Author Topic: EM Drive Developments - related to space flight applications - Thread 2  (Read 2106772 times)

Offline Flyby

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 ???
Starting to wonder if I'm reading an updated version of Hansel and Gretel.... with all those bread crumb references ?

Seriously TheTraveler, I'd rather see you start building your setup instead of getting entangled in endless debates about R.Shawyer's merits.
With your insights and eye for detail, I'm sure your test will be much more informative then the crude (but very interesting/promising) test Iullian made.

So please man, stop digging trenches and go for what you originally planned to do : build a working model...

All this ping-pong stuff about what or what not Shawyer said/did/might have said/ could have meant...sigh... you should not take the criticism on Shawyer's texts as personal "insult"(maybe a big word).... it is all a distraction...let it go...and focus again...

You started so well... :-\

Offline phaseshift

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???
Starting to wonder if I'm reading an updated version of Hansel and Gretel.... with all those bread crumb references ?

Seriously TheTraveler, I'd rather see you start building your setup instead of getting entangled in endless debates about R.Shawyer's merits.
With your insights and eye for detail, I'm sure your test will be much more informative then the crude (but very interesting/promising) test Iullian made.

So please man, stop digging trenches and go for what you originally planned to do : build a working model...

All this ping-pong stuff about what or what not Shawyer said/did/might have said/ could have meant...sigh... you should not take the criticism on Shawyer's texts as personal "insult"(maybe a big word).... it is all a distraction...let it go...and focus again...

You started so well... :-\

TheTraveller is doing his due-dilligence to get the dimensions correct - otherwise there will be no thrust (or there will be by just dumb luck). Verification against what has been done before is all part of the process.  It's engineering and art, and I'm very impressed by what he's doing.
"It doesn't have to be a brain storm, a drizzle will often do" - phaseshift

Offline Mike-F

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OK forgive me if this is total rubbish! But looking at the COMSOL FEA Thermal Loss  diagram and the thermal camera image which verifies the calculated thermal losses. It strikes  me that this shows that internal energy is being converted to heat at the large end but not the side walls or small end. Could it be that in these areas the RF energy is being dissipated in another way i.e. generating thrust? So could lower  heat dissipation in these areas indicate energy transfer to something else unseen?

Hope that makes sense!

Mike.
« Last Edit: 05/22/2015 10:49 PM by Mike-F »

Offline Lobo

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Haven't seen anyone post this to the thread so far.

https://hackaday.io/project/5596-em-drive

Plus interview with the team leader.

http://n-o-d-e.net/post/119343131451/building-a-diy-emdrive
Excellent set of strategies these guys are using. In parallel they're doing a Shawyer/Chinese replication attempt @2.4 GHz, and also building a 25 GHz beast with the aim of popping it into a PocketQub and sending it into space (which one of them has already done with a different project).

There might be an even cheaper way of testing an EmDrive in weightlessness than a small space probe: A drop tower like the Fallturm in Bremen, Germany:

http://en.wikipedia.org/wiki/Fallturm_Bremen

At that particular facility you can get up to 9 seconds of weightlessness and the capsule for your experiment can be a lot bigger than a PocketQub for example. It can be up to 0.8m in diameter and up to 2.4m in length. The vacuum inside the structure during the experiment is probably not of a high quality but nothing is stopping you from having an even better vacuum inside your capsule. Using a drop tower would allow for multiple tests with the same hardware with modifocations in between the shots if needed.

I just wanted to put this idea out there.

Or something like this:

Quote
United States
Peter Diamandis of Zero Gravity Corporation

In late 2004, the Zero Gravity Corporation became the first company in the United States to offer zero-g flights to the general public, using Boeing 727 jets. Each flight consists of around 15 parabolas, including simulations of the gravity levels of the Moon and Mars, as well as complete weightlessness.[19] This profile allows ZERO-G's clients to enjoy weightlessness with minimal motion discomfort.

In 2014, Integrated Spaceflight Services, the Research and Education partner of Swiss Space Systems (S3) in America, began its offering of comprehensive reduced gravity services on S3's Airbus A340 aircraft, as well as FAA certification of science and engineering payloads.

