EMI issues in Mobile hnad phones

[egemini]

Hello,
What are the important parameters that are taken care in designing ,mobile phone PCBS , to avoid EMI related issues.
please share your views

 

[bschoo]

Some suggestions:

1. Use striplines whenever possible.
2. Keep clocks and other high-frequency signals at least
one-tenth of an inch away from I/O signals and connectors.
3. Route differential pairs together, so their lengths are
matched and any common-mode noise is cancelled out.
4. Watch out for high current traces, make sure they don't form loops (try to minimize) and are as short as possible.
5. Soften clock edges or high speed signals with series termination
6. Put decoupling caps at VCC pins of each components
7. Use shield can to cover area of high speed components

 

[egemini]

But we are facing problem with power amplifier, its ACPR is exceeding the limits. Any specific reason for this?