Browse Topic: Antennas

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Electromagnetic Interference Measurement Antennas; Calibration MethodARP958E (Current)9/1/2021
This SAE Aerospace Recommended Practice outlines a standardized and economical method for the checkout and calibration of electromagnetic interference measurement antennas. Its application is for use when measuring a source 1 m from the antenna in a shield room. This is the typical distance used in performing military EMC testing. The influence of the shield room on the measured field strength is not considered. This standard does not address the measurement of emissions from an unknown distributed source, yet it attempts to resemble reality by using another antenna, in the calibration method, that represents a distributed source. This document presents a technique to determine antenna factors for antennas used primarily in performing measurements in accordance with References 2.1 and 2.2. The purpose of Revision B was to include the calibration of other antennas, such as biconical, horn, monopole and small loop antennas that are also specified for use in these same references. Revision D includes a specific procedure for loop antennas that are separated by 1 m from the device under test. Revision E adds the inclusion of modern instrumentation, instruction on how to calibrate the hybrid antenna, and attempts to improve upon the clarity of this document for the user.
AE-4 Electromagnetic Compatibility (EMC) Committee
Atoms Can Receive Common Communications SignalsTBMG-359862/1/2020
A new type of sensor was developed that uses atoms to receive commonly used communications signals. Cesium atoms were used to receive digital bits (1s and 0s) in the most common communications format used in cellphones, Wi-Fi, and satellite TV. In this format, called phase shifting or phase modulation, radio signals or other electromagnetic waves are shifted relative to one another over time. The information (or data) is encoded in this modulation. The method works across a wide range of frequencies.
Virtually Optimizing Metasurface Topology with a Genetic AlgorithmTBMG-357641/1/2020
Often in engineering, we look to the natural world to find inspiration for new ways to approach our design problems. Whether we are taking inspiration from fluid flow around wings to inform a system for cooling devices, studying slug slime to invent better medical adhesives, or designing the nose of a bullet train to resemble the beak of a bird, nature holds the key to even the most elusive design solutions.
Sandia’s Nanoantennas Help Detectors See More Heat, Less NoiseTBMG-357611/1/2020
A team of researchers at Sandia National Laboratories has developed a nanoantenna-enabled detector that can boost the usable signal of a thermal infrared camera by up to three times and improve image quality by reducing dark current, a major component of image noise, by 10 to 100 times.
Wireless Sensor “Stickers” Track Physiological SignalsTBMG-358231/1/2020
Engineers have developed a way to detect physiological signals emanating from the skin with sticky sensors that beam wireless readings to a receiver clipped onto clothing. To demonstrate the wearable technology, the researchers stuck sensors to the wrist and abdomen of a test subject to monitor the person's pulse and respiration by detecting how their skin stretched and contracted with each heartbeat or breath. Likewise, stickers on the person's elbows and knees tracked arm and leg motions by gauging the minute tightening or relaxation of the skin each time the corresponding muscle flexed.
Method Produces Three-Dimensional, Curved ElectronicsTBMG-3545111/1/2019
Contact lenses that can monitor the wearer’s health and correct eyesight use embedded electronics. These, and other curved devices such as solar cells and electronics, could be manufactured using a new method called conformal additive stamp (CAS) printing.
Technique Locates Robots and Humans in GPS-Challenged EnvironmentsTBMG-3527810/1/2019
An algorithm enables localization of humans and robots in areas where GPS is unavailable. The Army needs to be able to localize agents operating in physically complex, unknown, and infrastructure-poor environments. This capability is critical to help find dismounted soldiers and for humans and robotic agents to team together effectively.
Structure Deformation Calculation Program for Structural Shape MonitoringTBMG-3528910/1/2019
Researchers at NASA’s Armstrong Flight Research Center are pioneering shape-sensing technologies that seek to maximize structural integrity and efficiency. A new and versatile computer program offers critical shape-monitoring capabilities and has applications for a wide variety of structures.
