GROUND plane or nor GROUND plane

[Bruce]

I always include a ground plane with the bottom layer solid copper, and each ground connection from the upper layer connected directly to the plane.

Attached is an example of an RF transmitter board. The lower layer is all copper connected to ground.

[xnihilo]

I see.
I have a ground plane on both top and bottom layer. Is that right or wrong, is there a reason why not have a ground plane also on the top layer?
I thought ground plane was used for reducing noise and acting as a heatsink.
I heard also about loops that can increase capacitance...?

[mackrackit]

I would avoid a ground plane on the top and bottom, you can make a capacitor if you have one on both sides of the PCB.

[aratti]

You can keep the ground plane on both sides providing that the electrical connection between the two grounds is done in one unique point.

Al.

[Bruce]

I've seen valid arguments for both, but it totally depends on what you have on the board,
and how you're connecting entry points to your ground plane.

In my own opinion, dual ground planes aren't necessary. Unless you're trying to save on the
cost of etching boards.

I've had over 40 boards FCC certified with only a single ground plane on the lower layer.

Edit: What AL said is good info. If you DO include a ground plane on both sides of your board
(make sure you have only 1 entry point from your power supply input) to both planes.

I.E. the ground from your power supply input connects to the entry point of the plane. There
should be NO ground traces to anywhere else on your PCB. Each IC should have a very short
trace directly to a "via" that connects directly to your ground plane. A 4-spoke thermal connection
point like the one in the attached graphic works extremely well - with single or dual planes.

[Ioannis]

To add something so you can be more dizzy now, if you do have Ground planes on both sides (especially at RF designs) then you MUST have vias all over the place! You can't have only a single point, though true for DC power supply, but for the RF case vias must be there at distances less than 10mm.

Ioannis

[Melanie]

I support Ioannis on this one... I put via's linking Ground planes on a 5mm grid spacing (at frequencies 50MHz to 2.5GHz) and at 3mm above that. Doesn't mean your circuit isn't going to work if you don't... just different approaches and points of view. You don't have to do this for your entire board... just the RF sections.