# Variables
c = 3.*10**8; #speed of light
f = 2.*10**9; #frequency
# Calculations and Results
lembda = c/f; #wavelength
print 'The wavelength of 2GHz is, = %.2f m'%(lembda);
D = 15.; #m
Rff = 2*D**2/lembda;
print ' The distance to the far field is, Rff = %i m'%(Rff);
import math
# Variables
Gmax = 10**5;
# Calculations
Gmax_dB = 10*math.log10(Gmax);
# Results
print 'Gmax, dB = %i dB'%(Gmax_dB);
import math
# Variables
d = 10.**5; #m
Pt = 100.; #W
# Calculations
Pd = Pt/(4*math.pi*d**2);
# Results
print 'The power density is ,Pd = %.1f pW/m**2'%(Pd*10**12);
import math
# Variables
d = 10.**5; #m
Pt = 100.; #W
Gt = 50;
# Calculations
Pd = Gt*Pt/(4*math.pi*d**2);
# Results
print 'The power density is ,Pd = %.2f nW/m**2'%(Pd*10**9);
import math
# Variables
c = 3.*10**8; #speed of light
f = 15.*10**9; #frequency
# Calculations and Results
lembda = c/f; #wavelength
print 'The wavelength of 15 GHz is, = %.2f m'%(lembda);
d = 41.*10**6; #m
Pt = 50.; #W
Gt = 10.**4;
Gr = 10.**5
Pr = lembda**2*Gr*Gt*Pt/((4*math.pi)**2*d**2);
print 'The power density is , Pr = %.1f pW'%(Pr*10**12);
# Variables
Pt = 2000.; #W
Irms = 5.;
# Calculations
Rrad = Pt/Irms**2;
# Results
print 'The radiation resistance is , Rrad = %i ohm'%(Rrad);
import math
# Variables
#misprinted example number
c = 3.*10**8; #speed of light
f = 10.*10**9; #frequency
# Calculations and Results
lembda = c/f; #wavelength
print 'The wavelength of 2GHz is, = %.2f m'%(lembda);
D = 12; #m
Ap = math.pi*D**2/4;
print ' a)The physical area is ,Ap = %.2f m**2 '%(Ap);
n1 = .7; #efficiency
Ae = n1*Ap;
print ' The effective capture area is ,Ae = %.2f m**2'%(Ae);
G = 4*math.pi*Ae/lembda**2;
print ' b) The gain is ,G = %i'%(G);
GdB = 10*math.log10(G);
print ' The gaindB) is , GdB = %.1f dB'%(GdB);
theta_3dB = 70*lembda/D;
print ' c) The 3 dB beamwidth = %.3f degrees'%(theta_3dB);
# Variables
c = 3.*10**8; #speed of light
f = 100.*10**6; #frequency
# Calculations and Results
lembda = c/f; #wavelength
print 'The wavelength of 2GHz is, = %i m'%(lembda);
Ac = 0.13*lembda**2;
print 'The capture area is , Ac = %.2f m**2'%(Ac);