Please help! How to reduce the patch antenna beamwidth
I am trying to design a patch antenna with <=70deg beamwidth. Right now, I can get about 80deg beamwidth. I know that I can use the larger ground, very thick substrate, or very thick superstrate to reach the goal. However, I can not do these things due to the size limitation. What else can I do to reduce the beamwidth?
Best regards,
any suggestions? Appreciate your help!
select lower relative permittivity,of course you will reduce the efficiency also.
yes, I am using the very low permitivity material with low loss tangent.
Using different Er for substrate will affect the Frequency Bandwidth and not the Radiation Beamwidth.
One way to change slightly the Radiation Beamwidth is to use fringing shape at the edge of the patch, or fringing-shape for the ground-plane if this one is small (if it has the same dimension as the active element).
What about PBG around the patch. That will make the radiation pattern narrower, since the surface mode is suppressed.
vfone,
Thank you very much for your suggestion. I can't make changes to the ground since it is possible that the antenna is put on the metal top.
By the way, I think that the smaller Er requires larger antenna, i.e., larger ground plane, therefore higher direcitivty.
Added after 2 minutes:
rfmw,
Thank you for your suggestion. Unfortunately I can't use PBG, I have a very limited dimension requirement. The whole antenna can't be much larger than the patch size.