A double-rhomboid bowtie-slot on-chip antenna aided by a back-to-back E-shaped electromagnetic bandgap (EBG) surface for gain enhancement at W-band is presented. The specific structure of both the antenna and the EBG surface is being reported for the first time in an on-chip implementation. The antenna is analyzed independently as well as backed by different electromagnetic bandgap reflective surfaces using standard 0.13 μ m BiCMOS process. The proposed EBG surface provides a measured gain enhancement of 2 and 8 dB when used as a frequency selective surface and as an artificial magnetic conductor, respectively. With an overall chip size of 1 ×1 mm2 , the on-chip antenna demonstrates a − 6 dB impedance bandwidth from 75–100 GHz and an effective gain bandwidth from 80–90 GHz with a peak measured gain of − 0.58 dBi at 84 GHz. The antenna has the smallest reported size and the highest gain in W-band with artificial magnetic conductor as reflective surface.