Aurora Aerospace in Oldsmar, Florida offers zero-g flights using a Fuji/Rockwell Commander 700. It is also used to simulate the gravity of the Moon and Mars.[21]

Online Rodal

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OK forgive me if this is total rubbish! But looking at the COMSOL FEA Thermal Loss  diagram and the thermal camera image which verifies the calculated thermal losses. It strikes  me that this shows that internal energy is being converted to heat at the large end but not the side walls or small end. Could it be that in these areas the RF energy is being dissipated in another way i.e. generating thrust? So could lower  heat dissipation in these areas indicate energy transfer to something else unseen?

Hope that makes sense!

Mike.
1) The COMSOL FEA is only solving Maxwell's differential equations to obtain the electromagnetic fields.  The COMSOL FEA thermal loss analysis uses the results of the magnetic field calculations.

2) Heating of the big diameter end is entirely due to induction heating due to the transverse magnetic field producing eddy currents on the inner copper surface of the big end.

3) The small end is internally isolated from the magnetic field by a relatively thick HDPE polymer dielectric and the magnetic field in mode TM212 has higher intensity near the big end. 

4) The lower amount of heating of the walls is due to the direction and magnitude of the magnetic field in mode TM212 (please look at the vector plot at the bottom of my prior post).

5) Hence the heating of the walls and the ends of the truncated cone are entirely explainable by classical physics as embodied in the COMSOL FEA, and nothing exotic needs to be involved to explain the thermal losses.

6) Although you didn't ask this, but apparently others are confused, COMSOL FEA and the exact solution successfully predict the experimentally verified natural frequencies.  The mode shape for mode TM212 is also verified.  If there is any thrust from the EM Drive, such thrust is not affecting the natural frequencies and the mode shapes predicted by classical physics.  If there is thrust such thrust involves a process which is esentially uncoupled from equations governing the natural frequency and mode shapes of the cavity.
« Last Edit: 05/22/2015 11:14 PM by Rodal »

Offline PaulF

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OK forgive me if this is total rubbish! But looking at the COMSOL FEA Thermal Loss  diagram and the thermal camera image which verifies the calculated thermal losses. It strikes  me that this shows that internal energy is being converted to heat at the large end but not the side walls or small end. Could it be that in these areas the RF energy is being dissipated in another way i.e. generating thrust? So could lower  heat dissipation in these areas indicate energy transfer to something else unseen?

Hope that makes sense!

Mike.
You mean that the IR photons also contribute to the thrust? I believe that was already debunked, but I am just a  layman.
To my knowledge, the total amount of thrust possible from the microwaves + heat dissipation IR photons is on the order of three magnitudes smaller than the measured thrust.

Offline Blaine

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I'm beginning to the think the thrust is attributed to a polarizable vacuum as extreme as that may sound.  Whatever is happening is not just because of the microwaves or Maxwell's equations for the magnetic fields.  It is something else.  I think its more like pulling than it is thrust/pushing.
Weird Science!

Offline frobnicat

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IULIAN:

Hi,
.......snip
Iulian

Another thing to consider; From your video you have the unit on the end of a looped spring hanging from a shelf....  For the Downwards test you are trying to force the unit downwards AGAINST the natural TENSION of the spring...  you need to measure just how much energy it takes to pull the spring down as much as the unit did when you powered it up.!

The original "thrust was with the aid of the spring pulling the unit upwards. 

Placing the complete unit onto a balance board "like a child's see-saw,  American teeter-totter"  with an equal weight on the other end will enable you to perform these types of measurements

Before this get buried...

