Results for “frequency radio array” — Page 6

NASA NTRS2006

Overview of Small and Large-Scale Space Solar Power Concepts

An overview of space solar power studies performed at the Boeing Company under contract with NASA will be presented. The major concepts to be presented are: 1. Power Plug in Orbit: this is a spacecraft that collects solar energy and distributes it to users in space using directed radio frequency or optical energy. Our concept uses solar arrays having the same dimensions as ISS arrays, but are assumed to be more efficient. If radiofrequency wavelengths are used, it will necessitate that the receiving satellite be equipped with a rectifying antenna (rectenna). For optical wavelengths, the solar arrays on the receiving satellite will collect the power. 2. Mars Clipper I Power Explorer: this is a solar electric Mars transfer vehicle to support human missions. A near-term precursor could be a high-power radar mapping spacecraft with self-transport capability. Advanced solar electric power systems and electric propulsion technology constitute viable elements for conducting human Mars missions that are roughly comparable in performance to similar missions utilizing alternative high thrust systems, with the one exception being their inability to achieve short Earth-Mars trip times. 3. Alternative Architectures: this task involves investigating alternatives to the traditional solar power satellite (SPS) to supply commercial power from space for use on Earth. Four concepts were studied: two using photovoltaic power generation, and two using solar dynamic power generation, with microwave and laser power transmission alternatives considered for each. All four architectures use geostationary orbit. 4. Cryogenic Propellant Depot in Earth Orbit: this concept uses large solar arrays (producing perhaps 600 kW) to electrolyze water launched from Earth, liquefy the resulting hydrogen and oxygen gases, and store them until needed by spacecraft. 5. Beam-Powered Lunar Polar Rover: a lunar rover powered by a microwave or laser beam can explore permanently shadowed craters near the lunar poles to search for water ice and other frozen volatiles. Near such craters are mountain peaks and highlands that are in near permanent sunlight. Power can be beamed from a collector on a sunlit mountain or crater rim to a rover inside a crater. Near-term applications of space solar power technology can therefore pave the way toward large-scale commercial power from space.

Potter, Seth↗

DOE OSTI2022

Wireless power transfer to biomedical implants

Various examples are provided for wireless power transfer to implants. In one example, a system includes a radio frequency (RF) power source and a transmitter (TX) array comprising an excitation coil and resonant coils distributed about the excitation coil. The TX array can transfer power from the RF power source to a biomedical implant inserted below a skin surface of a subject when the TX array is positioned on the skin surface adjacent to the biomedical implant. A receiver (RX) coil of the biomedical implant can inductively couple with the TX array for the power. The resonant coils can allow power transfer when the RX coil is not aligned with the excitation coil.

Lin, Jenshan↗

DOE OSTI2023

Wireless power transfer to biomedical implants

Various examples are provided for wireless power transfer to implants. In one example, a system includes a radio frequency (RF) power source and a transmitter (TX) array comprising an excitation coil and resonant coils distributed about the excitation coil. The TX array can transfer power from the RF power source to a biomedical implant inserted below a skin surface of a subject when the TX array is positioned on the skin surface adjacent to the biomedical implant. A receiver (RX) coil of the biomedical implant can inductively couple with the TX array for the power transfer. The resonant coils can allow power transfer when the RX coil is not aligned with the excitation coil.

