Browse Topic: Antennas
The U.S. Space Force (USSF) Space Systems Command (SSC) achieved a major milestone during a demonstration event in August, showcasing the Joint Antenna Marketplace (JAM) and successfully transferring the U.S. Naval Research Laboratory's (NRL) Transmit/Receive Enterprise (TREx) Service from a research and development project into an SSC operational prototype. During the demonstration, the team demonstrated the use of commercial antennas for real-time contacts between a Space Development Agency's (SDA) satellite operations center and their Tranche 0 satellites using JAM which leveraged the newly integrated TREx system.
Dangling from a weather balloon 80,000 feet above New Mexico, a pair of antennas sticks out from a Styrofoam cooler. From that height, the blackness of space presses against Earth’s blue skies. But the antennas are not captivated by the breathtaking view. Instead, they listen for signals that could make air travel safer.
The U.S. Space Force (USSF) Space Systems Command (SSC) achieved a major milestone during a demonstration event in August, showcasing the Joint Antenna Marketplace (JAM) and successfully transferring the U.S. Naval Research Laboratory’s (NRL) Transmit/Receive Enterprise (TREx) Service from a research and development project into an SSC operational prototype.
Reliable antenna performance is crucial for aircraft communication, navigation, and radar detection systems. However, an aircraft’s structure can detune the antenna input impedance and obstruct radiation, creating a range of potential problems from a low-quality experience for passengers who increasingly expect connectivity while in the air, to violating legal requirements around strict compliance standards. Determining appropriate antenna placement during the design phase can reduce risk of costly problems arising during physical testing stages.
Data security remains an issue of the utmost concern in contested environments. Mechanisms such as data encryption, beam-forming antennas, and frequency-hopping radio have emerged to mitigate some of the concerns in radio-frequency (RF) communications, but they do not remove all risk. Consequently, there is still a consistent appetite for alternative solutions. This paper presents a case for the use of the free-space optical (FSO) communications technology ImpLi-Fi as one such alternative. FSO communication is promising because of the ease with which the signal beam may be steered and limited, making detection and interception more difficult than with RF, and ImpLi-Fi in particular is desirable for its exceptional outdoor performance and ease of integration into existing light sources. The paper briefly illustrates the origins of the contested logistics (CL) problem and CL use cases for secure communication channels, before describing the ImpLi-Fi technology in some detail; exploring how its field deployment might look, including a telling example with a handheld transmitter device; and foretelling additional potential areas of application. Throughout the paper, ImpLi-Fi is shown to have remarkably high potential utility in contested logistics and beyond.
When an earthquake, flood, or other disaster strikes a region, existing communication infrastructure such as cell phone and radio towers are often damaged or destroyed. Restoring emergency communications as quickly as possible is vital for coordinating rescue and relief efforts.
Testing aircraft antennas is challenging since optimal tests are made after antenna installation. Aircraft are often taken to anechoic antenna test facilities which create long lead times, transportation hassle, and very high costs. Portable alternatives exist but often have compromised testing fidelity. Innovators at the NASA Glenn Research Center have developed the PLGRM system, which allows an installed antenna to be characterized in an aircraft hangar. All PLGRM components can be packed onto pallets, shipped, and easily operated.
Researchers from Stanford and the American University of Beirut have developed a lightweight, portable antenna that can communicate with satellites and devices on the ground, making it easier to coordinate rescue and relief efforts in disaster-prone areas. Stanford University, Stanford, California When an earthquake, flood, or other disaster strikes a region, existing communication infrastructure such as cell phone and radio towers are often damaged or destroyed. Restoring emergency communications as quickly as possible is vital for coordinating rescue and relief efforts. Researchers at Stanford University and the American University of Beirut (AUB) have developed a portable antenna that could be quickly deployed in disaster-prone areas or used to set up communications in underdeveloped regions. The antenna, described recently in Nature Communications, packs down to a small size and can easily shift between two configurations to communicate either with satellites or devices on the ground without using additional power.
Researchers at the University of Birmingham have developed a new type of high-performance “phase shifter” using a liquid gallium alloy — which varies the phase angle of microwave and millimeter-wave radio signals — for use in advanced phase array antenna systems.
Researchers have created electrostatic materials that function even with extremely weak ultrasound, heralding the era of permanent implantable electronic devices in biomedicine. Recent research explores implantable medical devices that operate wirelessly, yet finding a safe energy source and protective materials remains challenging. Presently, titanium (Ti) is used due to its biocompatibility and durability. However, radio waves cannot pass through this metal, necessitating a separate antenna for wireless power transmission. Consequently, this enlarges the device size, creating more discomfort for patients.