I agree teeter-totter setup would be better (to get rid of lifting spring, that likely introduces more spurious vibrations), but your comment on going against or with the tension of supporting spring as an explanation for a different apparent force magnitude (upward vs downward) is misleading. It takes no more nor less energy (or force magnitude) to deviate a spring one direction or the other from a rest position, even if there is a constant force bias (in present case, a weight). This is all linear (Hooke's law). Moreover the electronic scale that supports what part of the weight (plus or minus thrust) is left from the up-pulling of the spring, has transducer much stiffer than the spring, meaning that the actual displacement (that makes a force reading possible) is negligible when compared to rest length of the spring : the force exerted by the spring can be considered constant to a good approximation (I would bet well within 1%). Considering the overall setup, delta weight readings on the scale (plus or minus) are just proportional to whatever thrust or force is applied on the lever, with no distinction between upward and downward (same constant of proportionality).
 
That is, provided the upward force is not enough to make the lever leave contact from the electronic scale, which would limit upward readings, not downward, and would hardly go unnoticed. Paul March also mentioned the possibility of an asymmetric force/displacement relation (in their "horizontal" balance) to explain the manifest discrepancy of magnitudes when reversing the frustum 180 : short of support leaving contact (backlash or loose fixation) or dry friction (sliding) I fail to see what could make for such direction dependant non-linearity...

Looks like those frustums don't like being nudged around 180, and thinking too much about reactionless physics makes people loose basic mechanical common sense. Small displacements => usually linear, otherwise is bad news for a measuring setup (unless carefully designed and understood non-linearity).

Now that I clarified that point on a ground I know, here is a more shaky idea I'd like to see either investigated or debunked by people with more intuition (than me) about aerodynamics : could it be that the convection likely occurring on the outside of the frustum, when small end down (Iulian reversal), would do some kind of Venturi effect that could be "sucking" the conical surface downward ? Also the rising stream of heated air would have a lifting effect from viscosity, maybe of higher magnitude that the hypothetical downward effect I'm contemplating... (this is separate from the previously discussed "hot air balloon" and "warm air jet" effects). Playing with dynamic pressures can be tricky... this would need only fraction of a Pa on the outside of the cone.
« Last Edit: 05/22/2015 11:46 PM by frobnicat »

Offline aero

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Warptech

Quote
PP195:
Quote from: arc on Today at 05:16 AM
        Warptech
        If the thruster had 2 compartments, a cylinder, where resonance was easy to establish at high Q, and a long frustum designed for maximum attenuation connected at one end of the cylinder. Between the two, there is a "shutter" that can rapidly open and close. When closed, the cylinder resonates as a cylinder. When open, energy expands into the frustum chamber where it is attenuated. After the shutter closes again, the energy in frustum attenuates and energy in cylinder recharges.... repeat. I keep looking for ways to decouple the resonant amplifier from the attenuator.

Quote
    Firstly I need to ask what sort of timeframes you are looking at for connecting/ disconnecting cycle, 
micro_sec, milli_sec, seconds?.
    How long do you think the coupling will need to be in place to create resonance inside the thruster cavity...{or are you thinking the resonance is not even needed in that chamber at all, just force fed from the attached cylinder in burst mode}.  I think I see where you are going with this but more info may help clarify the desired method, and help refine a model im working on for mechanical distribution of em waves.

Quote

I don't like posting my equations until I know they're right, but I believe I have shown that the force;

F ~ (alpha) * d(alpha)/dx

Where alpha is the attenuation "variable" of the waveguide. Alpha is larger for a small half-angle taper, so a long tapered pipe like a flagpole should be used for the attenuator. Alpha is variable in a frustum, it is not the same in both directions.

Also, the TC of alpha is Np/m, and it has very little effect over 1/2 a wavelength. Therefore, my thinking is that the resonant amplifier should be just a short cylinder to build up a high Q*P, then release that energy into a very long frustum pipe where all the momentum can be absorbed in the forward direction. Resonance is not needed, we want it to decay quickly, because faster decay is higher dp/dt = Force.

In reply to deltaMass, if you are only considering "reflection" then p = 0. But what happens when a wave is attenuated in a perfectly conducting circular waveguide? That energy is not lost as "heat" because there is no resistance to dissipate it.
Todd

Ok
If Im following your thought train correctly then, from my limited perspective on handling microwaves.