Lin, Jenshan↗

NASA NTRS2023

Flexible User Radio for Lunar Missions

NASA’s Artemis program and other lunar exploration and development programs are planning over 40 lunar missions before 2030. Lunar missions, both crewed and uncrewed, include orbiters, landers, rovers, and surface stations. All these missions require communications with Earth, either via Direct to Earth (DTE) links or through relays in lunar orbit. Multiple DTE options are available among existing and planned ground stations: Deep Space Network (DSN), European Space Agency, and others. Relay options include the planned Lunar Gateway, LunaNet compliant relays, and some lunar landers propose to launch dedicated orbiters. The dilemma for lunar system designers is to identify a communication link which meets mission requirements but does not have issues of limited access (e.g. DSN is in high demand supporting deep space missions with high priority and some with inflexible schedules), system impacts (high power Radio Frequency (RF) for DTE links), cost (dedicated relay), or operational date. To avoid this difficult decision, a Flexible Radio for Lunar Missions is proposed, which will enable system designs to proceed prior to any final decision on the communication network to be used, by enabling compatibility with any of multiple DTE or orbital relay communication systems. The Flexible Radio will support the necessary frequency, bandwidth, modulation, and power requirements to interoperate with the majority of known or planned DTE or relay systems, and can be designed into a lunar mission without prior knowledge of which link will ultimately be used. Furthermore, the link being used can be changed as needed during the mission, in near real time. The Flexible Radio design will leverage work already completed at NASA in the areas of Wideband RF, Software Defined Radio, Adaptive Coding and Modulation, and Phased Array antennas. The Flexible Radio requires sufficient bandwidth to cover the allocated frequencies for both the operation of links in cislunar space and for space-to-Earth links; the flexibility to support multiple modulations, data rates, and coding schemes; the ability to identify available relays, detect and recognize the signals of those relays, and adapt its own frequency, modulation, symbol rate, and code rate to operate with the detected relay (or DTE station); and finally, it requires appropriate software to support network configuration and interoperability with the detected network. The Flexible Radio can be designed in a sufficiently small, lightweight, and low-power package to be used in a wide variety of lunar systems. The initial implementation, as proposed, will focus on the Ka-band, supporting up to 2 GHz bandwidth around the 27 GHz frequency for return links, and 23 GHz for forward links. Other frequency bands are under consideration for future configurations. The software defined modem will support OQPSK, BPSK, and NASA-defined modulations which also support two-way ranging with data. For near-real time adaptation, the Flexible Radio will scan the sky for available relays, using a phased array antenna with Adaptive/Cognitive Communications. It will then configure for network interoperability supporting DTN and other protocol options. The Flexible Radio will support scheduled connections and on-demand use when available.

Lunar Space Communications↗

NASA NTRSDate not supplied

Flexible User Radio for Lunar Missions

NASA’s Artemis program and other lunar exploration and development programs are planning over 40 lunar missions before 2030. Lunar missions, both crewed and uncrewed, include orbiters, landers, rovers, and surface stations. All these missions require communications with Earth, either via Direct to Earth (DTE) links or through relays in lunar orbit. Multiple DTE options are available among existing and planned ground stations: Deep Space Network (DSN), European Space Agency, and others. Relay options include the planned Lunar Gateway, LunaNet compliant relays, and some lunar landers propose to launch dedicated orbiters. The dilemma for lunar system designers is to identify a communication link which meets mission requirements but does not have issues of limited access (e.g. DSN is in high demand supporting deep space missions with high priority and some with inflexible schedules), system impacts (high power Radio Frequency (RF) for DTE links), cost (dedicated relay), or operational date. To avoid this difficult decision, a Flexible Radio for Lunar Missions is proposed, which will enable system designs to proceed prior to any final decision on the communication network to be used, by enabling compatibility with any of multiple DTE or orbital relay communication systems. The Flexible Radio will support the necessary frequency, bandwidth, modulation, and power requirements to interoperate with the majority of known or planned DTE or relay systems, and can be designed into a lunar mission without prior knowledge of which link will ultimately be used. Furthermore, the link being used can be changed as needed during the mission, in near real time. The Flexible Radio design will leverage work already completed at NASA in the areas of Wideband RF, Software Defined Radio, Adaptive Coding and Modulation, and Phased Array antennas. The Flexible Radio requires sufficient bandwidth to cover the allocated frequencies for both the operation of links in cislunar space and for space-to-Earth links; the flexibility to support multiple modulations, data rates, and coding schemes; the ability to identify available relays, detect and recognize the signals of those relays, and adapt its own frequency, modulation, symbol rate, and code rate to operate with the detected relay (or DTE station); and finally, it requires appropriate software to support network configuration and interoperability with the detected network. The Flexible Radio can be designed in a sufficiently small, lightweight, and low-power package to be used in a wide variety of lunar systems. The initial implementation, as proposed, will focus on the Ka-band, supporting up to 2 GHz bandwidth around the 27 GHz frequency for return links, and 23 GHz for forward links. Other frequency bands are under consideration for future configurations. The software defined modem will support OQPSK, BPSK, and NASA-defined modulations which also support two-way ranging with data. For near-real time adaptation, the Flexible Radio will scan the sky for available relays, using a phased array antenna with Adaptive/Cognitive Communications. It will then configure for network interoperability supporting DTN and other protocol options. The Flexible Radio will support scheduled connections and on-demand use when available.

