Thread: Antenna

Hello everyone,

I've got an urgent question :

A uniform circular aperture has a far-zone pattern that has a sidelobe level of -17.6 relative to the mainlobe maximum.
we illuminate a symmetrical reflector antenna with a feed horn that has a very wide beamwidth, so that the feed field incident at the reflector rim is almost the same magnitude as that at the center of the reflector and the feed blockage effects are determined to negligible but we do not obtain a -17.6 sidelobe level.

explain why this is so?

Is this part of an assignment or a homework question?

If you want help, you need to tell us how far you've got with it. Or you should show the method you're using to solve it and where you seem to be losing your way.

Originally Posted by adelady

Is this part of an assignment or a homework question?

If you want help, you need to tell us how far you've got with it. Or you should show the method you're using to solve it and where you seem to be losing your way.

Hi,

That's an assignment.
I've got to this point that 17.6 is the maximum sidelobe level. Tapering causes decrease in directivity and sidelobe level.