Interference effects on integrated dipole antennas by a metal cover for an integrated circuit package

Abstract

To study the impact of the metal cover of IC packages on integrated antennas for wireless clock distribution, an on-wafer measurement set-up consisting of a probe station, a network analyzer, and a plate with adjustable height has been developed. For a typical spacing between the metal cover and IC of 1 to 2 mm, the impact on the antenna input impedance is negligible. A plate 1 mm above antennas on 20-/spl Omega/.cm substrates separated by 1 cm changes the phase of transmission gain by /spl sim/100 degrees. This is too large and should be accounted for in the design of a clock distribution system. The plate 1 mm above antennas also degrades gain by /spl sim/10 dB, which is a serious concern. If the plate height is higher than /spl sim/4.0 mm, the impact of the plate can be made negligible.