wideband uniform gain horn antenna design/plans? *double ridged*

[sarepairman2]

Does anyone know of a website or resource that would have plans for constructing a double ridged horn antenna?

 us patent #US20050078044 is the best I found.

Also, if I were to do this using thin copper that is easy to bend/cut/etc, how well would it work, being handmade etc the angles would not be perfect and whatnot, but I am willing to try it.

also, is it possible to just shrink the dimensions by X multiplier (not sure how to do this to the curved section) in order to reduce materials and make it smaller, or is everything non linearly related

[T3sl4co1l]

Frequency range is directly proportional to the length scale.  Adjust all axes proportionally.

These are usually used in the 10GHz+ range, so I would be rather impressed if you needed, and could get away with, shrinking an existing design.

At the back of the throat, there is a circular (or whatever) cutout, which the feedline connects across.  The equivalent inductance of this path (and the possibility of standing waves) will partly determine bandwidth.

How precise the pieces are made will determine how low and flat the SWR will be, and how even the radiation pattern will be.

The opposed ridges act like a coplanar waveguide; I don't know what effect the conductor thickness would have.  You could use thin copper sheet, bent in a box shape (or use two planes, closely spaced together, with an edge piece soldered in the gap), to accommodate this if needed.

One of these days, I need to build a massive one, just because.  A near-room-sized horn should be useful down to 30MHz or so, which would be easily measured with an economical oscilloscope.  Cardboard and aluminum foil would be good enough.

Ed: also, if you want uniform gain, but don't care about phase coherency, consider an Archimedes spiral.

Tim

[sarepairman2]

any resources on wideband spiral/etc antenna design? I see commercial ones that are like 2-18 GHz. I am interested in the GHz band, i see they are sold.

i got HFSS, I gotta give that a try

i wanna replicate this s
http://www.keysight.com/en/pd-1000001169%3Aepsg%3Apro-pn-11966E/ridged-waveguide-horn-antenna-to-18-ghz?cc=US&lc=eng

[LaserSteve]

Start by finding a PDF of Volume 12 of the Radlab handbook....

Samuel Silver. Microwave Antenna Theory and Design, volume 12 of MIT Radiation Laboratory Series. McGraw-Hill, New York, 1949.

While it does not cover double ridged very much, it will get you started.

You might also  want to take a look at Volume 11

Carol G. Montgomery. Technique of Microwave Measurements, volume 11 of MIT Radiation Laboratory Series. McGraw-Hill, New York, 1947.

Then take a look at the references here:

http://www.w1ghz.org/antbook/chap2.pdf

and here when you need to calibrate:

http://www.microwaves101.com/downloads/Slayton/William%20Slayton%20Electronics%201955.pdf

And here is the full report:

http://www.microwaves101.com/downloads/Slayton/William%20Slayton%20NRL%20Report%204433.pdf


This is interesting:

http://www.jpier.org/PIERC/pierc39/17.13032803.pdf

http://bbs.scu.edu.cn/wForum/bbscon.php?bid=153&id=8859&ap=528

Uncle Sam's design notes:

http://www.dtic.mil/dtic/tr/fulltext/u2/714994.pdf

Do you have access to a Microwave Sweeper, Network Analyzer, or Spectrum Analyzer?

Read the references in the attached links, then you can Google your way back to the standard designs...

Designing a good 10 Ghz feedhorn for  my Dish took a lot of work. I'm not envious of trying to design a broadband horn from scratch. 

Steve  (Microwave Ham)

[sarepairman2]

http://repository.up.ac.za/bitstream/handle/2263/20312/Jacobs_Improved%282012%29.pdf?sequence=1

I wanna build this, they give dimensions etc in a way much easier to comprehend then the patent, though idk about the brushes or dielectric sidewalls 

I have a HP8559A spectrum analyzer that goes to 22 GHz. I got some sharp cornered metal blocks to bend copper sheet around, so I will give it a try, worst that happens is I ruin some copper sheet somewhat.
I don't expect it to work well and what not, but I do expect to be entertained and excited with this process.  it seems I have alot of reading to do, but no harm will come from mangling 15$ of copper. i can eat that much money in like ~9 minutes.

or i can make a bunch of them from the calibration standards page, they look alot easier to fabricate..

