A Single Antenna for Multiple Sub-GHz Receivers

Question

I am thinking about making an inexpensive LoRa geteway by combining eight single-channel RFM95W 915 MHz transceivers. These would just work as receivers, and I would have a 9th one working separately as a transmitter. The point is that these modules are available cheaply.

I am wondering if it's possible to connect all eight to a single antenna. The ninth (transmitter) would be on a separate antenna, so there would be two antennas. This question is similar but is concerned about MIMO, which is not the case for me. I have also seen this question, where a power divider is suggested.

However, I am not sure that a power divider is appropriate. I have not seen an eight-channel one in IC form. The first question I referenced mentioned doing a microstrip Wilkinson power divider, but I am not sure if this is feasible for 8 receivers.

Is what I am thinking about doing reasonable/feasible?

I also thought about just laying out nine PCB antennas or using 9 chip antennas. Would placing these side-by-side on the PCB be reasonable?

Answer 1

Using a Wilkinson divider will effect the sensitivity of your receivers by 9dB. you can add an LNA to compensate that.

If you use a narrowband chain you can match the receivers to the antenna, but I guess you want to use different frequency for each receiver, therefore a matching is difficult in that case.

Answer 2

There are generally three solutions to this problem:

1. A power divider - An ideal resistive power divider will give you 9 dB loss. Actual power divider will have losses closer to 12 dB. There are off the shelf connectorized products for this function.
2. RF Multiplexer - Basically, only one receiver will be active at any given time.
3. Use an antenna for each receiver (or group of receivers) to get both spatial and frequency diversity.