The Ka-band receiver for the QUIJOTE experiment

The 26-36 GHz receiver for a radio astronomy radiometer, to characterize the polarization of the Cosmic Microwave Background, is presented. This receiver is based on very low noise cryogenically cooled amplifiers in the front-end module, while in the back-end module a broadband amplification and direct detection chain is operated at room temperature. Noise temperature of the low-noise amplifier (LNA) is 19 K when cooled at 18 K. Experimental results show a good sensitivity of the complete receiver with an effective bandwidth around 8 GHz. Moreover, output detected voltages agree with estimated values.