Connect Photon to External Antenna+Power Amplifier/Low Noise Amplifier (LNA/PA)


I’ve made power amplifier(PA) and low noise amplifier (LNA) modules. Each module is on the different PCB. So there are two PCBs. Both of them works in 2.4 GHz that supports WLAN 802.11n. I want to test PA and LNA using photon development kit. So the hardware will looks like illustration below.

PA testing :Photon --> uFL-SMA connector --> PA module --> External Antenna
LNA testing : External Antenna --> LNA module --> SMA-uFL connector --> Photon

So, Can I connect photon to External Antenna with power amplifier module (PA)/ LNA module? Will it work? Thank you.

I think the P0 and P1 modules already have a PA and LNA circuitry in-built.

Not sure if your testing would work.

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thank you for the response @kennethlimcp.
Yeah, you are right that P0 module has LNA and PA circuitry in-built. They are inside the BCM43362. But if I add the external LNA/PA, will the system work fine? because I cannot find any other modules that doesn’t have LNA/PA circuitry in-built.

No, your circuits won’t work; the main issue is that you need to know whether the 43362 is transmitting or receiving at any given time to enable the PA (and LNA) at the right moment.

The 43362 does have pins that can signal these states; the RF_SW_CTRL_x pins. On the P0, they’re currently used for antenna diversity, but with the right magic in the nvram file (and sacrificing antenna diversity) you can reassign them to give active high, mutually exclusive, signals for receive enable and transmit enable.

The P1 doesn’t have these pins exposed, though.

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Thank you @hfiennes for the response.
Actually, what I only need is to demo my LNA and PA module. So if I can make sure when I demo the PA module, I set the photon to a trasnmitting state only (no receiving) and vice versa for the LNA module demo. So the system will work fine, won’t it?

WiFi doesn’t really work like that; the device generally won’t transmit without having got permission from the AP, which involves making a request and receiving a reply (there’s typically an RTS/CTS handshake). Whilst you can do this sort of stuff when the WiFi chip is in test mode, that’s not exactly easy to drive from the MCU on the module.

If you’re trying to demo a 2.4GHz PA/LNA, maybe you should use something a lot simpler like an nRF24L01 ?


Thank you @hfiennes. Your answers really help me a lot.