Wideband Low-Loss Feed Design for the DSA-2000 Ambient Temperature Array in Radio Astronomy

The Deep Synoptic Array (DSA-2000) is the next generation ground-based radio astronomical array that will consist of 2000×5 m reflectors equipped with an ambient temperature feed package and electronics covering 0.7-2 GHz. The quad-ridge choke horn (QRCH) feed developed for the DSA-2000 is a wideband, low-loss, and low-cost design providing a wide radiation pattern to illuminate the deep prime-focus reflector. We present the predicted noise temperature contributions for the feed, low-noise amplifiers, and surrounding brightness - resulting in a remarkable 25 K system noise at ambient temperature.