My nrf24le1 cannot work farther than 0.5m :(

[Cao Jean]

I use nrf24le1 design a board, but it works abnormal when distance farther than 0.5m. This is my pcblayout,designed by ad14. Can someone help me to check is something wrong?antenna？ my_mouse2.zip

[FormerMember]

The reason for the short range is the that there is no ground plane in the layout. As you can see in the nRF24LE1 reference layout, there is a lot of ground, large ground planes. Ground is very important because it is the reference for the system (the antenna and the chip), among others:

• The impedance of the antenna should for instance be 50 Ohm, with respect to ground. Ground planes are needed to make sure that the ground is even across the board. In RF, the frequency is high and the wavelength short. Therefore, ground as a trace will act as an inductor for RF signals, and the ground will not be even across the board.
• The antenna, a quarter-wavelength monopole antenna, uses the ground plane to have the same characteristics as a dipole antenna (the ground plane will act as a mirror)

In addition, it could be worth checking the crystal, and its load capacitors. The value of the load capacitors can be calculated according to the formula in the "Crystal Oscillator Design Considerations" whitepaper.

Note: Apart from the missing ground layers, the layout looks good. Adding ground layers should make significant change in the range.

[FormerMember]

From your updated layout, there is no bottom ground layer under the RF part of the layout. I would think that that could be the reason for the short range. And also, yes, check the crystal load capacitors.