High impedance layer for CMOS on-chip antenna at millimeter waves

Abstract

The application of high impedance layer (HIL) in (Bi)CMOS millimeter wave on-chip antennas is studied. The HIL consists of grounded two-dimensional periodic dogbone-shaped elements that use a metal layer of the CMOS structure. Two different mechanisms that take advantage of the HIL in on-chip antenna design are investigated. First, we implant the HIL below the on-chip dipole antenna to act as an artificial magnetic conductor (AMC), which enhances the radiation of the dipole. We have obtained 1.2 dB realized gain for a dipole antenna placed above a 4×5 dogbone array at 90 GHz. The second use of the HIL is directly as a radiating antenna, without the need of the dipole antenna on top. In this case we have obtained -2dB accepted gain from a HIL made of 5×5 dogbone array, fed by two microstrip lines having 180° phase difference. The results are obtained by full-wave simulation.