Abstract: A selective low noise amplifier (LNA) comprising an input hybrid coupler receives a first input and a second input and to provide a first output and a second output; and an output hybrid coupler receives a first input and a second input and to provide for at least one output. A first amplifier and a second amplifier, each respective amplifier in first and second parallel paths are couple to and between the first output and the second output, respectively, of the input hybrid coupler and the first input and the second input, respectively, of the output hybrid coupler. A phase controller coupled to at least one of the first input and the second input of the output hybrid coupler delays signals from the first and second inputs of the output hybrid coupler to the at least one output of the output hybrid coupler. A method is also disclosed.

Abstract: Embodiments are directed to a dynamic multi-mode radiometer system and method for automated calibration of the system. In an embodiment, the system comprises a radiometer channel including an input selective low noise amplifier (LNA) and radiometer receiver. The LNA comprises a first input and second input and an output coupled to the radiometer receiver. The system includes an antenna coupled to the first input and a reference load selectively connected to the second input, the reference load configured to produce a first signal representative of a reference temperature. The system includes an internal calibrated noise generator selectively connected to the second input of the LNA and includes an internal noise source for producing a second signal representative of an injected noise temperature. The generator is configured to calibrate the radiometer receiver as a function of the injected noise temperature equalized to the reference temperature.