Publications

Refine Results

(Filters Applied) Clear All

By

Effect of a wet spherical radome on the reflected power for an S-band planar phased array radar antenna

October 24, 2021
  |
Conference Paper
Author:
Christine F. Parry
…
Published in:
2021 Antenna Measurement Techniques Association Symp., AMTA, 24-29 October 2021.
Topic:
antennas
R&D area:
R&D group:

Summary

An active S-band dual-polarized multifunction phased array radar (MPAR), the Advanced Technology Demonstrator (ATD), has recently been developed for weather sensing and aircraft surveillance. The ATD is an active electronically scanned array (AESA) with 4864 transmit/receive (T/R) modules and was installed in a spherical radome. Simulations and a novel phased array measurement technique have been explored to assess the impact of high reflectivity from a wet radome during rain that can potentially induce voltages exceeding the transmit amplifier breakdown voltage. The measurement technique uses array elements radiating one at a time to illuminate the radome, and uses superposition to quantify the received signal power in a reference antenna on the face of the array. It is shown that when the radome surface is wet and highly reflective, certain electronic steering angles sum to a large reflected signal focused on the array face. This measurement technique can be used prior to high-power phased array radar operation to monitor the magnitude of reflections and help avoid element transmit amplifier failures.
READ LESS

Summary

An active S-band dual-polarized multifunction phased array radar (MPAR), the Advanced Technology Demonstrator (ATD), has recently been developed for weather sensing and aircraft surveillance. The ATD is an active electronically scanned array (AESA) with 4864 transmit/receive (T/R) modules and was installed in a spherical radome. Simulations and a novel phased...

READ MORE
Effect of a wet spherical radome on the reflected power for an S-band planar phased array radar antenna

Modeling and validation of a mm-wave shaped dielectric lens antenna

July 29, 2018
  |
Conference Paper
Author:
David C. Mooradd
…
Published in:
2018 Int. Applied Computational Electromagnetics Society Symp., ACES, 29 July - 1 August 2018.
Topic:
antennas
R&D area:
R&D group:

Summary

The modeling and validation of a 33 GHz shaped dielectric antenna design is investigated. The electromagnetic modeling was performed in both WIPL-D and FEKO, and was used to validate the antenna design prior to fabrication of the lens. It is shown that both WIPL-D and FEKO yield similarly accurate results as compared to measured far-field gain radiation patterns.
READ LESS

Summary

The modeling and validation of a 33 GHz shaped dielectric antenna design is investigated. The electromagnetic modeling was performed in both WIPL-D and FEKO, and was used to validate the antenna design prior to fabrication of the lens. It is shown that both WIPL-D and FEKO yield similarly accurate results...

READ MORE
Modeling and validation of a mm-wave shaped dielectric lens antenna

Bringing physical construction and real-world data collection into a massively open online course (MOOC)

October 18, 2017
  |
Conference Paper
Author:
Julia Mullen
…
Published in:
IEEE Frontiers in Education Conf., FIE, 18-21 October 2017.
Topic:
supercomputing
R&D area:
R&D group:

Summary

This Work-In-Progress paper details the process and lessons learned when converting a hands-on engineering minicourse to a scalable, self-paced Massively Open Online Course (MOOC). Online courseware has been part of academic and industry training and learning for decades. Learning activities in online courses strive to mimic in-person delivery by including lectures, homework assignments, software exercises and exams. While these instructional activities provide "theory and practice" for many disciplines, engineering courses often require hands-on activities with physical tools, devices and equipment. To accommodate the need for this type of learning, MIT Lincoln Laboratory's "Build A Small Radar" (BSR) course was used to explore teaching and learning strategies that support the inclusion of physical construction and real world data collection in a MOOC. These tasks are encountered across a range of engineering disciplines and the methods illustrated here are easily generalized to the learning experiences in engineering and science disciplines.
READ LESS

Summary

This Work-In-Progress paper details the process and lessons learned when converting a hands-on engineering minicourse to a scalable, self-paced Massively Open Online Course (MOOC). Online courseware has been part of academic and industry training and learning for decades. Learning activities in online courses strive to mimic in-person delivery by including...

