I have a model in HFSS that I attached its picture that show the current surface, as it is shown there is no current from corners to the end, I want to know the reason, and if anyone can help me to find a way to figure it out.
The excitation in port is lumped port with 1V.
There is two PCB between coils.
frequency is 100MHz.
Can you explain me more about your problem. I am sure i will resolve your problem.
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We can't tell what you mean by corners or end.
There should be very little coupling between your two circuits. The outside circuit has two single turn coils in parallel, both working in the same direction creating a magnetic field in the x or -x direction.
The inside circuit has two single turn coils but which create magnetic field in the opposite direction to each other, so will not couple to the other circuit in total.
There is current on parts of both circuits. Maybe the current is in opposite directions in the two halves of the inside circuit so results in no current at the output.
There does not seem to be any problem with current disappearing. The current seems to be all on the inside surfaces.
Although you have told us the frequency, you haven't told us how big the circuit is, so that is not as helpful as it could be. However, the wavelength at 100 MHz is 3 m so if your circuit is less than 10 cm across the wavelength and delay are not likely to affect things much.
Check current distribution at different angles. Animate it and see its behavior. Maybe you can find the solution by yourself. In the present form, question is not fully clear.
There is no voltage across these terminals because the two parts of the output circuit are driven out-of-phase by the input circuit so the currents and voltages from the two halves cancel so there is no current or voltage at the output. Work out the direction of the currents and magnetic fields in each part of the circuit, or plot the directions from the simulation. I don't think there is any capacitive coupling between the ports either, or very little.
Malcolm White
Thank you again.
your explanation make sense, but the problem is that in experimental results we have bias.
Can you pls explain me in detail about the problem. Also share me your H field and current density files. I will 100% resolve your problem.
Please mail me
You would get coupling if one side of the output circuit was upside down, so that the two sets of coils coupled in phase. That would require a step between layers at the mid-plane.
Alternatively, they would couple if the input was fed in series in one of the cross-bars, and not between the cross bars.
Both of these would mean the coupling of the two halves of the circuit added at the output, rather than subtracting.
Malcolm White Hi
I did a change in my model, and I put a rectangular between two points of output and assigned Lumped RLC boundary as a 50 ohm series resistor, then I analyzed again. I thought that, now it should change and we can see the flow of current, because before it was like open circuit, But now there is still no current. How can I get that I am doing correct simulation or not?
@Najme Mohammadyahya. Can you explain your problem to me personally with surface current distribution and magnetic field distributions. I will resolve your problem immediately. Just drop your whatsapp message at +917983388622
Atul Varshney thank you for your help.
I explain everything in my question, if you need more information please let me know here.
I think you need to use the same kind of feed to both circuits. Either take out the vertical feed element on the input, and feed one of the loops in series, like the output, or join the output together like the input and take the output between the middle of the two loops. At the moment you have a series feed to one and a parallel feed to the other, and they are isolated from each other.
Or put a twist in one of the loops, as I said in my previous post.
Do you understand what I mean when I say that the two sides of the circuit couple out of phase? You can't change that by changing the boundary conditions.
Malcolm White I know what you mean, but I think I did the same as you said, I assigned lump port excitation on just top face of port (mean top coil), and define the bottom face as ground (by assigning perfect E). Is it correct or not? I would really appreciate if you can show me in picture that where should I feed. generally did I chose the correct solution?(Driven terminal and lumped port as excitation)
On your output port, the current for an output signal flows in the direction of the red arrow. In your input port the current flows in the direction of the blue arrow. Your ports are orthogonal to each other. You need the same direction of current flow in both ports.
The current in the input port flows in the direction of the blue arrow and then splits in two opposite directions, one the same way as the red arrow, and the other the opposite direction to the red arrow. These two currents result in two opposite direction currents in the secondary coil that result in no voltage across the output terminals.
Change your input port so it looks like your output port, or change your output port so it looks like your input port.
Or put a crossover in the output coil.
Malcolm White thank you for your explanation. Just some questions, first of all how can I change the input? because for having the lumped port excitation, I have to connect top and bottom coils together and then make the bottom face as ground and top one as excitation. Another question is that, about the induction voltage you are right they are opposite each other, but my question is that, in the internal coils that are like capacitor and one side of it is ground, should not have coupling and make voltage? because they are not opposite, in capacitor current flows to the ground ,so they should add together.
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