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Urgent (RF)

Posted Apr 1, 2013, 4:25 p.m. EDT RF & Microwave Engineering Version 4.3 2 Replies

Constantinos Tsangarides
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Hello,

I am having a deadline in less than a month and I need really your help.

I am trying to build an RF model with a layer of graphene that is going to be shined by light from different angles.
I am very new to Comsol and I do not have enough time to check all its examples and forums which have to do with my querries.

So a graphene layer cannot be modelled as it is too thin for electromagnetic waves to react with it, so I had to use the transition boundary method by having two layers of air and working out their intersection surface where they touch, to be the graphene layer.

I have set different properties of the graphene, such as conductivity and relative permittivity (equations) in the "Parameters" section. Such properties must change when the incoming frequency of ligtht changes (omega). But am not sure if is the correct way for inserting them in the Parameters section because it was difficult to find another method.

Then I tried to find a way to shine light onto the surface but this is the difficult part of it.

I will upload you the file of project with what I have done until now, later on.

Just to get you informed on what am working on and what difficulties I had. Thank you. Coming back in a bit.
2 Replies Last Post Mar 7, 2016, 12:25 a.m. EST
Constantinos Tsangarides
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Posted: 1 decade ago Apr 1, 2013, 4:48 p.m. EDT
I am posting you some pictures because I cannot upload it for the moment until tomorrow.

So, in the parameters I have written some equations in order to find out the conductivity (sigma_g)
and relative permittivities (real imaginary/ ereal eim)

In the Propagation wavevectors I have written the k-vector of light in order to emit it from port 1 in the x direction oscillating either in z or y and having an angle alpha to the z axis.

In the Port1 image, there is a trial for how to emit this light but I have no idea what to write in the propagation constant, and also I think I have written wrong the Ex,Ey,Ez fields.

And finally in the graphene image, I typed in the conductivity and any other relevant info needed for the studying.
I am posting you some pictures because I cannot upload it for the moment until tomorrow. So, in the parameters I have written some equations in order to find out the conductivity (sigma_g) and relative permittivities (real imaginary/ ereal eim) In the Propagation wavevectors I have written the k-vector of light in order to emit it from port 1 in the x direction oscillating either in z or y and having an angle alpha to the z axis. In the Port1 image, there is a trial for how to emit this light but I have no idea what to write in the propagation constant, and also I think I have written wrong the Ex,Ey,Ez fields. And finally in the graphene image, I typed in the conductivity and any other relevant info needed for the studying.
Rishad Arfin
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Posted: 9 years ago Mar 7, 2016, 12:25 a.m. EST
I am also trying to simulate Graphene in COMSOL. However, I was trying to simulate the electronic properties of Graphene.

I actually am trying to simulate a MOSFET, where I am using the channel as Graphene layer. As the Graphene is not a built in material in COMSOL, I have to define the parameters of Graphene.

Apparently, in this case I have to use semiconductor module in COMSOL to simulate MOSFET. But can I simulate Graphene in semiconductor module? If yes, then I need to define certain parameters such as-

- Bandgap
- Density of States in Conduction Band
- Density of States in Valence Band

Can you please help me with this. I feel like I am stuck here. Thanks !
I am also trying to simulate Graphene in COMSOL. However, I was trying to simulate the electronic properties of Graphene. I actually am trying to simulate a MOSFET, where I am using the channel as Graphene layer. As the Graphene is not a built in material in COMSOL, I have to define the parameters of Graphene. Apparently, in this case I have to use semiconductor module in COMSOL to simulate MOSFET. But can I simulate Graphene in semiconductor module? If yes, then I need to define certain parameters such as- - Bandgap - Density of States in Conduction Band - Density of States in Valence Band Can you please help me with this. I feel like I am stuck here. Thanks !

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