The generation side of the circuit requires cyclic refreshing to achieve resonance. {Unknown time-element at the moment}

Once resonance is achieved, {and not before} the energy is dumped into the "Load".

The operational functionality requires simplicity of operation.

The functionality requires the ability to alter running characteristics in realtime.

The length of the initial resonance chamber {ideally} needs to be automatically configurable {hence shawyers use of piezoelectric actuators inside his system}

The mechanical nature of the beam chopper requires simple operation but also an ability to tune in relation to time taken to achieve resonance compared with port-opening cycles. {potentially a software function to find the maximum thrust by adjusting resonance/port operation timing automatically, Microcontrollers are good for this, I use Arduino}

Thinking about the end product it may be easier engineering wise to have multiple attenuation chambers. This allows simplicity in design and beam chopper operation.

2 attenuators at 180, single beam splitter opening with weight adjusted disk to account for mass removed on one side.{less efficient model}

4 attenuation chambers equally spaced so any two are logically 180 degrees from each other, Both can be fed from the resonant chamber simultaneously via 2 opposed holes in the beam splitter. This also allows for slower rotation rate of the splitter as it has 2 holes not 1.

A variable speed rotary port opening  mechanism. The shape of the beam choppers pass-through-port determines the efficiency of the opening process, square, circle, ellipse, triangular

For shorter port opening times use 2 disks counter rotating with respect to each other. {or just smaller port openings}.

Personally I tend to favour 4 attenuators because 2 will be simultaneously active while the resonator recharges to pump the other 2 attenuators. {this is also because I have no idea how long it will take to attenuate the signals in relation to achieving resonance}

? any use or.. just junk?
Terrible drawing but you get the basic concept...


Could you perhaps use something like this? (attached)
Although the geometry is hard to see, there exists a 10% of radius gap between the two sections. The resonant cavity shows black because of the high energy level. The cavity resonates as long as the gap is less than about 25% of radius. With the gap closed, call the quality factor 100. It only drops to about 90 before falling out of resonance. While the gap size is increasing and the Q is falling, the resonant frequency is changing, but not in a predictable way. That could be a problem with -- well several things, take your pick.

I added another image without all the RF energy bouncing around. it's easier to see - I hope.
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Online SeeShells

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If there is any thrust from the EM Drive, such thrust is not affecting the natural frequencies and the mode shapes predicted by classical physics.  If there is thrust such thrust involves a process which is essentially uncoupled from equations governing the natural frequency and mode shapes of the cavity.
Just got on for a little, have a party to go to.
But first, big kudos to you Dr. Rodal, big kudos! This is the premise I've been fired up about. There is thrust with no adverse change in mode shape,  thermal, dang, there is nothing that shows in the COMSOL or real life tests, but it's there.  Pull the plug (so to speak) out and the thrust stops. Did I get that right, is this what I've been seeing it the data from several weeks ago that you sent me on this site?

Got to go but I'm going with a good feeling.

Shell

Online Rodal

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...
Just got on for a little, have a party to go to.
But first, big kudos to you Dr. Rodal, big kudos! This is the premise I've been fired up about. There is thrust with no adverse change in mode shape,  thermal, dang, there is nothing that shows in the COMSOL or real life tests, but it's there.  Pull the plug (so to speak) out and the thrust stops. Did I get that right, is this what I've been seeing it the data from several weeks ago that you sent me on this site?

Got to go but I'm going with a good feeling.

Shell
Shell,

You got it  :)
Yes, if the thrust is real (and the avalanche of replications like Iulian's make it feel more and more real) it looks to be produced by an uncoupled process.

Uncoupled processes are not uncommon, as you know actually more physical problems involve uncoupled physics or negligible amounts of coupling.  Strongly coupled processes are more unusual.  For example, most heat-transfer  effects on structures are essentially uncoupled: thermal expansion, thermal stress, etc.  The coupling in the equations of thermoelasticity is usually negligible.  One can solve Fourier's equations separately, figure out the temperature distribution and from the temperature distribution calculate a thermal stress analysis.  No coupling (with the exception of very thin shells, etc.).

