Browse Topic: Radio frequency
In military and aerospace systems, thin film patterned substrates literally serve as the foundation of some of the most critical electronic assemblies, including radio frequency (RF), microwave, millimeter wave, and high-speed digital circuits. These substrates are typically made by depositing extremely thin layers of conductive and dielectric materials on bases built from materials like alumina, aluminum nitride, quartz, or certain high-performance titanates with various dielectric constants up to a k of 4,000.
A new transceiver invented by electrical engineers at the University of California, Irvine boosts radio frequencies into 140-gigahertz territory, unlocking data speeds that rival those of physical fiber-optic cables and laying the groundwork for a transition to 6G and FutureG data transmission protocols.
RF and fiber have long co-existed within modern military and aerospace systems, with each medium dedicated to separate, mission-critical roles. Increasingly, however, system designers are turning to RF-over-fiber (RFoF) architectures to bridge the gap between over-the-air RF interfaces and the long, interference-resistant transport advantages of fiber. When it comes to over-the-air communications uses like tactical radio or satellite communications terminals, radio frequency (RF) is still the dominant signal format. RF is also commonly used at the front end of radar and electronic warfare, supporting search, tracking, fire control radar, missile seekers, jammers and electronic support measures.
The Department of Defense (DoD) is developing technology for satellites to communicate via lasers. Laser communications could transmit data faster and more securely than traditional radio frequency communications. DoD has made progress in developing this technology, but it has also faced delays and other issues-and hasn't fully demonstrated that it works in space. Despite these challenges, DoD plans to continue to develop and launch hundreds of satellites worth billions of dollars that require the use of laser communications.
British soldiers have successfully trialed for the first time a game-changing weapon that can take down a swarm of drones using radio waves for less than the cost of a pack of mince pies.
Imagine you had a dedicated wireless channel for communication that was hundreds of times faster than the Wi-Fi we use today, with hundreds of times more bandwidth. That dream may not be far off thanks to the development of metasurfaces: tiny engineered sheets that can reflect and otherwise direct light in desired ways.
Deliberate RF jamming of drones has become one of the most common battlefield tactics in Ukraine. But what is jamming, how does it work and how can it be countered by unmanned aerial vehicles (UAVs) in the field? Radio frequency (RF) jamming of drones involves deliberate interference with the radio signals used for communication between drones and their operators.
Hypersonic platforms provide a challenge for flight test campaigns due to the application's flight profiles and environments. The hypersonic environment is generally classified as any speed above Mach 5, although there are finer distinctions, such as “high hypersonic” (between Mach 10 to 25) and “reentry” (above Mach 25). Hypersonic speeds are accompanied, in general, by a small shock standoff distance. As the Mach number increases, the entropy layer of the air around the platform changes rapidly, and there are accompanying vortical flows. Also, a significant amount of aerodynamic heating causes the air around the platform to disassociate and ionize. From a flight test perspective, this matters because the plasma and the ionization interfere with the radio frequency (RF) channels. This interference reduces the telemetry links' reliability and backup techniques must be employed to guarantee the reception of acquired data. Additionally, the flight test instrumentation (FTI) package needs to perform optimally in and capture the higher acceleration, temperature, and vibration measurements that the hypersonic vehicle experiences.
This document establishes methods to obtain, store, and access data about the health of a fiber optic network using commercially available inline optical power monitoring sensors. This document is intended for: Managers Engineers Technicians Contracting officers Third party maintenance agencies Quality assurance
Delivered by Team Hersa, a joint Defense Equipment & Support (DE&S) and Defense, Science and Technology Laboratory (DSTL) enterprise, the Radio Frequency Directed Energy Weapon (RFDEW) can detect, track and engage a range of threats across land, air and sea. The system uses radio waves to disrupt or damage critical electronic components inside enemy platforms, such as drones, causing them to stop in their tracks or fall out of the sky. As such, it offers a solution for the protection and defense of critical assets and bases.
