jpeg file is attached with this question . Dimensions are also mentioned in this diagram.
This design is made in hfss2013.
FR4 substrate thickness 1.6mm
semi circle ground of radius 15mm is there at back side.
I have used wave port of dimension 6w and 5h for this design .
Please suggest me exact dimension for radiation box.
Its position and dimension in x y z directions.
At least lambda/4 at lowest frequency in radiation direction. If you don't know the radiation direction in advance, you can set it lambda/4 in all directions
At least lambda/4 at lowest frequency in radiation direction. If you don't know the radiation direction in advance, you can set it lambda/4 in all directions
Keep dimension such that it can cover your beam width area. For precise result, best part is to cover First null on both the side. Now keeping this in mind, dimensions will depend upon how far you are setting your box with ref. to your antenna.
Thanks for reply Ronis Sir
Sir Lambda/4 = 24mm calculated from lowest frequency of uwb range i.e 3.1GHz. .But my doubt is that Is the radiation box is 24 mm distance away from all the six sides of radiating edges . Means If the substrate length is 30mm then radiation box length will be 24+30+24=78mm. If Im correct please notify me and if I'm not correct please rectify me.
To Amipara Sir Thanks for your reply.
But Sir can you elobrate your answer.
You, your antenna radiate sideway or if you do not no how it radiate. But if it radiate in front you can set the length of radiation box same with the antenna length (30mm)
Let us say first null from maxima is 10 degree on both the sides of radiation maxima, as distance from radiation point increases, the area/volume covered increases. Mathematically, area of cone increases with distance.
Hi, as says Ronis you can make the radiation box at lambda/4 in the radiating direction from the side of your antenne. Or for simplivity you can put the radiation box at lambda/4 in all directions.
Hello, In the radiation direction of your antenna, take the radiation box length to be lambda / 4 at the mid frequency of your band. for the sides and the back of your antenna you can take the lengths less than that. However, if you have good machine try to have bigger radiation box (around lambda / 2)
And now the question is why is lambda/4? Regarding the boundary between near and far field, it seems that the radiation box should be larger to ensure that we are in the far field region.
From HFSS manual
"A radiation surface does not have to be spherical, but it must be exposed to the background, convex with regard to the radiation source, and located at least a quarter wavelength from the radiating source. In some cases the radiation boundary may be located closer than one-quarter wavelength, such as portions of the radiation boundary where little radiated energy is expected."
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