MILLIMETER-WAVE frequencies have long held the promise of generous bandwidths, if only the technology could be made more affordable. With that goal in mind, Thomas Zwick and researchers from the IGM Thomas J. Watson Research Center (Yorktown Heights, NY) set out to develop a broadband planar antenna for use in the 60-GHz Industrial-Scientific-Medical (ISM) band. Their design, which is suitable for integration with millimeter-wave transceiver integrated circuits (ICs), is printed on the bottom of a dielectric superstrate with a ground plane below, providing both wide bandwidth and high efficiency. It is fabricated on a planar printed-circuit board (PCB) which allows very-low-cost mass production.
The researchers developed a new antenna concept with a structure manufactured as a PCB in a dielectric substrate that can be flipped onto an IC or chip carrier. The ground of the IC package base also acts as the reflecting ground for the antenna. The superstrate has a material with low dielectric constant between the antenna and the ground plane and a higher dielectric constant material above the antenna structure.
The researchers tried two design approaches. The first involved a folded dipole with coplanar strip (CPS) feed and broadband balun. The second was a dual folded dipole array. Good agreement between computer simulations and measurements was found for both designs, with both approaches yielding better than 90-percent efficiency. See "Broadband Planar Superstrate Antenna for Integrated Millimeterwave Transceivers," IEEE Transactions on Antennas and Propagation, October 2006, Vol. 54, No. 10, p. 2790.