Highly Efficient Balanced Power Amplifiers for Carrier Aggregation

This paper presents a highly linear balanced power amplifier with miniaturised quadrature hybrid coupler for carrier aggregation (CA). The miniaturised quadrature coupler is designed using a novel U-shaped transmission line (USTL) concept to achieve good size reduction. The novel branch-line coupler is used to design a wideband balanced PA. The performance of the balanced PA is compared to a single PA solution. The balanced PA shows better performance with improved matching properties and better electrical stability. There was an increase in saturated maximum output power (Pout) from 8 dBm for the individual PA to 13.41 dBm for the balanced with a power aided efficiency (PAE) of 43.92%. The highly linear balanced PA achieves a 14 dB ACPR reduction and also improves ACPR by 12 dB for non-contiguous and 9 dB for contiguous carrier aggregation