Can I use the local oscillator and intermediate frequency pins as inputs on an HMC220B RF mixer?

Question

My goal is to take an FM signal centered at 5.8 GHz and up-convert it to 6.5 GHz, amplify and transmit the signal, then down convert the received signal from 6.5 GHz to 5.8 GHz on the receiver side.

I was planning on using this HMC220B RF mixer normally with LO and RF as inputs and IF as output but I saw that the frequency range of the RF and LO pins is 5-12 GHz and the IF range is DC-4 GHz, which wouldn't allow my LO of 700 MHz and IF of 6.5 GHz. I also saw that all three pins are referred to as inputs in the data sheet.

I'm wondering if on the transmit side I can use the mixer with an IF input of 700 MHz and an LO input of the 5.8 GHz centered FM signal with a high pass filter on the RF output to get only the 6.5 GHz centered FM signal out of the RF pin, and on the receive side if I could use an IF input of 700 MHz and an LO input of the 6.5 GHz centered FM signal on the receive side with a low pass filter on the output to get only the 5.8 GHz centered FM signal.

Please take a look at the data sheet and let me know if I would be able to use this mixer in this way.

Answer 1

Yes. Re-assigning the ports to suit the frequencies in use is a standard practice with passive diode ring mixers.

You might consider a bandpass filter rather than a HPF on the transmitter to catch any harmonics.

You might also consider a bandpass filter on the input of your receiver to reject image frequencies. It would reduce the receiver sensitivity so it's a trade-off between sensitivity and unwanted signal rejection. If you need both you'll need an RF pre-amp.

(I'm assuming you have a legal right to transmit on 6.5 GHz.)