Gain of a patch antenna

[mickey123]

Dear all,

1. Is there a possibility of obtaining a negative gain even at resonant frequencies in a patch antenna? (Simulated in CST Microwave Studio)
2. What are the reasons?

Thanks in advance

 

[volker@muehlhaus]

Sure, if your dielectric is very lossy you will have nice directivity but negative gain.

 

[mickey123]

Thanks so much for the reply

FR4 is the substrate used. Is there a possibility of obtaining a positive gain by any other method other than by changing the dielectric?

Please help

 

[volker@muehlhaus]

No, patch antenna requires low loss substrate. What is your frequency?

 

[PlanarMetamaterials]

Dear all,

1. Is there a possibility of obtaining a negative gain even at resonant frequencies in a patch antenna? (Simulated in CST Microwave Studio)
2. What are the reasons?

Thanks in advance

The radiation efficiency is too low. As volker stated, it could be the dielectric, but it could also be your antenna is too small.

If this is realized gain, then it could also be that your feed is not well-matched to the antenna (poor S11).

 

[Azulykit]

Another possibility is that you are measuring a crossed polarization gain or not cutting through the beam peak. It is most likely that the match is really deficient and you have a lossy dielectric. Patch gains are generally in the 6 dBi range with a couple of dB variability depending on the specifics of the design (and ground plane size).

Regards,

Azulykit