cassegrain antenna

Hi,

I wish to design a cassegrain feed antenna with feko, I couldnt find any card for Hyperboloidal curve surface has anyone some suggestion? i also wish to make a hole right at the centre of the main reflector, in which the feed is inserted.

Thanks

before Feko, choose hyperboliod by simple geometric analitic concepts.
The hyperboloid has 2 foci. One of them is coincident with the paraboloid, the 2nd may be choosed on a convenient Cassegrain region.
Then by a simple ray tracing, find diameter of sub reflector.

Remeber: choose a convenient position of horn, as horn is far from subref as the horn has smaller beam so as the horn is larger.

Someone thinks the best subreflector angle seen by horn is around +/-15...20 deg.

Hi ommumm,

I guess you already found the answer or you may not need this reply as it is so late, but just for record, you can use PB card in FEKO to generate a section of a parabolic reflector. Also, you will find the example_35 very helpful as it deals with the reflector antenna (where PB card is used) with equivalent surface currents or far field pattern as the excitation. The description for this example is attached. Some beautiful slides demonstrating similar situation for cassegrain antenna with hybrid MoM/PO using domain decomposition is also attached. Hope they can give you some insight on employing FEKO's powerful capabilities.