A 12-18 GHz fundamental resistive mixer is demonstrated using standard 0.13 μm CMOS technology. A Marchand Balun directly on lossy silicon substrate is integrated with the resistive mixer to generate equal-amplitude and out-of-phase signal for LO pumping. The size of the Ku-band Marchand balun only occupies 478 μm × 250 μm due to higher silicon dielectric constant. The measured conversion loss of the resistive mixer is around 22 dB under fIF=3 GHz and PLO= 6 dBm. The small required LO power reveals that the Marchand balun does not suffer serious loss from silicon substrate. The miniature technique makes passive components more compact and easier to be integrated with IC circuit design.