The success of the militarys most complex systems can depend on the performance of the humblest of miniature devices and components, such as low-loss cable assemblies.
Microwave companies have struggled with the economy in 2009 as have most firms involved in designing and selling electronic products. But those involved with military markets have enjoyed far greater success this past year than their counterparts selling to commercial customers, due to the steady flow of business opportunities in the military electronics sector.
For RF/microwave companies, opportunities with military customers begin at the system level and flow down through the parts for those systems, such as devices and components, as well as the software to model performance and the test equipment to evaluate that performance. To seek military business, RF/microwave companies must keep track of the program needs of military customers such as the United States Army and Navy and, perhaps more important, the requirements of their prime contractors, such as Boeing, General Dynamics, Northrop Grumman, and Raytheon. In general, as the contracts of prime contractors and their major subcontractors go, so go the military business fortunes of the high-frequency industry.
At the military system level, technologies of interest to RF/microwave designers include communications, electronic warfare (EW), signal intelligence (SIGINT), and surveillance, which cuts across some quasi-military markets, such as Homeland Security. Boeing's involvement with the US Missile Defense Agency (MDA) has resulted in the completion of a second interceptor test silo for the Ground-based Midcourse Defense (GMD) system at Vandenberg Air Force Base. The GMD, which is an integral element of the US global ballistic missile defense system, consists of radars, other sensors, command-and-control facilities, communications terminals and a 20,000-mile fiber-optic communications network. The system is this country's only defense against long-range ballistic missile threats.
According to Norm Tew, Boeing Vice President and GMD Program Director, "Having this second test silo to launch interceptors will allow us to test upgrades to the GMD system more quickly, improving the MDA's ability to stay ahead of evolving threats." Because a silo needs to be refurbished after its hot-burning interceptor is fired, having two test silos will allow one to support testing while the other is being refurbished. The new silo also has the unique ability to be configured for testing or tactical operations, providing even greater flexibility. Vandenberg's first test silo has been used in tests since 2006 and will continue to support future flight test operations. The GMD program has deployed more than 20 systems at Vandenberg and in Alaska as part of the missile defense system.
Boeing and the MDA also recently demonstrated the capabilities of its Airborne Laser (ABL) aircraft in flight for the first time (Fig. 1). During the test, a modified Boeing 747-400F took off from Edwards Air Force Base and fired its high-energy laser while flying over the California High Desert. The laser was fired into an onboard calorimeter, which captured the beam and measured its power. Greg Hyslop, Vice President and General Manager of Boeing Missile Defense Systems, summarized that "This was a significant test of the Airborne Laser's capabilities, demonstrating that the system has truly moved from the drawing board to reality. ABL is ready for more flight tests to further validate its viability as a mobile missile defense system."
Boeing provided the battle management system for ABL and is the prime contractor. Northrop Grumman designed and built ABL's high-energy laser and Lockheed Martin developed the weapon system's beam control/fire control system. The advanced system is designed to provide unprecedented speed-of-light capability to destroy all classes of ballistic missiles in their boost phase of flight. In addition, Boeing is using internal investments to examine directed energy's potential to address several other critical missions, including defending against aircraft, cruise missiles and surface-to-air missiles.
Rockwell Collins, an early developer of software- defined-radio (SDR) technology for the military, revealed its progress in another area of interest to high-frequency companies: unmanned aerial vehicles (UAVs) and unmanned aircraft systems (UASs). The company's Athena 411 provides full-state vector for navigation, attitude, heading and air data, as well as autopilot and flight management system (FMS) control laws, with accuracy that is superior to traditional systems. The system integrates solid-state gyros and accelerometers, magnetometer, GPS receiver and air data sensors into a single small unit.
