Sunday, April 1, 2007
Product Focus: Antennas
Smaller, lighter antennas are meeting the growing demand for broadband communications
New antenna and broadband technologies are bringing new capabilities and new scope to in-flight communications and entertainment systems.
Business travel used to mean putting some tasks on hold while in flight. Such disruptions theoretically became a thing of the past in 2005 with the adoption of Arinc 781, which sets the technology standard for next-generation airborne satellite communications equipment.
The installation of Arinc 781-compliant equipment, including antennas and appropriate newer generation receivers, will enable passengers and crew to access the Web, download files, talk on cell phones and enjoy live streaming video and audio.
Crew members, too, will benefit from the availability of increased data rates, as nearly real-time weather data will be streamed to the cockpit.
XM Satellite Radio and Sirius Satellite Radio are providing aviation weather data link services that offer "always-on" weather services.
XM and Sirius transmit data via the satellites that carry their radio content.
An aircraft needs a compatible receiver and an antenna that can be steered to the appropriate satellite in order to access the data. XM-approved antennas allow users to receive weather data and radio services via a single small antenna.
Up to eight radio and/or data receivers can be powered by a single antenna to access XM’s line of offerings.
"The ability to stay connected via the Internet or television while flying to Asia, boating off the coast of California or driving a Humvee on the road to Baghdad is phenomenal," said Raju Chandra, vice president of sales and marketing at Tecom Industries, Thousand Oaks, Calif.
"These new [antenna] technologies make this possible at a price point that allows mass adoption," Chandra said.
Broadband connectivity from anywhere at an affordable price is becoming a reality as the various communications service providers compete for customers and as antenna technology steps up to meet demand.
Inmarsat, one of the major players in the airborne communications market, this year will offer the new SwiftBroadband service via its three I-4 satellites.
These satellites, the first of which was launched in 2005, operate in the L-Band (1.5/1.6 GHz) and offer more capacity at higher data speeds.
A high-gain antenna that operates in the L-band will be necessary to access SwiftBroadband, as well as other broadband services.
"The antenna marketplace is benefiting from the demand for broadband communications in a number of market segments, including Inmarsat Satcom, Ku-band TV service and in-flight entertainment," Chandra said.
"Technologies that support broadband communications aboard commercial and private aircraft, such as phased arrays and low-profile positioning systems, are being integrated into sophisticated solutions to satisfy this appetite for uninterrupted access to high quality voice and data communication," Chandra said.
Arinc 781, Chandra said, is the result of a continuing push toward higher data rates over the L-band satellite network.
Tecom offers the HGA-2100 Satcom high-gain antenna, which is designed to meet Arinc 781 and SwiftBroadband specifications. All antenna manufacturers, Chandra said, are "rushing to complete" their Arinc 781 design offerings and certification processes in order to be the first to market.
Tecom’s HGA-2100 is a low-profile, high-gain antenna designed to fit most corporate aircraft.
The 22-pound, electronically steered phased array antenna also features an embedded steering unit. With no moving parts, it offers a high degree of reliability.
New Products Enter
CMC Electronics has introduced its SatLite High Gain Antenna system to support Inmarsat’s Aero-H, H+, Swift64 and SwiftBroadband satellite communications offerings.
It, too, is a low-profile, low-weight phased array antenna system designed to comply with Arinc 781.
The SatLite is comprised of two units, a high-gain antenna (HGA) and a diplexer/low noise amplifier. The high-gain antenna portion of the SatLite system contains an integral beam steering unit.
EMS Satcom, a division of EMS Technologies, Ottawa, Ontario, Canada, introduced its eNfusion AMT-3800 high-gain antenna system, which also meets Arinc 781 standards.
The unit is designed to fit smaller aircraft but is available as a light-weight solution for larger aircraft as well.
The possibility for streaming live television to airborne customers also exists via the Ku-band. Chandra says domestic and international aircraft passengers are demanding TV as well as broadband Internet connectivity.
"The key requirements are low-profile antennas, broadband frequency coverage accommodating various satellite frequency allocations, and continuous coverage over large swaths of the earth," Chandra says.
