High frequency amplifier
According to one embodiment, a high frequency amplifier having a division circuit, FET cells, a stabilization circuit and a combination circuit is provided. The division circuit divides an input signal to produce a plurality of signals. The FET cells amplify the signals produced by the division circuit. The stabilization circuit provided with RC parallel-connected circuits which are respectively connected in series between the division circuit and gates of the FET cells. Each of the RC parallel-connected circuits has a capacitor and a resistor connected in parallel with each other. The combination circuit combines the signals amplified by the FET cells.
1. A high frequency amplifier, comprising:
a division circuit which divides an input signal to produce a plurality of signals;
FET cells which amplifies signals produced by the division circuit;
a stabilization circuit provided with RC parallel-connected circuits which are respectively connected in series between the division circuit and gates of the FET cells, each of the RC parallel-connected circuits having a capacitor and a resistor connected in parallel with each other; and
a combination circuit which combines signals amplified by the FET cells, wherein the stabilization circuit is arranged on a substrate other than a semiconductor substrate on which the FET cells are arranged.
2. A high frequency amplifier according to claim 1 , wherein each of the FET cells and each of the RC parallel-connected circuits are connected with each other through a wire, respectively.
3. A high frequency amplifier according to claim 1 , wherein the division circuit, the stabilization circuit and the combination circuit are respectively arranged on substrates other than a semiconductor substrate on which the FET cells are arranged.
4. A high frequency amplifier according to claim 3 , wherein the division circuit and the stabilization circuit are arranged on the same substrate other than a semiconductor substrate on which the FET cells are arranged.
5. A high frequency amplifier according to claim 3 , wherein the stabilization circuit includes:
a circuit substrate of a dielectric material;
a first electrode formed on the circuit substrate;
a dielectric layer formed on the first electrode, the resistor being formed on the dielectric layer;
a second electrode formed on the dielectric layer to compose the capacitor with the first electrode and the dielectric layer; and
a third electrode formed in a through hole which is provided in the dielectric layer and connects the first electrode with the resistor electrically.
6. A high frequency amplifier according to claim 4 , wherein the stabilization circuit includes:
a circuit substrate of a dielectric material;
a resistor formed on the circuit substrate;
a capacitor formed on the circuit substrate, the capacitor having a first electrode, a dielectric layer formed on the first electrode, and a second electrode formed on the dielectric layer;
a first conductive line which connects an end of the resistor and the first electrode electrically; and
a second conductive line which connects the other end of the resistor and the second electrode electrically.
7. A high frequency amplifier according to claim 1 , wherein the substrate other than the semiconductor substrate is a dielectric substrate.