...If anyone is interested, meep does allow the source to be switched off. I could make a slightly different run so we could look at the field images immediately after power-off if that would be of interest....If that would provide helpful information, let me know.

...I am planing to build more than just two basic designs, I have on the drawing board injected microwaveguide phase locked magnetrons that the power supply has been modified to narrow the hash and be able to sweep and phase lock the to cavity and vary the duty cycles.

Quote from: aero on 07/12/2015 04:13 PM...If anyone is interested, meep does allow the source to be switched off. I could make a slightly different run so we could look at the field images immediately after power-off if that would be of interest....If that would provide helpful information, let me know.Yes! Why couldn't I have thought of that? One would think the ring down would look much like the ring-up.Are your latest models including copper loss? The heck with the real (reactive) component of complex permittivity for a metal, just the complex/lossy component should matter?

I'd really like to see are images of a comparison of the static fields and pressure, and doppler-shifted fields and pressures.

All Q measurements using S11 are suspect: everybody should take with a grain of salt the reported Q's from different EM Drive researchers, unless the procedure to measure the Q is detailed and they have used S21.

...Saw some questions while I was building...thks doc, S21 Q is only Q that matters. Antennas (S11) are measured not with Q but simple return loss or more commonly VSWR. This still is only a portion of what's important in an antenna. Radiation pattern and gain are just as important. An S11 is really only used to guarantee good match to the rf source. Outside that, it does not address antenna performance...an emdrive has more to it than a simple load match to the source, its more than an antenna....at least we think it is...

Quote from: rfmwguy on 07/12/2015 12:40 PMQuote from: TheTraveller on 07/12/2015 09:13 AMI would suggest to every EMDrive builder that having a Vector Network Analyser and understanding what it is telling you is critical to your success.Doing 1 cable SLOW sweeps can test your excitation antenna design, impedance matching, find your cavity resonances, peak return loss dBs, VSWR, reflection coefficient, Q and cavity bandwidth.Without a VNA, it is hard to understand how any build could achieve Force generation as there are so many VNA determinant / measurable variables that need to be all as close as possible to optimum values.My soon to arrive 100W Rf amp has the ability to be throttled from 50dBm (100W) output to 19dBm (79mW) output and has a real time analogue VSWR output pin, which I plan to use to generate a DIY VNA as knowing the VSWR, Rf amp impedance and the frequency will enable real time calculation of the return loss db, the reflection coefficient, how well the cavity is impedance matched to the Rf amp, the cavity unloaded Q and Q bandwidth.http://cgi.www.telestrian.co.uk/cgi-bin/www.telestrian.co.uk/vswr.plSeems a lot of information to get from 1 pin of analogue information, but the Rf amp is driving the cavity at it's impedance, output frequency and reporting on what is happening via the VSWR analogue output. Additionally doing it this way ensures each EMDrive is impedance matched as close as possible to it's 100W Rf amp.Comments from the experienced microwave guys that have used 1 cable VNA measurements most welcome.Agreed but a 1 port measurement is simply return loss or an antenna measurement not a bandpass cavity where a sample port is needed for S21. call it reflected S11 Q not forward S21 Q. This will give unnaturally high numbers leading to confusion. If u get the chance, ask shawyer for S21 plots since he had a sample port. This should illustrate assymetrical bandpass response.What are your thoughts on this solution?http://www.ebay.com/itm/138M-4-4G-SMA-signal-source-generator-simple-spectrum-analyzer-Tracking-source-/111493176997?pt=LH_DefaultDomain_0&hash=item19f582dea5Add a couple of SMA 3dB attenuators for mismatch.Add a sampling port to the frustum with the software and a laptop it should do what needs to be done.(much thanks to someone that has been a wonderful source of information saving me hours of research) Shell

