Substrate coupling effect under various noise injection topologies in LC-voltage controlled oscillator

摘要

[[abstract]]Impact of substrate noise coupling on a wideband VCO (5.6 to 7.5 GHz) was investigated using different noise injection topologies. Measured results indicated that IM2 increased by ~ 5 to 7 dB and IM3 by ~ 6 to 10 dB when the inductor guard ring floated. In addition, the noise at high frequencies still degraded the VCO performance even not injected directly to the substrate. The observed trends were modeled and explained by a simple physical-based resistive network together with the oxide layer capacitors successfully.