Quote from: aero on 06/19/2015 01:06 AMYou'll likely need to compile from source so get the latest from https://github.com/stevengj/meep/blob/master/src/meep.hpp#L169-L172 That way your software will be current with the latest documentation.Have found meep-mpich2 ! MPI Message Passing Interface, almost a standard parallel processing tool in large installations. It even has a installer for Ubuntu and .deb systems if anyone else out there is interested.(if you are running more than one box with linux/ubuntu/?, you can use all the machines as one single larger Virtual Machine, eg a quad desktop and a laptop work together to use all 8 cores for the single program)Need to sort out a few library, driver and complie conflicts and attempt to install alongside the present system.http://ftp.univ-nantes.fr/ubuntu/pool/universe/m/meep-mpich2/

You'll likely need to compile from source so get the latest from https://github.com/stevengj/meep/blob/master/src/meep.hpp#L169-L172 That way your software will be current with the latest documentation.

[quoteIn other words, their data is for the Optical range, much higher frequency than Microwave frequency.

@dustinthewind has linked to this paper many times but it didn't get discussed much. It has lots of good pertinent info in there including some surprising info for you near field fans:http://arxiv.org/pdf/1502.06288v1.pdf (note that ref 6 is our favorite anomalous thrust production...paper)Also pulled out reference 15 as it is of interest:http://www.asps.it/article2.pdfEdit:I was thinking, instead of spending thousands of man hours reading, researching, building stuff and generating hundreds of pages of thread content....how bout we just ask Watson?http://www.ibm.com/smarterplanet/us/en/ibmwatson/what-is-watson.html He better not say 42.

Quote from: Rodal on 06/19/2015 12:12 PMQuote from: deltaMass on 06/19/2015 08:23 AMQuote from: aero on 06/19/2015 06:07 AMQuote from: deltaMass on 06/19/2015 04:59 AMI need to tweak that value for the permittivity of copper. I had not used the effective mass of the electron. For copper, this turns out to be 1.38*m_{e}, and so the permittivity is correspondingly reduced.So fromEpsilon = i / (Rho (m_{eff}/m_{e}) w)we get at 2.4 GHzEpsilon = i0.00288Thanks so much for all your work, but since now I don't have a real part of permittivity, how will I impliment this model?http://ab-initio.mit.edu/wiki/index.php/Material_dispersion_in_Meep#Conductivity_and_complex_.CE.B5Sorry to send you down a link, but that provides a much better explaination of the model than I could. But just in case you miss it, the example model is given in italics in Scheme code as: (make medium (epsilon 3.4) (D-conductivity (/ (* 2 pi 0.42 0.101) 3.4))If you are concerned with expressing the relative permittivity only, then useEpsilon_{r} = 1 + i0.00288/Epsilon_{0}from which you can see how much bigger is the imaginary part - about a billion times larger than the real part, since Epsilon_{0} = 8.85*10^{-12}. The real part of the relative permittivity is almost exactly = 1 at these frequencies, for copper.From that you can verify the expression for absolute permittivity that I've been using:Epsilon = Epsilon_{0} * Epsilon_{r} ~= 10^{-11} + i0.00288This result is essentially correct, the known result for a conductive metal like copper that:The Real part of the relative permittivity is oneThe Imaginary part of the relative permittivity approaches + Infinity (+3.25*10^8)p. 29 and 30 of:http://www.phys.ufl.edu/~tanner/notes.pdfOne GHz corresponds to 0.033 1/cm frequency, or 30 cm wavelength (and to 4 μeV photon energy), which is way off to the left outside the range of the image below (observe how the Imaginary part of permittivity goes to +Infinity for low frequencies, and what a huge difference in the value of the imaginary permittivity frequency makes ), since the Imaginary part of permittivity goes to Infinity as 1/ω , this behavior makes the Imaginary permittivity of a metal a not a very useful function for conducting materials at microwave frequencies, also notice that the (much smaller) real part is negative:(*IMHO The Drude model is NOT a useful model to model Copper in the GHz range*)

