Thales

Thomson C&f Detexis

Claude Auric

Philippe Dueme

Jean-Philippe Plaze

The invention relates to a broadband microwave device with switchable gain comprising a microwave signal input E and output S, a distributed amplifier with a plurality of amplifying cells comprising an input transmission line for an input signal applied to the microwave signal input E, said input transmission line having one of its two ends linked to the microwave signal input E, an output transmission line for said amplified input signal having an output end of the distributed amplifier, the cells of the distributed amplifier settable either to an amplifying state or to a blocked state. A switch switches the microwave signal output S either to a non-amplification position linked to the other end of the input transmission line, or to an amplification position linked to the output end of the distributed amplifier. A control unit supplies switch position control and amplifying cell status control signals.

Broadband microwave device with switchable gain

An interface device is disposed between an optoelectronic sensor and a load the impedance of which is lower than that of the sensor. The interface device comprises an impedance adaptation stage, comprising a distributed amplifier with a broad band of frequencies, the input of which is directly connected to a terminal of the sensor, and constitutes an impedance with an ohmic value which is greater than that of the load, and the output of which is connected to the load. The device additionally comprises a bootstrap which comprises a field-effect transistor mounted in a common drain, the gate of which is connected to a terminal of the sensor, and the source of which is connected to the other terminal of the sensor, via a capacitor with a selected value. The noise factor of an optical connection which uses the said sensor is reduced, whilst maintaining a high, flat level of gain in a very broad frequency band ranging from a few kHz to a few GHz, whereas the bootstrap can compensate for the undesirable effects of the parasitic capacitor of the sensor.

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Chateaufort, France

Claude Auric