GaN-Based Digital Transmitter Chain Utilizing Push-Pull Gate Drivers for High Switching Speed and Built-In DPD
Proc. 12th European Microwave Integrated Circuits Conf. (EuMIC 2017), Nuremberg, Germany, Oct. 9-10, pp. 97-100 (2017).
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This paper presents a fully digital transmitter chain, including a modulator and a digital microwave power amplifier (PA) MMIC. It uses push-pull drivers for the gates of the class-D final stage for improved switching speed. To the authors’ knowledge this is the first time this approach is implemented on a GaN HEMT process. The performance of the flexible and compact chip is evaluated with modulated baseband signals at a 900MHz carrier. For encoding the IQ signals into a binary stream, a modulation scheme with a built-in DPD is used, resulting in a higher line-up efficiency as no additional computational power is dissipated. ACLR values of more than 43.5 dB are reached almost fulfilling the 3GPP spectral requirements. A comparison of achieved signal quality to other publications is given.
Ferdinand-Braun-Institut (FBH), Leibniz-Institut fuer Hoechstfrequenztechnik, 12489 Berlin, Germany
digital transmitter, digital pre-distortion, switchmode amplifier, digital PA.