microwave office question

[handsprince]

i just learn microwave office, now i need to design a single stage amplifier with specific gain. here i want to ask, should i use non-linear simulator or linear simulator to design my amplifier? thanks

 

[alexandr22061986]

This is related to in which class and regime your PA work. If he works in linear class A you can use small signal S-parameters or SPICE model of transistor for calculation of matching network. If he works in nonlinear regime (B, C) you should use nonlinear model of transistor, then you can not only calculate adequate matching circuits but also you can see nonlinear properties of PA, level of intermodulation distortion an so on.

 

[Advark]

Hello, could you explain more about the nonlinear regime. I'm trying to simulate a class C PA.

 

[alexandr22061986]

For class C PA you have to create nonlinear model of transistor (how do it, use example files) and provide inverse supply voltage for input and output (emmiter and collector for common base scheme) of transistor.
What transistor do you use?

 

[Advark]

I'm using VDMOS , ARF446-447 of MICROSEMI. I only got the spice model of the transistor. I check examples in MWO were use a text editor like a spice model and other wich draw a schematic of the spice model.

could you tell me wich is better and how to create i'm newbie in MWO software . the model i got is:

**********
*SRC=ARF446;ARF446A/B;MOSFETs N;Power >100V;APT 1000V 8A 1.5ohm TO247-rf
*SYM=POWMOSN
.SUBCKT ARF446 10 20 30
* TERMINALS: D G S
M1 1 2 3 3 DMOS L=1U W=1U
RD 10 1 0.712
RS 40 3 38.5M
RG 20 2 .2
CGS 2 3 1.47N
EGD 12 0 2 1 1
VFB 14 0 0
FFB 2 1 VFB 1
CGD 13 14 1.85N
R1 13 0 1
D1 12 13 DLIM
DDG 15 14 DCGD
R2 12 15 1
D2 15 0 DLIM
DSD 3 10 DSUB
LS 30 40 3N
.MODEL DMOS NMOS (LEVEL=1 LAMBDA=85.3u VTO=3.8 KP=6.06)
.MODEL DCGD D (CJO=1.85N VJ=0.6 M=0.68 )
.MODEL DSUB D (IS=31.1N N=1.5 RS=0.113 BV=1K CJO=519P VJ=0.8 M=0.42 TT=258N)
.MODEL DLIM D (IS=100U)
.ENDS
**********

 

[Manjunatha_hv]

Hello Advark,

You need to save this spice file as PSpice model (*.cir)...
Then Import it as a Netlist & Add as Subcircuit block....

Then setup the analysis & simulate the design...
I have attached all the steps as Picture files (*.jpg) & corresponding PSpice file, AWR Microwave Office (MWO) file for you...



---manju---