I want to use HMC 509 vco which has dual output i.e. RFout and RFout/2. I intend to use only RFout. So what to do with unused pin i.e. RFout/2 (in my case) ??
You could terminate this RFOUT/2 port in 50ohm impedance. This will ensure that you do not see Rf/2 harmonics on the RF output.