A Radiometer for a Space Communications Receiver

Abstract

By adding a square wave of noise to the input of an ultra‐low‐noise receiver via a directional coupler, a radiometer with a sensitivity greater than a Dicke type can be achieved when the basic system temperature is less than 18°K. A noise‐adding radiometer is compatible with a communications receiver and has been used (i) to measure and monitor the absolute system temperature and (ii) to check the boresighting of a space communications antenna by detecting and tracking radio stars.

L-band radiometer design for long-term stability measurement of one-port devices

“…It is clear from (11) and (13) that a low loss coupler is desired to minimize the measurement error. Equation 13can also be minimized if (15) is equal to 0, i.e.…”

“…The gain modulation radiometer is another type of receiver for obtaining balanced operation of the DR [1]. The Noise Adding Radiometer (NAR) does not require a switch at the receiver input [11]. An excess noise level is periodically added to the antenna input signal with the help of a directional coupler.…”

An electronically switched microwave radiometer

“…Hence, it is possible to satisfactorily pulse the reference noise source at 1 kHz. A similar technique has been used by Ohm and Snell (1963) in an added-noise radiometer.…”