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3D printed conformal array antenna: simulations and measurements

Published in:
6th Int. Symp. on Phased Array Systems and Technology, PAST 2016, 18-21 October 2016.

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.
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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...

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

Author:
Published in:
6th Int. Symp. on Phased Array Systems and Technology, PAST 2016, 18-21 October 2016.
Topic:
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.
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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...

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Multi-channel agile comb generator for antenna radiation pattern measurements

Published in:
IEEE Int. Symp. Antennas and Propagation (APSURSI), 26 June - 1 July 2016.

Summary

Antenna radiation patterns are typically measured using network analyzers, which are both expensive and physically large in size. These drawbacks can limit this test equipment's usage in universities that cannot afford to make such a purchase, as well as within applications that require mobile antenna measurements. An alternative approach is to combine a low-cost receiver with a flexible signal source. This paper presents the design of a tunable comb generator prototype that is capable of outputting frequencies up to 4 GHz. The compact nature of this source along with its potential to be dynamically reconfigured yields a device that can be used to measure antenna patterns for many different applications.
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Summary

Antenna radiation patterns are typically measured using network analyzers, which are both expensive and physically large in size. These drawbacks can limit this test equipment's usage in universities that cannot afford to make such a purchase, as well as within applications that require mobile antenna measurements. An alternative approach is...

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Single antenna in-band full-duplex isolation-improvement techniques

Published in:
IEEE Int. Symp. Antennas and Propagation (APSURSI), 26 June - 1 July 2016.
Topic:
R&D group:

Summary

Many in-band full-duplex wireless systems transmit and receive on a single antenna to minimize redundancy and maintain compact form factors. For effective operation, all of these systems need to maximize transmit-to-receive isolation, which is limited by non-ideal antenna matching and non-zero circulator leakage. Several isolation-improvement techniques are investigated in this paper, and illustrate how RF components can be used to minimize the consequential self-interference of these systems. Two unique cancellation schemes were validated, and the isolation of a single-antenna transceiver was measured to improve by 15 and 33 dB over the 100 MHz bandwidth centered at 2.45 GHz.
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Summary

Many in-band full-duplex wireless systems transmit and receive on a single antenna to minimize redundancy and maintain compact form factors. For effective operation, all of these systems need to maximize transmit-to-receive isolation, which is limited by non-ideal antenna matching and non-zero circulator leakage. Several isolation-improvement techniques are investigated in this...

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Switched antenna array tile for real-time microwave imaging aperture

Published in:
IEEE Int. Symp. Antennas and Propagation (APSURSI), 26 June - 1 July 2016.
Topic:
R&D group:

Summary

A switched array tile which is part of a large aperture for near-field microwave imaging is presented. The tile is based on the Boundary Array (BA), a sparse array topology for hardware efficient realization of imaging apertures. The larger array formed with the tile samples a scene with no redundancy, and is compatible with fast imaging techniques. Details on the design and realization of the tile are presented, as well as experimental images formed with a tile prototype.
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Summary

A switched array tile which is part of a large aperture for near-field microwave imaging is presented. The tile is based on the Boundary Array (BA), a sparse array topology for hardware efficient realization of imaging apertures. The larger array formed with the tile samples a scene with no redundancy...

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The evolution to modern phased array architectures

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Published in:
Proceedings of the IEEE, Vol. 104, No. 3, March 2016, pp. 519-529.
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Summary

Phased array technology has been evolving steadily with advances in solid-state microwave integrated circuits, analysis and design tools, and reliable fabrication practices. With significant government investments, the technologies have matured to a point where phased arrays are widely used in military systems. Next-generation phased arrays will employ high levels of digitization, which enables a wide range of improvements in capability and performance. Digital arrays leverage the rapid commercial evolution of digital processor technology. The cost of phased arrays can be minimized by utilizing high-volume commercial microwave manufacturing and packaging techniques. Dramatic cost reductions are achieved by employing a tile array architecture, which greatly reduces the number of printed circuit boards and connectors in the array.
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Summary

Phased array technology has been evolving steadily with advances in solid-state microwave integrated circuits, analysis and design tools, and reliable fabrication practices. With significant government investments, the technologies have matured to a point where phased arrays are widely used in military systems. Next-generation phased arrays will employ high levels of...

