antenna-theory.com

[David M]

I need to design an antenna from 360-400 MHz that fits to a form factor of 4"x4"x0.35". I was thinking something like an inverted F type with a ground plane under it (metal plate) with the antenna either printed on FR4 or maybe even a metal structure of some kind. It will lay parallel to the ground and need to radiate in an omni-like pattern in all directions parallel to the ground. There is no need for it to radite in the Z direction, but it doesn't matter either way. I really dont need any gain so 0dBi or even negative gain is ok within reason.


I can answer more question as people have them and i would appreciate the help and suggestions!

[bigSteve]

Ok so what is the half-wavelength of 380 MHz is 15.5 inches. You don't have that much space.

IFAs won't work with a ground plane under it - think image currents.

Your only shot is possibly a non-cavity backed spiral antenna, but it won't be easy.

References:
http://www.antenna-theory.com/antennas/travelling/spiral.php
http://www.antenna-theory.com/antennas/aperture/ifa.php