Homework 19 Solution.
7.3-11 A horn antenna with a 185.5 137.4cm rectangular aperture has the
following measured parameter values at 0.44GHz : HPE o = 30o , HPH o = 27o ,
and G = 15.5dB .
a. Compute the aperture eciency.
b. Estimate the gain from the meas
Homework 1 Solution.
1. Calculate and compare the power density and electric eld strength for
= 90 for a distance of 20 km from dipole antennas radiating 100 W of
power at 1.25 MHz. Consider antennas of the following lengths:
L = 0.04
L = 0.32
L = 0.5
Homework #2 Solution
% Problem 4 Matlab code
clc, clear all, close all
L = 0.04; %0.04, 0.5, 1.25 % dipole lengths
theta = linspace(0,359,1000)*pi/180; % define angle
betaL = pi*L; % beta*L/2
dBmin = 40; % plot the minimum dB value as -40 dB
Ftheta = abs(
Homework 3 Solution.
2.4-6. A single turn circular loop 15cm in radius is made of 3mm diameter copper wire. Calculate the radiation resistance, ohmic resistance, input
impedance and radiation eciency at 1M Hz .
Solution:
= 300m, f = 1M hz, b = 0.15m, d =
Homework 18 Solution.
33. Calculate the gain of a slot antenna of dimensions 29cms 2.0cms for
use at a frequency of 500M Hz . Calculate the center-feed-point impedance
for this antenna.
Solution:
=
3 108
= 0.6m
500 106
L = 0.29m = 0.4833
W = 0.02m
a = 0.2
Homework 17 Solution.
6.1-6 Plot the linear, polar plot of a traveling wave long wire antenna that is
eight wavelengths long.
Solution:
Matlab Code
clc, clear all, close all
L=8;
betaL=pi*L;
theta=linspace(0,360,360)*pi/180;
thetaMax=acos(1-0.371/L)*pi/18
Homework 14 Solution.
5.4-9 The input impedance of a driven element in the presence of a shortcircuited parasitic element is 40 45o and is 60 30o when the terminals of
the parasitic element are open-circuited. What is the approximate selfimpedance of the
Homework 13 Solution.
5.1-13 Use the length reduction procedure for half-wave resonance in Table
5-2 to calculate the resonant frequencies of the two dipoles in Fig. 5-7.
Solution:
For dipole wire with radius a = 0.005m.
L
= 50
2a
L = 0.5m = 0.475, = 1.05
Homework 12 Solution.
5.8-1 Show how the normalized principal plane patterns of (5-74) follow from
(5-73). Discuss the electric eld polarization in each plane.
Solution:
E = Eo cos()f (, )
E = Eo cos() sin()f (, )
f (, ) =
sin
W
sin() sin()
2
W
sin() sin(
Homework 11 Solution.
14. A cellular telephone monopole antenna of equivalent impedance ZA =
20 j 90 is to be matched for maximum power at the midband transmission
frequency of 837M Hz . Design a two reactance or a three reactance network
for this purpose
Homework 8 Solution.
18. Calculate the feed point impedances and radiation patterns for the following 3-element antenna arrays:
a. Side-by-side parallel dipole antennas each of length L = 0.4781 (nominal half-wave dipoles); inter-element distance d/ = 0.4
Homework 5 Solution.
2.5-11. A Low Earth Orbit (LEO) satellite system transmits 1W at 1.62GHz
using a 29dB gain antenna with spot beams directed towards users on earth
that are a maximum of 1500Km away. Find the required satellite transmitter
power in ord
Homework 4 Solution.
2.5-5. The eective aperture of a 1.22 diameter parabolic reector antenna
is 55% of the physical aperture area. Compute the gain in dB at 20GHz .
Solution:
d = 1.22m,
= 0.015m, f = 20GHz, r = 55%
2
d = 1.169m2
4
Ae = r Ap = 0.643m2
Ap