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Vehicle-mounted STAR antenna isolation performance

Published in:
IEEE Antennas and Propagation Society Int. Symp. 2015, 19-25 July 2015.
Topic:
R&D group:

Summary

Vehicle-to-vehicle communication systems promise enhanced safety for passengers, but require access to a crowded wireless spectrum to enable their data links. Simultaneous Transmit and Receive (STAR) systems can facilitate this spectrum access by increasing the number of users within a given frequency band. Since high isolation is needed for STAR system operation, the effect of mounting a STAR antenna on a vehicle is investigated in this paper. The omni-directional antennas isolation performance was measured to be 53 dB at 2.45 GHz across a 60 MHz bandwidth, which confirms that the vehicle does not significantly degrade isolation performance.
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Summary

Vehicle-to-vehicle communication systems promise enhanced safety for passengers, but require access to a crowded wireless spectrum to enable their data links. Simultaneous Transmit and Receive (STAR) systems can facilitate this spectrum access by increasing the number of users within a given frequency band. Since high isolation is needed for STAR...

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Simultaneous transmit and receive antenna isolation improvement in scattering environments

Published in:
APS/URSI 2014, IEEE Int. Symp. on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 6-11 July 2014.

Summary

Simultaneous transmit and receive (STAR) systems require high isolation between the transmitter and receiver to avoid self-interference. Antenna isolation degradation stems from errors in the physical construction and beamformer design, as well as reflections from scattering objects in the environment. An RF canceller subsystem can be inserted at the antenna feeds to improve the isolation in the presence of reflecting objects by 30 dB over 30 MHz centered at 2.45 GHz. This results in 90 dB of effective antenna isolation when paired with a high-isolation antenna that exhibits omni-directional radiation patterns, signifying that STAR systems can be practically deployed.
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Summary

Simultaneous transmit and receive (STAR) systems require high isolation between the transmitter and receiver to avoid self-interference. Antenna isolation degradation stems from errors in the physical construction and beamformer design, as well as reflections from scattering objects in the environment. An RF canceller subsystem can be inserted at the antenna...

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Wideband antenna array for simultaneous transmit and receive (STAR) applications

Published in:
2014 IEEE Int. Symp. on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 6-11 July 2014.
Topic:
R&D group:

Summary

A wideband antenna array for Simultaneous Transmit and Receive (STAR) applications is presented. The design is comprised of a ring array of TEM horns, and a monocone at the array's center. When the array is phased with the first order circular mode, it is isolated from the monocone. Thus, the array may be used in reception while the monocone is used in transmission, or vice versa. The array and monocone both produce quasi-omnidirectional patterns in the azimuthal planes. Simulations suggest that the design operates across an 8.4 : 1 bandwidth. This wide bandwidth is possible through the use of a novel capacitive feed employed in the TEM horn array.
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Summary

A wideband antenna array for Simultaneous Transmit and Receive (STAR) applications is presented. The design is comprised of a ring array of TEM horns, and a monocone at the array's center. When the array is phased with the first order circular mode, it is isolated from the monocone. Thus, the...

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Adaptive RF canceller for transmit-receive isolation improvement

Published in:
2014 IEEE Radio and Wireless Symposium (RWS), 19-23 January 2014.

Summary

For effective operation, Simultaneous Transmit and Receive (STAR) systems require high isolation between the transmitted signals and the receiver input, the absence of which can lead to the saturation of a receiver's front end. This paper presents an adaptive RF canceller used to improve isolation. The canceller is configured as an RD tapped delay line with four taps, each with independent amplitude and phase weights that are tuned by a Dithered Linear Search algorithm. This canceller produces 30 dB of signal cancellation over a 20 MHz bandwidth centered at 2.45 GHz in an isolated environment. When combined with a high-isolation antenna, an overall STAR system isolation of 90 dB is achieved, while also maintaining omnidirectional transmit and receive antenna patterns.
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Summary

For effective operation, Simultaneous Transmit and Receive (STAR) systems require high isolation between the transmitted signals and the receiver input, the absence of which can lead to the saturation of a receiver's front end. This paper presents an adaptive RF canceller used to improve isolation. The canceller is configured as...

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