# Chapter 4:Microwave Components¶

## Example 1,Page No:167¶

In [30]:
import math

# Variable Declaration
Pi      = 10;           # Input power in mW
CF      = 20;           # coupling factor in dB

# calculations
# CF(db)   = 10*math.log(Pi/Pc)
Pc      = Pi/(float((10**(CF/float(10)))));# antilog conversion and coupling power

# Result
print'Coupled Power = %d uW'%(Pc*10**3);
Coupled Power = 100 uW

## Example 2,Page No:167¶

In [1]:
import math

# Variable Declaration
Pi      = 10;           # Input power in mW
IL      = 0.4;          # insertion loss in dB

# calculations
# ILdb   = 10log(Pi/Po)
Po      = Pi/float((10**(IL/10))) # antilog conversion and coupling power

# Result
print'Power available at the straight through port output = %3.3f mW'%Po;
Power available at the straight through port output = 9.120 mW

## Example 3,Page No:168¶

In [2]:
import math

# Variable Declaration
CF      = 20;       # Coupling factor in dB
I       = 50;       # Isolation in dB
Pc      = 100*10**-6; # coupling power in W

# calculations
# D    = 10log(Pc/Piso)
D       = I - CF;           # Directivity in dB
Piso    = Pc/float((10**(D/float(10))))  # antilog conversion and coupling power

# Result
print'Directivity = %d dB\n'%D,'Power at isolated port = %d nW'%(Piso*10**9);
Directivity = 30 dB
Power at isolated port = 100 nW

## Example 4,Page no:168¶

In [7]:
import math

# Variable Declaration
CF      = 20;           # coupling factor in dB
D       = 30;           # Directivity in dB
Pin     = 10;           # input power in dBm

# Calculations
# 10logPi = Pin
Pi      = 10**(Pin/10);   # power in mW
I       = D + CF          # isolation in dB
Pc      = Pin - CF;
Pcwatts = 10**(Pc/10)     # power at coupled port in mW
Piso    = Pin - I
Pisowatts = 10**(Piso/10) # Power at isolated port in mW
Po      = Pi -(Pcwatts + Pisowatts);    # power at o/p port in mW

# Result
print'Power Available at the output port = %3.5f mW'%Po;
Power Available at the output port = 9.89990 mW

## Example 5,Page No:169¶

In [9]:
import math

# Variable Declaration

Pi      = 5*10**-3;            # Input power in W
CF      = 10;                  # coupling factor
Piso    = 10*10**-6            # power at isolated port in w

# calculations
# CF   = 10log(Pi/Pc)
Pc      = Pi/(10**(CF/10))  # antilog conversion and coupling power
# D    = 10log(Pc/Piso)    # Directivity
D       = 10*math.log10(Pc/Piso)

# Result
print'Directivity = %3.0f dB\n'%D;
Directivity =  17 dB

## Example 6,Page No:169¶

In [35]:
import math
# given data
a       = 2;        # width in cm
b       = 1;        # Height in cm
d       = 3;        # length in cm
c       = 3*10**10;  # vel in free space in cm/s
# For TE101 mode
m       = 1
n       = 0;
p       = 1;

# Calculations
fo      = (c/float(2))*math.sqrt((m/float(a)**2)+ ((n/float(b))**2 )+ (p/float(d))**2);

# Output
print'Resonant Frequency = %d Ghz' %(fo/float(10**9));
Resonant Frequency = 9 Ghz

## Example 7,Page No:170¶

In [3]:
import math
# given data
fo      = 10;       # resonant freq in Ghz
# output
print'The Resonant frequency for a TM mode in a rectangular cavity resonator for a given integral\n';
print'values of m,n and p is same as that of a TE mode for same values of m,n and p\n';
print'Therefore,TM111 mode resonant frequency = %d Ghz'%fo;
The Resonant frequency for a TM mode in a rectangular cavity resonator for a given integral

values of m,n and p is same as that of a TE mode for same values of m,n and p

Therefore,TM111 mode resonant frequency = 10 Ghz

## Example 8,Page No:170¶

In [40]:
import math

# Variable Declaration
a       = 4;        # width in cm
b       = 2;        # Height in cm
c       = 3*10**10;  # vel in free space in cm/s
fo      = 6*10**9;    # resonator frequency in Ghz
# For TE101 mode
m       = 1
n       = 0;
p       = 1;

