A 2–20-GHz 10-W High-Efficiency GaN Power Amplifier Using Reactive Matching Technique

In this article, we present the analysis, design, and implementation of a wideband 10-W monolithic microwave integrated circuit power amplifier (PA), fabricated in a low-cost 0.1-μm gallium nitride (GaN) on Si technology. The design is focused on the realization of a low-loss and wideband impedance transformation networks across 2-20 GHz using a reactive matching (RM) technique. The two-stage GaN PA achieves an average output power of 40.1 dBm and a peak output power of 41.6 dBm at 13 GHz, in the CW-mode operation, with a smallsignal gain of S₂₁ > 25.5 dB over the entire bandwidth. The average power-added efficiency (PAE) is 21%, with a peak PAE of 29% at 6 GHz. The PA chip occupies an area of 2.9×2.6 mm². To the best of our knowledge, the PA presented in this work demonstrates the highest broadband gain among the reported GaN-based RMPAs with a corresponding output power of about 10 W.

I. Introduction

With the growth in applications of the millimeter-wave spectrum for terrestrial wireless communication, satellite radio, automotive radar, electronic warfare, and instrumentation systems, the demand for fully integrated broadband high-power, high-efficiency power amplifiers (PAs) is growing [1]–[4]. To meet this demand, the III–V compound semiconductor monolithic microwave integrated circuit (MMIC) is the preferred choice for such PAs [5]. In order to obtain the high-power level for the abovementioned systems, it is a common method to combine the output power () of several individual MMIC PA chips [6]. However, this combination can cause an increased loss in the synthetic network. Thus, to compensate for this loss, it is generally necessary to add a driver amplifier chip appropriately. As a result, the increased number of amplifier chips in the system leads to a higher production cost. Meanwhile, in order to improve the interstage stability, it is necessary to add isolators to guarantee the multistage amplifier cascade work properly [7], [8], which also can make the system more complex and expensive. In conclusion, to simplify the system structure and to reduce the cost, the high-gain and high-power MMIC PA is extremely desired [9]–[11].