PORTLAND, Ore. -- Wireless personal area networking (WPAN) got another boost today, when Motorola Labs (Tempe, Ariz.) announced that its joint-development agreement with Phiar Corp. (Boulder, Colo.) had succeeded in validating metal-insulator electronics as a viable alternative to semiconductors for millimeter wavelength 60-GHz WPAN devices. IBM recently announced a deal with Taiwan's MediaTek to supply chip sets for the IEEE 802.15.3c WPAN standard using IBM's silicon germanium (SiGe) BiCMOS radios. Motorola claims to be developing a rival 60-GHz radio sans semiconductors.
"Phiar's devices perform very well when compared with the benchmark devices we selected," said Rudy Emrick, manager of Millimeter Wave RF Technology at Motorola Labs. "And [it's] at a lower cost than our benchmark devices."
Cost is the main technical obstacle to creating 60-GHz WPANs. Off-the-shelf gallium arsenide and indium phosphide discrete devices are available today to create 60-GHz radios, but they drive the cost of WPAN devices up to more than $10,000. However, by switching to metal-insulator electronics--which can be fabricated on standard CMOS lines atop ultra-cheap plastic substrates--Motorola reports being able to drive the cost down to rival that of semiconductors. By way of comparison, IBM estimates that its SiGe BiCMOS 60-GHz radio chips will enable WPAN devices to be priced as low as $100.
The IEEE 802.15.3c WPAN standard is aimed at providing short-range wireless gigabyte data connections, so that all the interconnections among components in a single room can be wireless, including the transmission of high-definition (HD) video and high-speed file transfers that could sync an iPod in just a few seconds.
Motorola reports successfully building a prototype WPAN device, with Phiar diodes receiving the 60-GHz radio signal and stepping it down to a 2GHz to 3GHz signal using an inexpensive analog metal-insulator circuit. Phiar's ultra-inexpensive approach met or exceeded the performance specifications set by the IEEE standard. Bit error rates and minimum detectable power levels were all within Motorola's design specifications, giving its engineers a green light to start optimizing metal-insulator devices for future commercial WPAN products.
Metal-insulator electronics work by substituting a second layer of insulator and metal for the semiconductor found in metal-oxide semiconductors (MOS), ending up with a four-layer stack of metal-insulator-insulator-metal (MIIM). Phiar is keeping as a closely held trade-secret the specific two metals, and the insulators, that are used. The technique forms a quantum well between the insulators that only allows high-energy tunneling. Consequently, when a voltage is applied to the top metal that exceeds its threshold, a ballistic transport mechanism accelerates tunneling electrons across the gap.
Other companies developing millimeter wavelength 60-GHz WPAN chip sets besides Motorola and IBM include the Wireless HD Consortium (LG Electronics, Matsushita Electric Industrial Co.[Panasonic], NEC Corp., Samsung Electronics, SiBeam Inc., Sony and Toshiba); STMicroelectronics; Bridgeway Systems Inc.; and TeraBeam Inc.
In addition to 60-GHz antenna-edge frequency conversion, Phiar also claims to be developing metal-oxide electronics with other industrial partners for parallel flash solid-state hard drives, monolithic millimeter-wave radar, integrated terahertz detector arrays for safe "x-ray vision," and chip-to-chip radio-frequency interconnects.