Lunar Space Communications↗

NASA NTRS1972

Airborne electronically steerable phased array

The results are presented of the second stage of a program for the design and development of a phased array capable of simultaneous and separate transmission and reception of radio frequency signals at S-band frequencies. The design goals of this stage were the development of three major areas of interest required for the final prototype model. These areas are the construction and testing of the low-weight, full-scale 128-element array of antenna elements, the development of the RF manifold feed system, and the construction and testing of a working module containing diplexer and transmit and receive circuits.

Source record↗

NASA NTRS2016

The Gamma-Ray Emitting Radio-Loud Narrow-Line Seyfert 1 Galaxy PKS 2004-447 II. The Radio View

Context. gamma-ray-detected radio-loud narrow-line Seyfert 1 (gamma-NLS1) galaxies constitute a small but interesting sample of the gamma-ray-loud AGN. The radio-loudest gamma-NLS1 known, PKS2004447, is located in the southern hemisphere and is monitored in the radio regime by the multiwavelength monitoring programme TANAMI. Aims. We aim for the first detailed study of the radio morphology and long-term radio spectral evolution of PKS2004447, which are essential for understanding the diversity of the radio properties of gamma-NLS1s. Methods. The TANAMI VLBI monitoring program uses the Australian Long Baseline Array (LBA) and telescopes in Antarctica, Chile, New Zealand, and South Africa to monitor the jets of radio-loud active galaxies in the southern hemisphere. Lower resolution radio flux density measurements at multiple radio frequencies over four years of observations were obtained with the Australia Telescope Compact Array (ATCA). Results. The TANAMI VLBI image at 8.4GHz shows an extended one-sided jet with a dominant compact VLBI core. Its brightness temperature is consistent with equipartition, but it is an order of magnitude below other gamma-NLS1s with the sample value varying over two orders of magnitude. We find a compact morphology with a projected large-scale size 11 kpc and a persistent steep radio spectrum with moderate flux-density variability. Conclusions. PKS2004447 appears to be a unique member of the gamma-NLS1 sample. It exhibits blazar-like features, such as a flat featureless X-ray spectrum and a core-dominated, one-sided parsec-scale jet with indications for relativistic beaming. However, the data also reveal properties atypical for blazars, such as a radio spectrum and large-scale size consistent with compact-steep-spectrum (CSS) objects, which are usually associated with young radio sources. These characteristics are unique among all gamma-NLS1s and extremely rare among gamma-ray-loud AGN.

