A Design of InP-HBT 100-GHz Diode Linearizer Toward 6G

In this paper, we present a 100-GHz linearizer to improve the linearity of 100-GHz amplifier for sub-THz band (frequency range above 100-GHz) wireless communications in the sixth-generation mobile communication system (6G). The linearizer is designed using the InP-based heterojunction bipolar transistor (InP-HBT) with f
T
/f
MAX
of 450/450 GHz. P-N diode of the base-emitter junction in InP-HBT was used to form the diode. To operate the linearizer in this high-frequency region, we propose the linearizer employing the diode, which has a transmission line (TL) to cancel out a parasitic capacitance of the InP-HBT. To show the validity of the proposed linearizer, we calculated the output-referred 1-dB compression point (OP1dB), gain/phase deviation versus output power, and third-order intermodulation (IM3) of the 100-GHz amplifier with the proposed linearizer using the harmonic-balance simulation. The OP1dB of the amplifier is improved by 1.4 dB at 100 GHz by using the proposed linearizer. The gain/phase deviation and IM3 are also improved at 100 GHz. To the best of the authors’ knowledge, this is the first study of the diode linearizer in sub-THz band.