Antenna Gain

Visit http://www.swisswireless.org/wlan_calc_en.html

and go to the Antenna section. Observe the dynamics between the signal frequency, antenna diameter, and antenna gain of a parabolic antenna. 1. Next to frequency band, select 2.41-2.48 GHz. ?Next to antenna diameter in meters, type 0.5 (0.5 meters = 19.7 inches). The most common dish antenna ranges in size from 18 to 20 inches. ?Click D ? dB. What is the maximum theoretical antenna gain of a common dish antenna at the 2.4 GHz band? _________

?Next to frequency band, select 5.15-5.85 GHz. ?Next to antenna diameter in meters, type 0.5 (0.5 meters = 19.7 inches) ?Click D ? dB. What is the maximum theoretical antenna gain of a common dish antenna at the 5 GHz band? _________ Given the same-sized reflector, which signals, high-frequency, or low-frequency, can be more efficiently focused by a common dish antenna (i.e., result in a higher antenna gain)? INCLUDE YOUR ANSWERS in the Course Project PPT template for this module. 2. Next to frequency band, select 5.15-5.85 GHz. ?Next to antenna diameter in meters, type 25 (25 meters = 82 feet). Each of the 27 antennas of the very large array (VLA) radio telescope (one of the world's premier astronomical radio observatories in New Mexico) is 25 meters in diameter. Note that this telescope operate at a much higher frequency in real life. ?Click D ? dB. What is the maximum theoretical antenna gain of the dish antenna used in the VLA radio telescope in New Mexico at the 5 GHz band? ________ Given the same signal frequency, which dish antennas, large-sized or small-sized, are more efficient at focusing the signal (i.e., result in a higher antenna gain)? INCLUDE YOUR ANSWERS in the Course Project PPT template for this module.

1. What is the maximum theoretical antenna gain of a common dish antenna at the 2.4 GHz band? [4 points]

Answer:

2. What is the maximum theoretical antenna gain of a common dish antenna at the 5 GHz band? [4 points]

Answer:

3. Given the same sized reflector, which signals, high-frequency, or low-frequency, can be more efficiently focused by a common dish antenna (i.e., result in a higher antenna gain)? [5 points]

Answer:

4. What is the maximum theoretical antenna gain of the dish antenna used in the VLA radio telescopes in New Mexico at the 5 GHz band? [4 points]

Answer:

5. Given the same signal frequency, which dish antennas, large-sized or small-sized, are more efficient at focusing the signal (i.e., result in a higher antenna gain)? [5 points]

Free Space Path Loss

Visit http://www.swisswireless.org/wlan_calc_en.html and go to the Free space loss section. Observe the dynamics between the signal frequency, distance, and free space loss. 1.Next to the frequency band, select 2.41-2.48 GHz. ?Next to kilometers, type 0.1 (100 meters = 0.1 kilometers). ?Click dB ? km. What is the free space path loss in dB at the 2.4 GHz band? _____ ?Change the frequency band to 5.15-5.85 GHz. ?Next to kilometers, type 0.1 (100 meters = 0.1 kilometers). ?Click dB ? km. What is the free space path loss in dB at the 5 GHz band? _____

How does the free space path loss at a higher frequency (e.g., the 5 GHz band) compare with that at a lower frequency (e.g., the 2.4 GHz band)? INCLUDE YOUR ANSWERS in the Course Project PPT template for this module. 2. Next to the frequency band, select 2.41-2.48 GHz. ?Next to kilometers, type 0.02 (20 meters = 0.02 kilometers). ?Click dB ? km. What is the free space path loss in dB over 20 meters at the 2.4 GHz band? _______ ?Next to kilometers, type 0.04 (40 meters = 0.04 kilometers). ?Click dB ? km. What is the free space path loss in dB over 40 meters? _____ ?Next to kilometers, type 0.08 (80 meters = 0.08 kilometers). ?Click dB ? km. What is the free space path loss in dB over 80 meters? _____ When the distance doubles, how does free space path loss in dB change approximately? INCLUDE YOUR ANSWERS in the Course Project PPT template for this module. 3. The free space loss??? can be expressed as???= 20log?+20????+?, where C is a constant that depends on the units of frequency (Hz, KHz, MHz, or GHz) and the distance from the antenna. The distance may be expressed in meters, Km, or miles. Moreover, for a given frequency and a fixed set of units of distance, we may express the free- space loss??? as follows: ???= 20log?+?, where K = 20 log f + C Therefore, the change in the free space loss (Delta???) corresponding to a change from D1 to a larger distance D2 is Delta???= 20log?1?20log?2 , for any given frequency 4. Here are the basic operations of common logarithms (Log10(X) = Log(X) to the base 10). Zero Exponent Rule Log 1 = 0 (100 = 1) Product Rule Log (M*N) = Log M + Log N Quotient Rule Log (M/N) = Log M - Log N Power Rule LogMp = P*Log M Applying the quotient rule, the change in the free space loss (Delta???) corresponding to a change from D1 to a larger distance D2 is expressed as: Delta???= 20log (?1/? 2) , for any given frequency

5. Use a scientific calculator to calculate Delta??? for D1 = 20 meters and D2 = 40 meters. Delta???= ___________ Is your calculation approximately the same as the result from Part 2 Step 2?

1. What is the free space path loss in dB at the 2.4 GHz band? [4 points] Answer:

2. What is the free space path loss in dB at the 5 GHz band? [4 points] Answer:

3. How does the free space path loss at a higher frequency (e.g., the 5 GHz band) compare with that at a lower frequency (e.g., the 2.4 GHz band)? [5 points]

Answer:

4. What is the free space path loss in dB over 20 meters at the 2.4 GHz band? [4 points]

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5. What is the free space path loss in dB over 40 meters at the 2.4 GHz band? [4 points]

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6. What is the free space path loss in dB over 80 meters at the 2.4 GHz band? [4 points]

Answer:

7. When the distance doubles, how does free space path loss in dB change approximately? [5 points]

Answer:

8. Use a scientific calculator to calculate Delta

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