Abstract: A multifinger transistor in which source fingers (201 to 206) and drain fingers (301 to 305) are arranged alternately with each of gate fingers (101 to 110) being sandwiched between one of the source fingers and one of the drain fingers is used. Line (10) and line (20) are attached to the source fingers (201 to 206) in an area on a gate side and causing a phase rotation such that the nearer to a central part a gate finger is, the more inductive the gate finger is.

Abstract: A multifinger transistor in which source fingers (201 to 206) and drain fingers (301 to 305) are arranged alternately with each of gate fingers (101 to 110) being sandwiched between one of the source fingers and one of the drain fingers is used. Line (10) and line (20) are attached to the source fingers (201 to 206) in an area on a gate side and causing a phase rotation such that the nearer to a central part a gate finger is, the more inductive the gate finger is.

Abstract: A power amplifier includes: an amplifier; an input matching circuit connected to an input of the amplifier; an output matching circuit connected to an output of the amplifier; and a low-frequency processing circuit connected to the input matching circuit or the output matching circuit, wherein the low-frequency processing circuit includes a first line having a first end connected to the input matching circuit or the output matching circuit, a first shot stub connected to a second end of the first line and including a second line and a first capacitor connected in series each other, and a second short stub connected to the second end of the first line in parallel with the first short stub and including a third line and a second capacitor which are connected in series each other, the first line has a length of ?/8, the second line has a length of ?/4, and the third line has a length of ?/8 with respect to a wavelength ? of a fundamental frequency.

Abstract: A power amplifier includes: an amplifier; an input matching circuit connected to an input of the amplifier; an output matching circuit connected to an output of the amplifier; and a low-frequency processing circuit connected to the input matching circuit or the output matching circuit, wherein the low-frequency processing circuit includes a first line having a first end connected to the input matching circuit or the output matching circuit, a first shot stub connected to a second end of the first line and including a second line and a first capacitor connected in series each other, and a second short stub connected to the second end of the first line in parallel with the first short stub and including a third line and a second capacitor which are connected in series each other, the first line has a length of ?/8, the second line has a length of ?/4, and the third line has a length of ?/8 with respect to a wavelength ? of a fundamental frequency.

Abstract: A power amplifying device includes a stabilizing circuit between an input terminal and an amplifier. The stabilizing circuit has a first line, a second line, and a third line. The first line is connected to the ground. The length of the first line is equal to or longer than three fourths of the wavelength of the operating frequency.

Abstract: A power amplifying device includes a stabilizing circuit between an input terminal and an amplifier. The stabilizing circuit has a first line, a second line, and a third line. The first line is connected to the ground. The length of the first line is equal to or longer than three fourths of the wavelength of the operating frequency.

Abstract: A field effect transistor (FET) having a stabilization circuit with a stabilization condition not affected by another circuit element, for example, a matching circuit. The stabilization circuit is pre-formed inside of the FET, thereby pre-stabilizing the FET in a frequency range in which a power amplifier is used.

Abstract: A semiconductor device includes a high-power output transistor chip in which transistor cells are connected in parallel, each transistor cell including stripe-shaped gate electrodes connected to a gate bus, stripe-shaped drain electrodes connected to a drain pad, and stripe-shaped source electrodes connected to a source pad, wherein the drain electrodes and the source electrodes are alternatingly arranged and pairs of source and drain electrodes face each other across one of the gate electrodes; and a resistor including a portion of the gate bus between adjacent transistor cells, for preventing oscillation between the adjacent transistor cells. Since the resistor serves as a loss component, oscillation due to an imbalance in characteristics between adjacent transistor cells is cancelled so that the synthesis efficiency of the transistor cells is improved.