External 90º Hybrid for HMC525ALC4

Hi, I'm sorry if my question is too basic. I want to build FMCW radar with range 4-7GHz. Now I'm looking for the downconverter with the expected IF signal (LO-RF) is at 10-100 kHz. And I found HMC525ALC4.

But based on its datasheet, it mentions about external 90º Hybrid. Is it compulsory for me if I just need one IF port? What happen if I terminate one port with 50ohm dummy load and use another IF port directly without external 90º Hybrid?

Or, do you have any recommendation components either for the 90º Hybrid or the downconverter mixer?

Thanks,

Ghozali Hadi