What advantage does surface-mount technology offer at RF compared to using through-hole components?
Why Surface-mount parts sit directly on the board pads with no wire leads passing through holes, so all three benefits apply at once. The tiny packages let a given circuit occupy less board area, which in turn shortens the traces between stages, and the absence of long leads removes the series lead inductance and stray pad-to-lead capacitance that degrade performance as frequency rises. At VHF, UHF and microwave, even a few nanohenries of lead inductance can detune a circuit, so SMT is the norm for modern RF design.
Watch out Each individual benefit listed is true on its own, so picking just the smaller area or just the shorter traces leaves out equally valid advantages; the parasitic reduction is actually the most important one at RF.
No leads means no lead inductance: SMT wins on size, trace length and parasitics all at once.