Question
Which frequency band has the smallest first Fresnel zone?
Answer Options
- A) 5.8 GHz
- B) 3.4 GHz
- C) 2.4 GHz
- D) 900 MHz
Correct Answer: A
Explanation
The Fresnel zone is an elliptical volume between two antennas in a line-of-sight path, and the first Fresnel zone (F1) defines the region where, ideally, the majority of the radio wave energy should propagate without obstruction. The radius of this zone is inversely proportional to the square root of the operating frequency.
This means that as the frequency increases, the radius of the Fresnel zone decreases. Therefore, the 5.8 GHz frequency band (the highest frequency listed) will have the smallest first Fresnel zone. The smaller the Fresnel zone, the less likely that obstacles like trees or buildings will cause destructive interference (multipath), which is a key advantage of operating at microwave frequencies.
This topic was automatically created to facilitate community discussion about this exam question. Feel free to share study tips, memory tricks, or additional explanations!