Delivered by Team Hersa, a joint Defense Equipment & Support (DE&S) and Defense, Science and Technology Laboratory (DSTL) enterprise, the Radio Frequency Directed Energy Weapon (RFDEW) can detect, track and engage a range of threats across land, air and sea. The system uses radio waves to disrupt or damage critical electronic components inside enemy platforms, such as drones, causing them to stop in their tracks or fall out of the sky. As such, it offers a solution for the protection and defense of critical assets and bases. Capable of downing dangerous drone swarms with instant effect, at only 10p per shot, the RFDEW is a highly capable and cost-effective alternative to traditional missile-based air defense systems. It will be able to effect targets up to 1 km away, with further development in extending the range ongoing. Its high level of automation also means the system can be operated by a single person.
Riding aboard NASA's Psyche spacecraft, the agency's Deep Space Optical Communications technology demonstration continues to break records. While the asteroid-bound spacecraft doesn't rely on optical communications to send data, the new technology has proven that it's up to the task. After interfacing with the Psyche's radio frequency transmitter, the laser communications demo sent a copy of engineering data from over 140 million miles (226 million kilometers) away, 1. times the distance between Earth and the Sun. This achievement provides a glimpse into how spacecraft could use optical communications in the future, enabling higher-data-rate communications of complex scientific information as well as high-definition imagery and video in support of humanity's next giant leap: sending humans to Mars.
Modern cars and autonomous vehicles (AVs) use millimeter wave (mmWave) radio frequencies to enable self-driving or assisted driving features that ensure the safety of passengers and pedestrians. This connectivity, however, can also expose them to potential cyberattacks.
Riding aboard NASA’s Psyche spacecraft, the agency’s Deep Space Optical Communications technology demonstration continues to break records. While the asteroid-bound spacecraft doesn’t rely on optical communications to send data, the new technology has proven that it’s up to the task. After interfacing with the Psyche’s radio frequency transmitter, the laser communications demo sent a copy of engineering data from over 140 million miles (226 million kilometers) away, 1½ times the distance between Earth and the Sun.
The development of hypersonic missiles represents the most significant advancement of defense weaponry since the 1960s. However, they also pose unique challenges for both design and technology. The term “hypersonic” refers to any speed faster than five times the speed of sound, or above Mach 5. Modern hypersonic missile systems require extensive communications interconnects within a highly confined space. This space requirement creates a demand for solutions combining small form factor with reduced weight and rugged construction to withstand high vibration and impact conditions from deployment to target. Currently there are two types of hypersonic weapons. Hypersonic glide vehicles (HGVs), also known as boost-glide vehicles, typically launch from ballistic missiles and are released at a specific altitude, speed, and with the flight path tailored to a target without being powered. Hypersonic cruise missiles (HCMs) are powered all the way to their targets, flying at lower altitudes than HGVs and launched from rockets or jet aircraft. Power for HCMs comes from air-breathing scramjet engines, which have been in development since the 1950s and most successful since the 2000s.
Rydberg Technologies, an Ann Arbor, Michigan-based quantum technology startup, demonstrated the use of an atomic receiver for long-range RF applications during the NetModX23 event hosted by the U.S. Army Combat Capabilities Development Command (DEVCOM) C5ISR Center in December. The 2023 edition of NetModX featured 10 weeks of experimentation spanning 62 different technologies across 17 focus areas and five modernization priorities including “Future Vertical Lift, Long-Range Precision Fires, Network, Next Generation Combat Vehicle and Soldier Lethality,” according to the Army. A major goal sought by the C5ISR Center with NetModX is to take technologies that are nearing maturity from research labs directly into operational environments for assessments by active warfighters.
Traditionally, heterodyne architectures have been the preferred choice for radio frequency (RF) and millimeter-wave (mmWave) receiver architectures, excelling in noise performance, dynamic range, frequency coverage, selectivity, and reduction of EMI. However, recent advancements in high sample rate analog to digital converters (ADCs) and embedded signal processing have prompted a reassessment of both architectures. A thorough examination of the components in the channel design is essential to minimize distortion into the differential ports of the ADC, guaranteeing optimal signal integrity and dynamic bandwidth for the system. This article will overview the design approach as well as when to use a particular component type depending on performance and signal requirements.
