yellowtooth
Full Member level 3

We use the chip NRF24E1.
Now we have a problem of the impedance matching at the RF output port of ANT1 (pin 19) and ANT2 (pin20).
I wonder how to design the impedance match circuits (L1, C11, C12, C13) form ANT1 and ANT2 to the antenna.
For the datasheet of NRF24E1 does not have the impedance of the ANT1 and ANT2 at all.
I think the ANT1 and ANT2 are differential bi-directional port, and the antenna is a single ended port.
So the matching network (L1, C11, C12, C13) should be a balun.
Or it is just a matching network without balun function at all, and just put one port to the antenna and the other port to the ground.
Would you please tell me the detail of the network?
As we know, the shunt cap and the series cap make different direction on the smith chart.
Why place a shunt cap (C13) after a series cap (C11 or C12) ?
Thank U very much!
Now we have a problem of the impedance matching at the RF output port of ANT1 (pin 19) and ANT2 (pin20).
I wonder how to design the impedance match circuits (L1, C11, C12, C13) form ANT1 and ANT2 to the antenna.
For the datasheet of NRF24E1 does not have the impedance of the ANT1 and ANT2 at all.
I think the ANT1 and ANT2 are differential bi-directional port, and the antenna is a single ended port.
So the matching network (L1, C11, C12, C13) should be a balun.
Or it is just a matching network without balun function at all, and just put one port to the antenna and the other port to the ground.
Would you please tell me the detail of the network?
As we know, the shunt cap and the series cap make different direction on the smith chart.
Why place a shunt cap (C13) after a series cap (C11 or C12) ?
Thank U very much!