Reflectarray for 120-GHz beam steering application: Design, simulations, and measurements

a. Tamminen, J. Ala-Laurinaho, David Gomes Martins, Janne Häkli, Päivi Koivisto, M. Kärkkäinen, S. Mäkelä, Pekka Pursula, Pekka Rantakari, Markku Sipilä, Jussi Säily, Reijo Tuovinen, Arttu Luukanen, A.V. Räisänen

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    12 Citations (Scopus)


    Development of a 120-GHz FMCW radar with a reflectarray as focusing element is described. The reflectarray is realized on a 150-mm silicon wafer and it has 3700 phase-modulating elements on it. The phase shifters have four discrete values to cover full phase modulation with 90° steps. The reflectarray element is realized with a conductor-backed coplanar waveguide patch antenna with a phase shifter coupled to it. The required phase modulation for each reflectarray element is determined with an in-house physical optics simulation combined with genetic-algorithm-based optimization. The reflectarrays are developed in two stages. First, preliminary reflectarrays with static phase shifters have been manufactured and tested at 120-GHz antenna measurement range. The static reflectarrays are found to perform as designed in their capability to steer the beam to a desired direction and to a distance of 3 m. The reflectarrays have-3-dB beam width from 1.1° to 1.3° depending on the beam tilt. After the preliminary verification with the static phase shifters, the reflectarrays will be assembled together with actively controlled MEMS-based phase shifters. The MEMS switches are controlled with dedicated high-voltage CMOS electronics, forming a system-in-a-package (SiP). First, the MEMS phase shifters are modeled, are being fabricated, and will be measured separately to verify their phase-shifting capability.
    Original languageEnglish
    Title of host publicationProceedings of SPIE 8362
    Subtitle of host publicationPassive and Active Millimeter-Wave Imaging XV
    EditorsDavid A. Wikner
    PublisherInternational Society for Optics and Photonics SPIE
    ISBN (Print)978-0-8194-9040-7
    Publication statusPublished - 2012
    MoE publication typeNot Eligible
    EventPassive and Active Millimeter-Wave Imaging XV - Baltimore, Maryland, United States
    Duration: 26 Apr 2012 → …

    Publication series

    SeriesProceedings of SPIE


    ConferencePassive and Active Millimeter-Wave Imaging XV
    Country/TerritoryUnited States
    CityBaltimore, Maryland
    Period26/04/12 → …


    • imaging
    • microelectromechanical
    • millimeter-wave
    • millimeter-wave identification
    • radar
    • reflectarray


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