I am designing a pcb which has the module ublox neo 6m, instead of using the normal antenna I was looking to use a ceramic which should work with ublox.

I have got this: http://uk.farnell.com/johanson-technology/2450at43a100e/antenna-ceramic-2-45ghz/dp/1885498

But I am not sure how I wired the antenna to the module is correct.

enter image description here

And looking for a similar configuration I found this enter image description here

So in my case it is using a different antenna so I am not that adding a resistor and inductor will make the antenna working or I need to change the type of antenna. What I want is to keep the antenna as small as possible and on the the PCB board.

I followed the datasheet of the antenna to leave a NON GROUND plate around the antenna but still, after 20 minutes my GPS cant get a lock.

Any tips?

  • 2
    \$\begingroup\$ If that antenna is tuned to 2.45GHz it's a helluva long way off GPS frequencies. The listing says "Bandwidth : 100 MHz. Centre freq : 2.45 GHz". What makes you think it'll work for GPS? The same source lists 8 antennas on the right band (1.575GHz). \$\endgroup\$
    – user16324
    Oct 8, 2015 at 16:15
  • \$\begingroup\$ I see, I might have made a mistake on picking up the right antenna, but what about the inductor and resistor? is it needed for a integrated antenna? \$\endgroup\$
    – max246
    Oct 8, 2015 at 16:31
  • 1
    \$\begingroup\$ The inductor and resistor supply power to an "active antenna" or "LNB" which has a built in amplifier. You don't need them for a passive antenna. Your GPS module's databook should confirm that's what the "VCC_RF" pin is for. \$\endgroup\$
    – user16324
    Oct 8, 2015 at 16:34

1 Answer 1


According to the 2450AT43A100 Datasheet the area around the antenna needs to be free of ground plane (or other conductors) for a distance of about 5mm.

Also the antennas seem to be orientation dependant with a feed end and a radiating end.

The following advice is for the traditional square patch antennas and can be glossed over when looking at these LTCC mini antennas.

First I would look at pictures of other peoples implementations to get a feel. Then I would read the datasheet for the ceramic patch in question carefully and see if they have a reference layout, if the datasheet is a translation you may not be able to take all text advice literally, mistranslations do occur.

All the implementations I have seen have the patch mounted on a ground plane. It may be soldered, glued or stuck with double sided tape as required. The ground plane is usually on the top side of the PCB as this will give more predictable results than assuming it has to be behind a unknown pcb substrate dielectric. It is possible that the antenna is not supposed to make electrical contact with the ground plane for some reason, I think this unlikely but would not rule it out, in this case a tape or soldermask may be the correct remedy.

It is true that you should not have other unspecified ground below or next to the antenna or even dielectric materials adjacent or above the antenna unless specified in the datasheet, these may cause the antenna centre frequency to shift and cause problems with sensitivity.

You should not need to supply power to a passive patch and the power pins should probably be left floating so an antenna short detector is not triggered. There may be a current controlled antenna detector in some implementations and this will need to be turned off or a load resistor placed on the Vcc-RF pin.


  • \$\begingroup\$ Thanks, but probably what I have done wrong is to get the wrong frequency antenna as Brian said above. Will give a try to get another antenna an see if I made a stupid mistake \$\endgroup\$
    – max246
    Oct 8, 2015 at 16:32
  • \$\begingroup\$ Yes, I did see the freq spec of your part but it has been a long time since I made a note of the GPS freqs, @Brian is on the ball. \$\endgroup\$
    – KalleMP
    Oct 8, 2015 at 17:05

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.