Graphics Programs Reference
In-Depth Information
e
j
2
ka
π 2
(
⁄
)
σ
5
V
=
1
-------------------------
(11.56)
8π
k
(
3
4
e
jka
π 4
(
+
⁄
)
σ
2
H
=
-----------------------------
(11.57)
2π
k
(
12
⁄
jk
asin
θ
e
σ
3
H
=
--------------------
(11.58)
1
sin
θ
e
jk
asin
θ
σ
4
H
=
--------------------
(11.59)
1
+
sin
θ
e
j
2
ka
(
+
(
π 2
⁄
)
)
σ
5
H
=
1
-----------------------------
(11.60)
2π
k
()
Eqs. (11.50) and (11.51) are valid and quite accurate for aspect angles
. For aspect angles near , Ross
1
obtained by extensive fitting
of measured data an empirical expression for the RCS. It is given by
0°θ80
≤≤
90°
σ
H
→
0
ab
2
λ
π
22
a
λ
π
22
a
λ
3π
5
(11.61)
--------
σ
V
=
1
+
------------------------
+
1
------------------------
cos
2
ka
------
)
2
)
2
(
⁄
(
⁄
The backscattered RCS for a perfectly conducting thin rectangular plate for
incident waves at any
θϕ
,
can be approximated by
4π
a
2
b
2
λ
2
2
sin
ak
(
ak
sin
θ
cos
ϕ
)
sin
bk
(
bk
sin
θ
sin
ϕ
)
)
2
------------------
-------------------------------------------
------------------------------------------
σ
=
(
cos
θ
(11.62)
sin
θ
cos
ϕ
sin
θ
sin
ϕ
Eq. (11.62) is independent of the polarization, and is only valid for aspect
angles .
Fig. 11.27
shows an example for the backscattered RCS of a
rectangular flat plate, for both vertical (
Fig. 11.27a
) and horizontal (
Fig.
and wavelength . This plot can be repro-
duced using MATLAB function
Ðrcs_rect_plateÑ
given in Listing 11.10.
MATLAB Function Ðrcs_rect_plate.mÑ
θ
≤
20°
ab
10.16
cm
==
λ
=
3.33
cm
The function
Ðrcs_rect_plate.mÑ
calculates and plots the backscattered RCS
of a rectangular flat plate. Its syntax is as follows:
[rcs] = rcs_rect_plate (a, b, freq)
1. Ross, R. A., Radar Cross Section of Rectangular Flat Plate as a Function of Aspect
Angle,
IEEE Trans
., AP-14,320, 1966.
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