Gain-controlled amplifier and distributed amplifier

Claim 1

A distributed amplifier comprising: an input inductor circuit including a plurality of inductance elements connected in series, the input inductor circuit having first and second terminals; an output inductor circuit including a plurality of inductance elements connected in series, the output inductor circuit having first and second terminals; a plurality of gain-controlled amplifier units, each unit including a transistor amplifier and output means dc-coupled to the transistor amplifier, each unit having input and output terminals, the input terminal of each unit being coupled to the respective junction of the inductance elements of the input inductor circuit, the output terminal of each unit being coupled to the respective junction of the inductance elements of the output inductor circuit; means for providing an amplifier gain control signal to each of the gain-controlled amplifier units; an input network coupled to the second terminal of the input inductor circuit, the input network providing an input dc bias voltage to the transistor amplifier of each unit via the respective inductance elements of the input inductor circuit and functioning as an input impedance element; and an output network coupled to the first terminal of the output inductor circuit, the output network providing a dc operating voltage to the output means of each unit via the respective inductance elements of the output inductor circuit and functioning as an output impedance element, wherein an input signal is fed to the first terminal of the input inductor circuit and an amplified output signal is provided from the second terminal of the output inductor circuit, the transistor amplifier of each of the gain-controlled amplifier units comprising: first and second transistors, the emitters of which are coupled to each other; first and second resistance elements coupled to the collectors of the first and second transistors, respectively; third and fourth transistors, the emitters of which are coupled to each other, the collectors of the third and fourth transistors being coupled to the collectors of the second and first transistors, respectively, the bases of the third and fourth transistors being coupled to the bases of the first and second transistors, respectively; first current means for providing a first coupled emitter current flowing in the coupled emitters of the first and second transistors, the first current means including a fifth transistor, the collector of which is coupled to the coupled emitters of the first and second transistors; second current means for providing a second coupled emitter current flowing in the coupled emitters of the third and fourth transistors; and input means coupled to the respective junction of the inductor elements of the input inductor circuit, the input means providing a dc bias in response to the input dc bias voltage from the input network and providing an ac signal in response to the input signal, the dc bias and ac signal being applied to the base of the fifth transistor of the input means, the output means of each of the gain-controlled amplifier units comprising a sixth transistor, the base of which is dc-coupled to the collector of the second transistor, the collector of the sixth transistor being coupled to the respective junction of the inductance elements of the output inductor circuit.