Quote from: TheTraveller on 07/12/2015 09:13 AMI would suggest to every EMDrive builder that having a Vector Network Analyser and understanding what it is telling you is critical to your success.Doing 1 cable SLOW sweeps can test your excitation antenna design, impedance matching, find your cavity resonances, peak return loss dBs, VSWR, reflection coefficient, Q and cavity bandwidth.Without a VNA, it is hard to understand how any build could achieve Force generation as there are so many VNA determinant / measurable variables that need to be all as close as possible to optimum values.My soon to arrive 100W Rf amp has the ability to be throttled from 50dBm (100W) output to 19dBm (79mW) output and has a real time analogue VSWR output pin, which I plan to use to generate a DIY VNA as knowing the VSWR, Rf amp impedance and the frequency will enable real time calculation of the return loss db, the reflection coefficient, how well the cavity is impedance matched to the Rf amp, the cavity unloaded Q and Q bandwidth.http://cgi.www.telestrian.co.uk/cgi-bin/www.telestrian.co.uk/vswr.plSeems a lot of information to get from 1 pin of analogue information, but the Rf amp is driving the cavity at it's impedance, output frequency and reporting on what is happening via the VSWR analogue output. Additionally doing it this way ensures each EMDrive is impedance matched as close as possible to it's 100W Rf amp.Comments from the experienced microwave guys that have used 1 cable VNA measurements most welcome.Agreed but a 1 port measurement is simply return loss or an antenna measurement not a bandpass cavity where a sample port is needed for S21. call it reflected S11 Q not forward S21 Q. This will give unnaturally high numbers leading to confusion. If u get the chance, ask shawyer for S21 plots since he had a sample port. This should illustrate assymetrical bandpass response.

I would suggest to every EMDrive builder that having a Vector Network Analyser and understanding what it is telling you is critical to your success.Doing 1 cable SLOW sweeps can test your excitation antenna design, impedance matching, find your cavity resonances, peak return loss dBs, VSWR, reflection coefficient, Q and cavity bandwidth.Without a VNA, it is hard to understand how any build could achieve Force generation as there are so many VNA determinant / measurable variables that need to be all as close as possible to optimum values.My soon to arrive 100W Rf amp has the ability to be throttled from 50dBm (100W) output to 19dBm (79mW) output and has a real time analogue VSWR output pin, which I plan to use to generate a DIY VNA as knowing the VSWR, Rf amp impedance and the frequency will enable real time calculation of the return loss db, the reflection coefficient, how well the cavity is impedance matched to the Rf amp, the cavity unloaded Q and Q bandwidth.http://cgi.www.telestrian.co.uk/cgi-bin/www.telestrian.co.uk/vswr.plSeems a lot of information to get from 1 pin of analogue information, but the Rf amp is driving the cavity at it's impedance, output frequency and reporting on what is happening via the VSWR analogue output. Additionally doing it this way ensures each EMDrive is impedance matched as close as possible to it's 100W Rf amp.Comments from the experienced microwave guys that have used 1 cable VNA measurements most welcome.

Quote from: TheTraveller on 07/12/2015 09:13 AMI would suggest to every EMDrive builder that having a Vector Network Analyser and understanding what it is telling you is critical to your success....a real time analogue VSWR output pin, which I plan to use to generate a DIY VNA as knowing the VSWR, Rf amp impedance and the frequency will enable real time calculation of the return loss db, the reflection coefficient, how well the cavity is impedance matched to the Rf amp, the cavity unloaded Q and Q bandwidth....Comments from the experienced microwave guys that have used 1 cable VNA measurements most welcome.I've used VNA's to do antenna sweeps. I taught cellular engineers how to do antenna sweeps. The VNA was 2 port that went to a duplexer to make it 1 port.Anyways, your transmitter VSWR isn't a VNA, it gives you a scalar, not vector (phase information) that is useful for determining Q. I've tuned a lot of stuff, but never needed to measure Q. BW, Ripple, insertion loss, return loss, but never was the Q of anything spec'd for the systems I worked on.Anyways, doing the VNA thing means applying loads (open, short, 50ohm) and hitting the apt. calibrate buttons. Otherwise, how do you know your coax/waveguide isn't affecting the inferred reading you get from the return loss?Putting a sample port on the frustrum isn't a bad idea anyways. You can make a very simple diode detector (resistor, cap, diode - costs $1) and see the peak on a $5 DVM.Although, the ancient and venerable grid dip meter can give you an indication of Q, but I think you'd have a heck of a time coupling to a closed frustrum. Just don't bother with that!Best use a very lightly, barely, coupled sample port. There's a lot of power in your 100K+ Q cavity!

I would suggest to every EMDrive builder that having a Vector Network Analyser and understanding what it is telling you is critical to your success....a real time analogue VSWR output pin, which I plan to use to generate a DIY VNA as knowing the VSWR, Rf amp impedance and the frequency will enable real time calculation of the return loss db, the reflection coefficient, how well the cavity is impedance matched to the Rf amp, the cavity unloaded Q and Q bandwidth....Comments from the experienced microwave guys that have used 1 cable VNA measurements most welcome.

