Dual-Mode Substrate Wave Cancellation in a 120 GHz 2 × 2 On-Chip Dipole Array

In this article we present the design of a 120 GHz 2
$\times $
2 dipole array in a 130 nm SiGe technology, which employs dual mode substrate wave cancellation to improve radiation efficiency and to avoid uncontrolled radiation from the chip edges. We show a systematic analysis of the involved dielectric slab modes TM
₀
and TE
₁
and their effects on the radiation pattern and efficiency. Based on this, the position and orientation of the array elements are derived for optimal cancellation of substrate waves and different feeding techniques are compared. The dipole array shows a measured realized gain of 1 dBi [including ground signal ground (GSG)-pad, Balun, and matching-capacitor, all on-chip], an
$S_{11}$
-bandwidth of 18 GHz, and a realized gain bandwidth of 16 GHz. Very good correlation between simulations and measurements is achieved through careful modeling of the probe effects. The presented results provide useful insight on the design of on-chip dipole arrays for future millimeter-wave applications in standard SiGe or CMOS technologies.