Reflectarray Design for 120-GHz Radar Application

Measurement Results

A. Tamminen, S. Mäkelä, J. Ala-Laurinaho, Janne Häkli, Päivi Koivisto, Pekka Rantakari, Jussi Säily, Arttu Luukanen, A.V. Räisänen

Research output: Contribution to journalArticleScientificpeer-review

9 Citations (Scopus)

Abstract

In this paper, we present design and experimental results on reflectarrays at 120 GHz. The offset-fed reflectarrays consist of conductor-backed coplanar patch antennas with phase-shifting stubs. Three 138-mm reflectarrays are lithographically fabricated and evaluated in a near-field measurement range. Their measured beam patterns are compared to the theoretical ones. The theoretical -3-dB beam width is 60-64 mm at 3-m distance from the reflectarray. Measured beam widths of the different reflectarrays deviate less than 10% from the theoretical values. The beam pointing is found to be close to theoretical, whereas the sidelobe level is up to 5 dB higher. The efficiency, alignment accuracy, and surface shape of the reflectarray are studied with near-field imaging of the reflectarray aperture field. The measured average efficiency is 0.11 whereas the predicted average efficiency is 0.54. The low efficiency is most likely due to over-etching of the structures of the reflectarray element, and could be improved in future fabrication processing rounds. Beam pattern measurement close to the main beam is well suited for evaluating the beam width and pointing accuracy, but it gives little information on the element performance. We propose near-field imaging of the reflectarray to evaluate both element efficiency and phase shift.
Original languageEnglish
Pages (from-to)5036-5047
Number of pages11
JournalIEEE Transactions on Antennas and Propagation
Volume61
Issue number10
DOIs
Publication statusPublished - 2013
MoE publication typeA1 Journal article-refereed

Fingerprint

Radar measurement
Imaging techniques
Antenna feeders
Microstrip antennas
Phase shift
Etching
Fabrication
Processing

Keywords

  • antenna arrays
  • millimeter-wave measurements
  • near-field imaging
  • reflectarray

Cite this

Tamminen, A., Mäkelä, S., Ala-Laurinaho, J., Häkli, J., Koivisto, P., Rantakari, P., ... Räisänen, A. V. (2013). Reflectarray Design for 120-GHz Radar Application: Measurement Results. IEEE Transactions on Antennas and Propagation, 61(10), 5036-5047. https://doi.org/10.1109/TAP.2013.2273256
Tamminen, A. ; Mäkelä, S. ; Ala-Laurinaho, J. ; Häkli, Janne ; Koivisto, Päivi ; Rantakari, Pekka ; Säily, Jussi ; Luukanen, Arttu ; Räisänen, A.V. / Reflectarray Design for 120-GHz Radar Application : Measurement Results. In: IEEE Transactions on Antennas and Propagation. 2013 ; Vol. 61, No. 10. pp. 5036-5047.
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Tamminen, A, Mäkelä, S, Ala-Laurinaho, J, Häkli, J, Koivisto, P, Rantakari, P, Säily, J, Luukanen, A & Räisänen, AV 2013, 'Reflectarray Design for 120-GHz Radar Application: Measurement Results', IEEE Transactions on Antennas and Propagation, vol. 61, no. 10, pp. 5036-5047. https://doi.org/10.1109/TAP.2013.2273256

Reflectarray Design for 120-GHz Radar Application : Measurement Results. / Tamminen, A.; Mäkelä, S.; Ala-Laurinaho, J.; Häkli, Janne; Koivisto, Päivi; Rantakari, Pekka; Säily, Jussi; Luukanen, Arttu; Räisänen, A.V.

In: IEEE Transactions on Antennas and Propagation, Vol. 61, No. 10, 2013, p. 5036-5047.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Reflectarray Design for 120-GHz Radar Application

T2 - Measurement Results

AU - Tamminen, A.

AU - Mäkelä, S.

AU - Ala-Laurinaho, J.

AU - Häkli, Janne

AU - Koivisto, Päivi

AU - Rantakari, Pekka

AU - Säily, Jussi

AU - Luukanen, Arttu

AU - Räisänen, A.V.

PY - 2013

Y1 - 2013

N2 - In this paper, we present design and experimental results on reflectarrays at 120 GHz. The offset-fed reflectarrays consist of conductor-backed coplanar patch antennas with phase-shifting stubs. Three 138-mm reflectarrays are lithographically fabricated and evaluated in a near-field measurement range. Their measured beam patterns are compared to the theoretical ones. The theoretical -3-dB beam width is 60-64 mm at 3-m distance from the reflectarray. Measured beam widths of the different reflectarrays deviate less than 10% from the theoretical values. The beam pointing is found to be close to theoretical, whereas the sidelobe level is up to 5 dB higher. The efficiency, alignment accuracy, and surface shape of the reflectarray are studied with near-field imaging of the reflectarray aperture field. The measured average efficiency is 0.11 whereas the predicted average efficiency is 0.54. The low efficiency is most likely due to over-etching of the structures of the reflectarray element, and could be improved in future fabrication processing rounds. Beam pattern measurement close to the main beam is well suited for evaluating the beam width and pointing accuracy, but it gives little information on the element performance. We propose near-field imaging of the reflectarray to evaluate both element efficiency and phase shift.

AB - In this paper, we present design and experimental results on reflectarrays at 120 GHz. The offset-fed reflectarrays consist of conductor-backed coplanar patch antennas with phase-shifting stubs. Three 138-mm reflectarrays are lithographically fabricated and evaluated in a near-field measurement range. Their measured beam patterns are compared to the theoretical ones. The theoretical -3-dB beam width is 60-64 mm at 3-m distance from the reflectarray. Measured beam widths of the different reflectarrays deviate less than 10% from the theoretical values. The beam pointing is found to be close to theoretical, whereas the sidelobe level is up to 5 dB higher. The efficiency, alignment accuracy, and surface shape of the reflectarray are studied with near-field imaging of the reflectarray aperture field. The measured average efficiency is 0.11 whereas the predicted average efficiency is 0.54. The low efficiency is most likely due to over-etching of the structures of the reflectarray element, and could be improved in future fabrication processing rounds. Beam pattern measurement close to the main beam is well suited for evaluating the beam width and pointing accuracy, but it gives little information on the element performance. We propose near-field imaging of the reflectarray to evaluate both element efficiency and phase shift.

KW - antenna arrays

KW - millimeter-wave measurements

KW - near-field imaging

KW - reflectarray

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DO - 10.1109/TAP.2013.2273256

M3 - Article

VL - 61

SP - 5036

EP - 5047

JO - IEEE Transactions on Antennas and Propagation

JF - IEEE Transactions on Antennas and Propagation

SN - 0018-926X

IS - 10

ER -