Effect of spherical and plane wave in the radiation pattern
I would like to know the influence of plane wave and spherical wave on the radiation pattern. I am working on lens antenna, I read that lens converts the spherical wave into plane wave, so interested to know its effets on the radiation pattern.
Regards
Manu
Through the lens, of course, directivity will be increased.
For example, one arbitrary ideal point source generate the spherical wave..
so, the radiation pattern become a isotropic pattern. that, Directivity=1 dBi !
but, if the spherical wave can be transformed to plane wave (perpectly in one direction) through lens, this radiation patten of that point source with such a ideal lens will be very very high directive pattern. over 20dBi ~
I'm wondering my short knowldege could be helpful to your question. ^^
Thank you very much for your reply. I got an idea about the advantage of a lens.
one more question. Now i am dealing with single surface lens, it is reciprocal?
ie. does it work if place the point source on the right side of the plain face of a single surface lens ?
Basically when a soure of radiation has the dimension smaller than wavelength,then it will transmit the spherical waves and vice versa.
Lens and reflectors come under complementory aperture antenna types,which convert spherical waves to plane waves. Of course at very large distance from source the wavefronts are always plane and radition field will contain only theta and phi componetns.They don't depend upon R value.