Chapter 11: Broadband and Frequency-Independent Antennas

Example 11-1.1, Page number: 423

In [1]:
#Variable declaration
d = 4       #spacing (mm)
D = 100     #distance between the openings (mm)

#Calculation
lambda_short = 10*d     #Shortest wavelength (mm)
lambda_long = 2*D       #Longest wavelength (mm)
bandwidth = lambda_long/lambda_short    #Bandwidth (unitless)

#Result
print "The approximate bandwidth is", bandwidth,"to 1"

The approximate bandwidth is 5 to 1

Example 11-7.1, Page number: 438

In [2]:
from math import atan,pi,log

#Variable declaration
gain_dbi = 7.0        #Gain (dBi)
bandwidth = 4          #Relative bandwidth (unitless)
s_lambda = 0.15       #Spacing (lambda)
k = 1.2               #Scale constant (unitless)

#Calculation
alpha = atan((1-1/k)/(4*s_lambda))*180/pi   #Apex angle (degrees)
n = round(log(bandwidth)/log(k))    #Number of elements(unitless)
n += 1
n += 2      #Number of elements considering conservative design (unitless)

#Result
print "The apex angle is", round(alpha,1), "degrees"
print "The number of elements is", n

The apex angle is 15.5 degrees
The number of elements is 11.0