A 3.3 V mode-switching RF CMOS power amplifier (PA) for WLAN applications is presented, which is integrated into a 55-nm bulk CMOS process. The proposed PA offers both static control and dynamic power control, allowing it to operate efficiently in both low-power and high-power modes. The pure low-power mode is achieved by reducing power cells, which are also used for linearization in high power mode. The low-power mode is achieved by reducing the number of power cells which are also used for linearization in the high-power mode. In the dynamic power control mode, the total AM–AM and AM–PM distortion is effectively compensated for by dynamically controlling the number of power cells and adjusting the matching input. The proposed PA achieves an output P1dB of 27.6 dBm with a PAE of 32.7% and an output P1dB of 17.7 dBm with a PAE of 10% in high-power and low-power modes, respectively. It is measured with an 802.11 n 64-quadrature-amplitude-modulation (MCS7) signal and shows a maximum average power of 19 dBm under an error-vector-magnitude (EVM) of −27 dB.

In this paper, a methodology for designing a distributed model for coplanar asymmetry transformer on gallium nitride (GaN) process is proposed, which can accurately characterize the transformer’s feature up to a millimeter-wave band. The paper analyses a transformer-based matching circuit and proposes a practical transformer design procedure. A two stage, transformer matching based X-band power amplifier (PA) is reported here. Using the proposed transformer model and correlated transformer design procedure can sharply reduce schematic design period and optimum process time. The PA chip is designed on a 0.25 µm GaN technology process and occupies a 1.515 mm² area. At a 28 V supply, the gain and output power of the PA reaches 15 dB and 29 dBm respectively, and the wideband matching transformer reaches 47.6% bandwidth. To the best of our knowledge, the distributed model for coplanar asymmetry transformer and transformer-based X-band MMIC PA on GaN process in this work is the first case among the reported papers.

This paper presents a dual-band fully integrated high linearity CMOS power amplifier (PA). The PA employs a reconfigurable transformer in the input matching network to achieve low reflection coefficient across both bands, demonstrating significant flexibility in the design of dual-band power amplifiers with high output powers. Additionally, a detailed design methodology for the dual-band matching network is introduced. By utilizing this methodology, the PA has been designed using 55 nm CMOS technology. For continuous-wave operation, the PA achieves a saturated power ($P_{sat}$) of 28.03 dBm and 27.5–28.2 dBm, with power-added efficiency (PAE) of 33.2% and 24.6–31.1%, in the 2.4 GHz and 5 GHz WLAN bands, respectively. Concurrently, the PA power cells, which employ multi-gate transistor (MGTR) technology, achieve an intermodulation distortion (IMD3) of below 30 dBc at an output power of 15 dBm in both the 2.4 GHz and 5 GHz WLAN bands. The proposed PA outperforms other dual-band or multi-band PAs in terms of output power and exhibits great potential for WLAN applications.