Short backfire antenna with concentric sleeves for highly sensitive radio astronomical receivers

A broadband 800-MHz short backfire antenna (SBA) integrated with a cryogenic vacuum chamber is designed for astronomical applications. The cryostat offers the low-temperature condition to front-end components because of low-noise demands for the astronomy observations. In order to overcome the impacts from the cryostat, the SBA adopts a pair of concentric sleeves to replace the conventional double-discs design. It features a dual-mode response and enhances the bandwidth. The simulated results show the VSWR less than 2.2 and the gain of 11-15 dBi over the band of 700-945 MHz.