Shape-Shifting Origami Could Help Antenna Systems Adapt On-the-FlyTBMG-351079/1/2019
Conventional reconfigurable electrical and radio frequency (RF) structures commonly used in applications involving real-time reconfigurability in response to fast varying operational scenarios require specialized substrates or complex electrical circuits. Origami-based RF reconfigurable components and modules offer a solution with unique properties. First, they enable re-configurability over continuous-state ranges (as opposed to discrete states). Second, they do not require specialized mechanical support for multilayer frequency-selective surface structures. Moreover, deployable origami-based RF structures can achieve large surface re-configurability ratios from folded to unfolded states. Finally, these structures allow for independent control of multiple figures of merit: bandwidth, frequency of operation, and angle of incidence.
Multi- and Wide-Band Single-Feed Patch AntennaTBMG-351309/1/2019
A novel patch antenna technology was developed that provides significant benefits to NASA satellite communication applications, offering a unique wide-band/multi-band operating capability. For other non-space applications, the antenna design also offers broadband capability with high gain for applications where signal strength and smaller antenna sizes are important. The technology was developed to design antennas for satellites where the target communication frequency is unknown or unassigned.
Antenna Near-Field Probe Station ScannerTBMG-351349/1/2019
Antenna characterization techniques are often expensive and time-consuming. NASA’s Glenn Research Center developed a highly versatile and automated system to perform characterization of single or multiple small circuit antennas, printed on-wafer or on other substrates, by measuring the antenna’s near-field radiated power.
Technology Produces Unclonable Digital Fingerprints for Internet of Things DevicesTBMG-349328/1/2019
Researchers have created technology that is 10 times more reliable than current methods of producing unclonable digital fingerprints that can be used to authenticate devices linked to the Internet of Things (IoT).
Products of Tomorrow: July 2019TBMG-347577/1/2019
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
Multi-Agent RF Propagation SimulatorTBMG-345316/1/2019
A desirable interface between multi-agents is through over-the-air RF connections that include not only the intended direct RF communications paths but also highly variable multi-ray propagation, range attenuation, external RF influences, and near-earth influence. These influences are all difficult to predict, control, and repeat in an outdoor environment. This outdoor testing, as has traditionally been done, is extremely expensive while simultaneously providing fewer data points than more controlled events and the testing events are generally not repeatable.
Affordable integrated Antennas on HelicoptersF-0075-2019-145505/13/2019
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.
DUTRUC, Herve, Filias, François-Xavier
Wireless Sensor Monitors Blood Flow after SurgeryTBMG-339973/1/2019
A new device developed by Stanford University researchers could make it easier for doctors to monitor the success of blood vessel surgery. The sensor, detailed in a paper published in Nature Biomedical Engineering, monitors the flow of blood through an artery. It is biodegradable, battery-free, and wireless, so it is compact and doesn't need to be removed, and it can warn a patient's doctor if there is a blockage.
Hardware Design of a High Dynamic Range Radio Frequency (RF) Harmonic Measurement System19AERP02_052/1/2019
Radio frequency (RF) circuit elements that are traditionally considered to be linear frequently exhibit nonlinear properties that affect the intended operation of many other RF systems. Devices such as RF connectors, antennas, attenuators, resistors, and dissimilar metal junctions generate nonlinear distortion that degrades primary RF system performance. The communications industry is greatly affected by these unintended and unexpected nonlinear distortions. The high transmit power and tight channel spacing of the communication channel makes communications very susceptible to nonlinear distortion. To minimize nonlinear distortion in RF systems, specialized circuits are required to measure the low-level nonlinear distortions created from traditionally linear devices, i.e., connectors, cables, antennas, etc. Measuring the low-level nonlinear distortion is a difficult problem. The measurement system requires the use of high-power probe signals and the capability to measure very weak nonlinear distortions. Measuring the weak nonlinear distortion becomes increasingly difficult in the presence of higher-power probe signals, as the high-power probe signal generates distortion products in the measurement system.
