Ka-band cryogenic low-noise receiver of the Misasa 54 m antenna for deep-space communications and radio astronomy.

This article focuses on the development and performance evaluation of a Ka-band dual-circular-polarization low-noise receiver for the Misasa 54 m parabola antenna in Japan, designed for simultaneous operation with an X-band transmitter and receiver system. The Ka band, around 30 GHz, is significant for deep-space communications and radio astronomy due to its low atmospheric attenuation and wider bandwidth compared to the X band (~8 GHz). The receiver incorporates waveguide components—including a feed horn, circular polarizer, band-pass filter, and cryogenic low-noise amplifiers—cooled to 4 K to achieve low noise temperatures (~14 K), well below the required 35 K. System-noise temperatures measured at the antenna site ranged from 29 K to 42 K depending on conditions and configuration, demonstrating performance comparable to or better than existing systems like the Green Bank Telescope. The design also ensures high isolation (>114 dB) between the Ka-band receiver and the high-power X-band transmitter to prevent interference, enabling its use in deep-space telecommunications and radio-astronomy observations.