Light fidelity (LiFi) technology holds immense potential to revolutionize wireless communication networks by utilizing light bulbs for reliable and cost-effective interconnections. Integration of LiFi technology with advanced solutions is proposed to significantly enhance the passenger experience in autonomous buses. The reliability and performance limitations inherent in traditional radio frequency (RF) technologies are addressed, resulting in a consistent and reliable wireless connection for self-driving cars. The proposed solution incorporates key features such as a LiFi-powered real-time tracking and notification system, on-board assistance for seat location, and precise bus seat occupancy information gathering. Additionally, the paper aims to improve punctuality through a LiFi-powered passenger boarding system, facilitating the widespread adoption of autonomous vehicles as a trusted and efficient mode of transportation. A thorough technical examination and a successful demonstration validate the practical applicability of the proposed solution, improving safety, convenience, and reliability in practical scenarios.
A team of University of Otago researchers and physicists have demonstrated a new form of antenna, developed with a small glass bulb containing an atomic vapor. The bulb was wired with laser beams and could therefore be placed far from any receiver electronics. Dr. Susi Otto, from the Dodd-Walls Centre for Photonic and Quantum Technologies, led the field testing of the portable atomic radio frequency sensor. Such sensors, that are enabled by atoms in a so-called Rydberg state, can provide superior performance over current antenna technologies as they are highly sensitive, have broad tunability, and small physical size, making them attractive for use in defense and communications.
More airports are starting to adopt and test the use of radio frequency (RF) mitigation techniques to counter the operation of unmanned aircraft systems (UAS) in violation of civilian airspace rules. While civilian aviation regulatory agencies are welcoming the integration of more commercially operated UAS into civilian airspace, airports are responding to the growing number of incidents in recent years with counter measures to ensure drones do not interfere with regular operations. In the U.S., the Federal Aviation Authority (FAA) now receives more than 100 reports per month from pilots that have observed UAS operating near airports or within a restricted area of civilian airspace. The problem is a unique one for the FAA and other civilian aviation regulatory agencies who want to unleash as much commercial UAS innovation as possible within civilian airspace, but simultaneously recognize rogue operators are a problem. The FAA's method for addressing the operation of drones near airports or in violation of civilian airspace rules is currently a loose collection of reactionary penalties or fines based on what occurred. But that is starting to change, and RF is one of several counter measures under evaluation at U.S. airports.
More airports are starting to adopt and test the use of radio frequency (RF) mitigation techniques to counter the operation of unmanned aircraft systems (UAS) in violation of civilian airspace rules. While civilian aviation regulatory agencies are welcoming the integration of more commercially operated UAS into civilian airspace, airports are responding to the growing number of incidents in recent years with counter measures to ensure drones do not interfere with regular operations.
It is hard to imagine an industry more reliant on seamless, resilient, and secure communication than aerospace and defense (A&D). Communication and electromagnetic signal processing are at the core of advanced systems, which is why the trend towards higher frequencies (and millimeter waves) makes optoelectronic signal transmission a critical topic in this sector as technology advances at a rapid pace and demands better performance. A&D communication networks use a mix of digital and analog transmission, with emphasis on the former, but given the industry's proclivity towards lower latency and higher bandwidth applications, analog transmission will play an even larger role in the future. Passive and active electromagnetic sensing (e.g., radar, radio telescopes, and other listening devices) requires high fidelity signal transport for “remote” processing. It brings transport of radio frequency signals over fiber (RFoF) to the forefront, which is an analog technique of converting radio frequency (RF) into light waves for secure, resilient, long-distance data/signal transmission.
The rapid advancement of military avionics technologies is revolutionizing the capabilities of next-generation aircraft. One of the common features of modern military avionics systems is the adoption of high-frequency and millimeter-wave (mmWave) communications to achieve higher data rates and enhanced resistance to interference.