galaxies: active / galaxies: individual: PKS 2004-↗

NASA NTRS2012

670-GHz Schottky Diode-Based Subharmonic Mixer with CPW Circuits and 70-GHz IF

GaAs-based, sub-harmonically pumped Schottky diode mixers offer a number of advantages for array implementation in a heterodyne receiver system. Since the radio frequency (RF) and local oscillator (LO) signals are far apart, system design becomes much simpler. A proprietary planar GaAs Schottky diode process was developed that results in very low parasitic anodes that have cutoff frequencies in the tens of terahertz. This technology enables robust implementation of monolithic mixer and frequency multiplier circuits well into the terahertz frequency range. Using optical and e-beam lithography, and conventional epitaxial layer design with innovative usage of GaAs membranes and metal beam leads, high-performance terahertz circuits can be designed with high fidelity. All of these mixers use metal waveguide structures for housing. Metal machined structures for RF and LO coupling hamper these mixers to be integrated in multi-pixel heterodyne array receivers for spectroscopic and imaging applications. Moreover, the recent developments of terahertz transistors on InP substrate provide an opportunity, for the first time, to have integrated amplifiers followed by Schottky diode mixers in a heterodyne receiver at these frequencies. Since the amplifiers are developed on a planar architecture to facilitate multi-pixel array implementation, it is quite important to find alternative architecture to waveguide-based mixers.

Chattopadhyay, Goutam↗

NASA NTRS1973

The log-periodic array at the Clark Lake Radio Observatory

A log-periodic array, 3 km in length, is operating at Clark Lake Radio Observatory. It makes one-dimensional sweeps of the solar brightness distribution in the frequency range 20 to 65 MHz once per sec. The phasing of the array and the receiving system are described, as well as how the dynamic spectra are analyzed for the positions of solar radio sources. Simultaneous measurements at many frequencies enable the observer to remove the effects of ionospheric refraction and to obtain fundamental positions to an accuracy of about one arc min at decametric wavelengths. Fundamental positions are given for Cassiopeia A.

Erickson, W. C.↗

NASA NTRS1989

Operating and environmental characteristics of Sigma Tau hydrogen masers used in the Very Long Baseline Array (VLBA)

Presented here are the results obtained from performance evaluation of a pair of Sigma Tau Standards Corporation Model VLBA-112 active hydrogen maser frequency standards. These masers were manufactured for the National Radio Astronomy Observatory (NRAO) for use on the Very Long Baseline Array (VLBA) project and were furnished to the Jet Propulsion Laboratory (JPL) for the purpose of these tests. Tests on the two masers were performed in the JPL Frequency Standards Laboratory (FSL) and included the characterization of output frequency stability versus environmental factors such as temperature, humidity, magnetic field, and barometric pressure. The performance tests also included the determination of phase noise and Allan variance using both FSL and Sigma Tau masers as references. All tests were conducted under controlled laboratory conditions, with only the desired environmental and operational parameters varied to determine sensitivity to external environment.

Tucker, T. K.↗

NASA NTRSDate not supplied

Gbps High Speed Antenna Arraying for Ground-Based Network

Combining the output signals from two or more ground station antennas can increase the gain of the received signal, providing the critical flexibility to increase the science data rate from space missions. NASA’s Near Space Network (NSN) has developed a gigabits/sec high rate antenna arraying system, based on the coherent combination of signals derived from multiple directive antennas. This arraying system is called the “High Data Rate Signal Combiner (HDRSC).” This arraying design approach/technology has been used previously at very low data rates. This work, however, focuses on gigabits/sec high rate antenna arraying system architecture. When coherently combining just two signals there is ideally a doubling of power, i.e., a 3dB signal-to-noise improvement. Arraying of small antennas can easily outperform a single large aperture antenna not only in radio-frequency performance but also in a substantial reduction of cost. This paper will cover the design approach for Gbps arraying, hardware architecture, test philosophy, and results.