READ MORE
Bringing physical construction and real-world data collection into a massively open online course (MOOC)

3D printed conformal array antenna: simulations and measurements

October 18, 2016
  |
Conference Paper
Author:
Alan J. Fenn
…
Published in:
6th Int. Symp. on Phased Array Systems and Technology, PAST 2016, 18-21 October 2016.
Topic:
antennas
R&D area:
R&D group:

Summary

A conformal array antenna has been investigated using a combination of 3D printer and copper plating techniques. Circular patch antenna elements were copper plated onto a 3D printed dielectric substrate made of ABS-M30 material. Measured and simulated element reflection coefficient, element gain patterns, and array scanned beam radiation patterns at L band are in good agreement.
READ LESS

Summary

A conformal array antenna has been investigated using a combination of 3D printer and copper plating techniques. Circular patch antenna elements were copper plated onto a 3D printed dielectric substrate made of ABS-M30 material. Measured and simulated element reflection coefficient, element gain patterns, and array scanned beam radiation patterns at...

READ MORE
3D printed conformal array antenna: simulations and measurements

Design and analysis of an axisymmetric phased array fed Gregorian reflector system for limited scanning

October 18, 2016
  |
Conference Paper
Author:
Alan J. Fenn
…
Published in:
6th Int. Symp. on Phased Array Systems and Technology, PAST 2016, 18-21 October 2016.
Topic:
antennas
R&D area:
R&D group:

Summary

An axisymmetric phased array fed confocal parabolic Gregorian reflector system is explored. The antenna utilizes a planar phased array located near the vertex of the primary reflector. Numerical electromagnetic simulations based on the multilevel fast multipole method (MLFMM) were used to analyze and optimize the antenna parameters for limited scanning. Simulations of the scanning performance of a dual reflector system with a 2 meter diameter primary reflector operating at Ku band are presented.
READ LESS

Summary

An axisymmetric phased array fed confocal parabolic Gregorian reflector system is explored. The antenna utilizes a planar phased array located near the vertex of the primary reflector. Numerical electromagnetic simulations based on the multilevel fast multipole method (MLFMM) were used to analyze and optimize the antenna parameters for limited scanning...

READ MORE
Design and analysis of an axisymmetric phased array fed Gregorian reflector system for limited scanning

HF vector sensor for radio astronomy: ground testing results

September 13, 2016
  |
Conference Paper
Author:
Mary Knapp
…
Published in:
AIAA Space 2016 Conf. and Exposition, 13-16 September 2016.
Topic:
sensors
R&D area:
R&D group:

Summary

The radio sky below ~10 MHz is largely unexplored due to the inability of ground-based telescopes to observe near or below the ionospheric plasma frequency, or cut-off frequency. A space-based interferometric array is required to probe the portion of the electromagnetic (E-M) spectrum below 10 MHz with sufficient angular resolution and sensitivity to be scientifically useful. Multi-spacecraft constellations scale quickly in cost and complexity as the number of spacecraft increases, so minimizing the number of required spacecraft for an interferometric array (while maintaining performance) is critical for feasibility. We present the HF (High Frequency, 3 to 30 MHz) Vector Sensor as a high performance spacecraft instrument in a future space-based interferometric array. The HF Vector Sensor is composed of three orthogonal dipoles and three orthogonal loop antennas with a common phase center. These six elements fully measure the E-M field of incoming radiation. We present the design of two prototype HF Vector Sensors, ground-based data collection at frequencies above the ionospheric cut-off, and imaging results using several different algorithms.
READ LESS

Summary

The radio sky below ~10 MHz is largely unexplored due to the inability of ground-based telescopes to observe near or below the ionospheric plasma frequency, or cut-off frequency. A space-based interferometric array is required to probe the portion of the electromagnetic (E-M) spectrum below 10 MHz with sufficient angular resolution...

READ MORE
HF vector sensor for radio astronomy: ground testing results

Vector antenna and maximum likelihood imaging for radio astronomy

March 5, 2016
  |
Conference Paper
Author:
Mary Knapp
…
Published in:
2016 IEEE Aerospace Conf., 5-12 March 2016.
Topic:
simulation
R&D area:
R&D group:

Summary

Radio astronomy using frequencies less than ~100 MHz provides a window into non-thermal processes in objects ranging from planets to galaxies. Observations in this frequency range are also used to map the very early history of star and galaxy formation in the universe. Much effort in recent years has been devoted to highly capable low frequency ground-based interferometric arrays such as LOFAR, LWA, and MWA. Ground-based arrays, however, cannot observe astronomical sources below the ionospheric cut-off frequency of ~10 MHz, so the sky has not been mapped with high angular resolution below that frequency. The only space mission to observe the sky below the ionospheric cut-off was RAE-2, which achieved an angular resolution of ~60 degrees in 1973. This work presents alternative sensor and algorithm designs for mapping the sky both above and below the ionospheric cutoff. The use of a vector sensor, which measures the full electric and magnetic field vectors of incoming radiation, enables reasonable angular resolution (~5 degrees) from a compact sensor (~4 m) with a single phase center. A deployable version of the vector sensor has been developed to be compatible with the CubeSat form factor.
READ LESS

