user67471: I am working on pcb design with nrf24l01 smd. I have read somewhere that nrf24l01 module has problem while communication when it is placed with its antenna within the pcb. I want my module to be within the pcb as much as possible to save some space. I will be making the pcb at home and will be placing atmega 328p smd on the opposite layer. Should I fill the opposite layer with ground pad?

user4143: You need to keep the ground plane away from the antenna. The rest of the module doesn't care (and having a ground plane under it can help with unwanted EMI).
Here's a design I did recently for a customer with the same module in it. It's placed near the edge of the PCB with the ground plane cut out around the antenna:

That layout is actually set up for either the small SMD, the SMD with PA+LNB or the thorugh-hole version. The important thing is that there is a nice big exclusion zone in the ground plane where the antenna is.

67471: <p>I am working on pcb design with nrf24l01 smd. I have read somewhere that nrf24l01 module has problem while communication when it is placed with its antenna within the pcb. I want my module to be within the pcb as much as possible to save some space. I will be making the pcb at home and will be placing atmega 328p smd on the opposite layer. Should I fill the opposite layer with ground pad?</p>
 4143: <p>You need to keep the ground plane away from the antenna. The rest of the module doesn't care (and having a ground plane under it can help with unwanted EMI).</p>
<p>Here's a design I did recently for a customer with the same module in it. It's placed near the edge of the PCB with the ground plane cut out around the antenna:</p>
<p><a href="https://i.stack.imgur.com/jy7XF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jy7XF.png" alt="enter image description here" /></a></p>
<p>That layout is actually set up for either the small SMD, the SMD with PA+LNB or the thorugh-hole version. The important thing is that there is a nice big exclusion zone in the ground plane where the antenna is.</p>
