Antenna Ground Plane

There has been a lot of forum discussion about the antenna ground plane.

I found some literature from UBlox on the topic:
GPS Antennas: RF design considerations for u-blox GPS recievers (pdf)

And here is the datasheet on the antenna supplied with Reach:
Tallysman TW4721 (pdf)

What I got out of it is:

  • Our antenna is:

  • tuned for 1559 to 1606 Mhz

  • measures 38mm square (the ceramic patch is 25mm approximately)

  • Manufacturer recommended ground plane size:

  • Ublox: 50 to 70mm

  • Tallysman: 100mm (see post below)

  • However, the size of the ground plane changes the tuning of the frequency, so when considering frequency alone, I calculate:

  • 35mm is best for GPS or Galileo or QZSS

  • 48mm is best for GPS and Glonass and Galileo and QZSS and Beidou

  • 95mm is best for GPS and Glonass and Galileo and QZSS

  • very small for Beidou alone or Beidou and GPS/Galileo/QZSS (beyond the chart scale)

  • very large for Glonass alone (beyond the chart scale)

For reference, a chart of frequencies:

  • However, the size of the ground plane increases the gain of the antenna, so when considering gain alone, I calculate:

  • 100mm+ (the bigger, the better)

  • It seems that, except for Glonass, the needs of gain and frequency conflict. Also the thickness of our patch antenna also makes a difference to the gain, so I calculated the minimum ground plane size before gain drops off substantially:

  • if our ceramic patch antenna is 2mm thick, then 60mm minimum

  • if our ceramic patch antenna is 4mm thick, then 50mm minimum
    (How thick is our patch antenna? Anyone know?)

  • After considering all of that, I would think a good ground plane size would be:

  • 50mm-60mm for GPS or Galileo or QZSS

  • 60mm for GPS and Glonass and Galileo and QZSS and Beidou

  • maybe no ground plane for Beidou alone?

  • probably 100mm or bigger for Glonass alone

This leaves some questions unanswered (edit: some are answered now):

  • What material is best?
  • below, Tallysman says any RF reflective material: aluminum, copper, etc.
  • What thickness is best?
  • below, Tallysman says thickness doesn’t matter.
  • What shape is best?
  • I hear it doesn’t make much difference if round or square.
  • What about the edges?
  • I hear it is better if they are rolled down.
  • What to do with the antenna wire running over the ground plane?
  • below, Tallysman says route under the ground plane as close as possible.
  • Off topic, but what about using a radome to cover the antenna when left out in the weather?
  • I thought of a hemispherical cover which could snap on the ground plane like this thin plastic cup lid:

Please check my work and give your opinion, expertise, and especially links.


Very interested in replies to this. I jury rigged a ground plane out of a 70x70mm sheet of PET cut from some packaging and laminated on both side with copper foil tape. A bit Blue Peter but it seems to work OK. Still not worked out a base station gound plane and stand, quick test flight yesterday made it pretty clear getting the antenna up to a decent height off the ground is going to help…and that a taranis flight case is not much use as a ground plane…

Dumb question regarding material to use.

Would aluminum work as a ground plane?


Quoted from another reply:

So… I don’t see why aluminum wouldn’t work. :smiley:

1 Like

Nice catch kk6mrp! Thanks for the pointer! :slight_smile:

Not ideal size for sure, but this is what I am currently using:


Sweet. I have setup using aluminum 160mm square, antenna in the middle as well. Will start with that and see how it goes.

I am the Director of Sales and Marketing for Tallysman. We recommend a ground plane of 10cm. The ground plane should be symmetrical about the antenna and perfectly flat. The cable exiting the antenna should be routed under the ground plane as close to the housing of the antenna as possible.

It doesn’t matter if the ground plane is made from aluminum, copper, or any other metal. The important feature is that the material is an RF reflective material.

Thickness also doesn’t matter.


Thank you @Allen_Crawford for your recommendations.

  • Could you elaborate a little for us on why the larger size?
    (e.g. 100mm instead of 50-70mm)

  • Would the smaller size be better for GPS constellation (no Glonass)?

We have done simulations on various sizes of ground planes and have found that the ideal size is between 10cm and 12cm. Our recommendations are based upon these simulations. Of course, any sized ground plane improves the gain of the antenna element.


Does the TW2405/6/7/8 come with a case over the antenna? What is pictured in the product display appears to be bare.

Thanks for you assistance and input.

HI Tim,

thank-you for your interest. The TW2405/6/7/8 do NOT come with any enclosure. These antennas are intended for integration to customer’s products. These antennas are tuned high in anticipation of detuning by the environment of the antenna (ground plane and radome) The housed equivalent is the TW2410 or TW2412.


The only difference being the enclosure? Will check these as well.


Hi Allan, thank you for your contribution to this thread. I greatly appreciate hearing directly from Tallysman. I understand that any size ground plane is an improvement, but in the interest of optimization I have a couple of questions.

First, I see people creating square(ish) ground planes. This seems to violate the “symmetrical” principle you posted. (corners are farther away from the antenna than midpoints) Is a circular shape superior?

Second, there seems to be a variety of understandings regarding dimensions. You contributed “10cm to 12cm” as the ideal size. Is that a radius, diameter, edge length of square or distance from center to mid-point? Also, can you give us any idea what db gains can be expected from using this ground plane?


I was wondering if a CD covered in foil would work as a ground plane for the REACH stock antenna? A CD is nominally 120mm diameter.

Works just fine.

Hi! Please help!
I want install GPS patch antenna 25Ń…25Ń…4 in smartphone, bit it is unsufficient space, so i must schoose between several variants of ground plane.

  1. Symmetric but small ground plane, approx 45Ń…45 and antenna exactly in the center
  2. Non symmetric ground plane aprox 60x80, but antenna not in center, shifted along one of the axis (25 from one side and 55 from another)
  3. Symmmetric ground plane 65x65 but it wiil be a small hole 5mm (for camera). 20mm from the edge…

Wich of this variants are better?

May be the best variant it is a ground plane with full size of smartfone back cover (120x70) to completely isolate the antenna from the electronics of smartphone, but in this case antenna will be shifted along one of the axis (40 and 80 mm). and 5mm hole for camera,

Thanks in advance.

Another question is what effect will the GPS ground plane have on the reception of cellular/wifi/bluetooth antennas? Also, if the GPS antenna is on back of smartphone, then to use the smartphone and have best GPS reception, you must lay on your back and hold phone with the back facing the sky and the screen facing you. Otherwise if phone and GPS antenna are held vertically, then half the sky view is blocked and more disorienting multipath signals will be present for the visible satellites.

Definitely not a great choice for an RTK setup. It would be better to put the antenna on it’s own separate ground plane which can always point to the sky.

But what about simmetry of ground plane… is it important?
Which ground plane will be better - 55x55mm or 55x70mm?
I can’t install 70х70mm (there is not enough space).

10x10cm or minimum 10cm diameter should be sufficent size. Its the recommende minimum size.
Any size less then that could affect performance.