Hardware Design of a High Dynamic Range Radio Frequency (RF) Harmonic Measurement SystemTBMG-337622/1/2019
Radio frequency (RF) circuit elements that are traditionally considered to be linear frequently exhibit nonlinear properties that affect the intended operation of many other RF systems. Devices such as RF connectors, antennas, attenuators, resistors, and dissimilar metal junctions generate nonlinear distortion that degrades primary RF system performance. The communications industry is greatly affected by these unintended and unexpected nonlinear distortions. The high transmit power and tight channel spacing of the communication channel makes communications very susceptible to nonlinear distortion.
Miniaturizing Smart Wearables for Fitness and Activity TrackingTBMG-337292/1/2019
Traditionally, small chip antennas used in Bluetooth-enabled devices have required a designated ground “keep out” area to minimize interference from other components and ensure the ideal radiation pattern for wireless signals. In some cases, this reserved space can eat up as much as 15 × 20 mm of the printed circuit board (PCB).
Ricocheting Radio Waves Monitor the Tiniest MovementsTBMG-336131/1/2019
Infrared motion detectors can cover only a limited amount of space, a person has to be within the detector's line of sight to be detected, and lights can go off when a person remains still for too long. Work has demonstrated that patterns made by radio waves can detect a person's presence and location anywhere inside a room. A new motion sensor based on metamaterials is sensitive enough to monitor a person's breathing.
5 Ws of Spray-On AntennasTBMG-3340112/1/2018
Manufacturers and users of wearables, functional fabrics, mobile devices, wireless routers, and Internet of Things devices.
2018 Create the Future Design Contest: Electronics/Sensors/IOT Category WinnerTBMG-3331311/1/2018
Soft, Pliable, 3D Stretchable ElectronicsTBMG-3312010/1/2018
By stacking and connecting layers of stretchable circuits on top of one another, soft, pliable 3D stretchable electronics were fabricated that can pack a lot of functions while staying thin and small in size.
Merging Antenna and Electronics Boosts Energy and Spectrum Efficiency18AERP09_069/1/2018
By integrating the design of antennas and electronics, researchers from the Georgia Institute of Technology have boosted the energy and spectrum efficiency for a new class of millimeter-wave transmitters, allowing improved modulation and reduced generation of waste heat. The new co-design technique - achieved through research sponsored by the U.S. Army Research Laboratory and Intel Corp. - allows simultaneous optimization of the millimeter-wave antennas and electronics. The hybrid devices use conventional materials and integrated circuit (IC) technology, meaning no changes would be required to manufacture and package them. The co-design scheme allows fabrication of multiple transmitters and receivers on the same IC chip or the same package, potentially enabling multiple-input-multiple-output (MIMO) systems as well as boosting data rates and link diversity.
Toon, John
Merging Antenna and Electronics Boosts Energy and Spectrum EfficiencyTBMG-329109/1/2018
By integrating the design of antennas and electronics, researchers from the Georgia Institute of Technology have boosted the energy and spectrum efficiency for a new class of millimeter-wave transmitters, allowing improved modulation and reduced generation of waste heat.
Tech Briefs: September 201818AERP099/1/2018
Enhanced SATCOMs for Unmanned Aerial Systems The Bus Too Tough to Die Combating Infrared Threats on the Battlefield Optical Interconnect Design Challenges in Space High-Performance Computing for the Next-Generation Combat Vehicle Merging Antenna and Electronics Boosts Energy and Spectrum Efficiency Integrated Magneto-Optical Devices for On-Chip Photonic Systems Development of magneto-optical (MO) materials could lead to a range of nonreciprocal optical devices for emerging standardized photonic integrated circuit (PIC) fabrication processes. Low Power Optical Phase Array Using Graphene on Silicon Photonics Electrostatic doping of 2D materials embedded in waveguides could enable ultrafast devices with unprecedented power. Spatial Resolution and Contrast of a Focused Diffractive Plenoptic Camera New technology captures spectral and spatial information of a scene in one snapshot while raising pixel counts and improving image quality. Ultracompact, High-Speed Field-Effect Optical Modulators Conductive oxides-based modulator devices could provide promising candidates for ultra-compact and ultra-fast optical interconnects in future integrated photonic circuits.