The traditional centralized random access (RA) and data transmission (DT) protocol used to transmit small-sized packets suffers from high signaling overhead and low channel utilization. To cope with that, this paper proposes a novel distributed queuing random access and data transmission protocol based on multiple-input multiple-output (MIMO) technology for intelligent aircraft scenarios. In the RA phase, the collided, successful, and idle states are redefined according to the degree of freedom (DOF) in MIMO to utilize the RA channel effectively. In the DT phase, the optimal number of simultaneously transmitted M2M devices in the data queue is derived by the number of base station’s antennas to enhance throughput and reduce signaling. Results reveal that the proposed protocol can not only improve the efficiency of RA but also increase the throughput and reduce the delay of DT with the aid of DoF in MIMO while reducing the signaling overhead.
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.
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.
Recent advances in the operation of advanced CMOS processes for extremely high-speed and high dynamic range analog-to-digital (ADC) and digital-to-analog (DAC) data converters has led to their use in directly sampling microwave and even millimeter wave signals. Typically, in these applications, minimal pre or post-conditioning stages separate the ADCs and DACs from the antenna or, for Active Electronically Steered Arrays (AESA) antenna elements. This results in an extremely compact and flexible system solution and this has enabled a generation of fully digital phased arrays that are capable of being dynamically reconfigured to perform a multitude of functions.
Recent advances in the operation of advanced CMOS processes for extremely high-speed and high dynamic range analog-to-digital (ADC) and digital-to-analog (DAC) data converters has led to their use in directly sampling microwave and even millimeter wave signals. Typically, in these applications, minimal pre or post-conditioning stages separate the ADCs and DACs from the antenna or, for Active Electronically Steered Arrays (AESA) antenna elements. This results in an extremely compact and flexible system solution and this has enabled a generation of fully digital phased arrays that are capable of being dynamically reconfigured to perform a multitude of functions.
A new paper on wireless connectivity from researchers at the lab of Dinesh Bharadia, an affiliate of the UC San Diego Qualcomm Institute (QI), introduces a new technique for increasing access to the 5G-and-beyond millimeter wave (mmWave) network.
Historically, patch antennas have been used for SmallSat communications. While new antenna technologies are in development, some are not optimized for size, mass, and performance — especially beyond low-Earth orbit (LEO). Engineers at NASA’s Marshall Space Flight Center identified the need for a small form factor antenna to provide high data rate communications for such missions.
Innovators at NASA Johnson Space Center have developed a quarter-wavelength RFID slot antenna that provides polarization diversity and employs dual resonances, but in a form factor that is much smaller than other RFID antennas that provide similar functionality.
Antennas are used in many industries and products where quality and reliability are crucial. Testing aircraft antennas is challenging since optimal tests are made after antenna installation. Aircraft are often taken to anechoic antenna test facilities which create long lead times, transportation hassle, and very high costs. This makes such testing cost-prohibitive for early R&D work. Portable alternatives exist but often have compromised testing fidelity. Innovators at the NASA Glenn Research Center have developed the PLGRM system, which allows an installed antenna to be characterized in an aircraft hangar. All PLGRM components can be packed onto pallets, shipped, and easily operated.
HUBER+SUHNER (Herisau, Switzerland) has developed the SENCITY Road MULTI antenna, which reportedly enables multiple onboard applications to be hosted in a single antenna. It was designed specifically for commercial vehicles, such as buses, trucks, ambulances, forest harvesters and agricultural machines. The company states that the antenna groups a number of required elements within one low-profile housing, with single-hole mounting and easy cabling feed-through. The company also claims that through the antenna, customers can deploy 4X4 MIMO wireless modules, including the latest cellular frequencies, as well as up to 8X8 MIMO for Wi-Fi applications. https://www.hubersuhner.com/en
Rohde & Schwarz's (Munich, Germany) R&S ATS1500C automotive radar test chamber now offers a new temperature test option and a new feed antenna. According to the company, these additional features enable temperature-controlled measurements in a wide range, as well as parallel access to both polarizations, increasing test efficiency and flexibility. The ARC-TEMP temperature test supports a range from −40 °C to +85 °C (−40° to 185° F). The heated or cooled air is provided by an external thermal air stream system that supplies the air to the temperature bubble mounted on the positioner. The new ARC-FX90 universal-feed antenna supports 60 GHz to 90 GHz and includes an orthomode transducer, which reportedly enables parallel access to vertical and horizontal polarizations. For more information, visit http://info.hotims.com/84487-400
Engineers have added a new capability to electronic microchips: flight. About the size of a grain of sand, the new flying microchip (microflier) does not have a motor or engine. Instead, it catches flight on the wind — much like a maple tree’s propeller seed — and spins like a helicopter through the air toward the ground. The microfliers also can be packed with ultra-miniaturized technology including sensors, power sources, antennas for wireless communication, and embedded memory to store data.
