<s>
A	O
magic	B-Algorithm
tee	I-Algorithm
(	O
or	O
magic	B-Algorithm
T	I-Algorithm
or	O
hybrid	O
tee	O
)	O
is	O
a	O
hybrid	O
or	O
3	O
dB	O
coupler	O
used	O
in	O
microwave	O
systems	O
.	O
</s>
<s>
It	O
is	O
an	O
alternative	O
to	O
the	O
rat-race	B-Algorithm
coupler	I-Algorithm
.	O
</s>
<s>
In	O
contrast	O
to	O
the	O
rat-race	O
,	O
the	O
three-dimensional	O
structure	O
of	O
the	O
magic	B-Algorithm
tee	I-Algorithm
makes	O
it	O
less	O
readily	O
constructed	O
in	O
planar	O
technologies	O
such	O
as	O
microstrip	O
or	O
stripline	O
.	O
</s>
<s>
This	O
allows	O
it	O
to	O
be	O
used	O
as	O
a	O
duplexer	O
;	O
for	O
instance	O
,	O
it	O
can	O
be	O
used	O
to	O
isolate	O
the	O
transmitter	O
and	O
receiver	O
in	O
a	O
radar	B-Application
system	I-Application
while	O
sharing	O
the	O
antenna	O
.	O
</s>
<s>
In	O
practical	O
examples	O
,	O
it	O
is	O
used	O
to	O
both	O
isolate	O
circuits	O
and	O
mix	O
signals	O
,	O
for	O
instance	O
in	O
a	O
COHO	O
radar	B-Application
.	O
</s>
<s>
The	O
magic	B-Algorithm
tee	I-Algorithm
was	O
originally	O
developed	O
in	O
World	O
War	O
II	O
,	O
and	O
first	O
published	O
by	O
W	O
.	O
A	O
.	O
Tyrell	O
of	O
Bell	O
Labs	O
in	O
a	O
1947	O
IRE	O
paper	O
.	O
</s>
<s>
Robert	O
L	O
.	O
Kyhl	O
and	O
Bob	O
Dicke	O
independently	O
created	O
magic	B-Algorithm
tees	I-Algorithm
around	O
the	O
same	O
time	O
.	O
</s>
<s>
The	O
magic	B-Algorithm
tee	I-Algorithm
is	O
a	O
combination	O
of	O
E	O
and	O
H	O
plane	O
tees	O
.	O
</s>
<s>
To	O
function	O
correctly	O
,	O
the	O
magic	B-Algorithm
tee	I-Algorithm
must	O
incorporate	O
an	O
internal	O
matching	O
structure	O
.	O
</s>
<s>
Dependence	O
on	O
the	O
matching	O
structure	O
means	O
that	O
the	O
magic	B-Algorithm
tee	I-Algorithm
will	O
only	O
work	O
over	O
a	O
limited	O
frequency	O
band	O
.	O
</s>
<s>
The	O
name	O
magic	B-Algorithm
tee	I-Algorithm
is	O
derived	O
from	O
the	O
way	O
in	O
which	O
power	O
is	O
divided	O
among	O
the	O
various	O
ports	O
.	O
</s>
<s>
Now	O
by	O
reciprocity	O
,	O
the	O
coupling	O
between	O
any	O
pair	O
of	O
ports	O
is	O
the	O
same	O
in	O
either	O
direction	O
(	O
the	O
scattering	O
matrix	O
is	O
symmetric	B-Algorithm
)	O
.	O
</s>