Structural Multifunctionality for Weight ReductionF-0074-2018-128835/14/2018
ABSTRACT 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.
Robeson, Mark
Cup Cylindrical Waveguide AntennaTBMG-287084/1/2018
NASA Glenn’s cup cylindrical waveguide antenna (CCWA) is a short backfire microwave antenna capable of simultaneously supporting the transmission or reception of two distinct signals having opposite circular polarizations. Short backfire antennas are widely used in mobile satellite communications, tracking, telemetry, and wireless local area networks because of their compactness and excellent radiation characteristics.
Remote Detection of Electronic DevicesTBMG-285593/1/2018
Non-Linear Junction Detection is a well-known technique for detecting electronics that utilize semiconductor (solid-state) junctions. The current state of the art for finding hidden electronics — such as electronic eavesdropping devices — using this technology has a maximum range of about 2 m, and more typically between 6 and 12”.
Laser Direct Structuring for Sensor ManufacturingTBMG-283622/1/2018
Every day the world’s leading medical device companies rely upon laser direct structuring (LDS) to meet their most demanding design and performance requirements. Millions of electronic components with complex geometries are cost-effectively manufactured each year through the use of LDS to create circuit traces on three-dimensional molded interconnect devices (3D-MID).
3D-Printed Objects Connect to WiFi Without ElectronicsTBMG-281651/1/2018
CAD models have been developed that enable objects to be 3D-printed out of commercially available plastics; these objects can wirelessly communicate with other smart devices, including a battery-free slider that controls music volume, a button that automatically places an order with Amazon, or a water sensor that sends an alarm to a smartphone when it detects a leak.
Printable Structures Self-Fold Without Heating or Immersion in WaterTBMG-281581/1/2018
As 3D printing has become a mainstream technology, studies have investigated printable structures that will fold themselves into useful three-dimensional shapes when heated or immersed in water. A new printable structure, however, was developed that begins to fold itself up as soon as it is peeled off the printing platform.
Products of Tomorrow: December 2017TBMG-2800712/1/2017
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
Wideband RetroreflectorTBMG-272247/1/2017
There are many known methods of retransmitting radio wave signals intra-building and inter-building, as well as ground-to-aircraft or ground-to-satellite. Some techniques modulate the reflection coefficient of an antenna. Prior art has used frequency multiplication or field effect transistor (FET) mixing to modulate the reflection coefficient of an antenna, and therefore the reflected amount of incident power to perform this function. This method is limited by its instantaneous bandwidth to about 50 MHz and its overall efficiency, in addition to the tendency to produce large amounts of harmonics. Other techniques include optical retroreflectors and RFID transponders. Optical retroreflectors reflect the illuminating energy; RFID transponders use a fixed RF frequency with resonant circuits.
Digital Beamforming InterferometryTBMG-270246/1/2017
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).
Cellular Reflectarray Antenna and Method of Making SameTBMG-268625/1/2017
NASA's Glenn Research Center invites companies to license a new concept design for terrestrial satellite dishes and communications systems. The Cellular Reflectarray Antenna (CRA) has been developed and tested for use with next-generation Ka-band satellites, although it can be used with all bands of satellite communication. The design's flat, planar configuration all but eliminates the wind-loading problems associated with larger parabolic reflectors for dish systems. The technology also offers unique features that provide ease of installation and improved signal reception, while deterring piracy and theft of subscription satellite services.
Negative Dielectric Constant Material Based on Ion Conducting MaterialsTBMG-266564/1/2017
NASA Langley Research Center has developed a novel negative dielectric constant material based on ion-conducting materials. A negative dielectric constant material is an essential key for creating metamaterials, or artificial negative index materials (NIMs). NIMs have generated great attention due to their unique and exotic electromagnetic properties, and could be used for unique optical and microwave applications, including new methods of electromagnetic cloaking and extremely lowloss communications.
