Reference no: EM132297245

Antenna and Wave Propagation

outcomes

The assignment will help you in assessing your understanding on the transmission line circuits and their solutions, in applying smith chart in analyzing and solving transmission line problems, impedance matching and also differentiate between various important antenna parameters. Specifically:

1. Analyze transmission line circuits based on the voltage and current distributions on them;
2. Apply Smith chart for analyzing and solving transmission-line problems and for impedance matching;
3. Discuss and analyze the important terminologies related to antennas.

Question 1. a. The constants of a 100km transmission line are R = 6 ohms/km, L = 2.2 mH/km, C = 0.005 mF/km, G = 0.25 micro mho/km. Calculate the terminating impedance for which no reflection will be set up in the line at the frequency of 1000 Hz.

b. An Ethernet cable is used to connect a computer to the server and it found experimentally that Z_o.c is 120 Ω and Z_s.c is 500 Ω. The cable is terminated with a sever having a load resistance Z_L of 500Ω at frequency of 300MHz. Design a single stub matching to minimize the reflection on this cable.

Question 2. a. Explain the term polarisation in antennas and discuss the three different types of polarisation.

b. A Wi-Fi access point radiates a signal using dipole antenna at frequency of 2.4 GHz with the current (IRMS) of 8 A. It is given in the antenna manual specification that the antenna Gain G=16.98 dB and Directivity D=17.78 dB. Assume that the loss resistance is 10 Ω, for the antenna obtain:

i. Antenna efficiency.
ii. Radiation resistance.
iii. Radiated power.
iv. Total input Power fed to the antenna

Question 3. a. A 75 Ω lossless transmission line is terminated into a load 100 + j150 Ω . For this line, find:
i. The load admittance;
ii. The input impedance at 0.4λ from load.

b. With necessary equations show that the input impedance of a quarter wavelength long lossless line terminated in a short circuit appears as an open circuit.

Question 4.
a. A transmission line of characteristic impedance 60 Ω is terminated by an antenna of impedance 48-j54 Ω. Using a Smith Chart calculate the following:
i. VSWR and
ii. Load Admittance YL.

b. A 45.6 m long transmission line with a characteristic impedance of 100ohms is terminated with an antenna of unknown impedance. There is mismatch in the system and the standing waves have a Vmax =6 V and V min=1.5 V. The distance between two successive minima is 6 m. Distance of the first voltage minima from the load end is at 2.4 m. Using a Smith Chart calculate the following:

i. Calculate the reflection coefficient;

ii. Calculate the input impedance of the line;

iii. Design a short circuited stub to match the antenna to the line.