Chapter 16: Practical Design Considerations of Large Aperture Antennas

Example 16-2.1, Page number: 608

In [2]:
from math import cos, pi, log10

#Variable declaration
delta = 1/20.0        #rms deviation (lambda)

#Calculations
del_phi = 4*pi*delta*180/pi #Phase error (degrees)
kg = cos(del_phi*pi/180)**2        #Gain-loss (unitless)
kg = 10*log10(kg)           #Gain-loss (dB)

#Result
print "The gain reduction is", round(abs(kg),1), "dB"

 The gain reduction is 1.8 dB

Example 16-2.2, Page number: 609

In [4]:
from math import tan,pi, log10

#Variable declaration
del_phi = 36.0    #rms phase error (degrees)
n_irr = 100.0     #Number of irregularities

#Calculations
max_side = tan(del_phi*pi/180)**2
max_side = -10*log10(max_side)
            #Maximum side-lobe level (dB)
ran_side = (1/n_irr)*tan(del_phi*pi/180)**2
ran_side = -10*log10(ran_side)
            #Random side-lobe level (dB)

#Result
print "The maximum side lobe level from main lobe is", round(max_side,1),"dB"
print "The random side lobe level from main lobe is", round(ran_side,1),"dB"

The maximum side lobe level from main lobe is 2.8 dB
The random side lobe level from main lobe is 22.8 dB