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

Isolation between patch antennas

Isolation between patch antennas

Isolation between patch antennas


I am trying to get maximum isolation between two 8 dBpatch antennas. I have tried using a metal plate but doesnt produce the desired effect.

Any other ways to maximize the isolation? Any Feedbacks will be appreciated


RE: Isolation between patch antennas

Disconnect one and bury it in your backyard. winky smile  Seriously, you'll need to provide more details.

One for transmit, one for receive? Both aimed in the same direction? Limited space? Application - RFID du jour?

RE: Isolation between patch antennas

I'd assume they are very close to each other. Crosspolarized is the best quick solution if they're close to each other.

If co-polarized is required, orient them similar to laying out two pencils on a desk in parallel with each other, one atop the other, and not end to end. Space them apart as far apart as possible on a flat metal ground plane (desk) and add a long metal rectangular box between the two antennas. The box will prevent current from going over top of it since the E-field will be shorted out and the currents will have to go to the ends of the box and back to your other antenna. Current will also reflect off the ground plane edge and go around this box too.

Good results require good crosspole purity for your patches. This gives you some basic improvement. As VE1BLL stated, more detail is required, like how much isolation do you need and do you have a spade shovel or a gardener to help dig. It's always good to have more info.

Standard isolation numbers would be -12 dB if they're closely spaced and if you use the added box arrangement I mentioned and it was say 1/2 wave wide x 4 wavelengths long, you'd probably jump to the -35 dB isolation range. Crosspole and closely spaced can provide -35 dB, but you'd need to finely orient the two and maybe add some sort of cross pole tune-me-out screw posts between them to even better tune each other out.

PS: Our company specializes in isolating two antennas very closely. We take the two antennas and and modify their nearfield polarization while maintaining good far field patterns to isolate them. I'm pretty sure we are the only ones to know how to do that. If that sounds like blatant advertising, sorry about the spam.

RE: Isolation between patch antennas

Sorry missed out quite a few details

One will be used as a receiver and the other as a transmitter. Both are horizontally polarized Operating frequency is 5.3 GHz both pointing in the same direction. trying to confine them within a area of 4 metre square.  

Each patch antenna is about 10 cm X 10 cm

RE: Isolation between patch antennas

And also I am trying to gain an isolation of about -60 dB or more if possible

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


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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