
52 Microwave Engineering
For TE waves:
α
π
βωµ
=
2
2
3
( )m R
a
s
(2.64)
For TM waves:
α
β
=
2
a
R
s
(2.65)
where,
R X
s s
m
m
= =
ωµ
σ2
(2.66)
β ω µε
π
= −
2
2
m
a
(2.67)
In Equations 2.63 through 2.67
μ
m
and
σ
m
are the values of
μ
and
σ
for
metallic conductor of planes, a is the separation, b is the width of strip
taken in y direction and
η
is the characteristic impedance. In deriving
these relations it is assumed that losses have negligible effect on eld dis-
tribution. Substitution of values of parameters, involved in expressions of
α
, leads to the curves of Figure 2.25. These curves lead to the following
conclusions.
1. The attenuation fo ...