A microwave sensor assembly comprising: at least one probe comprising an emitter having at least one resonant frequency within a microwave frequency range, the emitter configured to: generate an electromagnetic field from at least one microwave signal, the at least one microwave signal having a frequency equal to the at least one resonant frequency; change the at least one resonant frequency in response to an object entering the electromagnetic field or a change in relative position of an object within the electromagnetic field generate at least one loading signal representative of a loading induced within said emitter by the object entering the electromagnetic field or by a change in relative position of the object within the electromagnetic field; and a signal processing device coupled to said at least one probe, wherein said signal processing device comprises a linearizer including a loop amplifier and a transfer function device, the linearizer configured to generate a substantially linear output signal based on the at least one loading signal and a transfer function feedback loop provided by the transfer function device. at least one probe comprising an emitter having at least one resonant frequency within a microwave frequency range, the emitter configured to: generate an electromagnetic field from at least one microwave signal, the at least one microwave signal having a frequency equal to the at least one resonant frequency; change the at least one resonant frequency in response to an object entering the electromagnetic field or a change in relative position of an object within the electromagnetic field generate at least one loading signal representative of a loading induced within said emitter by the object entering the electromagnetic field or by a change in relative position of the object within the electromagnetic field; and a signal processing device coupled to said at least one probe, wherein said signal processing device comprises a linearizer including a loop amplifier and a transfer function device, the linearizer configured to generate a substantially linear output signal based on the at least one loading signal and a transfer function feedback loop provided by the transfer function device. generate an electromagnetic field from at least one microwave signal, the at least one microwave signal having a frequency equal to the at least one resonant frequency; change the at least one resonant frequency in response to an object entering the electromagnetic field or a change in relative position of an object within the electromagnetic field generate at least one loading signal representative of a loading induced within said emitter by the object entering the electromagnetic field or by a change in relative position of the object within the electromagnetic field; and a signal processing device coupled to said at least one probe, wherein said signal processing device comprises a linearizer including a loop amplifier and a transfer function device, the linearizer configured to generate a substantially linear output signal based on the at least one loading signal and a transfer function feedback loop provided by the transfer function device.