High efficiency high isolation amplifier

Claim 2

A broadband amplifier comprising a common emitter stage, a common base stage, a common collector stage, and biasing means, wherein the common emitter stage is connected in a cascode configuration to the common base stage, and the common collector stage is connected to the cascode configuration so as to be driven by the common emitter stage in a push-pull configuration with the common base stage.

Claim 3

An amplifier according to claim 1, wherein: (a) the common emitter stage comprises a first transistor having base, collector, and emitter connected in a common emitter configuration, and a resistive feedback loop connected from the first transistor collector to the first transistor base; (b) the common base stage comprises a second transistor having base, collector, and emitter connected in a common base configuration, and a first resistor connected from the second transistor emitter to the first transistor collector; and (c) the common collector stage comprises a third transistor having base, collector, and emitter connected in a common collector configuration, with its base connected to the collector of the first transistor, and a second resistor connected from the third transistor emitter to the second transistor collector.

Claim 4

An amplifier according to claim 2, wherein the second resistor has a resistance of 50 ohms.

Claim 5

An amplifier according to claim 3, wherein the first resistor has a resistance of 50 ohms.

Claim 6

An amplifier according to claim 3, wherein the first resistor has a resistance greater than 50 ohms.

Claim 7

An amplifier according to claim 2, further comprising a first inductive choke attached in parallel with the first resistor and a second inductive choke attached in parallel with the second resistor.

Claim 8

A broadband RF amplifier comprising: (a) an input terminal; (b) a first transistor having base, collector, and emitter; (c) a first bypass capacitor connecting the input terminal to the first transistor base; (d) a first resistor connecting the first transistor emitter to ground; (e) shunt feedback connected from the first transistor collector to the first transistor base, said shunt feedback comprising a second bypass capacitor and a second resistor; (f) a second transistor having base, collector, and emitter; (g) a third bypass capacitor connecting the second transistor base to ground; (h) a third resistor connecting the second transistor emitter to the first transistor collector; (i) a third transistor having base, collector, and emitter; (j) a fourth bypass capacitor connecting the third transistor collector to ground; (k) a fifth bypass capacitor connecting the third transistor base to the first transistor collector; (l) a fourth resistor connecting the third transistor emitter to the second transistor collector; (m) an output terminal; (n) a sixth bypass capacitor connecting the output terminal to the second transistor collector; and (o) biasing means.

Claim 9

A broadband RF amplifier comprising: (a) an input terminal; (b) a first transistor having base, collector, and emitter; (c) a first bypass capacitor connecting the input terminal to the first transistor base; (d) a first resistor connecting the first transistor emitter to ground; (e) shunt feedback connected from the first transistor collector to the first transistor base, said shunt feedback comprising a second bypass capacitor and a second resistor; (f) a second transistor having base, collector, and emitter; (g) a third bypass capacitor connecting the second transistor base to ground; (h) a third resistor connecting the second transistor emitter to the first transistor collector; (i) a third transistor having base, collector, and emitter; (j) a fourth bypass capacitor connecting the third transistor collector to ground; (k) a fifth bypass capacitor connecting the third transistor base to the first transistor collector; (l) a fourth resistor connecting the third transistor emitter to the second transistor collector; (m) an output terminal; (n) a sixth bypass capacitor connecting the output terminal to the second transistor collector; and (o) biasing means.

Claim 10

An amplifier according to claim 7, wherein the fourth resistor has a resistance of 50 ohms.

Claim 11

An amplifier according to claim 8, wherein the third resistor has a resistance of 50 ohms.

Claim 12

An amplifier according to claim 8, wherein the third resistor has resistance greater than 50 ohms.

Claim 13

An amplifier according to claim 7, further comprising a first inductive choke attached in parallel with the third resistor and a second inductive choke attached in parallel with the fourth resistor.