antennas↗

NASA NTRSDate not supplied

Gbps High Speed Antenna Arraying for Ground-Based Network

Combining the output signals from two or more ground station antennas can increase the gain of the received signal, providing the critical flexibility to increase the science data rate from space missions. NASA’s Near Space Network (NSN) has developed a gigabits/sec high rate antenna arraying system, based on the coherent combination of signals derived from multiple directive antennas. This arraying system is called the “High Data Rate Signal Combiner (HDRSC).” This arraying design approach/technology has been used previously at very low data rates. This work, however, focuses on gigabits/sec high rate antenna arraying system architecture. When coherently combining just two signals there is ideally a doubling of power, i.e., a 3dB signal-to-noise improvement. Arraying of small antennas can easily outperform a single large aperture antenna not only in radio-frequency performance but also in a substantial reduction of cost. This paper will cover the design approach for Gbps arraying, hardware architecture, test philosophy, and results.

antenna arraying↗

NASA NTRS1994

Pulsed laser illumination of photovoltaic cells

In future space missions, free electron lasers (FEL) may be used to illuminate photovoltaic array receivers to provide remote power. Both the radio-frequency (RF) and induction FEL provide FEL produce pulsed rather than continuous output. In this work we investigate cell response to pulsed laser light which simulates the RF FEL format. The results indicate that if the pulse repetition is high, cell efficiencies are only slightly reduced compared to constant illumination at the same wavelength. The frequency response of the cells is weak, with both voltage and current outputs essentially dc in nature. Comparison with previous experiments indicates that the RF FEL pulse format yields more efficient photovoltaic conversion than does an induction FEL pulse format.

Yater, Jane A.↗

NASA NTRS1973

Adaptive ground implemented phase array

The simulation of an adaptive ground implemented phased array of five antenna elements is reported for a very high frequency system design that is tolerant to the radio frequency interference environment encountered by a tracking data relay satellite. Signals originating from satellites are received by the VHF ring array and both horizontal and vertical polarizations from each of the five elements are multiplexed and transmitted down to ground station. A panel on the transmitting end of the simulation chamber contains up to 10 S-band RFI sources along with the desired signal to simulate the dynamic relationship between user and TDRS. The 10 input channels are summed, and desired and interference signals are separated and corrected until the resultant sum signal-to-interference ratio is maximized. Testing performed with this simulation equipment demonstrates good correlation between predicted and actual results.

Spearing, R. E.↗

NASA NTRS2003

Arrays of Carbon Nanotubes as RF Filters in Waveguides

Brushlike arrays of carbon nanotubes embedded in microstrip waveguides provide highly efficient (high-Q) mechanical resonators that will enable ultraminiature radio-frequency (RF) integrated circuits. In its basic form, this invention is an RF filter based on a carbon nanotube array embedded in a microstrip (or coplanar) waveguide, as shown in Figure 1. In addition, arrays of these nanotube-based RF filters can be used as an RF filter bank. Applications of this new nanotube array device include a variety of communications and signal-processing technologies. High-Q resonators are essential for stable, low-noise communications, and radar applications. Mechanical oscillators can exhibit orders of magnitude higher Qs than electronic resonant circuits, which are limited by resistive losses. This has motivated the development of a variety of mechanical resonators, including bulk acoustic wave (BAW) resonators, surface acoustic wave (SAW) resonators, and Si and SiC micromachined resonators (known as microelectromechanical systems or MEMS). There is also a strong push to extend the resonant frequencies of these oscillators into the GHz regime of state-of-the-art electronics. Unfortunately, the BAW and SAW devices tend to be large and are not easily integrated into electronic circuits. MEMS structures have been integrated into circuits, but efforts to extend MEMS resonant frequencies into the GHz regime have been difficult because of scaling problems with the capacitively-coupled drive and readout. In contrast, the proposed devices would be much smaller and hence could be more readily incorporated into advanced RF (more specifically, microwave) integrated circuits.