Kongsberg Defence & Aerospace selected a radar test setup from Rohde & Schwarz based on the R&S SMW200A vector signal generator for multi-channel phase-coherent radar signal generation. Kongsberg is Norway's premier supplier of defense and aerospace-related technologies. The joint strike missile (JSM) is a fifth generation long range precision strike missile. Using advanced sensors, the JSM can locate targets based on their electronic signature. Qualification of the JSM is under way with the Royal Norwegian Air Force (RNoAF). Kongsberg's JSM must operate autonomously in highly contested environments. To increase mission success, the missile has a passive RF sensor that can locate and identify radio frequency emitters. To test and verify this RF direction finding capability in a laboratory, Kongsberg required a multi-channel phase coherent vector signal generator that could be linked to existing test environments.
Designing the next generation of RF systems, such as high performance active electronically scanned arrays (AESA), requires contributions from a multidisciplinary team of engineers. Customers within the Department of Defense (DoD) require performance beyond the current state of the art in order to stay ahead of adversaries' capabilities. As engineering teams work to meet these requirements, invariably, limitations in the available design, fabrication, and verification technologies consume the teams' budget for design flexibility, performance, and novel solutions. Ultimately, this leads to concessions in the design and puts the overall project at risk for cost and schedule overruns. Teams must consider the sources of error that drive down design margins and seek newer technologies to ensure projects meet performance and cost objectives on schedule. The process of going from ideation to simulated design to fabricated and measured prototype accrues errors at each step. Identifying technologies that can advance the design process while reducing such errors becomes more critical as the systems become more complex. Leveraging the latest advancements in RF simulation software is one such area that can reduce critical errors while also improving the timeliness of the design process (see Figure 1).
Printed radio frequency (RF) surface acoustic wave (SAW) sensor devices are a promising technology for providing highly reconfigurable, cost-effective, and multi-parameter sensing. A new method was developed to print high-fidelity, passive sensors for energy applications that can reduce the cost of monitoring critical power grid assets.
As commercial drone technology continues to expand, small unmanned aircraft systems (sUAS) are making it increasingly difficult to secure battlefields and military installations. In response to these challenges, Trust Automation has developed an innovative counter sUAS system to disrupt and defeat hostile unmanned aircraft system (UAS) threats at the field level. Called the Ghoul-Tool Attachable Transmitter (GAT), this compact, weapons-mountable system is the easiest way to field a jammer for UAS, providing command and control (C2), radio frequency (RF) and global positioning system (GPS) denial capabilities. Measuring just 6 inches long and 3.2 inches across and weighing less than a pound, it also supports mounting configurations on the side and bottom of small arms via a standard NATO accessory rail. A handheld grip also allows for standalone use.
This SAE Standard covers the measurement of voltage transient immunity and within the applicable frequency ranges, audio (AF) and radio frequency (RF) immunity, and conducted and radiated emissions. By reference, ISO 11452-3, ISO 11452-7, ISO 11452-8, ISO 11452-10, ISO 11452-11, ISO 11452-2, and the emissions portion of ISO 7637-2 are adopted in place of SAE J1113-24, SAE J1113-3, SAE J1113-22, SAE J1113-2, SAE J1113-28, SAE J1113-21, and SAE J1113-42, respectively. In the event that an amendment is made, or a new edition is published, the new ISO document shall become part of this standard 6 months after the publication of the ISO document. SAE reserves the right to identify exceptions to the published ISO document with the exceptions to be documented in SAE J1113-24, SAE J1113-3, SAE J1113-22, SAE J1113-2, SAE J1113-28, SAE J1113-21, and SAE J1113-42, respectively. By reference, IEC CISPR 25 is adopted as the standard for the measurement of component emissions. In the event that an amendment is made, or a new edition is published, the new IEC document shall become part of this standard 6 months after the publication of the IEC document. SAE reserves the right to identify exceptions to the published IEC document with the exceptions to be documented in SAE J1113-41. Emissions from intentional radiators are not controlled by this document. (See applicable appropriate regulatory documents.) The immunity of commercial mains powered equipment to over voltages and line transients is not covered by this document.
