I have an mBed Lora 915Mhz shield I attached to a Raspberry Pi. I had some questions about the feeder network. In the attached schematic. Why isn't a simple cap/inductor pair sufficient for an impedance match in this case? Also, they use a capacitor and inductor in series. Is this a resonant band pass filter? Then why is the resonant frequency 1.4Ghz (22pF/5.6nH) and not 915Mhz? I checked the BOM and half the components are DNP. I attached a spice simulation with the actual component values.
Here is the simulation with the resistor removed: