I am trying to simulate a pair of NMOS transistors as varactors (BSD connected). However, am not getting any resonance at the particular frequency of interest. When I am simulating it, it is giving a negative drain current with zero transconductance. Also, I want to see the CV curve of this but I am not sure how to do it? Can anybody help me in this?

P.S : I don't know how to add a picture in the comments section so I editing my answer and uploading it here.

This one is a schematic for the varactor simulation and the resultant S11. enter image description here

enter image description here

  • 1
    \$\begingroup\$ Welcome to EE.SE. It would be significantly easier to help you if you posted a schematic and simulation result screen shots. \$\endgroup\$ – Phil C May 8 '18 at 4:23
  • \$\begingroup\$ "BSD connected"? \$\endgroup\$ – Andy aka May 8 '18 at 8:44
  • \$\begingroup\$ How high are the losses at your chosen frequency? \$\endgroup\$ – analogsystemsrf May 9 '18 at 3:23
  • \$\begingroup\$ Phil C - Alright I will post the schematics. \$\endgroup\$ – Umber Abbas May 9 '18 at 5:03
  • \$\begingroup\$ Andy - What i mean is that the source body and drain are connected together to form one terminal and the gate as the other to make it behave as a capacitor. \$\endgroup\$ – Umber Abbas May 9 '18 at 5:04

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