Radio Frequency (RF) Amplifier Thermal Analysis with AEDT Icepak: Part 1

Hello everyone, today we're going to do a deep dive into AEDT i-SPAC. What I would like to do is replicate an exact same problem which I have solved in some videos before using classic i-SPAC in AEDT i-SPAC. So we are going to see a lot of primitive object creations within AEDT i-SPAC.

The basic boundary conditions or objects to these existing CAD model parts are the usual procedure. But here, I want to show is we can really do a lot of things without even having a CAD data.

So if your customer or colleagues need some quick and dirty analysis and are not able to provide you with the data, this tutorial may be very helpful. I'm going to show in great detail how to create all these features and put them together and execute an AEDT i-SPAC model.

So we're going to build a radio frequency amplifier model. For that, I've opened AEDT i-SPAC. Here we go. And what I would like to do is go to project. I'd like to insert an i-SPAC design all the way down here. And it's going to work.

And as you can see, it's going to switch to i-SPAC mode, hopefully soon. And then we can now see our working area, our model. And here, we start building. The first thing I want to do is I want to add the box for the amplifier. Now this box is going to be hollow.

So what I would like to do is just define six separate thin walls to represent this box. I'm going to go ahead and define our plane in the minimum Y direction. My starting position will be this. It will be a Y plane with a width of 200 millimeters. The length of... 0.06 millimeters. Let's hit OK.

And what we see is our first plane. I'd like to now define the Y max plane. I'll just go duplicate this object. Just move it in the Y direction by 0. 3. So that's great. Now we have our new object here. Let's add our Z plane. Again, let's put our reference starting point.

This plane is going to lie on the Z axis. And its length will be... 0.2 millimeters. So the length of this plane is going to be... 0.2 millimeters. 0.2 millimeters. Let's see if I got it right. Oh, looks like it's short. So let's go ahead. We can double click. It is actually 300 millimeters.

Let's hit OK. And then we want to take this object and duplicate it in the positive Z direction. 0. 2. So now what we're missing are our extraction plates.

So in the extraction, it's going to be a little different because we're going to put a heat sink at the X max location and we're going to put a wall on the X min location. Therefore they're not going to be plates there.

So here what we would like to do is we want to assign these four sheets to objects. So I'm going to check it. And I'm going to assign thermal. And I'm going to treat these as conducting plates. Now we can define their properties.

So let's just say they're of thickness one millimeter and we'll use the default solid material. Then we can hit finish. Now what you'll notice is two things. Now these are conducting plates. And also under here, on the thermal, they're collected under this boundary condition.

So if we click here, we're able to change this. One thing I forgot to do is, when I look at here, so we're going to have shell conduction through these conductors. So we're going to have shell conduction through these conductors. Now we can rate it here based on whatever cutting area.

So I'm going to update the controlling plate. So we can actually overwrite the control at every field. Now we have a cup in order to think with the back side.

So if we do just that, we're going to see the drop until state of cell to wait but the EU leer Continuous Always S net course in the back floor pink. So here we just change to account function, we're going to set URL into today. And now we're going to eternal using new object. Enter s dot.

Similar strategy, positioning is similar as before. Now we're going to define one millimeter thickness in the X direction. 0.2 and 0.3 and 0.2 in the other directions. That's it. Okay. And what we can see is our new object sealing up the bottom side. And we can rename this if we like.

We can call this MinX surface. Another thing I want to do with the surface is, so if I double click on this, I want to change the material. So I go on the material. Let's click edit. We can see that the material is now in the middle. Which is going to bring up our vast material database.

And I would like to assign this to a particular object. And there I see it. And I'm going to hit okay. Hit apply and close this window. Now we have our material assigned. To our thin wall. On the top side of our enclosure is our PCB. Again, where we're going to do a 3D material to represent our PCB.

So let's put our location. But this is going to be up behind. X direction. It's going to be again, pretty thin. The X direction and the same sizes in the Y and Z directions. So let's click this. As you can see now we have this object closing. And what we'd like to do is... . rename it as our PCB.

Next, we'd like to work on the material properties of our PCB, which is critical. So what we're going to do is go here, and let's just hit edit. We want to use an FR4 material, but what I'll do is I want to change the properties on this.

So I click FR4 ref, and then I'm going to say clone materials and define my own material. I'll just call it PCB.use. And then the key parameter I'd like to change is thermal conductivity. So I'm going to go to type, and isotropic. And then our...

Our plane direction is Y and Z, and our normal is the X. So our normal conductivity is pretty low. 0.36, but in plane conductivity is higher. We're going to, due to the copper content, we're going to change this to 9. 3. And we're going to hit OK. And then we'll say OK.

Now we're using our new material. So we can hit apply. And OK. Next step is defining our heat generating devices. And for this purpose, we're just going to use an approximation, where we approximate these devices.

And we're going to define our heat generating devices as rectangular heat sources on the PCB surface. So again, what we'd like to do is go and define these 2D heat sources. So for that, I'd like to create a rectangle. And this is going to be on the top side for our PCB.

And I'd like to loop through this. I think we have an approach going into that. I want to do reference support for theizz So this is going to be thengulo. And since we're not in the X axis... Let's see what happens if you're useful. And it's even to the still Barcelona point. Right.