Recently, the contractor detailed a current project with Hawker Beechcraft Corporation (HBC) to explore and adapt advanced flight control technologies originally developed for UAS for future use in general aviation airplanes. As David Vos, Senior Director of Control Technologies for Rockwell Collins, explained: "This project with HBC shows what is possible by leveraging our UAS technology to potentially serve as a digital parachute in emergency situations. Advanced automation and sensing technology, such as the Rockwell Collins Athena 411 flight control system that was used on this project, can play a critical role in enhancing the safety operations of both manned and unmanned aircraft. This is especially important as we move toward a future airspace that integrates both platforms."
Further down the military electronics "food chain," the Enerdyne division of ViaSat Inc. has developed its EnerLinksIII Autotracking Antenna System (ETAS), a complete, high-performance ground station for video and ISR data links using the Ener- LinksIII Ground Modem Transceiver. It is designed for use at L-, S-, or C-band frequencies. With ETAS, the EnerLinksIII transceiver can provide a downlink line-of-sight range of at least 75 nautical miles at 11 Mb/s, and over 100 nautical miles range at 5 Mb/s. The complete ETAS system includes a 24-in. parabolic antenna, an omni-directional antenna, a radio interface module (RIM), a gimbal to point the antenna, a rugged tripod to support the equipment, and two transit cases for the antenna assembly and electronics. Steve Gardner, Enerdyne's General Manager, notes that "The combination of the autotracking antenna system with the EnerLinksIII digital data link is a totally integrated sensor to ISR display system," said "It provides our customers with a single point of contact for reliable data link system performance."
Recently, TiaLinx launched its Eagle60 (Fig. 2), a handheld precision target and motion-detection system with RF imaging that operates at V-band frequencies. Operating with less than 1 mW transmit power, the portable, battery-powered scanner is ideal for wireless network surveillance and motion tracking. The millimeter-wave system can be used to detect objects behind walls with better than 5-cm location resolution. It is ideal for locating unexploded ordnances and surveillance of objects of interest.
Development of the ultrawideband (UWB) scanner was made possible by SBIR phase II (W15QKN-08-C0247) and CPP awards from the US Army. According to Dr. Fred Mohamadi, Founder and CEO of TiaLinx, "The Army's awards have enabled development of the advanced Eagle60 system to further enhance the resolution of detected objects compared to the current generation of Eagle products. TiaLinx's highly integrated Eagle60 system is capable of detecting objects with a fraction of centimeter resolution. The Eagle60 system has also been used to demonstrate the real-time imaging of live object movement behind a wall. Its unique capability is being alpha-tested and will pave the road for further system integration to deliver the ultimate miniaturized handheld radar and RF Imager."
Cables and interconnects are often overlooked but vital parts in military electronic systems and MegaPhase, LLC recently celebrated shipping over 100,000 cables for use in jamming systems used to combat improvised explosive devices (IEDs) in Iraq and Afghanistan. The cables are installed in systems known as counter remote-controlled electronic warfare (CREW) platforms and help prevent detonations of roadside bombs common to those battlegrounds. The systems and their low-loss cables have made a difference in the war effort, according to William Pote, CEO and President of MegaPhase, "Our sense of urgency comes from knowing our cables are saving lives."
Another key component in many military electronic systems is the frequency source, using a stabilized oscillator or synthesizer. Teledyne Electronics & Communications recently introduced a line of single-loop synthesizers for use from 1.5 to 12.8 GHz with maximum bandwidths of 25 percent. The firm's 9700 models feature phase noise of -120 dBc/Hz offset 100 kHz from carriers to 3.2 GHz and -108 dBc/Hz offset 100 kHz from carriers to 12.8 GHz. The frequency synthesizers tune in 1-kHz steps and deliver typical output power of +12 dBm. The complete synthesizer assembly is constructed on two surface-mount boards, thus ensuring very low cost and repeatable quality and performance and are ideally suited for systems where low phase noise and spurious are essential. Applications include satellite communications (satcom) frequency converters, test and measurement equipment, point-to-point microwave radios, and military communications systems.
