ADS Simulation of Half-Wave Rectifier
As @BrianDummond pointed out, Vf is way larger than your test voltage, the diode doesn't conduct at all.
Also the capacitance of the diode is maximum 2pF according to the datasheet for the BAS70, which corresponds to 33ohm@2.4GHz. In series with 10pF//50ohm, calculate the output voltage from that and you will probably figure out why you are seeing this amplitude at the output.