Help with Accurate Extraction of Ron and Coff for RF Switches in Ku-Band Phase Shifter Design

Hi everyone,

I’m currently working on designing a Ku-band switch-type analog phase shifter using LC-based circuits as part of my internship. One of the key challenges I’m facing is determining the accurate value of the off-state capacitance (Coff​, labeled as C2) between the drain and source* of the MOSFET switches used in my design.

I’ve been checking the operating point (OP) values in Cadence Virtuoso, but I’m unsure whether they reflect the true off-state parasitic capacitance, or how to interpret them correctly for this purpose. Additionally, I’m also trying to accurately extract the on-state resistance (Ron​) and confirm that it aligns with the expected RF switch behavior.

I would also like to understand which specific parasitic capacitances contribute to the effective drain-to-source capacitance when the transistor is OFF. I know that components like Cgd, Cgd​, Cgs​, and junction capacitances (e.g., Cdb​, Csb​) may play a role, but I’m unclear how these combine — especially in a body-source connected switch configuration.

Can anyone guide me on the best methodology to simulate or measure Coff​ and Ron​ accurately in Cadence or Spectre for high-frequency (Ku-band) applications? Any advice, references, or tips from those with experience in switch-type phase shifters or mm-wave design would be greatly appreciated!

Thanks in advance!