CC1120-CC1190EM868RD: CC1120-CC1190 for 865-867 MHz band

The suggested SAW filter looks good.

Note that the ref design is designed with two notches for 2. harmonic. For 865 MHz operation you should consider checking if you have to move the notches slightly down in frequency.

Hi TER,

Thanks for verifying the SAW filter.  

I do not know enough about RF circuit design to check if the 2nd harmonic for 865-867 MHz operation is being filtered out by the notch filters in the existing design.

Can you help with this so that I can avoid making a  second  PCB.

Also,  can you tell me why there are two notch filters instead of one ? 

Thanks

Kris

When developing this board I found that the radiated 2. harmonic is 10 - 20 dB higher than the conducted value. Therefore an extra notch was used to suppress the conducted harmonic to be able to pass EN300 220.

A different PCB layout will give different parasitics and to get optimal component values measurements has to be done on the actual PCB. If you don't have a VNA you can start with the component values in the ref design and increase one of the notch components with one value to see if the 2. harmonic decreases and the output power is still the same.

Hi  TER,

Thanks for the response. In the first para,  you added the extra notch to suppress the radiated harmonics  (instead of conducted harmonic) ?

Will try to experiment with the component values to see if the harmonics are diminished.

Thx

Kris