Prediction Method for Automobile EMI Test Result in AM Frequency Band *CSP Meta QA Testing*2017-01-00143/28/2017
The EMI, electromagnetic interference, is tested for automobiles and components by the method defined in the international standard, CISPR 25. Regarding the automobile test, the EMI from the component installed in the automobile is measured by the antenna of an automobile. On the other hand on the component test, the EMI from the component is measured by a mono-pole antenna set forward of the component. However, components sometimes fail the automobile test even if its passed the component test due to the difference of the method. In this case, the component has to be designed again to pass the automobile test. Therefore, the prediction method of the automobile test result is required. In this paper, we tried to modify the standard component test configuration to predict the automobile test result for a fuel pump system in AM frequency band. At first, to show the noise propagation mechanism of the automobile test, the mechanism was modeled by an electrical circuit by focusing on the parasitic capacitances between the fuel pump system, the antenna and the chassis. Next, to realize the same electrical circuit as the automobile, the standard component test configuration was modified. For example, in the standard component test, the fuel pump should be set on the grounded ground plane. On the other hand, in the modified component test, the fuel pump was set between the floor and floating ground plane. As the result, the modified component test result agreed with the automobile test result, meaning automobile test result could be predicted.
Nomura, Takashi, Kawai, Kazuma
3D Automotive Millimeter-Wave Radar with Two-Dimensional Electronic Scanning2017-01-00473/28/2017
The radar-based advanced driver assistance systems (ADAS) like autonomous emergency braking (AEB) and forward collision warning (FCW) can reduce accidents, so as to make vehicles, drivers and pedestrians safer. For active safety, automotive millimeter-wave radar is an indispensable role in the automotive environmental sensing system since it can work effectively regardless of the bad weather while the camera fails. One crucial task of the automotive radar is to detect and distinguish some objects close to each other precisely with the increasingly complex of the road condition. Nowadays almost all the automotive radar products work in bidimensional area where just the range and azimuth can be measured. However, sometimes in their field of view it is not easy for them to differentiate some objects, like the car, the manhole covers and the guide board, when they align with each other in vertical direction. In other words, those objects are counted as one erroneously because of absence of height information. In practice, road conditions are complicated and unpredictable, these unexpected mistakes will make the ADAS poor performance or even collapse, e.g. unwanted abrupt brake due to the detected manhole cover or guide board. Plus, the subsequent target tracking would be made an arduous task and with untrusted output. This paper proposes an automotive radar architecture with two-dimensional electronic scanning, which can obtain 3D information--range, azimuth and height. Four antennas including one transmitting antenna and three receiving antennas are used in this scheme. In addition to two conventional receiving antennas placed in horizon, another receiving antenna is arranged in vertical aligning with one of the other two to obtain the height information so that the corresponding detected targets can be distinguished clearly. Furthermore, when more antennas utilized this architecture can be extended easily for higher autonomous driving requirements. A range of simulation indicates that this radar architecture can measure object height and the effectiveness of proposed architecture is further verified in actual experiments on the corresponding radar prototype. It is low-cost and with small size, and the car grade design and development make the further application in ADAS possible.
Bai, Jie, CHEN, Sihan, Cui, Hua, Bi, Xin, Huang, Libo
Design of a 5.9 GHz High Directivity Planar Antenna Using Topology Optimization for V2V Applications2017-01-16913/28/2017
A low profile high directivity antenna is designed to operate at 5.9 GHz for Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communications to ensure connectivity in different propagation channels. Patch antennas are still an ongoing topic of interest due to their advantages: low profile, low cost, and ease of fabrication. One disadvantage of the patch antenna is low directivity which results in low range performance. In this paper, we introduce an efficient and novel way to improve the directivity of patch antenna using topology optimization and design of experiments (DoE). Numerical simulations are done using Method of Moments (MoM) technique in the commercially available tool, FEKO. We use global response surface method (GRSM) for double objectives topology optimization. Numerical results show a promising use of topology optimization and DoE techniques for the systematic design of high directivity of low profile single element patch antennas. The optimized directivity is 10.4 dBi, which is 3 dB higher than the directivity of the original patch antenna.
