New
Scanning-Spot Beam Reflectarray Antenna Design
Yusuke Kaimori/Shota Takino/
Sanshiro Shigemitu/Shigeru Makino

Hiromasa Nakajima/Michio Takikawa
Mitsubishi Electric Corporation
5-1-1 Ofuna, Kamakura-shi, Kanagawa, Japan.

Kanazawa Institute of Technology
7-1 Ohgigaoka, Nonoichi-shi, Ishikawa, Japan.
Mail:b1714005@planet.kanazawa-it.ac.jp
Abstract—In this report, a new design for a reflectarray
antenna using mirror configuration will be proposed. By adapting
to the two characteristics of a reflectarray antenna that changes
beam directions using frequency and polarization, it is possible torealize a multi-scanning beam whose performance is as good as aconventional multi-spot beam with one reflecting mirror. Herein,
we examine a scanning-spot beam that changes the beam direction
by using frequency in the elevation direction and polarization in
the azimuth direction in the Ka band. As a result, the proposed
design efficiently covered the desired service area.
Keywords—reflectarray, scanning spot beam, polarization,
frequency

I. INTRODUCTION
According to research, in a multi-beam communication
system using reflectarray antennas, covering a service area usinga few mirror planes can be realized by changing the beam
direction according to the polarization and frequency[1][2][3][4]. In this paper, a new reflectarray design using amirror configuration and a linear element is proposed to change
the beam direction.

Fig. 1. Element shape

TABLE I ELEMENT DESIGN PARAMETERS

II. DESIGN REFLECTARRAYAs shown in Fig. 1, a linear element is used to change thephase according to the polarization of the reflectarray [5]. The
parameters of the elements are shown in TableⅠ.
Fig. 2 demonstrates the mirror configuration, and Table Ⅱ
list the specification. The five primary radiators were placed ina way that beams of frequencies fL and fH are located 1 beamwidth away from the beam at the center frequency f0. Radiators
1 and 3 were located +2 beam widths and -2 beam widths awayfrom the center respectively, in the elevation direction whileRadiator 2 was located at the center. Radiator 4 was +0.87 and+0.5 beam widths away from the center in the azimuth andelevation directions, respectively, whereas Radiator 5 was+0.87 and -0.5 beam widths away from the center in theazimuth and elevation directions, respectively.
Fig. 2. Mirror configuration

978-1-7281-4670-6/21/$31.00 ©2021 IEEE1921

APS 2021

TABLE II MIRROR SURFACE DESIGN PARAMETERS

III. ANALYSIS RESULT
Based on the design parameters, an analysis was performed
using the aperture distribution method. The resonant element
used in the design was assumed to be an ideal element with nofrequency characteristics. Fig. 3 and Fig. 4 show the analysis
results of the V-pol and H-pol in the elevation cut, respectively.
It can be verified that the fL beam of Horn 1 and fH beam of Horn
2 overlap ±1 beam width away from the f0 beam. Similarly, thefL beam of Horn 2 and fH beam of Horn 3 overlap ±1 beamwidths away from the f0 beam. As seen in Fig. 5, the analysis
results at frequency f0 in the azimuth cut confirm that the verticaland horizontal polarizations (V-pol and H-pol) emitted thebeams in the directions of -0.65 and +0.65 degrees, respectively.
Fig. 6 shows the 35 dBi contour map for three frequencies andtwo polarizations at each of the five horns. As a result, it can beseen that a single reflectarray can efficiently cover the desired
service area.

Fig. 5. Radiation pattern of f0 (Azimurth cut)

Fig. 6. 35dBi contour map

IV. CONCLUSION
The results show that the beam direction varies dependingon the polarization and frequency of the reflectarray, which was
the aim of this study. We will also fabricate a reflectarry basedon the design parameters of our study and further examine its
validity of the design.
Fig. 3. Radiation pattern of V polarization (Elevation cut)This study was supported by JSPS(20K04491).
REFERENCES
[1]
[2]

[3]

[4]

Fig. 4. Radiation pattern of H polarization (Elevation cut)

[5]

1922

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