Software Defined Radios or SDRs are used in a wide variety of design requirements. This includes spectrum monitoring and analysis, control and management of a network of radios, and designing and deploying next-generation wireless communications systems. These capabilities can lend themselves to applications such as drone detection/control and deterrence, controlling the wideband spectrum for electronic warfare, secure communications and networking, massive MIMO testbeds, passive RADAR, signals intelligence, and much more. There are various solutions for these applications, but one of the most ubiquitous approaches is utilizing NI's Ettus Research brand of SDRs. We'll use these enclosures for many of our examples, but a similar approach could apply to all types of SDR or radio frequency (RF) communications devices. All types of engineers and specialists in the RF communications and control arena have done prototyping and analysis using these kinds of lab and controlled-environment commercial grade systems. A key challenge has been adapting the systems to a wider range of environments. This includes outdoor applications; deployments in land, sea, and airborne craft; colder or hotter environments, or other implementations where the units are exposed to shock/vibration or debris ingress (sand, dust, salt-fog, etc.).
As radio frequency (RF) and digital hardware have advanced over the years, radar capabilities have progressed to provide higher resolution, greater tracking ranges and higher frequency agility as well as data processing and electronic counter-countermeasures (ECCM) for protection. Technology advancements in RF, digital hardware, active electronically scanned arrays (AESA), synthetic aperture radar (SAR) and cognitive electronic warfare (cogEW) have necessitated advances in test and training systems.
As radio frequency (RF) and digital hardware have advanced over the years, radar capabilities have progressed to provide higher resolution, greater tracking ranges and higher frequency agility as well as data processing and electronic counter-countermeasures (ECCM) for protection. Technology advancements in RF, digital hardware, active electronically scanned arrays (AESA), synthetic aperture radar (SAR) and cognitive electronic warfare (cogEW) have necessitated advances in test and training systems.
This method is used to define the immunity of electric and electronic apparatus and equipment (products) to radiated electromagnetic (EM) energy. This method is based on injecting the calibrated radio frequency currents (voltages) into external conductors and/or internal circuits of the product under test, measuring the strength of the EM field generated by this product and evaluating its immunity to the external EM field on the basis of the data obtained. The method can be utilized only when it is physically possible to connect the injector to the conductors and/or circuits mentioned before. The method allows: Evaluating immunity of the product under test to external EM fields of the strength equal to a normalized one; Calculating the level of external EM field strength at which the given (including maximum permissible) induced currents or voltages are generated in the equipment under test, or solving the “opposite” task; Finding potentially “weak” points of the product design (housing, shield, etc.), through which EM energy can enter inside the product. The method capabilities mentioned above define the sphere of its application: Measurements of electronic product immunity to external EM fields at different conditions (polygons, laboratories, in-situ) as an alternative to direct test methods; Operating instruments for a designer working out the product of a given immunity to external EM fields. This method can’t be directly applied to evaluate the immunity of the equipment under test to the pulse electromagnetic fields. But it can be used to get the initial data necessary to solve this task.
This SAE Aerospace Information Report (AIR) considers the issue of proper design guidance for high voltage electrical systems used in aerospace applications. This document is focused on electrical discharge mechanisms including partial discharge and does not address personnel safety. Key areas of concern when using high voltage in aerospace applications are power conversion devices, electrical machines, connectors and cabling/wiring. The interaction between components and subsystems will be discussed. The AIR is intended for application to high voltage systems used in aerospace vehicles operating to a maximum altitude of 30000 m (approximately 100000 feet), and maximum operating voltages of below 1500 VRMS (AC)/1500 V peak (DC). These upper voltage limits have been incorporated because this report focuses on extending the operating voltage of non-propulsive electrical systems beyond that of existing aerospace systems. It is noted that electrical systems for electrical propulsion may consider operating voltages beyond 1500 VAC/DC.
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