Microwave Journal
www.microwavejournal.com/articles/2176-appendix-a-the-mmicad-simulation-file

Appendix A: The MMICAD Simulation file

November 1, 1997

Appendix A
The MMICAD Simulation file
!NONLINEAR MESFET MODEL
!OPTOTEK LTD.
!
files
\mmicad\atten\p2vp47.s2p mescs 101
!
!set up the voltage control variable
var
vc1=20
!
ckt
!***************************************************
!a user defined mesfet nonlinear model
!as a function of gate bias
!rdist=-.2 + .98vg-.103vgˆ2+.0041VGˆ3
!-6.5E-5VGˆ4 + 3.65E-7VGˆ5
!cdist = .615/(1 + 0.01VG)ˆ1.8
srl 1 2 R=2.5 L=0.01
rclin 2 3 4 &
R={-.2+.98*VG-.103*VGˆ2+.0041*VGˆ3-6.5E-5 &
*VGˆ4+3.65E-7*VGˆ5 } &
C={ .615/(1.+.01*VG)ˆ1.8 } L=1
srl 3 5 R=3 L=0.05
srl 4 0 R=1.75 L=0.03
cap 2 4 C=0.05
cap 3 4 C=0.04
cap 2 3 C=0.014
!fmod is the model; the default value of !vg is 50%
def2p 1 5 fmod ( VG=50 )
!***************************************************
! connect the model

fmod 1 2 0 VG=VC1
def2P 1 2 mod
!connect the mEsfet
mescs 0 2 1 m=1
def2p 1 2 mes
freq
sweep 2 8 .5
!define the output definitions.
out
mod s11 io
mes s11 io
mod s12 io
mes s12 io
mod mag[s11] mpp
mes mag[s11] mpp
mod ang[s11] mpp r
mes ang[s11] mpp r
mod mag [s12] mpp
mes mag[s12] mpp
mod ang[s12] mpp r
mes ang[s12] mpp r
!
!define the output Grid
grid
mpp 2 8 0 1 R - 180 180
!label the graphs
label
optotek zero-drain-bias mesfet model