Parallel combination of high-efficiency amplifiers with spurious rejection for concurrent multiband operation

An efficient concurrent multiband power amplifier configuration has been proposed for high-data-rate wireless communication systems. Single-band high-efficiency power amplifiers are designed by adding spurious rejection functions which are embedded in input and output fundamental-frequency matching circuits. And those amplifiers are connected in parallel. In this configuration, significant merits exist in comparison with usual dual-band or broadband amplifiers, especially with regard to distortion characteristics. To confirm this, a 4.5-/8.5-GHz-band GaN HEMT amplifier was fabricated, and it exhibited maximum drain efficiencies of 64% and 54% and maximum power added efficiencies of 61% and 41% at 4.49 GHz and 8.42 GHz, respectively, on a concurrent operation with a highly suppressed near-band spurious level of less than −38 dBc.