Design and Evaluation of an Active Antenna for a 29–47 MHz Radio Telescope Array

Ellingson, S.W.; Simonetti, J. H.; Patterson, Cameron

doi:10.1109/tap.2007.891866

Cited by 47 publications

(43 citation statements)

References 6 publications

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“…A new generation of radio telescopes will search for transient pulses from the universe [1,2,3,4,5]. Such searches, using pre-existing data, have recently found surprising pulses of galactic and extragalactic origin [6,7,8].…”

Section: Introductionmentioning

confidence: 99%

Transient pulses from exploding primordial black holes as a signature of an extra dimension

Kavic

Simonetti

Cutchin

et al. 2008

J. Cosmol. Astropart. Phys.

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An evaporating black hole in the presence of an extra spatial dimension would undergo an explosive phase of evaporation. We show that such an event, involving a primordial black hole, can produce a detectable, distinguishable electromagnetic pulse, signaling the existence of an extra dimension of size L ∼ 10 −18 − 10 −20 m. We derive a generic relationship between the Lorentz factor of a pulse-producing "fireball" and the TeV energy scale. For an ordinary toroidally compactified extra dimension, transient radio-pulse searches probe the electroweak energy scale (∼0.1 TeV), enabling comparison with the Large Hadron Collider.

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Section: Introductionmentioning

confidence: 99%

Transient pulses from exploding primordial black holes as a signature of an extra dimension

Kavic

Simonetti

Cutchin

et al. 2008

J. Cosmol. Astropart. Phys.

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“…This e±ciency accounts for near-¯eld coupling between the antenna and the ground that results in loss in the ground manifesting as loss in the antenna itself. Typical values of range from about 0.5 (typical at 38 MHz above untreated earth without a conducting ground screen (Ellingson et al, 2007)) to very close to 1 (typical above 100 MHz or with a su±ciently large ground screen, as demonstrated in Sec. 6).…”

Section: Noise Temperature Requirementsmentioning

confidence: 83%

Practical Limits in the Sensitivity-Linearity Trade-off for Radio Telescope Front Ends in the HF and VHF-low Bands

Tillman

Ellingson

Brendler

2016

J. Astron. Instrum.

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Radio telescope front ends must have simultaneously low noise and su±ciently-high linearity to accommodate interfering signals. Typically these are opposing design goals. For modern radio telescopes operating in the HF (3-30 MHz) and VHF-low (30-88 MHz) bands, the problem is more nuanced in that front end noise temperature may be a relatively small component of the system temperature, and increased linearity may be required due to the particular interference problems associated with this spectrum. In this paper, we present an analysis of the sensitivity-linearity trade-o® at these frequencies, applicable to existing commercially-available monolithic microwave integrated circuit (MMIC) ampli¯ers in single-ended, differential, and parallelized con¯gurations. This analysis and associated¯ndings should be useful in the design and upgrade of front ends for low frequency radio telescopes. The analysis is demonstrated explicitly for one of the better-performing ampli¯ers encountered in this study, the Mini-Circuits PGA-103, and is con¯rmed by hardware measurements. We also present a design based on the Mini-Circuits HELA-10 ampli¯er, which is better-suited for applications where linearity is a primary concern.

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“…As an example of our ability to achieve the former, we have demonstrated front-end designs that are capable of expanding the effective (external noise-limited) sensitivity of dipole antennas from about 10% to about 25% using a front-end Bco-design[ strategy [67], [68]. We are seeking additional improvements using Bnon-Foster[ matching [69], which is a high-risk but high-payoff technique in which matching circuits are developed using active devices that achieve Bnonphysical[ impedance characteristicsVe.g., negative capacitanceVwhich result in dramatically improved impedance matching.…”

Section: Building Multiband Radiosmentioning

confidence: 99%

Cognitive Radio and Networking Research at Virginia Tech

et al. 2009

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A large research team with a wide range of expertiseVfrom ICs and reconfigurable computing to wireless networkingVworks to achieve the promise of cognitive radio. ABSTRACT | More than a dozen Wireless @ Virginia Tech faculty are working to address the broad research agenda of cognitive radio and cognitive networks. Our core research team spans the protocol stack from radio and reconfigurable hardware to communications theory to the networking layer.Our work includes new analysis methods and the development of new software architectures and applications, in addition to work on the core concepts and architectures underlying cognitive radios and cognitive networks. This paper describes these contributions and points towards critical future work that remains to fulfill the promise of cognitive radio. We briefly describe the history of work on cognitive radios and networks at Virginia Tech and then discuss our contributions to the core cognitive processing underlying these systems, focusing on our cognitive engine. We also describe developments that support the cognitive engine and advances in radio technology that provide the flexibility desired in a cognitive radio node. We consider securing and verifying cognitive systems and examine the challenges of expanding the cognitive paradigm up the protocol stack to optimize end-to-end network performance.Lastly, we consider the analysis of cognitive systems using game theory and the application of cognitive techniques to problems in dynamic spectrum sharing and control of multipleinput multiple-output radios.

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Design and Evaluation of an Active Antenna for a 29–47 MHz Radio Telescope Array

Cited by 47 publications

References 6 publications

Transient pulses from exploding primordial black holes as a signature of an extra dimension

Transient pulses from exploding primordial black holes as a signature of an extra dimension

Practical Limits in the Sensitivity-Linearity Trade-off for Radio Telescope Front Ends in the HF and VHF-low Bands

Cognitive Radio and Networking Research at Virginia Tech

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