Development of Characterization Methods for Antennas and Quasi-Optics

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School of Electrical Engineering | Doctoral thesis (article-based) | Defence date: 2015-01-30
Degree programme
72 + app. 52
Aalto University publication series DOCTORAL DISSERTATIONS, 8/2015
This dissertation focuses on the development of characterization methods for antennas and quasi-optical components. The dissertation presents three new methods to deal with certain limitations occurred during the antenna measurement processes. First, a new technique using the Chebyshev polynomials has been proposed to process the antenna measurements obtained in non-anechoic sites to obtain equivalent free space radiation patterns. This new technique combines the principle of a FFT-based method with the special relationship between coefficients of the Bessel-Chebyshev polynomials. Experimental results are presented to demonstrate the potential of this approach over conventional time gating techniques for a certain class of problems. Second, a new antenna pattern retrieval method is proposed. In this method, the antenna reflection coefficient is measured many times when a unique reflective load with known spatial reflection properties is placed near the antenna in each measurement. The antenna pattern is obtained from the measurements with an inversion algorithm. Simulations have been used to verify the theoretical basis and the method has been experimentally demonstrated at 30 GHz. The results show that the method could enable sufficient accuracy with low gain antennas or in the vicinity of main lobe with directive antennas. Third, a new technique is presented to realize a wideband hologram compact antenna test range (CATR) by linearly adjusting the feed location. The wideband formulas for linearly adjusting the feed have been discussed and verified. The performance of the wideband operation has been demonstrated by the measured results at W (95 GHz) and D (170 GHz) bands for the hologram aperture diameter of 350 mm. The dissertation also discusses characterization of quasi-optics, namely, MEMS-based high-impedance surface (HIS) and reflectarray elements. First, the reflection properties of the single unit cell structure of MEMS-based HIS is studied, tunability of the MEMS varactors and beam steering of a large structure at 80 GHz has been demonstrated with a simplified model. The structure allows steering of the beam within the range from -45º to +45°. A quasi-optical measurement setup has been built for the experimental characterization. Second, the design and optimization process of reconfigurable reflectarray element integrated with MEMS-based phase shifter at 120 GHz is studied. Also, the dielectric properties of SU-8 substrate have been characterized with on-wafer measurements. Several design parameters which could affect the modulation efficiency have been studied.
Supervising professor
Räisänen, Antti, Prof., Aalto University, Department of Radio Science and Engineering, Finland
Thesis advisor
Ala-Laurinaho, Juha, Dr., Aalto University, Department of Radio Science and Engineering, Finland
Viikari, Ville, Asst. Prof., Aalto University, Department of Radio Science and Engineering, Finland
antenna measurement, pattern retrieval, reflection coefficient, compact range, high-impedance surface, MEMS, reflectarray element
Other note
  • [Publication 1]: Z. Du, D. Chicherin, and A. V. Räisänen, “Millimeter wave beam steering with a MEMS-based high impedance surface,” in Proc. 41st European Microwave Conference, Manchester, UK, Oct. 10-14, 2011, pp. 1043-1046.
  • [Publication 2]: Z. Du, J. Ala-Laurinaho, D. Chicherin, A. V. Räisänen, M. Sterner, and J. Oberhammer, “Reflection phase characterization of the MEMS-based high impedance surface,” in Proc. 42nd European Microwave Conference, Amsterdam, The Netherlands, Oct. 29 – Nov. 1, 2012, pp. 617-620.
  • [Publication 3]: Z. Du, A. Tamminen, J. Ala-Laurinaho, J. Säily, P. Rantakari, A. Luukanen, and A. V. Räisänen, “Design and optimization of reconfigurable reflectarray element with MEMS phase shifter,” in Proc. 7th European Conference on Antenna and Propagation, Gothenburg, Sweden, Apr. 8-12, 2013, pp. 2422-2426.
  • [Publication 4]: Z. Du, J. Moon, S. Oh, J. Koh, and T. K. Sarkar, “Generation of free space radiation patterns from non-anechoic measurements using Chebyshev polynomials,” IEEE Transactions on Antennas and Propagation, vol. 58, no. 8, pp. 2785-2790, Aug. 2010.
    DOI: 10.1109/TAP.2010.2051130 View at publisher
  • [Publication 5]: Z. Du, V. Viikari, J. Ala-Laurinaho, A. Tamminen, and A. V. Räisänen, “Antenna pattern retrieval from reflection coefficient measurements with reflective loads,” Progress in Electromagnetics Research, vol. 148, pp. 15-22, 2014.
    DOI: 10.2528/PIER14050902 View at publisher
  • [Publication 6]: Z. Du, V. Viikari, J. Ala-Laurinaho, and A. V. Räisänen, “2D antenna radiation pattern retrieval using reflection coefficient measurements,” in Proc. 2014 Asia-Pacific Microwave Conference (APMC2014), Sendai, Japan, Nov. 4-7, 2014, pp. 846-848.
  • [Publication 7]: Z. Li, J. Ala-Laurinaho, Z. Du, and A. V. Räisänen, “Realization of wideband hologram compact antenna test range by linearly adjusting the feed location,” IEEE Transactions on Antennas and Propagation, vol. 62, no.11, pp. 5628-5633, Nov. 2014.
    DOI: 10.1109/TAP.2014.2351072 View at publisher