A 300GHz 40nm CMOS transmitter with 32-QAM 17.5Gb/s/ch capability over 6 channels

Kosuke Katayama, Kyoya Takano, Shuhei Amakawa, Shinsuke Hara, Akifumi Kasamatsu, Koichi Mizuno, Kazuaki Takahashi, Takeshi Yoshida, Minoru Fujishima

Research output: Chapter in Book/Report/Conference proceedingConference contribution

64 Citations (Scopus)


The vast unallocated frequency band lying above 275GHz offers enormous potential for ultrahigh-speed wireless communication. An overall bandwidth that could be allocated for multi-channel communication can easily be several times the 60GHz unlicensed bandwidth of 9GHz. We present a 300GHz transmitter (TX) in 40nm CMOS, capable of 32-quadrature amplitude modulation (QAM) 17.5Gb/s/ch signal transmission. It can cover the frequency range from 275 to 305GHz with 6 channels as shown at the top of Fig. 20.1.1. Figure 20.1.1 also lists possible THz TX architectures, based on recently reported above-200GHz TXs. The choice of architecture depends very much on the transistor unity-power-gain frequency fmax. If the fmax is sufficiently higher than the carrier frequency, the ordinary power amplifier (PA)-last architecture (Fig. 20.1.1, top row of the table) is possible and preferable [1-3], although the presence of a PA is, of course, not a requirement [4,5]. If, on the other hand, the fmax is comparable to or lower than the carrier frequency as in our case, a PA-less architecture must be adopted. A typical such architecture is the frequency multiplier-last architecture (Fig. 20.1.1, middle row of the table). For example, a 260GHz quadrupler-last on-off keying (OOK) TX [6] and a 434GHz tripler-last amplitude-shift keying (ASK) TX [7] were reported. A drawback of this architecture is the inefficient bandwidth utilization due to signal bandwidth spreading. Another drawback is that the use of multibit digital modulation is very difficult, if not impossible. An exception to this is the combination of quadrature phase-shift keying (QPSK) and frequency tripling. When a QPSK-modulated intermediate frequency (IF) signal undergoes frequency tripling, the resulting signal constellation remains that of QPSK with some symbol permutation. Such a tripler-last 240GHz QPSK TX was reported [8]. However, a 16-QAM constellation, for example, would suffer severe distortion by frequency tripling. If the 300GHz band is to be seriously considered for a platform for ultrahigh-speed wireless communication, QAM-capability will be a requisite.

Original languageEnglish
Title of host publication2016 IEEE International Solid-State Circuits Conference, ISSCC 2016
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages2
ISBN (Electronic)9781467394666
Publication statusPublished - 2016 Feb 23
Externally publishedYes
Event63rd IEEE International Solid-State Circuits Conference, ISSCC 2016 - San Francisco, United States
Duration: 2016 Jan 312016 Feb 4

Publication series

NameDigest of Technical Papers - IEEE International Solid-State Circuits Conference
ISSN (Print)0193-6530


Other63rd IEEE International Solid-State Circuits Conference, ISSCC 2016
Country/TerritoryUnited States
CitySan Francisco

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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