help required in Microwave office

[quazi alfred]

Iam going to designing microwave amplifier using BJT(NEC) by AWR Mic Office. But it is not giving any gain(-20 db). Again the Vce mesured for voltmeter -ve value (but it should be 10V, 7 mA). May be transitor is OFF? Biasing is simple voltage divider biasing. Help me.

 

[Manjunatha_hv]

Hello,


Which NEC BJT device you are using (Part Number) & do you have the Nonlinear model for the same to use in Microwave Office (MWO)?

Is it Power Amplifier or Low Noise Amplifier design!
Upload your MWO file (*.emp) so that we can help you to solve this problem...


---manju---

 

[quazi alfred]

Hello,


Which NEC BJT device you are using (Part Number) & do you have the Nonlinear model for the same to use in Microwave Office (MWO)?

Is it Power Amplifier or Low Noise Amplifier design!
Upload your MWO file (*.emp) so that we can help you to solve this problem...


---manju---

Thank you manju.
Now the negative Vce seems solved. I am using NE85635A NEC BJT and its s- parameter model at Vce=10V, Ic=7mA for simple maximum gain amplifier.
But the gain is still negative .

Find the attached MWO(*emp) file.
Help me .

Alfred

 

[Manjunatha_hv]

Hello Alfred,

Okay, You are using S-parameter data file (NE85635A.S2P) which is already
Biased ate VCE=10V, IC=7mA & which is a linear model...

Hence you should not bias once again, but for the layout you can lay down the Bias network.
if you have nonlinear model (Spice file) for this device then your bias setup is correct in MWO...

What you can do here is just remove the Bias network, only place the matching circuit
& then do the s-parameter simulation you may get the desired gain if not optimize ...
Also note that you need to remove the V & I meters as this is a Linear simulation only & you cannot see
the node / element voltages /currents (only possible to see in DC/Nonlinear simulation)...
Once you have nonlinear model you can do this simulation...


Also I observed that this model looks like obsolete on CEL website, see attached picture...


---manju---

 

[quazi alfred]

Hello Alfred,

Okay, You are using S-parameter data file (NE85635A.S2P) which is already
Biased ate VCE=10V, IC=7mA & which is a linear model...

Hence you should not bias once again, but for the layout you can lay down the Bias network.
if you have nonlinear model (Spice file) for this device then your bias setup is correct in MWO...

What you can do here is just remove the Bias network, only place the matching circuit
& then do the s-parameter simulation you may get the desired gain if not optimize ...
Also note that you need to remove the V & I meters as this is a Linear simulation only & you cannot see
the node / element voltages /currents (only possible to see in DC/Nonlinear simulation)...
Once you have nonlinear model you can do this simulation...


Also I observed that this model looks like obsolete on CEL website, see attached picture...


---manju---

Thanks you for your valuable suggestions and help. It is working now.
Let me know the best RF bipolar transsitor available in India .
Alfred