# Chapter 16 Microwaves and Lasers¶

## Example 16.1 Page no 753¶

In [1]:
#given
h=0.3                    #curve depth of parabolic reflector
D=3                      #diameter of parabolic reflector

#calculation
f=D/(16*h)               #focal

#result
print"The focal length is ",f," m out from the center of the parabolic reflector"

The focal length is  0.625  m out from the center of the parabolic reflector


## Example 16.2 Page no 755¶

In [2]:
#given
D=3.0                    #diameter of microwave dish
k=0.6                    #efficiency of reflector
c=2.997925*10**8         #velocity of light
f=10.0*10**9             #frequency

#calculation
import math
Ap=10*math.log10((c/f)*k*((math.pi*D)**2/(c/f)**2))      #powergain
B=(70*(c/f))/D                                         #beamwidth

#result
print"beamwidth = ",round(B,3),"micrometer"

beamwidth =  0.7 micrometer


## Example 16.3 Page no 756¶

In [5]:
#given
D=4.5                       #diameter of parabolic reflector
k=0.62                      #efficiency factor

#calculation
import math
Ae=(k*math.pi)*(D/2.0)**2                       #aperture efficiency
i=(math.pi*(D/2.0)**2)                #ideal capture area

#result
print"The ideal capture area for",D,"m","1f m parabolic antenna is",round(i,3),"sq.m"

The ideal capture area for 4.5 m 1f m parabolic antenna is 15.904 sq.m