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ashutoshkedar
Joined: 27 Oct 2005
Posts: 1
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 27 Oct 2005 15:25 helping me to design a coax to waveguide transition |
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I am trying with HFSS to design a circular waveguide to caxial transition in X-band but even after optimising the probe length and dia of short to waveguide wall i am not able to get the bandwidth
Can anybody help me with that
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flyhigh
Joined: 12 Nov 2003
Posts: 562
Helped: 32
Location: somewhere over the rainbow
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30 Oct 2005 19:10 Re: helping me to design a coax to waveguide transition |
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Hi,
maybe this can help?
flyhigh
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circo
Joined: 07 Sep 2005
Posts: 4
Location: Essex, England
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03 Nov 2005 14:17 Re: helping me to design a coax to waveguide transition |
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| Hello, you may be able to "tune" the device for increased bandwidth. You can do this by drilling and tapping holes into the waveguide wall and inserting screws. Once the screw is in, adjust the screw height to optimise performance, then lock the screw off with a locknut. In-line with the probe will probably work best and you may need more than one. You can also put "pucks" (dielectric or aluminium) into the waveguide aperture to tune the transition. This is a simple fix and you can play around with the diameter and location. Fix the pucks with a good qualitity adhesive, once you have found the best location (for epoxy; eccobond 286 or silicon; RT3145). I've even seen this done with steel nuts! Be careful if the device will see high power, as you might get some electrical arcing, try something like PTFE pucks if this is a concern and test at low power.
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Google
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03 Nov 2005 14:17 Ads |
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biff44
Joined: 24 Dec 2004
Posts: 1838
Helped: 244
Location: New England, USA
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03 Nov 2005 19:21 Re: helping me to design a coax to waveguide transition |
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| If all you are doing is a probe and a backshort, then do not expect to get much bandwidth. HP had a pretty good design where they used λ/4 transformers to step down the impedance to the probe, which was a centerpin of the coax connector grounded to the other side of the waveguide, with a backshort in reduced height guide.
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