11dbi circularly-polarized antenna beam width: 70°

[CaptKiwi 0]

Hello, just wanted to share this with you guys.

I came across a nice simple patch antenna which is easy to make and has a wide beam angle of 70°

11 dbi Circulary Polarized Antenna

Some Specs:

Frequency : 2.400 - 2.500 GHz

Gain : 11 dBiVSWR : < 1.22

POLARIZATION : Circular

BEAM WIDTH • Horizontal: 70° • Vertical: 70°

IMPEDANCE • 50 Ohms

DIMENSIONS • 25 x 102 x 102 mm

To get a wider beam width just set them in a array configuration.

Array antenna

Will let you now when I tested this patch antenna !

** Attached is the circle in fullsize.

Edited June 2, 2009 by CaptKiwi

[Terry 5]

I made one like that a while back but I could not get it to work well.

Terry

[W3FJW-Ron 0]

If indeed it is circular polarization, there will be a lot of db loss with a horizontal or vertical polarized antenna on the aircraft.

[Kilrah 2]

If indeed it is circular polarization, there will be a lot of db loss with a horizontal or vertical polarized antenna on the aircraft.

Not much, 3dB if I remember well. And in return, you avoid the -25dB or so you would get with a linearly polarised antanna when it's cross-polarised (oriented perpendicularly to the TX antenna).

In theory, it's more down to a (simplified) choice of "good all the time" vs "excellent in some conditions but awful in others".

But the most important is practice, and when testing linear 8dB vs circular 8dB I was having better quality with the linear one throughout an standard flight. So I stayed with linear ones. Might me more tricky if you don't know how to arrange your antennas though, the circular could be giving better results in that case.

[W3FJW-Ron 0]

Personally, I wouldn't trust it. Haven't looked at db tables for a long time but IIRC a 3db loss equates to a 50% loss in signal strength which would affect the range. Probably immaterial at the distances we fly at though.

[Kilrah 2]

3dB indeed equates to 50% less signal power, which in turns means a 0.7x factor in range. It'snot a big price to pay to avoid signal losses due to bad orientations, but as said (at least for me) it didn't cut it in practice.