Antonio wrote:
"And can someone send me some projects of antennas for 1.2 Ghz ----"

Microwave antennas can be scaled-down versions of lower frequency
antennas. But microwave path loss is greater and transmitter power is
often lower. Often microwaves are used for wider bandwidth signals
because they can easily handle it, as a fixed percentage of the higher
carrier frequency is more Hertz. A wideband receiver needs more signal
for quieting than does a narrowband receiver.

Highly directional antennas can be physically small at microwave
frequencies and are practical when microwave is used for fixed point to
point service. A narrow azimuth of coverage is usually desirable for
improved signal to noise, so the narrow beamwidth is no problem for
point to point.

Radio beams can be highly concentrated by a parabolic reflector. The
most common is the paraboloid of revolution with an antenna illuminating
the reflector at its focal point. Antenna gain depends on reflector size
in wavelengths. Gain grows with reflector size and shorter wavelengths.

Parabolic antenna gain:

Gain = (k) (pi diameter/wavelength)squared

k is an efficiency factor, often 0.55

At 1 GHz, a 36-ft. reflector has a gain of about 7000 or 38.6 dB.

Beamwidth is:
(70 degrees)(wavelength/diameter)

Beamwidth is 1.9-degrees for 1 GHz when the reflector has a diameter of
11 Meters

At 1.2 GHz, a 3 mtr. (10 ft) dia. dish will give a gain of about 28 dB.
Gains like this on both ends of a path can overcome increased losses and
more received signal requirements.

Parabems & best regards, Richard Harrison, KB5WZI