[sarepairman2]

ok I think I found the best resource for designing one of these, its called "short axial lenght broadband horns"

these army boys knew how to keep it simple and DIY, using printed circuit boards for walls and giving an outline so simple that I can draw it out from text. 

what I don't understand from the army text though is the wedges and flaps I see in all the other pictures, i drew my understanding of the army version base (minus the shorting cavity void) and the kind of structure I see in pretty much every modern documents, with flaps and wedges that look like a pain in the ass to make.

are these ridges and wedges critical or can I just do two tapered sections and have it be good enough for austrlia (I can see myself doing this out of 8 copper trapezoids, a backing plate, and a copper strip bent into a square to join the backing plate to flanged section #1 which is joined to flanged section #2,

then using 4 equal sized pieces of copper to make the ridges and give them depth with 2 copper strips

apparently "The Effect Of Manufacturing And Assembling Tolerances On The Performance Of Double-ridged Horn Antennas" has the answers I want, but IEEE is trying to shake me down! can anyone upload the paper?

[LaserSteve]

Hum, first page has this:

B. Jacobs*#1, J. W. Odendaal#2, J. Joubert#3
*SAAB Avitronics, Antennas Group
185 Witch Hazel Avenue, Centurion, South Africa
1bennie.jacobs@za.saabgroup.com
# Centre for Electromagnetism, Department of Electric, Electronic and Computer Engineering, University of Pretoria,
Pretoria 0042, South-Africa
2wimpie.odendaal@up.ac.za
3jjoubert@postino.up.ac.za


Here is the refs:

K. L. Walton and V. C. Sundberg, “Broadband ridged horn design,”
Microwave J., pp. 96–101, 1964.
[2] S. Hopfer, “The Design of Ridged Waveguides,” IRE Trans.
Microwave Theory and Techniques, vol 3, no. 5, pp. 20-29, 1955.
[3] J. L. Kerr, “Short axial length broad-band horns,” IEEE Trans.
Antennas Propagat., vol. 21, no. 5, pp. 710–714, 1973.
[4] C. Bruns, P. Leuchtmann, and R. Vahldieck, “Analysis and Simulation
of a 1-18-GHz broadband double-ridged horn antenna,” IEEE Trans.
Electromagn. Compat., vol. 45, no. 1, pp. 55–60, 2003.
[5] ——, “Comprehensive analysis and simulation of a 1-18 GHz
broadband parabolic reflector horn antenna system,” IEEE Trans.
Antennas Propagat., vol. 51, no. 6, pp. 1418–1422, 2003.
[6] ——, “Full wave analysis and experimental verification of a broad
band ridged horn antenna system with parabolic reflector,” IEEE
Antennas and Propagation Soc. Int. Symp. 2001, vol. 4, 2001.
[7] M. Abbas-Azimi, F. Arazm, and J. Rashed-Mohassel, “Sensitivity
analysis of a 1 to 18 GHz broadband DRGH antenna,” IEEE Antennas
and Propagation Society Int. Symp. 2006, pp. 3129–3132, 2006.
[8] M. Botello-Perez, H. Jardon-Aguilar, and I. G. Ruiz, “Design and
Simulation of a 1 to 14 GHz Broadband Electromagnetic Compatibility
DRGH Antenna,” 2nd Int. Conf. Electrical and Electronics
Engineering, pp. 118–121, 2005.
[9] V. Rodriguez, “New broadband EMC double-ridged guide horn
antenna,” RF Design, pp. 44–47, 2004.
[10] M. Abbas-Azimi, F. Arazm, J. Rashed-Mohassel, and R. Faraji-Dana,
“Design and optimization of a new 1-18 GHz double ridged guide horn
antenna,” J. of Electromagn. Waves and Appl., Vol 21, No. 4, pp. 501–
516, 2007.
[11] EM Software & Systems, FEKO User’s Manual, Suite 5.4, July 2008.

