An 18–28 GHz Power Amplifier with Drain-Distorted Linearizer in 90 Nm CMOS Process

An 18–28 GHz power amplifier (PA) featuring the characteristic of the in-band frequencies of sweet spots curves of IMD3 is presented. With the linearizer at the drain terminal of the transistor, the sweet spots curves of IMD3 tolerate a wide range of biases and frequencies variations. The performances of $P_{\text{sat}}, P_{1\text{dB}}$ , peak PAE of the proposed PA at 24 GHz are 21.7 dBm, 18.8 dBm, and 31.6 %, respectively. With the linearizer activated, the third order intermodulation distortion (IMD3)is improved by 27 dB. At frequencies of 18, 24, and 28 GHz with 40 dBc of IMD3, the output powers reach 10.4, 13.3, and 12.5 dBm, respectively. The chip size occupies 0.36 mm2. To the best of the authors' knowledge, this PA features the widest frequencies of sweet spots curves of IMD3 compared with the previous works. Additionally, this work is the first to address the tolerance of the linearizer against biases by inserting the linearizer into the PA at the drain terminal of the transistor.