gain planar antenna

Hi all,

I want to design a high gain antenna (~20dBi) on a relatively high dielectric constant substrate (Epsion r = 7).

Could you suggest what kind of antennas I should use to obtain that target?

Thanks in advance

This will be a p.atch type. Your problem will be that high dielectric constants will make the antenna have high loss and narrow bandwidth. You will have to use a grid (array) of them. Space them a half wavelength apart between centers and feed them all in phase with a tree of wilkinson splitters. There is on need for the balancing resistor since the loads (antenna elements) will all be identical and always connected.

Make sure that the lengths of all traces back to the feed point have equal lengths so that the beam will be normal to the antenna plane.

you can try vivaldi antenna

you may also think about a printed dipole array above a reflecting plate. the directivity may be lower than a patch, but won't have the same bandwidth issues as noted by flatulent.

cavity distance will be relative to the wavelength in the dielectric, so size must be considered.