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Broadband YIG oscillators are also vital frequency sources in many military electronic systems. Micro Lambda Wireless, for example, supports the traditional EW bandwidth of 2 to 18 GHz with its model MLXB-0218 YIG oscillator in a 1.25-in. cube-shaped housing. It delivers +13 dBm output power over the bandwidth with tuning sensitivity of 18 MHz/mA. The phase noise is only -120 dBc/Hz offset 100 kHz from carriers of 2 to 12 GHz and -112 dBc/Hz offset 100 kHz from higher-frequency carriers. The compact YIG oscillator features an FM coil for modulation and provides a 3-dB FM bandwidth of 1 MHz with tuning sensitivity of 410 kHz/mA.
When precise fixed frequencies are needed, Bliley Technologies can now offer a subminiature oven-controlled crystal oscillator (OCXO) for portable commercial and military applications. The OCXO is only 0.355 in. high for use in through-hole and surface-mount applications. With only 10 s warm-up time and less than 0.4 W power consumption and less than 250 mA current consumption during warm-up, the tiny NVG79 series OCXOs can be specified at fixed frequencies from 20 kHz to 54 MHz. Sinewave and HCMOS-compatible outputs are available for use at voltages of +3.3, +5, and +12 VDC. Dennis Barrick, Bliley's Global Vice President of Marketing and Business Development, offers that "As commercial and government mobile communications needs continue to expand, Bliley has developed its NVG79 OCXO series to facilitate greater real-time information reliability and optimized data transmission."
In military systems, amplifiers are required to boost the levels of high-frequency signals while withstanding harsh environments. The model SM2560-47GN power amplifier from Stealth Microwave is designed for use from 2.5 to 6.0 GHz. It generates +47 dBm typical output power (50 W) from 2.5 to 6.0 GHz. Based on gallium nitride (GaN) device technology, the amplifier provides 45 dB linear gain with +/-2 dB gain flatness across the frequency range. It has an integral heat sink and features overvoltage protection and thermal protection with an automatic reset feature. The temperature-compensated amplifier maintains gain variations within 1 dB over a temperature range of -40 to +85C. Available as a module 7.50 x 3.97 x 0.79 in.) or in a rack-mount unit, the power amplifier draws 7 A from a +28-VDC supply.
Although associated with larger systems, major contractors are often involved with technologies at the most fundamental levels. Raytheon, for example, reported that its work on GaN semiconductors has shown the technology to deliver the reliability and efficiency needed for next-generation radar systems. Raytheon engineers have successfully demonstrated the reliable operation of a GaN monolithic microwave integrated circuit (MMIC) power amplifier (PA) operating for more than 1,000 hours with no measurable performance degradation. Pete Franklin, Vice President for Raytheon Integrated Defense Systems, explains that "This milestone enables us to insert GaN next-generation capability into a multitude of air and missile defense programs. GaN will also give the warfighter significantly more mobility, capability and reliability on the battlefield. Its ability to run more efficiently than other technologies will help solve many of our customers' logistical concerns."
For high power from a single device, the model MRF6VP3450H power transistor from Freescale Semiconductor is a 50-V silicon LDMOS field-effect transistor (FET) capable of 90 W average output power and 450 W peak envelope power (PEP) at UHF. The company also offers the 50-V model MRF6V14300H LDMOS device for L-band radar applications, with 330 W pulsed output power from 1200 to 1400 MHz.
In terms of innovative software for military systems, Future Facilities announced its 6SigmaET electronic cooling software for electronics thermal analysis. The 6SigmaET software solves the thermal conduction equations required to accurately simulate rotated or angled device geometries on printed circuit boards (PCBs) and higher levels. 6SigmaET also provides an updated user interface that greatly reduces learning time and also reduces the time required to perform nearly all basic modeling and reporting tasks. Advanced multigrid solver technology makes the solution process faster and more robust. The tool is part of the firm's 6SigmaDC software suite, which is the first thermal analysis software that addresses the complete design chain running from PCB design to rack-level systems.