Summary

Radio astronomy using frequencies less than ~100 MHz provides a window into non-thermal processes in objects ranging from planets to galaxies. Observations in this frequency range are also used to map the very early history of star and galaxy formation in the universe. Much effort in recent years has been...

READ MORE
Vector antenna and maximum likelihood imaging for radio astronomy

Ultrawideband time-delay steered UHF dipole linear array antenna

October 15, 2013
  |
Conference Paper
Author:
Alan J. Fenn
…
Published in:
2013 IEEE Int. Symp. On Phased Array Systems and Technology, 15-18 October 2013.
Topic:
antennas
R&D area:
R&D group:

Summary

An ultrawideband fixed time-delay steered UHF dipole array antenna has been developed for coverage in the 300 to 450 MHz frequency range for communications or radar applications. The antenna utilizes a parasitically-tuned dipole array for linear polarization and is mounted over a ground plane. Numerical electromagnetic simulations were used to analyze and optimize the antenna parameters prior to fabrication. Measurements of the prototype antenna in an anechoic chamber demonstrate the antenna's reflection coefficient and radiation gain pattern performance.
READ LESS

Summary

An ultrawideband fixed time-delay steered UHF dipole array antenna has been developed for coverage in the 300 to 450 MHz frequency range for communications or radar applications. The antenna utilizes a parasitically-tuned dipole array for linear polarization and is mounted over a ground plane. Numerical electromagnetic simulations were used to...

READ MORE
Ultrawideband time-delay steered UHF dipole linear array antenna

Ultrawideband cavity-backed resistively loaded planar dipole array for ground penetrating radar

October 15, 2013
  |
Journal Article
Author:
Alan J. Fenn
…
Published in:
2013 IEEE Int. Symp. On Phased Array Systems and Technology, 15-18 October 2013.
Topic:
antennas
R&D area:
R&D group:

Summary

An ultrawideband (UWB) cavity-backed resistively loaded planar dipole array antenna has been developed for the 100 to 400 MHz frequency range for ground penetrating radar applications. The antenna has been designed with a 3m aperture to perform surveys of a wide swath of ground from a moving vehicle. The performance of the UWB array is quantified by moment method simulations of the electromagnetic field penetration into lossy soil. Integration of the UWB array onto vehicle is discussed.
READ LESS

Summary

An ultrawideband (UWB) cavity-backed resistively loaded planar dipole array antenna has been developed for the 100 to 400 MHz frequency range for ground penetrating radar applications. The antenna has been designed with a 3m aperture to perform surveys of a wide swath of ground from a moving vehicle. The performance...

READ MORE
Ultrawideband cavity-backed resistively loaded planar dipole array for ground penetrating radar

Ring array antenna with optimized beamformer for simultaneous transmit and receive

July 8, 2012
  |
Conference Paper
Author:
Kenneth E. Kolodziej
…
Published in:
2012 IEEE Antennas and Propagation Society International Symp. and USNC/URSI National Radio Sci. Mtg., 8-14 July 2012.
Topic:
antennas
R&D area:
R&D group:

Summary

In order to avoid self-interference, Simultaneous Transmit And Receive (STAR) systems require low mutual coupling between their respective transmit and receive antennas. This paper discusses the development of an 8-element transmit ring array antenna on a circular ground plane with a raised receive element. When combined with a beamformer that supplies linear progressive phase shifts to the array with opposing elements phased 180-degrees apart, the receive and transmit antennas are measured to exhibit 55 dB of isolation and omni-directional patterns in the 2.4 to 2.5 GHz band.
READ LESS

Summary

In order to avoid self-interference, Simultaneous Transmit And Receive (STAR) systems require low mutual coupling between their respective transmit and receive antennas. This paper discusses the development of an 8-element transmit ring array antenna on a circular ground plane with a raised receive element. When combined with a beamformer that...

READ MORE
Ring array antenna with optimized beamformer for simultaneous transmit and receive
1-10 of 18