Pull back, pull back. Pull back.

object okay so now what we see is one of the first heat sources uh what i would like to do is replicate this along the z and now y axis so we'll have a matrix of 12 of these devices providing heat to our system i'm gonna do the similar trick i'm going i want to do just replicate this in the z direction i'm going i want to have three of those and i want to have down 55 millimeters offset in the z direction let's see how this works okay now as you can see we have those added i'd like to then mark three of these and then let's see if in one shot we can sweet replicate these four times over in the y y direction and then we can see that we have a heat source of 64 millimeters 64 millimeters looks like that also worked now we have our 12 heat sources what i would like to do is select all of these and then i want to assign a thermal boundary condition these will be sources and we'll call this source one so we'll do a total power and each one of these are providing seven watts and we have 12 of those so total power should be 84 watts let's click finish so now as you can see we created on the sheets these are gathered under the source group and also under thermal we have our new boundary condition as source one Next step is building our heatsink for that purpose it's going to be a little different and but easier so we're going to go to 3d components and we're going to say create and then here we can just go ahead click heatsink and let's just you know let's click next and then here is essentially the definition of our heatsink it's going to be lying in the yz plane uh the overall height will be for 40 millimeters uh then length 300 width 200 millimeters with a base height of 0.04 we're going to have extruded fins in the and the flow will go in the y direction you can kind of see that we're going to have nine fins and their thickness is going to be two millimeters and then we can hit next where we define material properties we're going to stick with the defaults hit next and click finish so what you notice is we created our heat sink uh but it's uh obviously you know not not aligned uh with our geometry so we need to make sure that we have the right heat sink and we need to find a way to move our heat sink to the correct position So i need to move my heat sink what i will do is i'll go to the bottom surface find the central point click the left mouse middle mouse button and now as you can see it's selected and i can kind of move it with my mouse okay now we want to position it on the top surface of our box so that part is a little tricky i would like to kind of slowly move around kind of find the center point of that surface where it turns to a circle click the left mouse button as you can see now it's placed on top of our enclosure this is our heat sink the base heat sink and you can see the pcb here Now that our uh heat sink is defined and placed properly uh let's uh put our cooling fan in how do we do that uh we can um essentially you know define our fan in multiple different ways we can either use 3d components create fan and follow the wizard there or another option is uh all the way down here the way on the right hand side there's the small window where we have component libraries so and under there you see the fan option and for this particular case i do know what type of a fan i'd like to put in so i'm just going to use this library it's going to be a delta and then i'm going to select this one kind of just drop it into the domain before i uh place my fan i'd actually like to define my air domain uh you know finalize it so uh i've i'm gonna go ahead click create region and then this is going to open the properties window here and then i'm going to go ahead and select the domain and then i'm going to go ahead and let's kind of make this window a little larger and what i would like to do is let's start defining the x direction i'm going to use absolute position of 0.1 meters then again absolute offset and then let's see an absolute position of zero okay so i kind of bounded my problem or domain in the x direction so let's go to our y let's do an absolute position 0.6 meters oh okay that will bring the domain within reasonable number let's zero go to absolute position so that's zero that that is fine and then let's go ahead select z absolute 0.6 meters let's go ahead select z absolute position 0.6 meters 0.6 meters 0.6 meters 0.6 meters position 25 and then change it to absolute position minus 0.05 and hit enter okay so now you know that our air domain kind of captures every everything around that's good So next step is positioning our fan.

Let's go to our fan. Let's do edit definition. It's going to bring up the wizard. It's going to be a 3D circular. We want the ZX cross section which will provide flow in the Y direction. Okay. Okay. Next. Next.

So that, you know, actually did not work well because, you know, the fan's geometry was already defined which, you know, we didn't have to change because it came from library. We do actually have to physically replace our fan so that it's in the correct position. So let's do it.

Let's try the rotate function. And then we want to rotate around the X direction for 90 degrees. So what happened is now it's pointing outside. That's not good. So maybe now I want to rotate 180 degrees in the X direction. Which now is our fan is pointing in the right direction.

We just need to place it. To the right location in X and Z direction. To do that, let's use the same trick. Let's go to our move button. Let's select our central point. Click the mouse button left. Now click this. Let's see. Yep. And now as you can see, we have a little bit of a gap.

Now as you can see, we can move our object. Where we want to do is, let's see if we can find the surface of this plane. Turn to a circle. So I'm going to go ahead and click the button. Now we have our fan centered at our Y mid plane. So that's what we wanted.

So what I notice is we have our inlet for our fluid domain. But we do not have an outlet. Which should be on the opposite end of the fan. So let's hit the button F. Which will put us in face selection mode. Select that region with the left mouse button. To our right mouse button click.

Assign thermal. Opening. Free. And this will have ambient pressure and temperature. For at this face. And let's hit OK. Which is going to end and open. Another boundary condition I believe we're missing is we've defined a wall at the bottom.

But this wall will also have some cooling boundary condition on the back face. So let's assign that. That again. Let's pick this face at the bottom. Go to assign thermal. So assign thermal. And this is a wall. It's stationary. And then. We're gonna say this has a heat transfer coefficient.

For 5 watts meter. And then. We're gonna say this has a heat transfer coefficient. For 5 watts meter square kelvin. At ambient temperature. Note that we do not need to do a wall thickness as the thickness. It was already defined this is a 3D object. So we can now hit finish.

So this concludes the setup of our model boundary conditions. And what I'd like to do is wrap up this video. And I'll see you in the next video. Bye. Good luck.