<s>
This	O
band	B-Algorithm
of	I-Algorithm
frequencies	I-Algorithm
is	O
also	O
known	O
as	O
the	O
centimetre	O
band	O
or	O
centimetre	O
wave	O
as	O
the	O
wavelengths	O
range	O
from	O
one	O
to	O
ten	O
centimetres	O
.	O
</s>
<s>
The	O
small	O
wavelength	O
of	O
microwaves	O
allows	O
them	O
to	O
be	O
directed	O
in	O
narrow	O
beams	O
by	O
aperture	O
antennas	O
such	O
as	O
parabolic	O
dishes	O
and	O
horn	O
antennas	O
,	O
so	O
they	O
are	O
used	O
for	O
point-to-point	B-Architecture
communication	I-Architecture
and	O
data	O
links	O
and	O
for	O
radar	B-Application
.	O
</s>
<s>
This	O
frequency	O
range	O
is	O
used	O
for	O
most	O
radar	B-Application
transmitters	O
,	O
wireless	B-Architecture
LANs	I-Architecture
,	O
satellite	O
communication	O
,	O
microwave	O
radio	O
relay	O
links	O
,	O
satellite	O
phones	O
(	O
S	B-Algorithm
band	I-Algorithm
)	O
,	O
and	O
numerous	O
short	O
range	O
terrestrial	O
data	O
links	O
.	O
</s>
<s>
Frequencies	O
in	O
the	O
SHF	O
range	O
are	O
often	O
referred	O
to	O
by	O
their	O
IEEE	O
radar	B-Application
band	O
designations	O
:	O
S	B-Algorithm
,	O
C	B-Algorithm
,	O
X	B-Algorithm
,	O
Ku	O
,	O
K	B-Algorithm
,	O
or	O
Ka	O
band	O
,	O
or	O
by	O
similar	O
NATO	O
or	O
EU	O
designations	O
.	O
</s>
<s>
Therefore	O
,	O
they	O
are	O
used	O
in	O
point-to-point	B-Architecture
terrestrial	O
communications	O
links	O
,	O
limited	O
by	O
the	O
visual	O
horizon	O
to	O
30	O
–	O
40	O
miles	O
(	O
48	O
–	O
64km	O
)	O
.	O
</s>
<s>
This	O
and	O
the	O
narrow	O
beamwidths	O
possible	O
with	O
high	O
gain	O
antennas	O
and	O
the	O
low	O
atmospheric	O
attenuation	O
as	O
compared	O
with	O
higher	O
frequencies	O
make	O
SHF	O
the	O
main	O
frequencies	O
used	O
in	O
radar	B-Application
.	O
</s>
<s>
Omnidirectional	O
antennas	O
have	O
been	O
developed	O
for	O
applications	O
like	O
wireless	O
devices	O
and	O
cellphones	O
that	O
are	O
small	O
enough	O
to	O
be	O
enclosed	O
inside	O
the	O
device	O
's	O
case	O
.	O
</s>
<s>
The	O
main	O
antenna	O
used	O
for	O
these	O
devices	O
is	O
the	O
printed	O
inverted	O
F	B-Algorithm
antenna	O
(	O
PIFA	O
)	O
consisting	O
of	O
a	O
monopole	O
antenna	O
bent	O
in	O
an	O
L	O
shape	O
,	O
fabricated	O
of	O
copper	O
foil	O
on	O
the	O
printed	O
circuit	O
board	O
inside	O
the	O
device	O
.	O
</s>
<s>
Directive	O
antennas	O
at	O
SHF	O
frequencies	O
are	O
mostly	O
aperture	O
antennas	O
,	O
such	O
as	O
parabolic	O
antennas	O
(	O
the	O
most	O
common	O
type	O
)	O
,	O
lens	O
,	O
slot	B-Algorithm
and	O
horn	O
antennas	O
.	O
</s>
<s>
Another	O
type	O
of	O
antenna	O
practical	O
at	O
microwave	O
frequencies	O
is	O
the	O
phased	O
array	O
,	O
consisting	O
of	O
many	O
dipoles	O
or	O
patch	O
antennas	O
on	O
a	O
flat	O
surface	O
,	O
each	O
fed	O
through	O
a	O
phase	B-Algorithm
shifter	I-Algorithm
,	O
which	O
allows	O
the	O
array	O
's	O
beam	O
to	O
be	O
steered	O
electronically	O
.	O
</s>
<s>
SHF	O
frequencies	O
occupy	O
a	O
"	O
sweet	O
spot	O
"	O
in	O
the	O
radio	B-Algorithm
spectrum	I-Algorithm
which	O
is	O
currently	O
being	O
exploited	O
by	O
many	O
new	O
radio	O
services	O
.	O
</s>
<s>
The	O
high	O
frequency	O
gives	O
microwave	O
communication	O
links	O
a	O
very	O
large	O
information-carrying	O
capacity	O
(	O
bandwidth	B-Algorithm
)	O
.	O
</s>
