Aperture coupled antenna for 122.5 GHz applications with off-chip parasitic patch

In this paper a SiGe BiCMOS seven metal layer backend process is used for fabricating a strip-line fed on-chip aperture. An off-chip parasitic patch is fed by electromagnetic coupling through the aperture and is realized on a LCP substrate. The off-chip substrate is directly glued to the silicon die by using a compatible LCP bondply material. The antenna is therefore completely shielded from the high permittivity silicon, which results in a high radiation efficiency and higher bandwidth compared to complete on-chip solutions. The antenna covers the 122.5 GHz ISM frequency band by achieving a realized gain of 3.57 dB. The simulated efficiency exceeds 50%.