# Calculations
#fo      = (c/float(2))*math.sqrt((m/float(a)**2 + (n/float(b)**2 + (p/float(d)**2);
d       = math.sqrt(((p**2)/((((2*fo)/float(c))**2) - ((m/float(a))**2) -((n/float(b))**2))));

# Result
print'Length of cavity resonator = %3.1f cm'%d;
Length of cavity resonator = 3.2 cm

## Example 9,Page No:170¶

In [4]:
import math

# Variable Declaration
a       = 4;        # width in cm
b       = 2;        # Height in cm
c       = 3*10**10;  # vel in free space in cm/s
fo      = 6*10**9;   # resonator frequency in Ghz
d       = 3.2;      # length of cavity resonator in cm
# For TE101 mode
m       = 1
n       = 0;

# Calculations
lamda_c = 2/(float(math.sqrt(((m/float(a))**2) + ((n/float(b))**2))));      # cut-off wavelength in m
lamda   = c/float(fo);                             # operating wavelength in m
lamda_g = lamda/(float(math.sqrt(1 - ((lamda/float(lamda_c))**2))));# guide wavelength in m

# output
print'Length of resonator is %3.1f cm'%d,' and  guide wavelength is %3.1f cm'%(lamda_g);
print'\nlength of resonator is half of guide wavelength';
Length of resonator is 3.2 cm  and  guide wavelength is 6.4 cm

length of resonator is half of guide wavelength

## Example 10,Page No:171¶

In [22]:
import math

# Variable Declaration
di       = 8;        # internal diameter in cms
a        = 4;        # internal radius in cms
fo      = 10*10**9;  # operating frequency in Ghz
ha01    = 2.405;    # Eigen value of bessel function
c       = 3*10**10   # velocity of EM wave in cm/sec
# For TM011 mode
m       = 0
n       = 1
p       = 1

# Calculations
#f0  = (c/2*pi)*sqrt((ha/a)**2 + (p*pi/d)**2)  operating frequency
d     = (p*math.pi)/(math.sqrt((fo*2*math.pi/c)**2 - (ha01/a)**2))   #length of resonator

# result
print'Length of resonator = %3.3f cm'%d;
Length of resonator = 1.566 cm

## Example 11,Page No:172¶

In [5]:
import math

# Variable Declaration
di       = 6;        #internal diameter in cms
d        = 5;        #length in cm
a        = 4;        #internal radius in cms
fo      = 10*10**9; #perating frequency in Ghz
ha01    = 2.405;    #Eigen value of bessel function
ha11    = 1.841;    #Eigen value of bessel function
c       = 3*10**10   #velocity of EM wave in cm/sec
#For TM011 mode and TE111 mode
m0       = 0
m1       = 1
n1       = 1
p1       = 1
p2       = 2

# Calculations
f0  = (c/(2*math.pi))*math.sqrt((ha01/a)**2 + (p2*math.pi/d)**2)     #resonant frequency for TM012 mode
f01  = (c/(2*math.pi))*math.sqrt((ha11/a)**2 + (p1*math.pi/d)**2)        # resonant frequency for TE111 mode

# Result
print'Resonant frequency for TM012 mode = %3.3f Ghz\n'%(f0/float(10**9)), 'Resonant frequency for TM111 mode = %3.3f Ghz\n'%(f01/float(10**9 ));
Resonant frequency for TM012 mode = 6.651 Ghz
Resonant frequency for TM111 mode = 3.719 Ghz