
144 Microwave Engineering
The inductance and capacitance of another commonly used (radial) cavity
shown in Figure 4.4b with details in b′) are as follows:
L
l b
a
=
π2
ln
(4.6a)
C
a
d
a
l b a
= −
+ −
ε
π
0
2
2 2
4
0 765
ln
.
( )
(4.6b)
The resonance frequency for this cavity is given by
f
c
al
a
d l
l b a
b
a
r
r
= −
+ −
−
2
2
2 0 765
2 2
1 2
π ε
ln
.
( )
ln
/
(4.7)
where c is the velocity of light in vacuum or free space.
4.3 Cavity Formation
4.3.1 Formation of a Rectangular Cavity
A cavity resonator of rectangular shape is shown in Figure 4.5. It is simply a
section of rectangular waveguide, which is closed at both the ends by con-
ducting plates. The dista