Quote from: deltaMass on 06/19/2015 08:23 AMQuote from: aero on 06/19/2015 06:07 AMQuote from: deltaMass on 06/19/2015 04:59 AMI need to tweak that value for the permittivity of copper. I had not used the effective mass of the electron. For copper, this turns out to be 1.38*m_{e}, and so the permittivity is correspondingly reduced.So fromEpsilon = i / (Rho (m_{eff}/m_{e}) w)we get at 2.4 GHzEpsilon = i0.00288Thanks so much for all your work, but since now I don't have a real part of permittivity, how will I impliment this model?http://ab-initio.mit.edu/wiki/index.php/Material_dispersion_in_Meep#Conductivity_and_complex_.CE.B5Sorry to send you down a link, but that provides a much better explaination of the model than I could. But just in case you miss it, the example model is given in italics in Scheme code as: (make medium (epsilon 3.4) (D-conductivity (/ (* 2 pi 0.42 0.101) 3.4))If you are concerned with expressing the relative permittivity only, then useEpsilon_{r} = 1 + i0.00288/Epsilon_{0}from which you can see how much bigger is the imaginary part - about a billion times larger than the real part, since Epsilon_{0} = 8.85*10^{-12}. The real part of the relative permittivity is almost exactly = 1 at these frequencies, for copper.From that you can verify the expression for absolute permittivity that I've been using:Epsilon = Epsilon_{0} * Epsilon_{r} ~= 10^{-11} + i0.00288This result is essentially correct, the known result for a conductive metal like copper that:The Real part of the relative permittivity is oneThe Imaginary part of the relative permittivity approaches + Infinity (+3.25*10^8)

Quote from: aero on 06/19/2015 06:07 AMQuote from: deltaMass on 06/19/2015 04:59 AMI need to tweak that value for the permittivity of copper. I had not used the effective mass of the electron. For copper, this turns out to be 1.38*m_{e}, and so the permittivity is correspondingly reduced.So fromEpsilon = i / (Rho (m_{eff}/m_{e}) w)we get at 2.4 GHzEpsilon = i0.00288Thanks so much for all your work, but since now I don't have a real part of permittivity, how will I impliment this model?http://ab-initio.mit.edu/wiki/index.php/Material_dispersion_in_Meep#Conductivity_and_complex_.CE.B5Sorry to send you down a link, but that provides a much better explaination of the model than I could. But just in case you miss it, the example model is given in italics in Scheme code as: (make medium (epsilon 3.4) (D-conductivity (/ (* 2 pi 0.42 0.101) 3.4))If you are concerned with expressing the relative permittivity only, then useEpsilon_{r} = 1 + i0.00288/Epsilon_{0}from which you can see how much bigger is the imaginary part - about a billion times larger than the real part, since Epsilon_{0} = 8.85*10^{-12}. The real part of the relative permittivity is almost exactly = 1 at these frequencies, for copper.From that you can verify the expression for absolute permittivity that I've been using:Epsilon = Epsilon_{0} * Epsilon_{r} ~= 10^{-11} + i0.00288

Quote from: deltaMass on 06/19/2015 04:59 AMI need to tweak that value for the permittivity of copper. I had not used the effective mass of the electron. For copper, this turns out to be 1.38*m_{e}, and so the permittivity is correspondingly reduced.So fromEpsilon = i / (Rho (m_{eff}/m_{e}) w)we get at 2.4 GHzEpsilon = i0.00288Thanks so much for all your work, but since now I don't have a real part of permittivity, how will I impliment this model?http://ab-initio.mit.edu/wiki/index.php/Material_dispersion_in_Meep#Conductivity_and_complex_.CE.B5Sorry to send you down a link, but that provides a much better explaination of the model than I could. But just in case you miss it, the example model is given in italics in Scheme code as: (make medium (epsilon 3.4) (D-conductivity (/ (* 2 pi 0.42 0.101) 3.4))

I need to tweak that value for the permittivity of copper. I had not used the effective mass of the electron. For copper, this turns out to be 1.38*m_{e}, and so the permittivity is correspondingly reduced.So fromEpsilon = i / (Rho (m_{eff}/m_{e}) w)we get at 2.4 GHzEpsilon = i0.00288

(make medium (epsilon 3.4) (D-conductivity (/ (* 2 pi 0.42 0.101) 3.4))

I did a lot of checking around about the permittivity (or dielectric constant or "dielectric function" as it's called because it's complex) of copper and its domain of applicability. I stand by the value I calculated.Well below the plasma frequency the model is said to be quite reliable. Note that the operating frequencies that interest us here are six orders of magnitude down on the plasma frequency. Down at these lower frequencies, which is the case here, several sources have told me that the free electron gas model is perfectly fine for copper. The free electron model is what I used.Indeed matters become much more complex at optical frequencies, because the plasma frequency is being approached and indeed exceeded. But we need not worry about that.If it helps you to trust me on this, I should perhaps mention that I have a Masters in Physics with Honours from Oxford University, and that I gained my place there at age 16. Although that degree is now long in the tooth, I did actually study the physics of free electron gasses back then as it was part of the curriculum.

