I am working on a medical sensor on which I have a cortex M SMT32 micro controller.
The micro controller is doing all the job and with it's deep sleep I can have a very low power consumption.
That being said, I need a low power, low bandwidth (1kb per minute), low range but high penetration (should be able to penetrate a medical ward wall) wireless solution.
At first, I tried an NRF54820 based bluetooth solution, but I had some issues:
- bluetooth is so damn complicated...
- the SDK and tools are very heavy, and a simple hello world program can be very hard to manage
- the 2.4Ghz band is just too crowded where I would need to deploy those devices
- penetration of the 2.4Ghz band can be problematic, even with thin walls
For this reason, I am looking for a simple transceiver, in the 826Mhz band, SIP based with a simple interface (UART can work but SIP often provides better performances which yield to less time awake and lower power).
So far I found the analog ADF7024.
It seems to be the perfect candidate, it has a 240Bytes buffer and a simple SIP interface.
Now I have two questions:
- Anybody has experience with what I am doing, is this a good solution/chip?
- I have never done antenna design (except for NFC), and I would like to use a PCB trace antenna if possible. I found many different design and vague schema, but no proper schematic with specifications. I also have no idea how to tune the RF matching network highlighted in the datasheet (below image). I have a tinyVNA which I used a few times for NFC antenna designs, but those only have a single tune capacitor, so it is very easy. I realize this is a broad question, but this forum has always been very informative.