Antenna gain is negative

[Tianc]

What happens when the antenna gain is negative?
Why did the addition of reflective surfaces become negative?

Does anyone know?

[MODERATOR ACTION] : Translate title to English language

 

[volker@muehlhaus]

What happens when the antenna gain is negative?

This means the antenna radiation is lower than the reference antenna (isotropic radiator). One reason can be loss (dissipation) inside the antenna.

 

[Tianc]

This means the antenna radiation is lower than the reference antenna (isotropic radiator). One reason can be loss (dissipation) inside the antenna.

The antenna is above the EBG，the radiation pattern display that the backward radiation is decrease，but the gain is negative.The gain of antenna Without EBG is more than1dB

 

[volker@muehlhaus]

It is not possible to help you with such incomplete information. Can you show model and results (gain plot)?

 

[D.A.(Tony)Stewart]

On the log scale any attenuation <1 is negative.
By focusing waves to a smaller surface area from a sphere, allows power to be magnified with gain > 1 or positive.

Isotropic means equal in all directions out of a sphere = 1 = 0dB

 

[Tianc]

On the log scale any attenuation <1 is negative.
By focusing waves to a smaller surface area from a sphere, allows power to be magnified with gain > 1 or positive.

Isotropic means equal in all directions out of a sphere = 1 = 0dB

Sorry I don't understandso whats the reason when the gain is negative？Can you tell us about it？Thank you very much.

 

[D.A.(Tony)Stewart]

Sorry I don't understandso whats the reason when the gain is negative？Can you tell us about it？Thank you very much.

negative gain, Do you mean in terms of dB?
Linear inverting amplifiers are said to be negative from polarity inversion of gain.
- unity gain=1, is 0 dB since log 1=0 and any number less than 1 (and >0) is negative dB on a log scale .

Wikiwand - Logarithmic scale

A logarithmic scale is a method used to display numerical data that spans a broad range of values, especially when there are significant differences between the magnitudes of the numbers involved.

www.wikiwand.com

 

[Tianc]

negative gain, Do you mean in terms of dB?
Linear inverting amplifiers are said to be negative from polarity inversion of gain.
- unity gain=1, is 0 dB since log 1=0 and any number less than 1 (and >0) is negative dB on a log scale .

Wikiwand - Logarithmic scale

A logarithmic scale is a method used to display numerical data that spans a broad range of values, especially when there are significant differences between the magnitudes of the numbers involved.

www.wikiwand.com

Yes，dB，the peakdirectivity is also ＜1，I want the gain higher，but I don't know how to do

 

[D.A.(Tony)Stewart]

If your antenna has a peak directivity of less than 1 and you want to increase its gain, there are several design considerations that you can take into account. Here are a few suggestions:

1. Increase the size of the antenna: One way to increase the gain of an antenna is to increase its size. A larger antenna will have a larger aperture, which allows it to capture more of the incoming signal. However, increasing the size of the antenna may not be practical in all situations.
2. Use a higher frequency: Another way to increase the gain of an antenna is to use a higher frequency. Higher frequencies have shorter wavelengths, which means that the antenna can be made smaller and still be efficient. However, using a higher frequency may require specialized equipment and may be subject to regulatory restrictions.
3. Use a directional antenna: A directional antenna focuses its radiation pattern in a specific direction, which can increase its gain in that direction. There are many different types of directional antennas, such as Yagi-Uda antennas or parabolic reflector antennas, that can be used to achieve this.
4. Use antenna arrays: Antenna arrays are multiple antennas that are arranged in a specific pattern to increase the gain in a specific direction. By using multiple antennas, the array can create a combined radiation pattern that has a higher gain than any of the individual antennas.
5. Use advanced antenna design techniques: There are many advanced antenna design techniques, such as fractal antennas or metamaterial antennas, that can be used to increase the gain of an antenna. However, these techniques may require specialized knowledge and equipment.

It's important to note that designing an antenna can be a complex process that requires specialized knowledge and equipment. If you're not familiar with antenna design, it may be best to consult with a qualified engineer or seek out educational resources to learn more.

ref openAI chat.


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