In the process of using HMC608, we found that the input voltage is 5V, VGG is - 2.6V, input 0dBm signal, output only 10dBm, is this normal? For the gain that 29DB does not achieve above?
This seems like it maybe operating in low gain mode. Do you have VPD grounded to configure it in high gain mode?
Another possibility is that Idd set too low. -2.6V maybe the typical gate voltage but due to process variation it might need higher VGG to set Idd = 310mA. Can you check Idd current without RF?
Are you testing this on our evaluation board? If not could you please share you schematic and your operating frequency?