Abstract: A detection circuit for detecting the output power of a power amplifier comprises a first current minor transistor (Ti 1) having a base, which is connectable to a power transistor (T10), and a collector, a RF detection means (RF-det) for detecting the RF current flowing through the current mirror transistor (T11). Said RF detection means (RFdet) is connected to the collector of said first current mirror transistor (T11). Said detection circuit further comprises a biasing means (bias-RF-det) for biasing said RF detection means (RF-det), wherein said biasing means is connected to said collector of said first current mirror (T11) and said RF detection means (RF-det).

Abstract: An RF power amplifier according to the invention comprises a plurality of parallel output transistors (HBT,1,1 to HBT,1,N) connected to a power supply. A plurality of base resistors (Rb,1,1 to Rb,1,N) for the output transistors (HBT,1,1 to HBT,1,N) and a plurality of input capacitors (Cb,1 to Cb,N), each coupled in parallel to receive an RF signal input and connected via at least one additional passive component to the inputs of each corresponding output transistor (HBT,1,1 to HBT,1,N), are provided. An output for an RF output signal is obtained from the parallelconnection of the output transistors (HBT,1,1 to HBT,1,N). The transistors (HBT,1,1 to HBT,1,N) are heterojunction bipolar transistors.

Abstract: A bias circuit for a radio frequency linear power amplifier includes an input for selecting an operating mode varying in quiescent current of an output transistor. A sensor senses a current through the output transistor and a circuit biases the output transistor for maintaining linear performance in each of mode over a range of temperatures. A filter attenuates noise generated within the linear power amplifier. A tank circuit at the collector of a power radio frequency transistor, having an inductor capable of handling the collector current, resonating with a capacitor at the design frequency, permits a reduction in the required inductance and therefore higher levels of integration.

Abstract: A bias circuit for a radio frequency linear power amplifier includes an input for selecting an operating mode varying in quiescent current of an output transistor. A sensor senses a current through the output transistor and a circuit biases the output transistor for maintaining linear performance in each of mode over a range of temperatures. A filter attenuates noise generated within the linear power amplifier. A tank circuit at the collector of a power radio frequency transistor, having an inductor capable of handling the collector current, resonating with a capacitor at the design frequency, permits a reduction in the required inductance and therefore higher levels of integration.