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

Antenna ground plane

Antenna ground plane

Antenna ground plane

I have a large d/sided pcb with microcontroller and 433M Rx/TX module attached. I want a PCB track antenna of 16cm length along one edge.Track width is 60 thou ( 1.5 mm) . Do I/must I have a ground plane underneath it? I know about keeping other stuff 5mm away. I have a VCC plane on the topside. Does this have to be kept 5mm away from the aerial track as well?

RE: Antenna ground plane

One small point, your Vcc plane should be effectively grounded at RF (via the bypass capacitors).

As to your larger question - perhaps someone here will have some recent hands-on experience.  My guess is that you would want to keep your antenna away from everything else (including parallel surface ground planes).

RE: Antenna ground plane

The simplest way to make a 433MHz antenna on a PCB is to construct it as a track, clear of the ground.  It's length will be shortend by the velocity factor of the PCB dielectric, ie by 1/sqrt(Er).  Er will be from 2.5 - 4.5 on common PCB materials, so you need to find out what yours is.  Eg if Er = 3.5, then Vf = 0.534 and the length of your antenna element will be 53.4% of it's free space length which for a lamda/4 element @ 433MHz = 93mm.

You can further shorten the antenna by capacitively loading the far end to ground but this will need some more serious maths or modelling to get right.

RE: Antenna ground plane

Thanks guys, very useful. Appreciated.

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