Notsosureofit's formula is an uncoupled formula (notsosureofit please correct me if I'm wrong).  The thrust force is dependent on the mode shapes.  One can first calculate the mode shapes based on standard Maxwell's equations, and from them calculate the thrust force.  I suppose that if the theory matures one can then refine it and explore different types of coupling and nonlinearities like in every theory (publish of perish  :) ) but the main effect, to first order appears uncoupled, based on the experimental frequency and mode shape data.



Now to more salient, on-topic matters.

I hope you had fun in your party.  I have been to a few during the last couple of weeks and whenever I have broached the subject of the EM Drive, while seeping my vodka martini, (even with people I thought would be interested in) I invariably get big stares, faces like "you must be kidding" and the like and I have to embarrassingly switch the topic to something more socially acceptable like other people's private lives, Brangelina, the stock market or the weather :) 
« Last Edit: 05/23/2015 12:46 PM by Rodal »

Offline PaulF

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I'm beginning to the think the thrust is attributed to a polarizable vacuum as extreme as that may sound.  Whatever is happening is not just because of the microwaves or Maxwell's equations for the magnetic fields.  It is something else.  I think its more like pulling than it is thrust/pushing.
I was thinking more in the lines of this: Give the QV a punch (High energy density(flux), which is what sucks up most of the power, being converted into heat. The QV seems not to absorb any energy from this process) and it will react in a way I would like to compare with the rock in a pond example, and that we can hitch a ride on the wave crests. The energy consumption of throwing the rock is also much more than the actual kinetic energy we receive by riding the wave. By tuning the cavity and the frequency we can affect the wave crests and how much energy they carry. Of course the cavity contains standing waves, but the analogy is very good. I would like to think of the QV as an extradimensional or intrainterdimensional singularity (itself being 0-dimensional) from whence all that exists in the universe came from. But like a rocket, it didn't belch out it's entire contents, to prevent problems. Being of 0 dimensions, that also fits into relativity because the universe does not have a middle. QV is nowhere and everywhere underlying the spacetime fabric at any given moment and place, and extrapolating further I'd say that solves the absolute frame reference problem. Plus it does in a logical sense explain why i.e. each and every electron has the exact same rest mass. Because QV is the same QV in every planck volume of spacetime.

The other idea (Warp field) is also very compelling to me, although I am not a scientist and my understanding is limited.
« Last Edit: 05/23/2015 12:58 AM by PaulF »

Offline deltaMass

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I'm more of a fan of The Cosmic Badger theory. If there are systems which have excesses that violate conservation, The Cosmic Badger eats the excesses, which disappear, and The Cosmic Badger has made it all better.

Offline Notsosureofit

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You got it  :)
Yes, if the thrust is real (and the avalanche of replications like Iulian's make it feel more and more real) it looks to be produced by an uncoupled process.

Uncoupled processes are not uncommon, as you know actually more physical problems involve uncoupled physics or negligible amounts of coupling.  Strongly coupled processes are more unusual.  For example, most heat-transfer  effects on structures are essentially uncoupled: thermal expansion, thermal stress, etc.  The coupling in the equations of thermoelasticity is usually negligible.  One can solve Fourier's equations separately, figure out the temperature distribution and from the temperature distribution calculate a thermal stress analysis.  No coupling (with the exception of very thin shells, etc.).

Notsosureofit's formula is an uncoupled formula (notsosureofit please correct me if I'm wrong).  The thrust force is dependent on the mode shapes.  One can first calculate the mode shapes based on standard Maxwell's equations, and from them calculate the thrust force.  I suppose that if the theory matures one can then refine it and explore different types of coupling and nonlinearities like in every theory (publish of perish  :) ) but the main effect, to first order appears uncoupled, based on the experimental frequency and mode shape data.