Automotive millimeter-wave radar is used extensively in vehicle active safety. The Radar Cross Section (RCS) is one of the main parameters used by the automotive radar system to detect and identify surrounding vehicles. The RCS describes the electromagnetic scattering properties of objects. This paper describes a method and equipment to measure the RCS. An automobile-grade radar is used to measure the RCS of typical vehicles. A representative distance between the radar and the vehicle was chosen based on the analysis of the RCS of passenger vehicles in different distances in the near field. A cost-effective rotating platform was developed to rotate the passenger vehicles for RCS measurement in different azimuth angles. The RCS generated by the rotating platform was analyzed and mitigated. The measurement system can record the synchronized azimuth angle and RCS measurement. Different radar types, antenna response variations, and waveforms are eliminated by a calibration method using standard reflectors with the known theoretical RCS. The RCS measurement results and scattering centers of the Volkswagen Polo using the described method and equipment are presented in this paper.
A novel approach was developed to improve communications range and allow for covert behavior using a team of robots for future multi-domain operations. Specifically, researchers demonstrated an approach for enabling targeted wireless communication by exploiting miniature antennas and coordination of intelligent ground robots, each of which has a mounted antenna.
The antennas number is increasing on-board rotorcraft and this trend is not ready to slow down regarding the growing need of connectivity. Rotorcrafts, especially the lightest ones will soon be saturated in antennas. This paper, without being exhaustive, presents some ways to tackle this fact, with the use of integrated antennas. Besides technical difficulties, the current certification constraints should be re-defined or at least adjusted.
Radars based ADAS solutions are growing at a substantial rate in the automotive market since they play a fundamental role in increasing passengers and pedestrian safety. To support radar designers in reducing time and design cost, to meet the stringent vehicle safety norms, to reduce risks about final installed radar performance etc., more effective and efficient industrial approach have to be devised both in terms of simulation (working at 77 GHz poses several numerical challenges) and testing. This paper presents IDS/Siemens PLM Software technical approach and CAE tools, based on a synergic use of high-fidelity simulation models and measurement set-up’s to support the whole design, optimization and verification cycle, starting from the stand-alone radar antenna performance up to on-car installed radar operational performance verification.
The US Army's Aviation Development Directorate (ADD) has successfully collaborated with its industry partners to reduce system parasitic weight for aviation platforms through multifunctional structures technology development. In short, this can be generalized as achieving weight savings by replacing the combination of aircraft structure and an independent, add-on mission enabler with a singular system that performs the functions of both structure and mission enabler. This extensive multifunctional technology development for aviation structural applications has yielded significant weight savings over parasitic designs. Technologies demonstrating this structural multifunctionality for weight reduction include integrally armored helicopter floor, lightweight integrally armored helicopter floor, lightning-protected structure, structural antenna aperture, helicopter empennage antenna structure, combat tempered aft fuselage, blast attenuating aircraft structure, and highly durable floor armor for rotorcraft. The significance of weight savings that can be enabled via multifunctional structures technology development is clear. One case study exercise indicates a platform-level mission enabler weight savings of 17.8%. This significance of weight savings is analogous to other studies showing synergistic benefits from technology integration at the technology and system (platform) level.
A single antenna can be used for both transmission and reception. To accomplish this, the transmission must be isolated from the reception. In Figure 1, a radio frequency (RF) circulator is connected right after the antenna. The three-port device separates the transmit path from the receive path. After the circulator, a system can be used to identify the frequency of different signals. Once the frequency has been found, a filter with the right pass-band frequency can be used to isolate signals from each other.
Vehicle electrical/electronic systems may be affected when immersed in an electromagnetic field generated by sources such as radio and TV broadcast stations, radar and communication sites, mobile transmitters, cellular phones, etc. This part of SAE J551 specifies off-vehicle radiated source test methods and procedures for testing passenger cars and commercial vehicles within a Reverberation Chamber. The method is used to evaluate the immunity of vehicle mounted electronic devices in the frequency range of 80 MHz to 2 GHz, with possible extensions 20 MHz to 10 GHz, depending upon chamber size and construction. Three methods for calibrating and applying electromagnetic fields are described in the document: 1) Mode Tuned Reverberation Chamber method, 2) Mode Stir (Standard) Reverberation Chamber method and 3) Mode Stir (Hybrid) Reverberation Chamber method. Optional pulse modulation testing at HIRF (High Intensity Radiated Fields) test levels, based upon currently known environmental threats, has been included in this revision of the standard. Each method has its advantages and disadvantages which are discussed in each individual test section. All methods have been proven to be effective at finding potential field issues at the vehicle level. SAE J551-1 specifies general definitions, practical use, and basic principles of the test procedure. Specific chamber characterization procedures, formulas and calibration procedures for the Mode Tuned and Mode Stir (Standard) methods can be found in SAE J1113-28 and J1113-27 respectively. Chamber characterization procedures for the Mode Stir (Hybrid) method are described in 6.3 of this document.
NASA Goddard Space Flight Center has developed a new radar approach that uses a single phased array antenna and a single-pass configuration to generate interferograms, known as Digital Beamforming Interferometry. A digital beamforming radar system allows the implementation of nonconventional radar techniques, known as Digital Beamforming Synthetic Aperture Radar Multimode Operation (DBSAR).
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