Quasioptical characterisation of a mm-wave receiver for atmospheric remote sensing

In this paper, we present the quasioptics of a millimetre wave radiometer for the remote sensing of atmospheric water vapour. The presented work addresses the design of the quasioptics with special emphasis on the verification of theoretical aspects by measurements of phase, amplitude and polarisation. The optical behaviour of a quasioptical isolator and a Martin-Puplett interferometer for the suppression of the undesired sideband is discussed in detail. It is shown that the optical behaviour of a rooftop mirror is different from what is theoretically expected.