Must Ground Plane Connect Directly Under Antenna?

[theboom]

In this proximity coupled antenna, is it necessary to solder a ground connection directly beneath the antenna? Or can the ground plane be connected to ground point elsewhere on the ground plane, far away from the antenna?

Assume the patch substrate and ground plane are several wavelengths larger than the patch.

 

[BradtheRad]

Don't know about the proximity antenna but general instructions advise running an earth wire from the radio chassis to metal plumbing fixtures, etc. Presumably pipes enter the soil. (Plastic plumbing has gotten popular over the years so who can be sure?) Thus the electrons come and go from somewhere even if at a distance.

And this may or may not be relevant: We've had portable radios in cars, in our pockets, on our desks... and they lack an earth connection. Seems like there must be a workaround in such cases. Or could it be the ground plane isn't all that crucial?

 

[theboom]

Don't know about the proximity antenna but general instructions advise running an earth wire from the radio chassis to metal plumbing fixtures, etc. Presumably pipes enter the soil. (Plastic plumbing has gotten popular over the years so who can be sure?) Thus the electrons come and go from somewhere even if at a distance.

And this may or may not be relevant: We've had portable radios in cars, in our pockets, on our desks... and they lack an earth connection. Seems like there must be a workaround in such cases. Or could it be the ground plane isn't all that crucial?

This is a mobile, battery-powered device. There's no earth ground.
Are you saying the ground plane isn't needed? Are you speaking from experience?

 

[Aussie Susan]

In this case I take it that the 'ground plane' is connected to the 'ground' of the circuit that is generating the RF.
Therefore it is (presumably) the same ground plane that you might put onto a layer of your PCB.
In general, the antenna needs "something" to work against that (somehow) needs to also be part of the same circuit.
(And before you start going on about long wire external antennas etc., they use the earth but, as @BradtheRad mentions, these typically are used by radios that have an external 'earth' connection.)
Susan

 

[BradtheRad]

This is a mobile, battery-powered device. There's no earth ground.
Are you saying the ground plane isn't needed? Are you speaking from experience?

I figured your question deserved some kind of answer even if it's based on my general understanding. My experience is from building a few primitive AM receiver circuits, and I find my unceasing effort goes into experimenting with different connections of tapped-inductor-capacitor-antenna.

It's all in a quest to optimize our antenna of course. Good fortune in your design.

 

[D.A.(Tony)Stewart]

A 0 V = Gnd plane is needed. This is not to be confused with PE Gnd.

Patch antenna - Wikipedia

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