For comparison (stronger nonlinearity) here's an acoustic case:

http://www.zainea.com/lowresonances.htm
« Last Edit: 05/23/2015 01:42 AM by Notsosureofit »

Offline rfmwguy

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For comparison (stronger nonlinearity) here's an acoustic case:

http://www.zainea.com/lowresonances.htm
[/quote]

Interesting charts...acoustic waves almost appear to "break" in the frequency domain, leading me to visualize ocean waves: "Breaking Waves -As the wave moves into increasingly shallow water, the bottom of the wave decreases speed. There comes a point where the top of the wave overtakes it and starts to spill forward the wave starts to break. We're surfing! In general a wave will start to break when it reaches a water depth of 1.3 times the wave height"

http://www.surfing-waves.com/waves/how_waves_break.htm

A breaking ocean wave spills forward along the x axis, transfering amplitude energy (y axis) as the seafloor becomes shallow.

ok, em waves traveling towards the small diameter of the frustum are not ocean waves that "break", sending energy "forward" resulting in a push/thrust. If someone does prove this, however, they can name it after me  ::)

Offline zen-in

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...
...

If the air stream is going downwards, then everything is vice-versa from what was described above.




Don't be surprised if tomorrow I read this again and I tell to myself "did I write that" ?

That car could use a spoiler on the back like the one I had on my '86 Mustang GT.   It tracked really well when I got above 120 MPH.

Offline aero

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Paul answered a question for me back in mid April.
Quote
The high density polyethylene discs dielectric's relative permittivity is 2.27 at 2.0 GHz with a dissipation factor of ~0.0005.
So that is what Eagleworks used.

Thks Aero, this looks like an extruded rod, end sliced HDPE disc: http://www.amazon.com/Density-Polyethylene-Translucent-White-Diameter/dp/B00EVCG9FS

Unfortunately the ASTM rating does not provide the permittivity or dissipation factor.

Well, dissipation factor has a lot of names. I think I recall that I found 3 or 4 different ones that it either equalled or was the inverse of or 1 minus it. Maybe the "loss tangent" is documented. Dissipation factor ~= loss tangent for small factors, and I think 0.0005 is small enough to use that approximation.
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Offline WarpTech

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Impedance?

Impedances of a tapered waveguide are given in Zeng and Fan.

Offline WarpTech

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I also have a vague memory of someone saying that Sawyer used a T antenna parallel to the major axis of the fulstrum.

That could be another interesting breadcrumb, which may lend support to TM01 mode excitation in the Flight Thruster.

Does anybody have any other info as to Shawyer excites his Flight Thruster?

Dude. DUDE. The resonance modes for a spherical tapered cavity are solved, analytically. They are exact solutions. There is no doubt to any of them. Many simple cavity shapes have been solved for decades, and all experimental data backs these solutions very well. This is what Rodal is trying to tell you.

You cannot have a TM01 mode in any cavity. This is a waveguide mode. It is like saying 'I'm going to drive down the road at 100kph in my car, in the garage with the garage door closed'. It makes no sense. You can play semantic games and say it applies to infinitely long cavities, but that's just a waveguide.

The way you ignore salient posts with basic enclosed scientific facts makes you look like a VX Junky, and people won't take you very seriously after a while.

I'm just the messenger telling folks here what I have read many times and what Roger Shawyer has shared with me.

Ignore him if you will but his and the Chinese EM Drives are working based on his knowledge.

BTW he treats the Em Drive conic frustum as a infinite series of open circular waveguides, each with a different diameter, that cause the guide wavelength and group velocity to vary as per that diameter. Have you read what he says?

Regarding the TM01x modes. Why couldn't you drive them using a simple 1/4-wave stub antenna at the TM011 wavelength, based at the small end or the apex of a cone? The pattern of magnetic field is concentric around the central axis, just like a wire. The resonant modes, p are the same as on a wire. Regardless of which direction current is flowing in the wire, the Lorentz force on the opposing currents flowing in the frustum walls will always have a component in the forward direction, while the magnetic field at the location of the antenna wire will always be zero, according to the mode shapes.

I thought it was an interesting idea...

Todd

Offline deltaMass

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Impedance?
Impedances of a tapered waveguide are given in Zeng and Fan.
But this is a frustum. I wondered if Roval with his super mode program could trace the locus of 50+j0 ohm feed points?

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