Colorado Springs, Colo. -- A startup chaired by the former CEO of Apple Computer and National Semiconductor, Gil Amelio, is demonstrating a steerable smart-antenna technology that can be implemented in very small microstrips on FR4, or even on single chips. Yet Pinyon Technology Inc. will stay out of direct design and manufacturing at either level.
Borrowing algorithms from the phased-array radar world, the Reno, Nev., company is showing how resonant-slot concepts can be used in giving microstrip-based antennas a typical gain of 13 dBi. Multislot versions have been developed for access points and basestations, and Pinyon has even designed a single-slot antenna for handheld client platforms.
Slot-resonance concepts have been around since the 1940s, used in applications such as aircraft waveguide implementations. Each radiating element, or slot, is designed to operate at one octave of bandwidth, with the next designed to be 180° out of phase.
The accidental discovery by Pinyon chief technology officer Forrest Brown is that resonant slots can be current-driven by embedded microstrips within FR4 board materials. In the Pinyon prototypes, slots are spaced over a quarter-wave apart in a phased array. The phased array is managed by an off-the-shelf microcontroller.
Brown, who has worked with TRW, Litton and NASA Goddard Space Flight Center, got together with former colleague Debashis Bagchi to commercialize the concept as Airwire, a low-cost, high-gain smart antenna. Bagchi previously served as CEO of residential-gateway manufacturer ShareGate Inc., and is taking the same role at Pinyon.
"This time, our model is an intellectual-property pure play," he said. "We will license the microstrip IP today. We have plans for reducing this to a semiconductor substrate, but we have no interest in being a fabless chip house. It will be a licensing strategy in the future, as well."
To validate its claims of improved throughput, Pinyon conducted tests near Taipei, Taiwan, pitting a 2-dBi standard Wi-Fi antenna in an outdoor environment against a Pinyon prototype. Using a single-element PC card antenna, average data throughput declined from nearly 25 Mbits/ second at 100 meters to 500 kbits/s at 350 meters. The Pinyon an- tenna achieved close to 35 Mbits/s at 100 meters and maintained speeds above 10 Mbits/s at 350 meters.
Pinyon has implemented three versions of its design: a 7 x 6-inch steerable antenna with gain above 10 dBi; a 3.5 x 6-inch steerable antenna with gain above 7 dBi; and a passive single-element 3 x 1-inch antenna for handhelds with a gain in excess of 5 dBi. The largest of the three has a total bill-of-materials cost of $1.46, including diodes, resistors, capacitors and printed-circuit board material costs. Its current consumption is less than 100 milliamps.
"The power, footprint and component-cost impact of adding the microstrip is truly negligible," Bagchi said. In the passive version, he said, the bill of materials is 25 cents, and the current prototype fits inside BlackBerry, Treo and similar handhelds.
Bagchi said that several access point manufacturers have batted about the term "beam forming" in describing MIMO designs for advanced Wi-Fi networks. In all existing cases, he said, the antennas are low-gain systems that are not electronically steerable like a true phased array. Pinyon hopes to convince many OEMs in the residential-gateway market to turn first-generation beam-forming systems into true beam-steering systems with higher gain and greater throughput.
In addition to the Wi-Fi and WiMax prototypes, Pinyon is developing antenna systems specific for RFID, 3G/4G, ultrawideband and Bluetooth markets. In many cases, the coupled microstrips can be integrated on the same chip as a power amp and low-noise amp, likely in a silicon germanium or gallium arsenide process.
"One of the reasons for staying away from chip implementation ourselves is to give the chip vendor and OEM the freedom to look at the RF implementations that make sense for their design," Bagchi said. "We will provide design assistance along with IP licensing."