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{
"metadata": {
"name": "chapter 2.ipynb"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 2: Fundamental Parameters of Antennas"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.1, Page 37"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from scipy.integrate import quad,dblquad\n",
"\n",
"#formula for beam solid angle theta_a=double_integration of d_omega\n",
"theta_a=quad(lambda x:1,0,2*pi)[0]*quad(lambda x:sin(x),0,pi/6)[0]\n",
"print 'Exact Beam Solid Angle:',theta_a,'steradians'\n",
"\n",
"#formula for approx angle=delta1*delta2\n",
"delta1=pi/3\n",
"delta2=pi/3\n",
"theta_a1=delta1*delta2\n",
"theta_a1=delta1**2\n",
"print 'Approximate Beam Solid Angle:',theta_a1,'steradians'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Exact Beam Solid Angle: 0.841787214477 steradians\n",
"Approximate Beam Solid Angle: 1.09662271123 steradians\n"
]
}
],
"prompt_number": 31
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.7, Page 52"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"\n",
"#The half power point of the pattern occurs at 60 degrees. Therefore theta_1r=2*pi/3\n",
"theta_1r=(2*pi)/3\n",
"theta_2r=(2*pi)/3\n",
"\n",
"#Given U=B0*cos(theta)\n",
"exact_theta_a=dblquad(lambda x,y:cos(x)*sin(x), 0, (2*pi), lambda x:0, lambda x:(pi/2))\n",
"print 'Exact Beam Solid Angle:',exact_theta_a[0],'steradians'\n",
"\n",
"#Formula for approx theta = theta_1r*theta_2r\n",
"approx_theta_a=theta_1r*theta_2r\n",
"print 'Approximate Beam Solid Angle:',approx_theta_a,'steradians'\n",
"\n",
"#formula for exact directivity=4*pi/exact_beam_angle\n",
"exact_direct=((4*pi)/(exact_theta_a[0]))\n",
"\n",
"#formula for approx directivity=4*pi/approx_beam_angle\n",
"approx_direct=((4*pi)/(approx_theta_a))\n",
"\n",
"#exact directivity in dB\n",
"exact_direct_db=10*log10(exact_direct)\n",
"\n",
"#approx directivity in dB\n",
"approx_direct_db=10*log10(approx_direct)\n",
"\n",
"print 'Exact directivity:',exact_direct_db,'dB'\n",
"print 'Approx. directivity:',approx_direct_db,'dB'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Exact Beam Solid Angle: 3.14159265359 steradians\n",
"Approximate Beam Solid Angle: 4.38649084493 steradians\n",
"Exact directivity: 6.02059991328 dB\n",
"Approx. directivity: 4.57092636745 dB\n"
]
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.8, Page 58"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"\n",
"#Maximum intensity\n",
"u_max=1\n",
"\n",
"#Calculation of radiated power\n",
"p_rad=dblquad(lambda x,y:(sin(x)**2)*sin(x),0,2*pi,lambda x:0,lambda x:pi)\n",
"print 'Radiated Power:',p_rad[0],'W'\n",
"\n",
"#Calulation of maximum directivity\n",
"D0=(4*pi)/(p_rad[0])\n",
"\n",
"#Directivity in dB\n",
"D0_db=10*log10(D0)\n",
"print 'Directivity:',D0_db,'dB'\n",
"\n",
"deg=90\n",
"\n",
"#Calculation od directivity\n",
"D0_1=101/(deg-0.0027*deg**2)\n",
"D0_1_db=10*log10(D0_1)\n",
"print 'Directivity:',D0_1_db,'dB'\n",
"\n",
"#Calculation of directivity\n",
"D0_2=(-172.4)+(191*sqrt((0.818+(1/deg))))\n",
"D0_2_db=10*log10(D0_2)\n",
"print 'Directivity:',D0_2,'dB'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Radiated Power: 8.37758040957 W\n",
"Directivity: 1.76091259056 dB\n",
"Directivity: 1.70982984843 dB\n",
"Directivity: 0.346803154212 dB\n"
]
}
],
"prompt_number": 34
