A wide-band matching network using SIR concept applying on amplifier for LTE/ISM/Wi-Fi/Bluetooth application

This paper presents a wide-band SIR matching amplifier for implementation in ISM band, LTE, Wi-Fi and Bluetooth systems. In this design, resistance is shunted at the collector side to stabilize the BJT. Stepped-impedance resonators (SIRs) is applied in the matching network to achieve good reflection factor. SIR method is widely applied in filter design, it makes matching design more flexible and accurate because using microstrip line as resonator is easier to correct the value of capacitance and inductance. The proposed amplifier is designed by BJT (BFG425) and FR4 substrate and operates in the frequency range of 0.7-2.76GHz. The measurement also show gain>20dB.