Ultra-wideband dc-microwave amplifier device notably in integrated circuit form

Claim 1

An ultra-wideband dc-microwave amplifier, notably for the amplification of signals transmitted at very high bit rates on optic fibers, having a signal input where a signal to be amplified is susceptible to be supplied and a signal output providing for a corresponding amplified signal, the amplifier comprising: an amplification field-effect transistor operating in a common source mode and having a gate, a source and a drain, the gate of the amplification field-effect transistor being operatively connected to said signal input, offset means having an input terminal and an output terminal and comprising a diode bridge having at least one diode, said input terminal being operatively connected to the drain of said amplification field-effect transistor and said output terminal being operatively connected to said signal output, said offset means providing for a voltage drop substantially equal to the dc voltage between the drain and the source of said amplification field-effect transistor, load element means comprising a first field-effect transistor operating as a saturable load and having a gate, a source and a drain, the gate of the first field-effect transistor, being connected to the source of the first field-effect transistor and the drain of the first field-effect transistor being operatively connected to a positive direct current source, said load element means simultaneously maintaining a positive dc voltage bias on the drain of said amplification field-effect transistor and on the input terminal of said offset means; and means for maintaining a dc bias on the gate of said amplification field-effect transistor, comprising a resistor connected betweeen the gate of the amplification field-effect transistor and a source of negative or zero dc bias.