Abstract: A gallium arsenide (GaAs) radio frequency (RF) circuit is disclosed. The GaAs RF circuit includes a power amplifier and a low noise amplifier; a first transmit/receive (TR) switch, coupled to the power amplifier and the low noise amplifier, wherein the first TR switch is fabricated by a pHEMT (Pseudomorphic High Electron Mobility Transistor) process; and a first active phase shifter, coupled to the power amplifier or the low noise amplifier, wherein the first active phase shifter is fabricated by an HBT (Heterojunction Bipolar Transistor) process; wherein the GaAs RF circuit is formed within a GaAs die.

Abstract: A bias compensation circuit, coupled to an amplifying transistor, is disclosed. The bias compensation circuit comprises a voltage locking circuit, comprising a first terminal and a second terminal, wherein the first terminal is coupled to a third terminal the amplifying transistor, and the second terminal is coupled to a control terminal of the amplifying transistor; and a first resistor, coupled to the first terminal of the voltage locking circuit; wherein when the voltage locking circuit is conducted, a voltage difference between the first terminal and the second terminal is substantially constant.

Abstract: A bias compensation circuit, coupled to an amplifying circuit, is disclosed. The bias compensation circuit comprises a transistor, comprising a first terminal, a second terminal and a control terminal; a first feedback transistor, comprising a control terminal, coupled to the first terminal of the transistor; a first terminal, coupled to the control terminal of the transistor; and a second terminal; and a second feedback transistor, comprising a control terminal, coupled to the first terminal of the transistor; a first terminal, coupled to the amplifying circuit; and a second terminal; and a first resistor, comprising a first terminal, coupled to the first terminal of the transistor; and a second terminal, configured to receive a first voltage.

Abstract: A gallium arsenide (GaAs) radio frequency (RF) circuit is disclosed. The GaAs RF circuit includes a power amplifier and a low noise amplifier; a first transmit/receive (TR) switch, coupled to the power amplifier and the low noise amplifier, wherein the first TR switch is fabricated by a pHEMT (Pseudomorphic High Electron Mobility Transistor) process; and a first active phase shifter, coupled to the power amplifier or the low noise amplifier, wherein the first active phase shifter is fabricated by an HBT (Heterojunction Bipolar Transistor) process; wherein the GaAs RF circuit is formed within a GaAs die.