Radio Frequency Transmitter for Mobile Communications

Fully digital Radio Frequency Transmitter for Mobile Communications

The constantly increasing data rates leads to increasing power requirements in the domain of mobile communications. In addition to the required electrical power for operating the base stations, the resulting heat output must be dissipated. The CO2 emissions that can not be neglected today should be reduced in the future. Therefore, efficient and flexible solutions have to found to replace the conventional transmitter architectures. One possible solution for a fully digital transmitter is examined at INT. The transmitter is characterized by its high coding efficiency and linearity.

A block diagram of this transmitter is shown in the following figure. The transmitter circuit consists of a digital signal processing unit in the baseband, a digital pulse width and position modulator (DPWPM) and a switching amplifier (SMPA) to amplify the output power. A reconstruction filter removes unneeded harmonics so that only the modulated RF signal remains.

Fully digital transmitter concept
Fully digital transmitter concept

One goal is to integrate as many components as possible on a single chip. CMOS technologies are a good solution because of their low power and area requirements. The following figure shows the chip photographs of the DPWPM chip and the switching amplifier circuit. The DPWPM chip is manufactured in a 28 nm CMOS FDSOI technology, while the switching amplifier chip is manufactured in a 65 nm CMOS technology.

left: Chip photograph of DPWPM, right: Chip photograph of switching amplifier
left: Chip photograph of DPWPM, right: Chip photograph of switching amplifier

The long-term goal is to integrate both chips.

Publications

  1. 2023

    1. M. Wittlinger, M. Grözing, and M. Berroth, “Switching Mode Power Amplifier for Fully Digital RF Transmitter at 3.6 GHz in 22 nm FD-SOI CMOS,” in Conference on Ph.D. Research in Microelectronics and Electronics (PRIME), 2023, pp. 5--8.

  2. 2022

    1. J. Tonn, T. Veigel, M. Wittlinger, M. Grözing, and M. Berroth, “Real-Time Processing and Delta-Sigma Modulation on FPGA for Switching Mode RF Amplifiers,” in German Microwave Conference (GeMiC), 2022, pp. 184--187.
    2. M. Wittlinger, M. Grözing, and M. Berroth, “Switching Mode Power Amplifier Concept Combining Pulse-Width, Pulse-Position and Conductance Modulation,” in Kleinheubacher Tagung, U.R.S.I. Landesausschuss in der Bundesrepublik Deutschland e.V, 2022, pp. KH2022-C-1–3.

  3. 2020

    1. R. Bieg, M. Grözing, M. Schmidt, and M. Berroth, “Switching Mode Power Amplifier Concept Combining Multi-Level and Pulse-Width Modulation,” in German Microwave Conference (GeMiC), Cottbus, Germany, 2020, pp. 264--267.

  4. 2018

    1. R. Bieg, M. Schmidt, M. Grözing, and M. Berroth, “A Novel Multi-level CMOS Switching Mode Amplifier for Mobile Communication Signals,” in Conference on Ph.D. Research in Microelectronics and Electronics (PRIME), Prague, Czech Republic, 2018, pp. 149–152.
    2. M. Grözing, “Analoge Verzögerungsregelschleife für die digitale HF-Pulsweitenmodulation im Frequenzbereich von 170MHz bis 2,8GHz in 28nm FDSOI CMOS,” in Workshop Analogschaltungen, presented at 20. Workshop Analogschaltungen, Freiburg, Germany, 2018.
    3. M. Grözing, J. Digel, T. Veigel, R. Bieg, J. Zhang, S. Brandl, M. Schmidt, C. Haslach, D. Markert, and W. Templ, “A RF Pulse-Width and Pulse-Position Modulator IC in 28 nm FDSOI CMOS,” in Nordic Circuits and Systems Conference (NorCAS), Tallin, Estonia, 2018, pp. 1--4.

  5. 2017

    1. R. Bieg, M. Schmidt, M. Grözing, and M. Berroth, “A 6 V CMOS Switching Mode Amplifier for Continuous-Wave Signals from DC to 3 GHz,” in IEEE International Symposium on Circuits and Systems (ISCAS), Baltimore, MD, USA, 2017, pp. 1338--1341.

  6. 2015

    1. R. Bieg, M. Schmidt, and M. Berroth, “A CMOS switching mode amplifier with 3 V output swing for continuous-wave frequencies up to 4 GHz,” in Asia-Pacific Microwave Conference (APMC), Nanjing, China, 2015, pp. 1--3.
    2. J. Digel, M. Grözing, M. Schmidt, M. Berroth, and C. Haslach, “Digital pulse-width pulse-position modulator in 28 nm CMOS for carrier frequencies up to 1 GHz,” in IEEE Radio Frequency Integrated Circuits Symposium (RFIC), Phoenix, AZ, USA, 2015, pp. 99--102.
Additional Information
  • DFG project
    Radio frequency multilevel switching mode power amplifiers with pulse-position and pulse-width modulation for efficient power amplification of broadband mobile communication signals
  • DFG project
    Hocheffiziente CMOS-Schaltverstärkerstufen im Mikrowellenbereich

Contact

Manuel Wittlinger

M. Sc.

Research staff member

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