For This Module You Will Investigate The Operation Of Antenn
For This Module You Will Investigate The Operation Of Antennas Ante
For this module, you will investigate the operation of antennas. Antennas can both transmit and receive electromagnetic waves. You see antennas everywhere from portable radios and cell phones to radio transmission and cell network towers. In this laboratory, you will look at two types of antennas, a Linear Antenna (End-Fed) and a Linear Antenna (Center-Fed). Experiment with the simulation by changing the wavelength control (that is, the length of the antenna) and observe the changes in results.
Linear Antenna (End-Fed) shows the magnetic field near a half-wave linear antenna fed from one end. You can vary the length of the antenna using the "Length" slider. Linear Antenna (Center-Fed) shows the magnetic field near a full-wave linear antenna fed from the center. You can vary the length of the antenna using the "Length" slider and you can vary the separation between the two halves of the antenna using the "Feed Separation" slider. In terms of results: The Show Intensity checkbox determines whether to show the wave intensity, or the waves themselves.
When this is unchecked, the positive wavefronts are shown in green, and negative in red. Viewing the waves (instead of the intensity) only works well when zoomed in, using a low frequency; otherwise the individual waves are too small to see. The Show Graph checkbox shows the current distribution along the antenna (for linear antennas) or the excitation coefficients (for arrays). The phase is indicated using different colors. The Show Info checkbox can be used to turn off the information shown in the lower-right hand corner for some antenna setups.
The Stopped checkbox stops the applet, in case you want to take a closer look at something, or if you want to work on something with the mouse without worrying about it changing out from under you. The Alternate Rendering checkbox is used to speed up rendering, but it actually slows things down on some machines. The Speed slider controls how far the waves move between frames. The Zoom Out slider zooms out when you slide it to the right. This slows things down quite a bit.
The Resolution slider allows you to speed up or slow down the applet by adjusting the resolution; a higher resolution is slower but looks better. Also, increasing the resolution acts like zooming out. The Source Frequency slider controls the frequency of the signal. The Brightness slider controls the brightness, just like on a TV set. This can be used to view faint waves more easily.
Click on link 1 to access the simulation. If you need the Java plug-in to view the applet, download the plug-in at link 2. (By the way, link 2 contains a lot of really cool applets.) Sources 1 and 2 below are listed as 7 and 8 on the list of required readings and sources in this Module's Background Information section. Write a two to three page paper discussing your observations in terms of what you learned about electromagnetic waves and antennas by comparing the results using the Linear Antenna (End-Fed) with the Linear Antenna (Center-Fed).
Paper For Above instruction
The study of antennas provides profound insights into the propagation of electromagnetic waves and their practical applications in modern communication systems. By comparing the operation of the Linear Antenna (End-Fed) and the Linear Antenna (Center-Fed), one gains an understanding of how different feeding methods influence radiation patterns, impedance characteristics, and wave propagations, thus enriching the broader framework of electromagnetism and telecommunications.
The end-fed antenna, typically a half-wave dipole excited from one end, demonstrates a distinctive radiation pattern characterized by a single dominant lobe perpendicular to the wire in the far field. Using the simulation, varying the length of the end-fed antenna directly impacts the wave propagation and radiation pattern. When the antenna length approaches the half-wavelength, the electromagnetic radiation intensifies at the tip, forming a pattern with maximum amplitude perpendicular to the wire. The intensity of the wave, visualized through the simulation, reflects the antenna’s efficiency in transmitting electromagnetic energy. The phase distribution, indicated by different colors, elucidates the wavefront’s nature near the feed point and along the antenna length, revealing how standing waves form due to reflections at the feed point.
Conversely, the center-fed linear antenna, typically a full-wavelength dipole, exhibits a different radiative behavior. Simulation results show symmetrical phase and current distribution around the center, with a notable sinusoidal variation along the antenna length. When the feed separation is adjusted, the wave pattern adjusts accordingly, influencing the overall radiation properties. The full-wavelength design tends to produce a more directive radiation pattern with a maximum perpendicular to the antenna axis. The visualization of wave intensity and phase distribution reveals fundamental electromagnetic principles: how standing waves are established, the role of current distribution along the conductor, and how these factors influence the directionality and strength of emitted waves.
Notably, the simulation underscores the importance of antenna length relative to wavelength in governing electromagnetic wave behavior. At particular lengths—like half-wavelength or full-wavelength—the antennas optimize transmission and reception capabilities, evident in the intensified wavefronts and clear phase patterns. Furthermore, the ability to manipulate the antenna’s physical parameters and observe resulting electromagnetic phenomena exemplifies the practical applications of antenna theory in real-world radio communication, satellite transmission, and wireless networking.
In conclusion, comparing the end-fed and center-fed linear antennas through simulation facilitates a deeper understanding of how electromagnetic waves are generated, propagated, and received based on antenna design and feeding method. The visualizations of wave intensity and phase reinforce the core electromagnetic principles governing antenna operation. This knowledge supports the development of effective antenna systems and enhances communication network design, illustrating the integral role of electromagnetic wave behavior in everyday wireless technologies.
References
- Balanis, C. A. (2016). Antenna Theory: Analysis and Design (4th ed.). Wiley.