On the front-end design of mid-frequency aperture array for square kilometre array

Abstract

Complementary to the conventional dish radio telescopes, aperture arrays provide a technically attractive approach to achieve a large field of view and flexibility in observational parameters e.g. Sky area vs. bandwidth. Designs of both aperture array elements and overall geometry for the SKA Mid Frequency Aperture Array are presented here, together with resulting trade-offs. The paper reports the latest developments of global efforts on the front-end design of Mid-Frequency Aperture Array, not attempting to make technology selections, as the priority of sciences and the time for implementing Mid-Frequency Aperture Array is yet to be fully confirmed. Different ongoing front-end solutions are introduced, particularly crossed ring antenna array with a planar structure is explored in more detail as it is less known in the community. Key performances of the candidate front-end technologies are addressed by examining the prototypes. The objective of the collaborative study is to increase technology readiness for implementation of Mid-Frequency Aperture Array in the future.

Extraction of Electrical- and Noise-Parameters of Fully-Differential-Amplifier Subcircuits

“…A method of removing this assumption is discussed in Appendix B in which case current sources could be used instead. Although these assumptions are limiting, they are satisfied by many high-frequency integrated differential amplifiers, which are usually built based on single-ended amplifiers with inductors forming their common networks [1]- [9], [22]. Each input and output is outfitted with two connectors (in this work, a 50 coaxial connector) that allow for measurements using standard, single-ended equipment.…”

“…ferential amplifier subcircuits, thereby supplying additional information to the above-described measurement processes. The proposed method was initiated in response to the development of differential single-stage low-noise amplifiers (LNAs) for the Square Kilometer Array (SKA) radio telescope [1]- [9] and is intended for such differential amplifiers that comply with three requirements, namely: (a) passive common networks; (b) only one stage, and (c) no internal reference to ground in its subcircuits. The last requirement will be discussed in more detail in Section II-A while the first requirement is not necessary if only electrical parameters are of interest.…”

Triangular grid interconnected crossed rings antenna for large‐scale ultra‐wideband dual‐polarised arrays

“…For application such as the SKA mid‐frequency array, the required sensitivity is at the frequency of 800 MHz [21]. The number of elements needed to achieve this performance in a square grid is 25.3 M. Using a triangular grid, the number of elements needed for the same sensitivity is 22 M, reducing the total number of elements by 3.3M [23]. This investigation proves that the C‐ORA design with elements arranged on a triangular grid is a robust solution for such application.…”

Yield and Sensitivity Analysis of Multi-Element Antenna Arrays Using the Non-Linear Partial Least-Squares Polynomial Chaos Expansion Technique

“…Each antenna design requires a specific number of elements for the realization of the MFAA. C-ORA MFAA realization requires 20.3 million elements for triangular grid configuration with 7% thinning, 25.3 million for Vivaldi while LPDA implementation requires 6.5 million elements [2]. Therefore, determination of yield for each MFAA candidate antenna is of importance since a high volume of elements cannot be modified after manufacturing.…”