That looks like useful information, unfortunately it's Greek to me. Need to use a translator I guess.No, Meep doesn't use GPUs, but of course the source language code is available, written in C++, so someone really, really motivated could make it so.Same answer re. writing new functions for material characteristics, except Meep does already provide hooks for new user supplied functions in some instances and I think material characteristics is one place where it does.

Quote from: deltaMass on 06/19/2015 05:49 PMI did a lot of checking around about the permittivity (or dielectric constant or "dielectric function" as it's called because it's complex) of copper and its domain of applicability. I stand by the value I calculated.Well below the plasma frequency the model is said to be quite reliable. Note that the operating frequencies that interest us here are six orders of magnitude down on the plasma frequency. Down at these lower frequencies, which is the case here, several sources have told me that the free electron gas model is perfectly fine for copper. The free electron model is what I used.Indeed matters become much more complex at optical frequencies, because the plasma frequency is being approached and indeed exceeded. But we need not worry about that.If it helps you to trust me on this, I should perhaps mention that I have a Masters in Physics with Honours from Oxford University, and that I gained my place there at age 16. Although that degree is now long in the tooth, I did actually study the physics of free electron gasses back then as it was part of the curriculum.As I wrote here: http://forum.nasaspaceflight.com/index.php?topic=37642.msg1391527#msg1391527I agree with you that the value is essentially theoretically correct. However the issue in inputting these values in MEEP is one of numerical correctness due to numerical implementation in the code.As the Imaginary part of the relative permittivity approaches + Infinity as 1/ω, the value of (+3.25*10^8) being so large may result in numerical issues in MEEP's numerical implementation of the Drude model, if so it would not be a useful numerical model. There is no harm in trying these values in MEEP and seeing how MEEP handles it numerically...The Drude model in MEEP was written and used mainly for optical applications, in which range the value of the Imaginary part of pemittivity is much lower.The issue is how will MEEP handle these values (that's why the numbers used in machine precision are important in numerical implementations).Just because the value is theoretically correct, does not necessarily mean that MEEP will handle it correctly, if the person that wrote the MEEP code had in mind people using the model for optical applications and not for GHz applications.I will also be interested in finding out how MEEP handles this input for the microwave range.

Quote from: Rodal on 06/19/2015 06:14 PMQuote from: deltaMass on 06/19/2015 05:49 PMI did a lot of checking around about the permittivity (or dielectric constant or "dielectric function" as it's called because it's complex) of copper and its domain of applicability. I stand by the value I calculated.Well below the plasma frequency the model is said to be quite reliable. Note that the operating frequencies that interest us here are six orders of magnitude down on the plasma frequency. Down at these lower frequencies, which is the case here, several sources have told me that the free electron gas model is perfectly fine for copper. The free electron model is what I used.Indeed matters become much more complex at optical frequencies, because the plasma frequency is being approached and indeed exceeded. But we need not worry about that.If it helps you to trust me on this, I should perhaps mention that I have a Masters in Physics with Honours from Oxford University, and that I gained my place there at age 16. Although that degree is now long in the tooth, I did actually study the physics of free electron gasses back then as it was part of the curriculum.As I wrote here: http://forum.nasaspaceflight.com/index.php?topic=37642.msg1391527#msg1391527I agree with you that the value is essentially theoretically correct. However the issue in inputting these values in MEEP is one of numerical correctness due to numerical implementation in the code.As the Imaginary part of the relative permittivity approaches + Infinity as 1/ω, the value of (+3.25*10^8) being so large may result in numerical issues in MEEP's numerical implementation of the Drude model, if so it would not be a useful numerical model. There is no harm in trying these values in MEEP and seeing how MEEP handles it numerically...The Drude model in MEEP was written and used mainly for optical applications, in which range the value of the Imaginary part of pemittivity is much lower.The issue is how will MEEP handle these values (that's why the numbers used in machine precision are important in numerical implementations).Just because the value is theoretically correct, does not necessarily mean that MEEP will handle it correctly, if the person that wrote the MEEP code had in mind people using the model for optical applications and not for GHz applications.I will also be interested in finding out how MEEP handles this input for the microwave range.Well... if it all boils to the fact that copper in these ranges behaves very closely to a perfect metal, than Meep has a predefined material type for this: "perfect-metal". A predefined material type corresponding to a perfect electric conductor (at the boundary of which the parallel electric field is zero), technically epsilon = -infinity. That will simplify things and prevent numerical issues.

...No, Meep doesn't use GPUs, but of course the source language code is available, written in C++, so someone really, really motivated could make it so....

So the consensus is that I should use e = 1 +i 3.25E+8, correct?I'll try that, first to see what effect it has on the resonant frequency. I'll let you know.I don't anticipate that this will introduce numerical problems in meep but we will see.