Active antenna development for the SKA

The Square Kilometre Array (SKA) will be the most sensitive radio telescope ever built. It is divided into three operating bands. Sparse aperture arrays (SKA-low) are used at the lowest operating band of 70 – 450 MHz. The International Centre for Radio Astronomy (ICRAR) is exploring conical spiral antennas as one candidate antenna design for SKA-low. One of the attractive features of the conical spiral antenna is its frequency-stable impedance. This helps in matching it to external components such as a low-noise amplifier (LNA). A prototype LNA based on GaAs HEMT technology that might be suitable for the conical spiral antenna has been evaluated. Presented in this paper is the current design path for a conical spiral antenna with attached LNA.