Wireless Clock Distribution System Using an External Antenna

Abstract

A compact wireless clock distribution system with an external planar array antenna which can provide phase and amplitude distributions suitable for synchronizing circuits over a 35-mm diameter circular area at 3 GHz is proposed. The computer systems using this wireless clock distribution can have a comparable form factor as systems using a conventional clock network. The system is composed of a transmitter with an off-chip antenna, and multiple clock receivers with on-chip antennas distributed over an integrated circuit or over multiple ICs. The transmitter, which was fabricated in a 130-nm CMOS process, generates a 17-GHz clock signal which is periodically amplitude-modulated in order to initialize all of the receivers' clock dividers to the same clock phase. Besides increasing the synchronization area, this wireless approach effectively eliminates the dispersion problem in conventional clock networks. The experimental results presented show the feasibility and potential benefits of the wireless clock distribution system using an external antenna.