Hoppe, Daniel↗

DOE OSTI2023

Quantum Instrumentation Control Kit Defect Arbitrary Waveform Generator (QICKDAWG) v.0

SAND2024-08598O The Quantum Instrumentation Control Kit Defect Arbitrary Waveform Generator (QICKDAWG) characterizes nitrogen-vacancy centers in diamond and other defects. It does this by using a radio frequency system-on-a-chip (RFSoC) field programmable gate array (FPGA). QICKDAWG synthesizes microwave pulses from the RFSoC to change the spin state of the defects. The software also allows for laser control using the RFSoC, which optically pumps defects. Ultimately, QICKDAWG supports the implementation of RFSoC FPGAs in defect characterization. This replaces the slow, expensive, traditional hardware, thus lowering the cost and time for defect characterization. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

SciDAC↗

NASA NTRS2010

Massive Star Formation of the SGR a East H (sub II) Regions Near the Galactic Center

A group of four compact H II regions associated with the well-known 50 km/s molecular cloud is the closest site of on-going star formation to the dynamical center of the Galaxy, at a projected distance of approximately 6 pc. We present a study of ionized gas based on the [Ne II] (12.8 micron) line, as well as multi-frequency radio continuum, Hubble Space Telescope Pa alpha, and Spitzer Infrared Array Camera observations of the most compact member of the H II group, Sgr A East H II D. The radio continuum image at 6 cm shows that this source breaks up into two equally bright ionized features, D1 and D2. The spectral energy distribution of the D source is consistent with it being due to a 25 =/- 3 solar mass star with a luminosity of 8 +/- 3 x 10(exp 4) Solar luminosity . The inferred mass, effective temperature of the UV source, and the ionization rate are compatible with a young O9-B0 star. The ionized features D1 and D2 are considered to be ionized by UV radiation collimated by an accretion disk. We consider that the central massive star photoevaporates its circumstellar disk on a timescale of 3x (exp 4) years giving a mass flux approximately 3 x 10(exp -5) Solar Mass / year and producing the ionized material in D1 and D2 expanding in an inhomogeneous medium. The ionized gas kinematics, as traced by the [Ne II] emission, is difficult to interpret, but it could be explained by the interaction of a bipolar jet with surrounding gas along with what appears to be a conical wall of lower velocity gas. The other H II regions, Sgr A East A-C, have morphologies and kinematics that more closely resemble cometary flows seen in other compact H II regions, where gas moves along a paraboloidal surface formed by the interaction of a stellar wind with a molecular cloud.

Yusef-Zadeh, F.↗

DOE OSTI2020

W-band system-on-chip electron cyclotron emission imaging system on DIII-D

Monolithic, millimeter wave “system-on-chip” (SoC) technology has been employed in heterodyne receiver integrated circuit radiometers in a newly developed Electron Cyclotron Emission Imaging (ECEI) system on the DIII-D tokamak for 2D electron temperature profile and fluctuation evolution diagnostics. Here, a prototype module operating in E-band (72-80 GHz) was first employed in a 2 x 10 element array that demonstrated significant improvements over the previous quasi-optical Schottky diode mixer arrays during the 2018 operational campaign of the DIII-D tokamak. For compatibility with International Thermonuclear Experimental Reactor (ITER) relevant scenarios on DIII-D, the SoC ECEI system was upgraded with 20 horn-waveguide receiver modules. Each individual module contains a University of California at Davis designed W-band (75 -110 GHz) receiver die that integrates a broadband low noise amplifier (LNA), a double balanced down-converting mixer, and a x4 multiplier on the local oscillator (LO) chain. A x2 multiplier and two IF amplifiers are packaged and selected to further boost the signal strength as well as downconvert the signal frequency. The upgraded W-band array exhibits > 30 dB additional gain and 20x improvement in noise temperature comparing with the previous Schottky diode radio frequency (RF) mixer input systems; an internal 8 times multiplier chain is used to bring down the LO frequency below 12 GHz, thereby obviating the need for a large aperture for quasi-optical LO coupling and replacing it with coaxial connectors. The horn-waveguide shielding housing avoids out-of-band noise interference on each individual module. The upgraded ECEI system plays an important role for absolute electron temperature evolution and fluctuation measurements for edge and core region transport physics studies.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