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Simulation method for dual-Gate FET in ADS

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pthoppay

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dual gate mixer

HI all,

Please advise on how to simulate dual gate FET mixers in ADS. I am using BF998 transistor for dual gate. I have the S-parameters but it is rather a S2P file.

Now I am confused how to simulate my mixer using this S2P parameter file. Would like to know whether it is possible?? Else please let me know what are other solutions to simulate my mixer using BF998 (FYI: I can obatin SPICE file for BF998, does this help in any way).

Regards,
Prakash.
 

VSWR

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pspice dual gate mosfet

I understand you would like to do a nonlinear simulation, using the BF998 transistor. That is appling RF and LO signal, while watching the mixing result on the IF port?

If so, harmonic balance is suitable. But in this case the nonlinear SPICE model of the transistor shall be used. See below:

* BF998 SPICE MODEL OCTOBER 1993 PHILIPS SEMICONDUCTORS
* ENVELOPE SOT143
* 1.: SOURCE; 2.: DRAIN; 3.: GATE 2; 4.: GATE 1;
.SUBCKT BF998 1 2 3 4
L10 1 10 L=0.12N
L20 2 20 L=0.12N
L30 3 30 L=0.12N
L40 4 40 L=0.12N
L11 10 11 L=1.20N
L21 20 21 L=1.20N
L31 30 31 L=1.20N
L41 40 41 L=1.20N
C13 10 30 C=0.085P
C14 10 40 C=0.085P
C21 10 20 C=0.017P
C23 20 30 C=0.085P
C24 20 40 C=0.005P
D11 42 11 ZENER
D12 42 41 ZENER
D21 32 11 ZENER
D22 32 31 ZENER
RS 10 12 R=100
MOS1 61 41 11 12 GATE1 L=1.1E-6 W=1150E-6
MOS2 21 31 61 12 GATE2 L=2.0E-6 W=1150E-6

.MODEL ZENER D BV=10 CJO=1.2E-12 RS=10

.MODEL GATE1
+ NMOS LEVEL=3 UO=600 VTO=-0.250 NFS=300E9 TOX=42E-9
+ NSUB=3E15 VMAX=140E3 RS=2.0 RD=2.0 XJ=200E-9 THETA=0.11
+ ETA=0.06 KAPPA=2 LD=0.1E-6
+ CGSO=0.3E-9 CGDO=0.3E-9 CBD=0.5E-12 CBS=0.5E-12

.MODEL GATE2
+ NMOS LEVEL=3 UO=600 VTO=-0.250 NFS=300E9 TOX=42E-9
+ NSUB=3E15 VMAX=100E3 RS=2.0 RD=2.0 XJ=200E-9 THETA=0.11
+ ETA=0.06 KAPPA=2 LD=0.1E-6
+ CGSO=0.3E-9 CGDO=0.3E-9 CBD=0.5E-12 CBS=0.5E-12
 

boy

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bf998 s-parameters

This link might be helpful.

You can use the spice model to to the HB simulation and get the conversion gain. I think you cannot get the conversion gain or other parameters by using only s-parameters.
 

tm112

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model used by is undefined

Although this post is quite old - I also have a problem using the BF998 model file for PSICE . Here is the error message out of the *.out file:

ERROR -- Model C used by X_U9.C13 is undefined
ERROR -- Model C used by X_U9.C14 is undefined
ERROR -- Model C used by X_U9.C23 is undefined
ERROR -- Model C used by X_U9.C24 is undefined
ERROR -- Model L used by X_U9.L10 is undefined
ERROR -- Model L used by X_U9.L20 is undefined
ERROR -- Model L used by X_U9.L30 is undefined
ERROR -- Model L used by X_U9.L40 is undefined
ERROR -- Model L used by X_U9.L11 is undefined
ERROR -- Model L used by X_U9.L21 is undefined
ERROR -- Model L used by X_U9.L31 is undefined
ERROR -- Model L used by X_U9.L41 is undefined
ERROR -- Model R used by X_U9.RS is undefined

U9 is the BF998 in the circuit.

What wants me PSICE to say with that message?

Best Regards,
Thomas
 

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