Radiómetro en banda W para aplicaciones de radioastronomía

Abstract

A W-band radiometer with intermediate frequency down-conversion for radio astronomy applications is presented. The receiver consists of two W-band low noise amplifiers followed by a subharmonic mixer, intermediate frequency amplification and a square-law detector. The performance of the receiver subsystems is characterized experimentally. The receiver works in the 82 to 96 GHz frequency band, and using a local oscillator of 27.1 GHz with 8 dBm of available power, it exhibits an overall conversion gain around 48 dB, a noise figure of 4.5 dB, and an effective bandwidth of 10 GHz. The receiver performance is characterized when a broadband noise input signal is applied. The radiometer characteristic has been obtained working as a total power radiometer and as a Dicke radiometer when an optical chopper is used to modulate the incoming signal.