Investigating Concurrent-Mode Operation of Dual-Band Class-J/J Power Amplifiers: Analysis and Design Technique

In this paper, concurrent-mode operation of dual-band PAs under simultaneous drive of two stimuli is investigated. It is shown that Class-J operation is well suited for this mode of operation as its concurrent-mode efficiency is less affected by the load reactance tuning accuracy at inter-modulation frequencies. This characteristic results in preserved efficiencies over wider bandwidths, and simplicity of intermodulation tuning network (IMTN) realization. It has been also shown that dual-band Class-J/J PA fully takes advantage of the transistor's nonlinear output capacitance in case of simultaneously driven input by boosting the efficiency. A Class-J/J concurrent dual-band PA with IMTN is designed and implemented which operates over 1.842/2.655 GHz bands. About 40 dBm output power and efficiencies more than 70% at lower band and upper band are obtained according to the experimental results while the concurrent-mode efficiency is about 61.2%.