P. Benthem

SKA Mid Frequency Aperture arrays: Technology for the ultimate survey machine

Higher frequency Aperture Array technology, up to 1.5GHz, is being prepared for large scale deployment in radio astronomy. Novel approaches in order to increase performance and lower the production costs are a key element of the success as well as scientific demonstration. This paper describes the current status, technology innovations and planned demonstrators.

Improved sensitivity of a low noise aperture array tile for the SKA

Aperture array technology is one of the candidate technologies for the 500 MHz to 1500 MHz frequency range of the SKA. The feasibility and low noise potential of aperture arrays have been demonstrated with small test systems before, e.g. with a 50 K system noise temperature, measured on a 1 m2 prototype tile in 2010. However, further reduction of the array noise temperature is essential to optimize the ratio of effective collecting area and system noise temperature. This is made possible by applying new, lower noise, technology to the LNA design. Thus the sensitivity requirement for the Mid Frequency Aperture Array of the SKA could be satisfied at lower cost. Results of a step by step approach to reduce the system noise temperature to below 40 K, giving at least 20% improvement, are presented.

EMBRACE: First experimental Results with the Initial 10% of a 10,000 Element Phased Array Radio Telescope

The Electronic Multi-beam Radio Astronomy Concept (EMBRACE) is the first full-scale prototype of an SKA phased array station. This single polarization demonstrator operates between 500 and 1500 MHz. The station that is currently being built at the site of the Westerbork Synthesis Radio Telescope, will ultimately consist of 144 tiles with 72 single polarization Vivaldi antennas each, giving a total of ∼ 104 elements. The station is equipped with a LOFAR station backend with 192 input channels, which can be exploited for real-time digital beam forming in 248 frequency channels of 195 kHz (∼ 48 MHz total bandwidth) and correlation in a single 195 kHz frequency channel. In this paper we present the results from a number of system validation measurements and the first fringes on an astronomical source, the sun. These initial measurements indicate a system temperature between 103 K and 117 K. These results corroborate the feasibility and applicability of phased array technology at frequencies below 1500 MHz. They also provide valuable insights for the aperture array verification program, the next step in aperture array development towards the SKA.

Aperture array verification system 1: Overview of a square kilometre array prototype

Aperture Array Verification System 1 (AAVS1) is a prototype and verification platform for SKA-Low, the low-frequency component of the international Square Kilometre Array (SKA) radio telescope to be built at the remote, radio-quiet Murchison Radio-astronomy Observatory (MRO) in Western Australia. The 400-antenna AAVS1 is a sparse aperture array which will be built and characterized in 2016-17. It is the primary Critical Design Review demonstrator for SKA-Low and is an undertaking by the seven-member Aperture Array Design and Construction Consortium. AAVS1 is hosted at the MRO by the Murchison Widefield Array (MWA) radio telescope, the first operational SKA precursor telescope. This paper introduces the AAVS1 instrument and outlines its use in both stand-alone and MWA-adjunct modes.

The SKA low frequency aperture array

The deployment of the Square Kilometre Array (SKA) [1] starts with a ~10% instrument, phase 1, commencing with construction in 2018. This includes the SKA1-Low, a sparse Aperture Array (AA) covering 50 to at least 350MHz. SKA1-Low will consist of 512 stations, each with 256 antennas creating a total of more than 130.000 antennas. The configuration will be closed packed with a large fraction of the antennas within a 1.7km radius central area and the remaining collecting area situated on three spiral arms, extending to a radius of ~45km.

Mid frequency aperture array technology developments for the SKA

This paper describes the technology developments of antenna arrays for the mid frequency instrument of the Square Kilometre Array radio telescope.

The low frequency receivers for SKA 1-low: Design and verification

The initial phase of the Square Kilometre Array (SKA) [1] is represented by a −10% instrument and construction should start in 2018. SKA 1-Low, a sparse Aperture Array (AA) covering the frequency range 50 to 350 MHz, will be part of this. This instrument will consist of 512 stations, each hosting 256 antennas creating a total of 131,072 antennas. A first verification system towards SKA 1-Low, Aperture Array Verification System 1 (AAVSl), is being deployed and validated in 2017.