Introduction to Radar Basics - MATLAB Simulations for Radar Systems Design - page 23

and by using Eq. (1.40) in Eq. (1.71) we can define the search radar equation
for a circular aperture as

----------------------------- T sc
Ω

P av A σ
16 R 4 kT e LF

-------

SNR =

(1.72)

π D 2

where the relation

A = ⁄ 4

(aperture area) is used.

MATLAB Function Ðpower_aperture.mÑ

The function Ðpower_aperture.mÑ implements the search radar equation
given in Eq. (1.67); it is given in Listing 1.5 in Section 1.10. The syntax is as
follows:

PAP = power_aperture (snr, tsc, sigma, range, te, nf, loss, az_angle, el_angle)

where

Symbol Description Units Status

snr sensitivity snr dB input

tsc scan time seconds input

sigma target cross section m 2 input

range target range (can be either sin-

gle value or a vector)

meters input

te effective temperature Kelvin input

nf noise figure dB input

loss radar losses dB input

az_angle search volume azimuth extent degrees input

el_angle search volume elevation extent degrees input

PA P power aperture product dB output

Plots of the power aperture product versus range and plots of the average
power versus aperture area for three RCS choices are shown in Figure 1.16 .
MATLAB program Ðfig1_16.mÑ was used to produce these figures. It is given
in Listing 1.6 in Section 1.10. In this case, the following radar parameters were
used

T sc θ e = θ a R T e nf × loss snr

σ

2.5 sec 2° 900 K 13 dB 15 dB

m 2

250 Km

0.1