# Chapter 4. Linear Wire Antennas¶

## Example 4.1, Page 156¶

In [1]:
#lambda is very small
lamda=0.0001

#Length of infinitesimal dipole
l=lamda/50

R_r=80*(pi**2)*(l/lamda)**2


Radiation resisitance: 0.315827340835


## Example 4.3, Page 168¶

In [3]:
#Lamda is a variable value in this example and therefore we will write a function to calculate the differences by passing different values of lambda

def phase_diff(z,r,lamda):
R1=sqrt(z**2+r**2)
R2=r
phase_diff=(2*pi/lamda)*(R1-R2)

def amp_diff(z,r,lamda):
R1=sqrt(z**2+r**2)
R2=r
amp_diff=(1/R1)-(1/R2)
print 'The amplitude difference is:',amp_diff

#We will assume lamda = 50
lamda=50

#Given
l=5*lamda
r=60*lamda

#z=2.5lamda at 90 degree
z=2.5*lamda

phase_diff(z,r,lamda)
amp_diff(z,r,lamda)

The phase difference is: 0.327107322652 radians.
The amplitude difference is: 0.000333044357697


## Example 4.4, Page 194¶

In [4]:
#Given is the input resistance of dipole
R=50

#Calculation of gain G
G=pow(float(R)/24.7,1/2.5)

print G

1.32589526731