Homework 4 (10 pts total)

Villanova University ECE 8708: Wireless Communications

Dr. David C. Burnett, Fall 2025

Recommended resources: Chapter 4, chapter 5, lecture notes

Problem 1 (6 pts)

In class we discussed scattering signals off of the moon. During high meteor storm activity such as the Leonids meteor shower often in November, radio communications can also be scattered off of the ionized trails resulting from meteors entering Earth's atmosphere.

Like moon bounce, meteor bounce communications are often performed at a carrier frequency of 50 MHz and very narrow bandwidth. The transmit power needed for success is much lower, in part because signals are reflecting off of the E-layer of the ionosphere rather than going all the way to the moon. For this problem we can assume the radar cross section of an ionized meteor trail is about -49 dBsm [1].

Re-design the EME communication problem from lecture to fit the circumstances of meteor bounce communication. Choose or calculate:

• Bandwidth
• Reasonable antenna gain values
• Operating frequency
• Communication range

What's the maximum range you can communicate over while ensuring SNR of at least 10 dB? You can ignore the curvature of the earth and assume the radar cross section stays constant regardless of the signal's angle of incidence on the ionosphere.

[1] https://archive.ll.mit.edu/publications/journal/pdf/vol12_no1/12_1meteorshower.pdf

Problem 2 (4 pts)

Find an antenna used in your day to day life and calculate its far field distance. Provide a photo of the antenna.

• How much clutter (i.e., solid objects) is usually between the antenna and its far field distance?
• Do you observe any performance changes if you relocate the antenna such that its near field space is empty?