Some times ago i posted this picture. For this case i got some Results now. The qualitativ results may be interesting for the group.I Did an experiment with a Agilent Networkanalizer in the K band regime. I got used up to 8 identical conical cavities in the setup -BD; SD; length- all got the same cone angle and all got the same resonant frequency. CNC machine builded components... The small diameter matches exact to the Cut Off diameter. The mode was TE011 for a single cavity resonator. Of course if there are 2 cavities in line the Mode will be TE012 and so on for more resonators. The antenna was optimated for this mode and installed at the bigger diameter.Results:A following results got same resonant frequency.For only one resonator the S11 shows a curve whit a minimum |r|~0.1 if the small diameter was closed. If the cavity is open ended there is no detectable resonance (reference as expected).For 2 cavitys inline in the closed case the 3dB BW is even smaller than with only 1 cavity (this is normal for higher p value) the impedance matching was a little better with |r| ~0.05. If the double resonator was open there was a very less coupled resonance with large BW in the right frequency region.For 3 cavitys in the open ended case this resonance was couppled better- the Q was higher.I did this strate forworth up to 8 cavitys.In the last case the resonance in the open ended cavity was most equal to the case of a closed resonator |r|~0.12. There was only a little difference if the open end would closed up with a metal plate |r|~0.1.conclusions:Every half wavelength a part of the energy is reflected and goes back to the antenna. There will be a constructive interference all Lambda(0.5Lambda forward direction and 0.5Lambda backward) at the trace back to the antenna cause of the equal length of the single cavities.Based on the periodic structure with some regions equal to cutoff there is no long way propagation of the wave along the structure.The field strength in every single cavity in the forward direction will smaller from one to the next conical cavity in this case.So i am no longer sure that this structure is able to increase possible net forces. It may be helpful to do research in evanescent wave theories / effects of conical resonators like posted here in the forum.

Quote from: X_RaY on 07/12/2015 09:41 PMSome times ago i posted this picture. For this case i got some Results now. The qualitativ results may be interesting for the group.I Did an experiment with a Agilent Networkanalizer in the K band regime. I got used up to 8 identical conical cavities in the setup -BD; SD; length- all got the same cone angle and all got the same resonant frequency. CNC machine builded components... The small diameter matches exact to the Cut Off diameter. The mode was TE011 for a single cavity resonator. Of course if there are 2 cavities in line the Mode will be TE012 and so on for more resonators. The antenna was optimated for this mode and installed at the bigger diameter.Results:A following results got same resonant frequency.For only one resonator the S11 shows a curve whit a minimum |r|~0.1 if the small diameter was closed. If the cavity is open ended there is no detectable resonance (reference as expected).For 2 cavitys inline in the closed case the 3dB BW is even smaller than with only 1 cavity (this is normal for higher p value) the impedance matching was a little better with |r| ~0.05. If the double resonator was open there was a very less coupled resonance with large BW in the right frequency region.For 3 cavitys in the open ended case this resonance was couppled better- the Q was higher.I did this strate forworth up to 8 cavitys.In the last case the resonance in the open ended cavity was most equal to the case of a closed resonator |r|~0.12. There was only a little difference if the open end would closed up with a metal plate |r|~0.1.conclusions:Every half wavelength a part of the energy is reflected and goes back to the antenna. There will be a constructive interference all Lambda(0.5Lambda forward direction and 0.5Lambda backward) at the trace back to the antenna cause of the equal length of the single cavities.Based on the periodic structure with some regions equal to cutoff there is no long way propagation of the wave along the structure.The field strength in every single cavity in the forward direction will smaller from one to the next conical cavity in this case.So i am no longer sure that this structure is able to increase possible net forces. It may be helpful to do research in evanescent wave theories / effects of conical resonators like posted here in the forum.Interesting.What was your build geometry? Big dia, small dia, length and frequency? Will run the data through my EMDrive calculator and post the results.

The quality factor of this resonator under no load can be calculated by the following equation:Qu=∫|H|2dv/h/2∫|nxH|2ds+tgd∫|H|2dv = (14)Where tg is the electric loss within the cavity, n is the normal vector of the wall, s is the cavity surface area, v is the volume of the cavity.