Elfrgani, Aseim, Reddy, C. J.
A Multi-Function Automotive MM-Wave Radar Design2016-01-18959/14/2016
A 24GHz multi-function assist system has been developed for advanced automotive radar, which includes different applications in Blind Spot Detection (BSD), Lane Change Assist (LCA), Doors Open Warning (DOW) and Rear Cross Traffic Alert (RCTA). The multi-function radar is based on the micro-strip antenna, which has a reasonable design on main-lobe and side-lobes. According the antenna, the radar can operate in mid-range mode with a high gain and a narrow beam width, whilst performing well in short-range and wide-angle mode.
Bi, Xin, Ma, Zheng, Wang, Wei, Du, Jinsong
Integrated Circuit for Radio Astronomy Correlators Supporting Large Arrays of AntennasTBMG-248276/1/2016
Radio telescopes that employ arrays of many antennas are in operation, and ever-larger ones are being designed and proposed. Signals from the antennas are combined by cross-correlation. While the cost of most components of the telescope is proportional to the number of antennas, N, the cost and power consumption of cross-correlation are proportional to N2, and dominate at sufficiently large N. As radio telescopes get larger, there is a need to provide digital-signal-processing electronics that are smaller and less power-hungry than would be implied by the extrapolation of existing designs.
Dual-Use Structures: Composite Wing with Structural Antenna ApertureF-0072-2016-115525/17/2016
Many modern aircraft, including rotorcraft, require conformal antennas and fairings to reduce wind drag, ice accretion, lightning strikes, and impact damage. An innovative composite wing configuration with a structural Ultra High Frequency (UHF) antenna window "aperture" has been developed. The wing is based on variants of lightweight X-Cor® sandwich core technology for durability and damage tolerance, with tailored electromagnetic properties in the aperture region of the wing. This paper presents a brief introduction to helicopter wings, a summary of recent research at Boeing and Army leading to this design, and the development approach used for this project. Structural and electromagnetic analyses are provided, and measurement results of an early prototype are summarized. The emphasis of this paper is on the wing configuration details surrounding the antenna aperture. The approach can be replicated on almost any current or future aircraft or rotorcraft.
Tyrell, Stacey, Robeson, Mark, Kube, Courtney, McCarthy, Dennis, Lavin, Ronald
Architecture for an Intermediate-Frequency Digital Downconversion and Data Distribution NetworkTBMG-245445/1/2016
NASA’s Deep Space Network (DSN) is looking to modernize aging downlink receivers for telemetry, tracking, and radio science. It is looking to replace multiple types of custom-built, special-purpose receivers with a unified receiver architecture that can support the various downlink data types. As part of this modernization, it is desired to only digitize the data once and then distribute the data using commercial switching network technology to multiple back-end receiver processing hardware and software. The main problem to be solved is how to distribute efficiently and flexibly high-bandwidth intermediate-frequency (100 to 600 MHz) digitized signals across a signal processing center for use in the DSN.
Engineers Embroider Wearable AntennasTBMG-245024/17/2016
Researchers at The Ohio State University have embroidered circuits into fabric with 0.1 mm precision -- an ideal size for integrating sensors and electronic components into clothing. The achievement supports the development of new wearable technology, including a bandage that monitors tissue or a flexible fabric cap that senses brain activity.
