I'm designing what is essentially a small beacon board built around an nRF51822. On the antenna outputs I've used the discrete component balanced to unbalanced circuit shows in the reference design, and I'm including pads for an additional shunt capacitor immediately after that circuit to allow tuning of the antenna. My question is that I am trying to include a resistive attenuation circuit (3 resistors in a "pie" network) to the design as well, and am unsure exactly where it should be placed. Hopefully the attenuation circuit won't be necessary and we can just populate the series resistor with a 0 ohm and move on, but I'd rather be prepared in case we need to set the transmission power lower then the radio can be configured to go.
Should the attenuation circuit go immediately after the balanced to unbalanced conversion circuit, followed by the calibration shunt capacitor? Or should the shunt capacitor follow the conversion circuit, and place the attenuation circuit at the front of the antenna trace. The first configuration makes more sense to me intuitively, but in the world of RF I've learned not to put too much trust in intuition.
Thanks!
