillator (VCO) using down-converting mixers as sensors.