The present paper proposes an optimization design method for the Doherty output matching network (OMN) using impedance–phase hybrid objective function constraints, which possesses the capability of enhancing the efficiency consistency of the Doherty power amplifier (DPA) using integrated enhancing reactance (IER) during the back-off power (BOP) range. By calculating the desired reactance for an extended BOP range and combining it with the two-impedance matching method, the S -parameters of the OMN are obtained. Meanwhile, the impedance and phase constraints of the OMN are proposed to narrow the distribution range of the IER. Furthermore, a fragmenttype structure is employed in the OMN optimization so as to enhance the flexibility of the circuit optimization design. To validate the proposed method, a 1.7–2.5 GHz symmetric DPA with a large BOP range was designed and fabricated. Measurement results demonstrate that across the entire operating frequency band, the saturated output power is >44 dBm, and the efficiency ranges from 45% to 55% at a 9-dB BOP.

This article proposes a design and optimization method for Ultra-Wideband power amplifiers (PAs) using improved multiobjective evolutionary algorithm based on decomposition (MOEA/D) and mixed optimization objective function (MOOF). In order to address the insufficient optimization capabilities of conventional MOEA/D algorithm when dealing with complex Pareto fronts, the optimization algorithm is improved by using adaptive weights, neighborhoods, and global replacement. Initially, based on the sparsity of the population and an external population, the weight vectors corresponding to invalid or crowded individuals in the population are replaced. And, the neighborhoods are adaptively adjusted based on the number of iterations and the sparsity of each individual. Then, a global replacement is employed to accelerate the convergence process. Moreover, a MOOF using the load impedance, output power, efficiency and gain is conducted in the PA optimization design. To reduce the difficulty of impedance judgment, a construction method of impedance solution set based on Poisson disk sampling has been proposed and employed for optimization. For validation, an Ultra-Wideband PA operating at 100–4000 MHz (190.2% fractional bandwidth) was designed and optimized. Measured results show a drain efficiency ranging from 56.0% to 70.9% with an output power higher than 39 dBm at saturation within the whole operational frequency band.

A symmetric Doherty power amplifier (DPA) based on integrated enhancing reactance (IER) was proposed for large back‐off applications. The IER was generated using the peaking amplifier with the help of a desired impedance transformation in the low‐power region to enhance the back‐off efficiency of the carrier amplifier. To convert the impedances properly, both in the low‐power region and at saturation, a two‐impedance matching method was employed to design the output matching networks. For verification, a symmetric DPA with large back‐off power range over 2.2–2.5 GHz was designed and fabricated. Measurement results show that the designed DPA has the 9 dB back‐off efficiency of higher than 45%, while the saturated output power is higher than 44 dBm over the whole operation bandwidth. When driven by a 20 MHz LTE signal, the DPA can achieve good average efficiency of around 50% with adjacent channel leakage ratio of about –50 dBc after linearization over the frequency band of interest. The linearity improvement of the DPA for multistandard wireless communication system was also verified with a dual‐band modulated signal.