Hello everyone,
I'm actually interested in understanding the process/method for measuring antenna efficiency. Is there a straightforward method available to do it, or can we derive it from other measured parameters such as from measured gain, directivity or other ?
Thank you in advance !
Here's a comprehensive overview, covering key methods and considerations:
Understanding Antenna Efficiency:
- Definition: Antenna efficiency refers to the ratio of power radiated by an antenna to the total power delivered to it. It indicates how effectively an antenna converts electrical energy into radiated electromagnetic waves.
- Importance: High efficiency is crucial for maximizing signal strength, optimizing range, and minimizing power consumption in wireless systems.
Common Measurement Methods:
Factors to Consider When Choosing a Method:
- Antenna size and type: Wheeler cap method is suitable for small antennas, while other methods are better for larger or more complex antennas.
- Desired accuracy: Substitution and reverberation chamber methods generally offer higher accuracy than the Wheeler cap method.
- Available resources: Some methods require specialized facilities and equipment.
Additional Considerations:
- Measurement frequency: Efficiency can vary with frequency, so measurements should be performed across the intended operating range.
- Environmental factors: Temperature, humidity, and proximity to other objects can affect measurements.
- Calibration: Proper calibration of equipment is essential for accurate results.
Expertise and Guidance:
- Antenna efficiency measurements can be complex and require a good understanding of antenna theory and measurement techniques.
- It's often recommended to consult with experienced antenna engineers or testing facilities to ensure accurate and reliable results.
Do you really mean efficiency?
If you do, then most of the methods mentioned by Murtadha Shukur may work.
You need either to know the power you send to the antenna, and the total power radiated, or the power you send to the antenna and the power wasted, or the power wasted and the total power radiated.
It is very hard to measure the total power radiated. This requires accurate polar diagram measurement over a sphere around the antenna.
If you know the antenna pattern (directivity), and have another antenna with identical pattern, for which you know the efficiency, then you can compare the gain in any direction to get the efficiency. You can do the same if you are confident that you know what the antenna pattern is from calculations or simulation for a perfect, ideal, or lossless antenna or one for which you know the efficiency.
Usually it is necessary to measure the losses to get the efficiency. The losses include the loss due to S11, and loss in materials in the antenna. Losses in the antenna will all turn into heat, so could be measured using a calorimeter, but this would be difficult. The Wheeler cap is a good way to do this instead.
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