Phased Arrays for Radio Astronomy, Remote Sensing, and Satellite Communications

Warnick, Karl F.; Maaskant, Rob; Ivashina, Marianna; Davidson, David; Jeffs, Brian D.

doi:10.1017/9781108539258

Cited by 79 publications

(51 citation statements)

References 250 publications

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“…The odd numbered ports are the input ports of the multiport amplifier connected to antennas while the even numbered ports are the output ports. The noise waves due to internal sources alone emerging from the multiport network are described by (6) and are represented by dashed arrows. Noise waves emerging at the output ports undergo a weight (w i ) and sum operation.…”

Section: A Contribution Of Internal Noisementioning

confidence: 99%

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Noise Temperature of Phased Array Radio Telescope: The Murchison Widefield Array and the Engineering Development Array

Ung

Sokołowski

Sutinjo

et al. 2020

IEEE Trans. Antennas Propagat.

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This paper presents a framework to compute the receiver noise temperature (Trcv) of two low-frequency radio telescopes, the Murchison Widefield Array (MWA) and the Engineering Development Array (EDA). The MWA was selected because it is the only operational low-frequency Square Kilometre Array (SKA) precursor at the Murchison Radio-astronomy Observatory, while the EDA was selected because it mimics the proposed SKA-Low station size and configuration. It will demonstrated that the use of an existing power wave based framework for noise characterization of multiport amplifiers is sufficiently general to evaluate Trcv of phased arrays. The calculation of Trcv was done using a combination of measured noise parameters of the low-noise amplifier (LNA) and simulated S-parameters of the arrays. The calculated values were compared to measured results obtained via astronomical observation and both results are found to be in agreement. Such verification is lacking in current literature. It was shown that the receiver noise temperatures of both arrays are lower when compared to a single isolated element. This is caused by the increase in mutual coupling within the array which is discussed in depth in this paper.

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Section: A Contribution Of Internal Noisementioning

confidence: 99%

“…For example, the computation of T rcv using a voltage framework was demonstrated in [1], while other power based methods are covered in [2] and [3] which involves the calculation of available gain of the phased array. For radiation efficiency calculation, power based frameworks were demonstrated in [4]- [6].…”

Section: Introductionmentioning

confidence: 99%

Noise Temperature of Phased Array Radio Telescope: The Murchison Widefield Array and the Engineering Development Array

Ung

Sokołowski

Sutinjo

et al. 2020

IEEE Trans. Antennas Propagat.

Self Cite

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“…Let us collate the calculated matrices Z r and Z l with their counterparts from the previous example. Comparing the Z r matrices, (47) with (26), as well as (50) with (29), it is easy to see that each pair of matrices has not only the same structure but also has elements of similar magnitude, the difference between which does not exceed 2-4 Ohms. A similar comparison of the loss resistance matrices Z l , (48) with (27) and (51) with (30), shows that they also have the same structure, but they noticeably differ in magnitude, the elements of these matrices for array antennas in free space are about 2-3 times less than for arrays above the imperfect ground.…”

Section: Dipole Array With Lossy Parasitic Elementmentioning

confidence: 99%

“…is property of the loss resistance was confirmed by an analysis of the mutual coupling between two lossy dipoles [22], as well as by investigation of the array of vertical [23] and horizontal [24,25] dipoles located above the imperfect ground. In recent years, in connection with the construction of new ground-based radio telescopes using large aperture arrays, as well as the reflector antennas with phased array feeds [26], explorations of the effect of losses on the different array parameters have been intensively continued [27][28][29]. Despite this, the mutual coupling properties in the lossy array antenna have not yet been fully studied.…”

Section: Introductionmentioning

confidence: 99%

Mutual Impedance Properties in a Lossy Array Antenna

Tokarsky

2019

International Journal of Antennas and Propagation

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The impedance matrix of an arbitrary multiport array antenna with Ohmic losses was studied. It was assumed that the partial current distributions in the array, corresponding to the alternate exciting one of its terminals while the other ones are open-circuited, are known. Consideration of the power balance in the lossy array antenna has allowed ascertaining that its impedance matrix is a sum of the radiation resistance matrix and loss resistance matrix, which are in general case complex Hermitian matrices and only in some particular cases can be real. The theoretical statements obtained are confirmed by two numerical examples, where analysis of two lossy dipole arrays was performed. In the first example, the dipoles were located above the imperfect ground, which served as a source of losses, and in the second example, the same dipoles were located in free space, and the embedded parasitic element was the source of losses. The results of the analysis showed that the asymmetric placement of energy absorbers in the array antennas leads to the appearance of imaginary parts in the matrices of radiation and loss resistances, which allow one to correctly predict the behavior of the array radiation efficiency during beam scanning.

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“…There is no improvement in the mapping efficiency on account of these effects. In the last decade, a set of smaller focal plane radiating elements referred to as PAFs have been employed which has gained wide interest among the radio astronomy community (Fisher & Bradley 2000;Hay & Bird 2015;Warnick et al 2016). In such PAF receivers, each element is electrically small, and thus does not optimally illuminate the reflector.…”

Section: Focal L-band Array For the Green Bank Telescope (Flag)mentioning

confidence: 99%

Phased Array Feed Beamforming and its Application in Mapping Extended Sources

Roy¹

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Ever since the detection of radio signals, technology has strived to improve the performance of the hardware associated with detecting and observing faint radio sources by improving signal processing and detection techniques. Phased array feeds (PAFs) for radio telescopes can yield in an increase in the survey speed and field of view for reflector antennas. Beamforming, calibration, and imaging are some of the challenges that need to be addressed in order to further the development of PAFs. There is a trade-off between achieving high sensitivity and maintaining a stable clean beam pattern when it comes to beamforming design strategies. A new beamforming strategy is discussed in this paper which is sub optimal but can be improved with time.

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Phased Arrays for Radio Astronomy, Remote Sensing, and Satellite Communications

Cited by 79 publications

References 250 publications

Noise Temperature of Phased Array Radio Telescope: The Murchison Widefield Array and the Engineering Development Array

Noise Temperature of Phased Array Radio Telescope: The Murchison Widefield Array and the Engineering Development Array

Mutual Impedance Properties in a Lossy Array Antenna

Phased Array Feed Beamforming and its Application in Mapping Extended Sources

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