EM THEORY & TRANSMISSION LINE LABORATORY

Radio signals are a form of electromagnetic wave, and as they are the way in which radio signals travel, they have a major bearing on RF antennas themselves and RF antenna design. Electromagnetic waves are the same type of radiation as light, ultra-violet and infra red rays, differing from them in their wavelength and frequency. Electromagnetic waves have both electric and magnetic components that are inseparable. The planes of these fields are at right angles to one another and to the direction of motion of the wave. This electric field is measured in terms of the change of potential over a given distance, e.g. volts per meter, and this is known as the field strength. When an RF antenna receives a signal the magnetic changes cause a current flow, and the electric field changes cause the voltage changes on the antenna. Whether the RF antenna is used for broadcasting, WLAN, cellular telecommunications, PMR or any other application, the performance of the RF antenna is paramount, and the antenna resonant frequency and the antenna bandwidth are of great importance.

 Objective:

This lab is intended to give the students a practical experience in working with different types of antenna in hand and its radiation pattern. Also student will experimentally calculate different antenna parameters (beam-width, gain, directivity) in this lab. Exceptional infrastructure of this lab also provide an ability to identify, formulate, and solve engineering problems by means of  comparative study and characteristic study of transmission line with various load, no load and matched load condition. An additional objective is to provide some practice and experience with relevant software tools for stub matching simulation.

List of Major Experiments:

Module I:

  1. Plotting of Standing Wave Pattern along a transmission line when the line is open-circuited, short-circuited and terminated by a resistive load at the loaded.
  2. Input Impedance of a terminated coaxial line using shift in minima technique.
  3. Study of Smith chart on MATLAB platform.
  4. Simulation study of Smith chart – Single and double stub matching.

Module II:

  1. Radiation Pattern of dipole antenna.
  2. Radiation Pattern of a folded-dipole antenna.
  3. Radiation pattern of a 3-element Yagi-Uda Antenna.
  4. Beam width, gain and radiation pattern of a 3-element, 5-element and 7-element Yagi-Uda antenna – Comparative study.
  5. Radiation pattern, Gain, Directivity of a Pyramidal Horn Antenna.
  6. Study of Spectrum Analyzer.

Major Equipments:

  1. Cathode Ray Oscilloscope-30 MHz (APLAB)
  2. Digital Storage Oscilloscope (TEKTRONIX TPS2024)
  3. Function Generator (SCIENTIFIC)
  4. Spectrum Analyzer (TEKTRONIX RSA306)
  5. ATS-A transmitter
  6. ATS-A receiver
  7. ATS-A stepper motor connector
  8. 20 sets of Antennas(FALCON)
    1. Dipole ½ L
    2. Dipole L
  • Folded Dipole ½ L
  1. Yagi 3 Elements
  2. Yagi 5 Elements
  3. Yagi 7 Elements
  • Yagi 3 Elements Folded
  • Loop Square ¼ L
  1. QUAL 1/4L
  2. Vertical 1/4L
  3. Discone 1/4L
  • Endfire Array 1/2L
  • Broadside Array 1/2L
  • Helical
  1. Loop
  • Slotted Cylindrical 1/2L
  • Rectangular Slot
  • Telescopic dipole
  • Shielded Loop
  1. Horn Antenna
  1. Transmission Line Trainer kit (FALCON)