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.9(a), Page 61"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"\n",
"B0=1\n",
"#Maximum intensity\n",
"u_max=1\n",
"\n",
"#Array containing angles in radians\n",
"a=sin(array([10,20,30,40,50,60,70,80,90,100,110,120,130,140,150,160,170,180])*pi/180)**2\n",
"\n",
"#Calculation of radiated power\n",
"p_rad1=B0*((pi/18)**2)*sum(a)*sum(a)\n",
"print 'Power Radiated:',p_rad1,'W'\n",
"\n",
"#Calculation of directivity\n",
"D0=(4*pi)/(p_rad1)\n",
"\n",
"print 'Directivity using numerical techniques:',D0\n",
"\n",
"#Calu=culation of radiated power\n",
"a=quad(lambda x:sin(x)**2,0,pi)\n",
"b=quad(lambda x:sin(x)**2,0,pi)\n",
"p_rad2=a[0]*b[0]\n",
"\n",
"#Directivity\n",
"D01=(4*pi)/(p_rad2)\n",
"\n",
"print 'Directivity:',D01"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power Radiated: 2.46740110027 W\n",
"Directivity using numerical techniques: 5.09295817894\n",
"Directivity: 5.09295817894\n"
]
}
],
"prompt_number": 33
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.9(b), Page 63"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"\n",
"\n",
"B0=1\n",
"\n",
"#Maximum intensity\n",
"u_max=1\n",
"\n",
"#Arrays containing angles in radians\n",
"a=sin(array([5,15,25,35,45,55,65,75,85])*pi/180)**2\n",
"b=sin(array([5,15,25,35,45,55,65,75,85])*pi/180)**2\n",
"\n",
"#Calculation of radiated power\n",
"p_rad=B0*((pi/18)**2)*(2*sum(a))*(2*sum(b))\n",
"\n",
"#Calculation of directivity\n",
"D0=(4*pi*u_max)/(p_rad)\n",
"\n",
"print 'Directivity using 18 divisions:',D0"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Directivity using 18 divisions: 5.09295817894\n"
]
}
],
"prompt_number": 16
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.10, Page 68"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"\n",
"#maximum intensuty\n",
"u_max=1\n",
"B0=1\n",
"\n",
"#Input impedance in Ohms\n",
"inp_imp=73\n",
"#Characteristic impedance in Ohms\n",
"char_imp=50\n",
"\n",
"#Calculation of radiated power\n",
"p_rad=B0*quad(lambda x:1,0,2*pi)[0]*quad(lambda x:sin(x)**4,0,pi)[0]\n",
"\n",
"#Calulation of directivity\n",
"D0=(4*pi*u_max)/(p_rad)\n",
"\n",
"#conduction & dielectric efficiency ecd=1 since antenna is loseless\n",
"ecd=1\n",
"\n",
"#Maximum Gain\n",
"G0=ecd*D0\n",
"G0_db=10*log10(G0)\n",
"\n",
"#Reflection Coefficient Tau\n",
"tau=float(inp_imp-char_imp)/float(inp_imp+char_imp)\n",
"\n",
"#Reflection efficiency=1-tau**2\n",
"er=1-tau**2\n",
"er_db=10*log10(er)\n",
"\n",
"#Total efficiency\n",
"e0=er*ecd\n",
"e0_db=10*log10(e0)\n",
"\n",
"#Absolute Gain\n",
"G0_abs=e0*D0\n",
"G0abs_db=10*log10(G0_abs)\n",
"\n",
"print 'Maximum Gain:',G0_db\n",
"\n",
"print 'Reflection efficiency:',er_db\n",
"\n",
"print 'Total efficiency:',e0_db\n",
"\n",
"print 'Absolute Gain:',G0abs_db"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Maximum Gain: 2.29848855242\n",
"Reflection efficiency: -0.154573670944\n",
"Total efficiency: -0.154573670944\n",
"Absolute Gain: 2.14391488148\n"
]
}
],
"prompt_number": 17
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.11, Page 77"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"\n",
"#unit vector of the wave\n",
"rho_w=array([1,0])\n",
"\n",
"#unit vector of the electric field\n",
"rho_a=array([1/sqrt(2),1/sqrt(2)])\n",
"\n",
"#Polarization factor\n",