Just to throw another log on the fire in Bringing Light into the Dark.In the 2010 Chinese paper, Prof Yang discloses the equation they use to calculate cavity Q. Yes that is right, they don't measure Q, they calculate it from their in-house developed equation.Search for equation 14 in the 2010 paper:http://www.emdrive.com/NWPU2010translation.pdfQuoteThe quality factor of this resonator under no load can be calculated by the following equation:Qu=∫|H|2dv/h/2∫|nxH|2ds+tgd∫|H|2dv = (14)Where tg is the electric loss within the cavity, n is the normal vector of the wall, s is the cavity surface area, v is the volume of the cavity.Who will be the 1st to post an Excel spreadsheet that duplicates Prof Yang's equation?

Quote from: TheTraveller on 07/12/2015 10:28 PMJust to throw another log on the fire in Bringing Light into the Dark.In the 2010 Chinese paper, Prof Yang discloses the equation they use to calculate cavity Q. Yes that is right, they don't measure Q, they calculate it from their in-house developed equation.Search for equation 14 in the 2010 paper:http://www.emdrive.com/NWPU2010translation.pdfQuoteThe quality factor of this resonator under no load can be calculated by the following equation:Qu=∫|H|2dv/h/2∫|nxH|2ds+tgd∫|H|2dv = (14)Where tg is the electric loss within the cavity, n is the normal vector of the wall, s is the cavity surface area, v is the volume of the cavity.Who will be the 1st to post an Excel spreadsheet that duplicates Prof Yang's equation?Sorry mr t, this is an arbitrary equation of limited value imo. One must ask why estimate when one can measure.

Quote from: rfmwguy on 07/12/2015 10:51 PMQuote from: TheTraveller on 07/12/2015 10:28 PMJust to throw another log on the fire in Bringing Light into the Dark.In the 2010 Chinese paper, Prof Yang discloses the equation they use to calculate cavity Q. Yes that is right, they don't measure Q, they calculate it from their in-house developed equation.Search for equation 14 in the 2010 paper:http://www.emdrive.com/NWPU2010translation.pdfQuoteThe quality factor of this resonator under no load can be calculated by the following equation:Qu=∫|H|2dv/h/2∫|nxH|2ds+tgd∫|H|2dv = (14)Where tg is the electric loss within the cavity, n is the normal vector of the wall, s is the cavity surface area, v is the volume of the cavity.Who will be the 1st to post an Excel spreadsheet that duplicates Prof Yang's equation?Sorry mr t, this is an arbitrary equation of limited value imo. One must ask why estimate when one can measure.My point is this equation is what the Chinese use when they quote device Q. They don't, as far as I know, measure the quoted devices Q.

Doctor Rodal,if I understand correctly, you are calculating the Poynting vector by hand?Because I believe MEEP has functions to do this automatically: (get-poynting which-band) (output-poynting which-band)(output-poynting-x which-band)(output-poynting-y which-band)(output-poynting-z which-band)http://ab-initio.mit.edu/wiki/index.php/MPB_User_Reference#Storing_and_combining_multiple_fields

Nice. The graph shows the mixing of the modes as a function of cavity shape.There is a choice of frequency, and dimension on graph. Any specific motivation?

I'm looking for a configuration when there is one hybrid mode, followed by any other mode very close.Why? Because I think there is another thing interacting with the electromagnetic field of cavity.This thing probally will have a very small coupling with the electromagnetic field.To enhance this coupling I need:- A mode excited by a source puting the max energy on cavity- At least one second mode with frequecy very close to the first but not excited by the source.In this situation, when a small region of the cavity has its electromagnetics properties changed to anything different of vacuum (epslon0 and mu0), then this little "scatter" region triggers a very strong perturbation called "ghost mode".In waveguides "ghost modes" are caused by deformations or imperfections on waveguide, but in principle, any "pertubation" can cause this effect.This "ghost modes" can in some situations, reflect almost all power flux in the waveguide, and the "scatter" will be under very strong radiation pressure.I don't know if this case can be considered also a type of Fano resonance, but I think if I want some type of interaction of the field inside of cavity with some "other thing", I would try to maximize this interaction with this setup.To me this thing is the axion field/particle. To others can be particles from "quantum vacuum" or a space-time flutuactions, but the result of the ghost mode arising is the same, change the incidence of electromagnetic radiation on the walls of cavity.