Military users are utilizing the Ku-band for Communications on the Move (COTM) capability via satellite networks. Tecom has a contract for a Ku-band antenna terminal that will allow two-way high data rate communications.
Chandra said this will enable applications "such as video uploads from the battlefield."
Joe Jahoda, chief technology officer at Sterling, Va.-based Astron Wireless Technologies, said broadband is the technology headlining the antenna market. But he said miniaturization is equally important.
Arinc 781 antennas, for instance, include only two units, while the previous Arinc 741 standard generally included three units. The smaller size equals smaller weight with resulting cost savings.
"Aircraft, helicopters and UAVs today require many antennas with limited real estate available," Jahoda said.
"Further, the close spacing of the antennas causes serious RFI/EMI problems. These problems can be greatly mitigated by combining the antenna frequency coverage into two or three antennas. Miniaturization allows the few antennas now required to be increasingly spaced."
Jahoda says while the cost of a new technology antenna may seem high, prices should come down as the units become more widely available.
There are cost savings on the installation end when fewer antennas are required, and there could be some savings with the fewer number of cables that are required.
Astron’s research and development efforts in recent years have yielded miniaturized antennas for communications and direction finding.
The firm dubbed its new technology "HESA" for high efficiency, sensitivity and accuracy. Jahoda says a major benefit of the HESA Platform technology is its "ability to co-locate multiple antennas and their associated electronics in a small package."
When it comes to selecting an antenna, beyond making certain the antenna can deliver what you want, Jahoda says it is important to consider the unit’s efficiency, its frequency band of coverage, size, RF coverage patterns and weight.
Additionally, proper location on the aircraft is critically important in order to maximize reception.
Kellie Griffin, marketing coordinator for New Berlin, Wis.-based Emteq, which provides RF coax cable assemblies for antennas, said additional consideration should be given to the cable.
"An antenna takes the RF currents and turns them into electromagnetic currents," Griffin said.
"If the power is too high, heating, arcing or sparking may happen within the antenna. If there is not enough power from the RF cable, the signal could be faulty in some way, or be unclear or not be transmitted and translated back to the RF by the receiver," Griffin said.
Jim Flansburg, sales manager for PM Research, Wellsville, N.Y., said protection for an antenna’s leading edge is important.
PM said it offers leading edge erosion protection products, including PM-T1 tape strips.
"A strip of the PM-T1 tape up front [on the antenna] will extend the life of the antenna for years," Flansburg said.
The tape offers optimal protection with minimal signal degradation, and, according to Flansburg, "about $1 worth of tape will protect equipment worth several hundred or more dollars from one painting to the next."
AeroAntenna Technology www.aeroantenna.com
Andrew Corp. www.andrew.com
Antenna Research Associates www.ara-inc.com
Arinc Inc. www.arinc.com
Astron Wireless Technologies www.astronwireless.com
BAE Systems www.baesystems.com
Ball Aerospace and Technologies www.ball.com/aerospace
Chelton Inc. www.cheltoninc.com
CMC Electronics www.cmcelectronics.ca
Comant Industries www.comant.com
Cubic Corp. www.cubic.com
Dayton-Granger Inc. www.daytongranger.com
EDO Corp. www.edocorp.com
EMS Technologies www.ems-t.com
Emteq Inc. www.emteq.com
Garmin International www.garmin.com
Harris Corp. www.harris.com
ITT Industries, Gilfillan www.gilfillan.itt.com
Jotron Electronics www.jotron.com
L-3 Communications www.l-3com.com
NovAtel Inc. www.novatel.com
PM Research www.papa-mike.com
Radiall Jerrik www.radiall.com
Radio Research Instrument Co. www.radiores.com
Rockwell Collins www.rockwellcollins.com
Saint Gobain www.saint-gobain.com
Sensor Systems www.sensorantennas.com
Starling Advanced Communications www.starling-com.com
Tecom Industries www.tecom-ind.com
Teledyne Controls www.teledyne-controls.com