So, is it 1.6Mbps or 48x1.5=72Mbps?
The modulator/demodulator can be configurated/controlled by the FPGA,
but you need analog RF circuits. You need to be very careful with PCB
layouts. RF PCB layouts are very tricky.
First thing is to pick your encoding scheme. Manchester FM sounds
good, as suggested by other posters.
I still don't know the OP's requirement for data rate, it's still
ambiguous; however, I meant to use the FPGA as the 2nd stage down-
conversion and the demodulator both. The whole receiver (all COTS):
1) 5.8 GHz BPF
2) Mini-circuits mixer
3) Fixed L.O. (with amp)
4) IF amp (assume a 1st I.F of about 1.2 GHz)
5) IF filter (e.g. EPCOS) - don't use SAW unless triple-transit ok.
6) ~500 MSPS converter (with at least 1200 MHz BW)
7) FPGA: Cyclone 3, Spartan, Virtex5, etc ...
The above is for 72Mbits/s. If it's only 1.5 Mbps, then it can be a
lot simpler. Step 4,5,6 could be adapted for direct conversion, which
would be cheaper, but lower performance.
Frank