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Radiated power
Posted 11 feb 2024, 21:05 GMT-5 RF & Microwave Engineering 1 Reply
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Hi,
Could you please tell me how to calculate total radiated power from antenna in COMSOL? I have been integrating the power outflow over the surface of the sphere defined as far-field but i dont get the resonance peak expected from the antenna dimensions does not come. Also, can i assume the total electrical energy emitted is a measure of the total radiated power? Thanks in advance
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- There are a number of ways to set up antenna models and the best or simplest ways to compute radiated power will vary, depending on how you set up the model. Are you working in frequency or time domain? What kind(s) of source boundary conditions have you chosen to excite your antenna? Are there lossy materials in your antenna?
- There exists no true finite-radius far-field sphere. You may (or may not) happen to have a spherical surface around your antenna in your model, but that is all it is, and its geometry may or may not provide a fair approximation to far field conditions. The far field computations are done in post-processing for a virtual sphere with a theoretical radius that goes to infinity, but for which the "far fields" are then scaled to correspond a sphere of R= 1m, but that distance has nothing to do with whether your antenna would fit inside such a sphere or not, or if you happen to draw such a sphere or not. It's just a scaling.
- You tell us basically nothing about your antenna or your model, so it is impossible to know why you are failing to see the "resonance peak" that you anticipated. Perhaps there is an error in your model, but who knows?
- Energy and power cannot be expressed in the same units, so no, the "total energy" radiated tells you basically nothing about "radiated power." After all, power = energy per time. Without defining a suitable time interval, you can't get one from the other... no more than you can tell how many total miles a car has been driven by measuring how fast it is traveling right now. SUGGESTION: There are example Comsol application files available to you (e.g., see the Comsol Application Library), that illustrate simple antenna models and various local field and far field computations. I encourage you to work your way through them, methodically and carefully. They should prove very helpful to you in improving your understanding. Good luck.
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