Development and Application of FM Multipath Distortion Rate Measurement System Using a Fading Emulator Based on Two-Stage Method2016-01-00824/5/2016
The suitability of FM radio receivers for automobiles has conventionally been rated by evaluating reception characteristics for broadcast waves in repeated driving tests in specific test environments. The evaluation of sound quality has relied on the auditory judgment due to difficulties to conduct quantitative evaluations by experiments. Thus the method had issues in terms of the reproducibility and objectivity of the evaluations. To address these issues, a two-stage method generating a virtual radio wave environment on a PC was developed. The research further defined the multipath distortion rate, MDr, as an index for the sound quality evaluation of FM receivers, and the findings concerning the suitability of the evaluation of FM terminals for automobiles were reported at the 2015 SAE World Congress. However, extended periods of measurement were necessary because the upper limit for delay time, τMax, cannot be determine in advance for the measurement of MDr using the Two-Stage Method. This research clarified the characteristics of the multipath distortion rate, MDr, in relation to the modulation frequency (fm) and the delay time (τ) of the FM broadcast wave, and preliminarily determined τMax, the upper limit for delay time necessary for the Two-Stage Method. The research also indicated the possibility of applying the Two-Stage Method to Intelligent Transport Systems (ITS) to evaluate reception in the case of vehicle-to-vehicle communication on PC. By comparison with conventional proving trials, the Two-Stage Method makes it possible to generate radio wave environment characteristics as desired, and represents a useful evaluation tool displaying good reproducibility.
Komatsu, Satoru, Karasawa, Yoshio, Kashiwa, Tatsuya, Taguchi, Kenji, Imai, Suguru
Fabrication of an Integrated Photonic Waveguide Joint in Micromachined SiliconTBMG-242554/1/2016
High-aspect-ratio silicon structures are necessary components in many MEMS (microelectromechanical systems). Aspect ratio is defined as the ratio of the height of the structure to its lateral width. The structures are typically fabricated through bulk micromachining steps such as deep reactive ion etching. In some cases, multiple levels of high-aspect-ratio structures are required. For instance, one may want to etch completely through a silicon wafer to thermally isolate a bolometer or provide waveguide coupling to an antenna defined on an insulating membrane, and at the same time have integrated high-topology structures required for microwave coupling or filtering. Definition of the structures typically uses photolithographic technology. But for high-aspect-ratio structures, spin cast resist becomes difficult to incorporate due to the non-uniform thickness of the resist around tall structures. One can cast very thick layers of photoresist, but this limits the minimum feature size, and additionally, very thick layers of photoresist are difficult to work with due to solvent release and moisture that can cause the resist to crack or swell. For electromagnetic reasons, the structures would preferably be made from conductive material such as metal or degeneratively doped silicon. The objective of this work was to incorporate multiple levels of conductive high-aspectratio structures with standard micromachining processes.
Mini-Stamp as a Micro-Display for At-a-Glance Subsystem Information for DSN LinksTBMG-240943/1/2016
Operators of the Deep Space Network (DSN) attend to numerous tasks with the overall goal of providing continuous support for the world’s deep space missions. This high-stakes operations environment requires operators to understand the state of the DSN and predict what will happen next. Under the Follow-the-Sun initiative that requires remote operations of the highly complex telecommunications equipment, operators will need to remain aware of the state of the entire network rather than just their own facility, and transition fluidly between periods of low activity and periods of high demand.
Rigorous Antenna Noise Temperature Calculation Method for International Space Station Visiting SpacecraftTBMG-241123/1/2016
The temperature of the orbiting space station’s Sun-facing side could be up to 250 °F (≈120 °C) and will be a significant antenna noise temperature contributor for visiting spacecraft communication and tracking systems during rendezvous. The conventional antenna noise temperature calculation does not take into account the space station reflection effects, and results in an underestimated antenna and system noise temperature. Thus, the visiting spacecraft communication and tracking system performance could be overestimated during rendezvous.
SIRE: A MIMO Radar for Landmine and IED DetectionTBMG-239482/1/2016
Low-frequency ultra-wideband (UWB) radar has garnered attention for the detection of landmines and improvised explosive devices (IEDs) in recent years. The low frequencies used by these radars provide the necessary ground penetration capabilities for detection, and the wide bandwidth signals used are necessary for range resolution. Cross-range resolution that depends on the size of the antenna aperture can be improved by generating a synthetic aperture. Typical airborne synthetic aperture radars (SAR) that can provide high resolution in cross range are not practical for this problem due to cost limitations.
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