"PLF=abs(dot(rho_w,rho_a))**2\n",
"print 'Polarization Factor:',PLF"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"0.5\n"
]
}
],
"prompt_number": 56
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.12, Page 78"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"\n",
"#unit vector of the wave\n",
"rho_w=array([1/sqrt(2),1/sqrt(2)])\n",
"\n",
"#unit vector of the electric field\n",
"rho_a=array([1/sqrt(2),-1/sqrt(2)])\n",
"\n",
"#Polarization Factor\n",
"PLF=abs(dot(rho_w,rho_a))**2\n",
"\n",
"print 'Polarization Factor:',PLF"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"0.0\n"
]
}
],
"prompt_number": 57
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.13, Page 86"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"\n",
"#Radiation Resistance\n",
"rad_res=73\n",
"\n",
"#Frequency of antenna\n",
"f=10**8\n",
"\n",
"#Velocity\n",
"v=3*10**8\n",
"\n",
"#Wavelength\n",
"lamda=v/f\n",
"\n",
"#Length of antenna\n",
"l=lamda/2\n",
"\n",
"#Perimeter of the antenna\n",
"b=(3*10**-4)*lamda\n",
"C=2*pi*b\n",
"\n",
"#value of omega\n",
"w=2*pi*f\n",
"\n",
"#Constant\n",
"mu0=4*pi*10**-7\n",
"\n",
"#Conductivity\n",
"sigma=5.7*10**7\n",
"\n",
"#High frequency resistance\n",
"Rhf=(l/C)*(sqrt((w*mu0)/(2*sigma)))\n",
"\n",
"#Load resistance\n",
"Rl=Rhf/2\n",
"\n",
"#calculation of conduction & dielectric efficiency\n",
"ecd=(rad_res)/(rad_res+Rl)\n",
"ecd_db=10*log10(ecd)\n",
"\n",
"print 'Conduction-dielectric efficiency:',ecd_db"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Conduction-dielectric efficiency: -0.0138216614754\n"
]
}
],
"prompt_number": 18
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.16, Page 98 "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"\n",
"lamda=1\n",
"\n",
"#Maximum directivity of transmitter\n",
"D0_t_db=16\n",
"D0_t=10**(float(D0_t_db)/10)\n",
"\n",
"#Maximum directivity of receiver\n",
"D0_r_db=20\n",
"D0_r=10**(D0_r_db/10)\n",
"\n",
"#Reflection coeficients of transmitter and receiver\n",
"tau_r=0.1\n",
"tau_t=0.2\n",
"\n",
"#Power at transmitter\n",
"P_t=2\n",
"\n",
"#Calculation of Power to the receiver\n",
"P_r=(1-tau_r**2)*(1-tau_t**2)*((lamda/(4*pi*100*lamda))**2)*D0_t*D0_r*P_t\n",
"print 'Power delivered to the load of receiver:',P_r,'W'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power delivered to the load of receiver: 0.00479199874075 W\n"
]
}
],
"prompt_number": 30
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.18, Page 108"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"\n",
"#antenna temp at receiver terminals\n",
"Ta=150\n",
"\n",
"#physical temp of transmission line\n",
"T0=300\n",
"\n",
"#thermal efficiency of the antennna\n",
"eA=0.99\n",
"\n",
"#antenna physical temperature\n",
"Tp=300\n",
"l=1\n",
"\n",
"#antenna temp at antenna terminals due to physical temperature\n",
"T_ap=Tp*(1/eA-1)\n",
"\n",
"#Loss of waveguide in dB/m\n",
"alpha_db=0.13\n",
"\n",
"#Loss of waveguide in Np/m\n",
"alpha_np=alpha_db/0.868\n",
"\n",
"#Calulation of effective temperature\n",
"T_A=Ta*exp(-l*alpha_np*2)+T_ap*exp(-l*alpha_np*2)+T0*(1-exp(-l*alpha_np*2))\n",
"print 'Effective temperature:',T_A,'K'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Effective temperature: 191.071984919 K\n"
]
}
],
"prompt_number": 23
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
|