Perhaps request a PDF from the authors?   I can view it but not download it.  :-)   See if your local library has  a program called "interlibarary loan" ?

Basically all it says is that small gaps of 0.5 to .005 inch on the ridges and edges of the planar pieces induce deep but very narrow spikes of low response in assembled antennas on the production line. They found that the overall gain pattern was fine, but these narrow spectral regions moved around each time the assembly was bolted together.  They also found the depth of teflon dielectric on the feed was critical.  They modeled it in a modeler called FEKO and determined which tolarences were sensitive to errors. Basically gave them a bad notch at 14 Ghz.

They then modeled the back box that does the coupling and found out it was very sensitive to small changes in placement and dimensions, especially the teflon covered probe. Specifically the placement of the probe.

Moral of the story, build an accurate back box for coupling, or make it adjustable in position, or add tuning flaps/screws.

They do not give plans for the antenna. The horn was screwed together, not soldered, so gaps would matter.  When it was bad, it was NOT that bad. Just a major dip at 14 Ghz.


------------------breaking news------------------------------------
SEE IF YOU CAN SEE THIS, 1-10 GHZ.....

http://deepblue.lib.umich.edu/bitstream/handle/2027.42/4877/bac2123.0001.001.pdf?sequence=5&isAllowed=y

Deep Blue usually allows public access... HAS COMPLETE DRAWINGS FOR A SIMPLE RIDGED HORN 1-10 GHZ  !!!


Steve

[LaserSteve]

Do you have modern three band  radar detectors in South Oz?  The modern ones have pretty good, but tiny, ridged horns.   Those would cover KA band...
At least I use a hacked one to cover KA...

Oh, and have some Horn CAD....

http://www.antennadesignassociates.com/pcaad7.htm

I've wanted a broadband reference horn for years, but I can't afford even a used one...  The UMich design covers the  2.4 Ghz, 3.5 ghz, 5.7 Ghz and 10.36 Ghz bands I need. :-)

Steve

[sarepairman2]

Speak of the devil, today I gutted a old Uniden LRD 2000 model radar/laser detector, I renembered it had a horn inside.


Apparently pretty ghetto ridged horns can be useable, look at this:

This thing claimed to be able to detect the band that goes to 40 GHz! (on the front panel LEDs).

And steve, I got the download. This looks good. It looks like I will be able to hail all frequencies                                                           

These horns are the next step after making some field probes for learning/doing pre compliance testing and interesting physics experiments. 

And I got the HFSS cad/simulator program, but I think I want to build a few toys to play with and get interested before I mess with that. If I go right into trying to do simulations/etc I will defiantly get bored.

Do you think anything could be done with that little horn antenna from the radar detector?

[LaserSteve]

Your well set with the radar  detector. They typically have a dielectric resonator oscillator (ring shaped ceramic puck in your photo) at around 11 Ghz, and a ~ 1.1 Ghz IF.  So its direct detection at ~ 10 Ghz and subharmonic or harmonic mixing detection at higher frequencies.

You could stick a piece of UT141 coax onto the that horn in lieu of the existing detector board, or you could feed its IF thru a 3dB  or 6 dB SMA attenuator into your SPEC AN, and use it as a downconverter.  Been there, done that, have the T Shirt.  MAtching the UT141 to the microstrip takes some thought. Also   you can remove the circuit board, strip back a millimeter of so of the UT141 outer jacket, and use it as a probe feed on the horn.

 Then sign up "listen only" on the W1MBA  ham radio microwave mailing list. Please be aware it is highly, highly moderated.

I assume you know about diode based harmonic generators as a WEAK signal source?  Even a 1n914 driven by a "clock in a can" oscillator can generate very weak but detectable  harmonics up to 10 Ghz.

Steve