Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

More Near field or less?

More Near field or less?

More Near field or less?

Will a patch with very high er (80) bring the near field/far field boundary closer to the antenna by concentrating the radiated field more closely to itself?
Thank you  

RE: More Near field or less?

The near to far field boundary will be closer because the patch antenna will be physically smaller due to that high dielectric loading.

It's not a concentration due to dielectric that changes the answer to your question, it's just a physical difference in antenna size. Larger antennas have a longer distance inherently to the far field region.

Two antennas of the same physical size have the same near field/far field distance. That distance isn't simply 2d^2/Lambda either, it's much closer. All depends on what you plan to do.

d^2/Lambda has only 1/2 dB inaccuracy compared to 2d^2/Lambda for standard antennas being tested.

0.4d^2/Lambda distance from the antenna is typically the peak power density. Good to know if you are transmitting and worry about burning up a radome or human. i.e. if you make a large radome for a smaller transmit antenna, spacing it away from your antenna might burn it up if you put it 0.4d^2/Lambda away.


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close