# Chapter07, Loop Antenna¶

## Example No. 7.10.1, page : 7-16¶

In :
import numpy as np
A=1 #m²(Area of loop)
N=400 #no. of turns
Q=100 #Quality factor
theta=60 #degree(angle)
Erms=10 #µV/m(field strength)
f=1 #MHz(tuned frequency)
c=3*10**8 #m/s##Speed of light
lamda=c/(f*10**6) #m(Wavelength)
Vr=Q*2*np.pi*A*N*np.cos(theta*np.pi/180)*Erms*10**-6/lamda #V(reciever input voltage)
print "Input voltage to the receiver = %0.3f mV  " %(Vr*1000)

Input voltage to the receiver = 4.189 mV


## Example No. 7.10.2, page : 7-17¶

In :
import numpy as np
N=12 #no. of turns
A=1 #m²(Area of loop)
Erms=100 #µV/m(field strength)
f=10 #MHz(tuned frequency)
theta=0 #degree(angle)
c=3*10**8 #m/s##Speed of light
lamda=c/(f*10**6) #m(Wavelength)
Vr=2*np.pi*A*N*np.cos(theta*np.pi/180)*Erms*10**-6/lamda #V(reciever input voltage)
print "Voltage induced in loop = %0.2f µV/m " %(Vr*10**6)

Voltage induced in loop = 251.33 µV/m


## Example No. 7.10.3, page : 7-17¶

In :
N=25 #no. of turns
Vrms=150 #µV(emf induced)
f=500 #kHz(tuned frequency)
A=0.5**2 #m²(Area of loop)
theta=0 #degree(angle)
c=3*10**8 #m/s##Speed of light
lamda=c/(f*10**3) #m(Wavelength)
Erms=lamda/(2*np.pi*A*N*np.cos(theta*np.pi/180))*Vrms*10**-6 #V/m(maximum emf induced)
print "Field strength = %0.3f mV/m  "%(Erms*10**3)

Field strength = 2.292 mV/m


## Example No. 7.10.4, page : 7-17¶

In :
N1=1.0 #no. of turns in primary
N2=8.0 #no. of turns in secondary
#a=lamda/25
aBYlamda=1.0/25 #(temporary calculation)
#A=np.pi*a**2
A_BY_lamda_sqr=np.pi*aBYlamda**2 #(temporary calculation)
Rr1=31200*(N1*A_BY_lamda_sqr)**2 #Ω(Radiation resistance for single turn)
print "Radiation resistance for single turn loop = %0.4f Ω " %(Rr1)
Rr2=31200*(N2*A_BY_lamda_sqr)**2 #Ω(Radiation resistance for 8 turn)
print "Radiation resistance for 8 turn loop = %0.2f Ω " %Rr2

Radiation resistance for single turn loop = 0.7883 Ω
Radiation resistance for 8 turn loop = 50.45 Ω


## Example No. 7.10.5, page : 7-18¶

In :
from __future__ import division
f=100 #MHz(Operating frequency)
c=3*10**8 #m/s##Speed of light
lamda=c/(f*10**6) #m(Wavelength)
C=2*np.pi*a #m(Circumference)
d=2*10**-4*lamda #m(Spacing)
print "For single turn : "
N=1 #n. of turns
RL_BY_Rr=3430.0/(C**3*f**(3.5)*N*d) #(temporary calculation)
print "Radiation efficiency of single turn = %0.2f %%" %K
print "For Eight turn : "
N=8 #no. of turns
RL_BY_Rr=3430/(C**3*f**(3.5)*N*d) #(temporary calculation)
print "Radiation efficiency of eight turn = %0.2f %%" % K

For single turn :
Radiation efficiency of single turn = 42.85 %
For Eight turn :
Radiation efficiency of eight turn = 85.71 %


## Example No. 7.10.6, page : 7-19¶

In :
from fractions import Fraction

Directivity : 3/2