A Calibration Method for Array Antenna using
Non-Resonant Probe
Atsushi KATSUTA1, Hiroyuki ARAI1 and Masami ARAI2 1Graduated school of engineering, Yokohama National University
79-5, Tokiwadai, Hodogaya, Yokohama, Kanagawa, 240-8501, Japan 2Huawei Technologies Japan K.K. , Japan Research Center
3-1, Kinko-cho, Kanagawa, Yokohama, Kanagawa, 221-0056, Japan
Abstract – This paper presents calibration method for array
antenna using non-resonant probe. The propose method uses measurement of electric field array antenna element using non-
resonant probe in reactive-near-field. Because the probe does not degrade the characteristics of the antenna element in reactive-near-field, this technique can measure pure electric
field using non-resonant probe. Both amplitude and phase change are measured by this method.
Index Terms — Calibration, Electric field measurement,
Electric probe, Array antenna.
1. Introduction
In recent years, as there has been an explosive increase in
wireless data traffic, high-capacity and high-speed mobile
communication is required. Therefore, multielement array
antenna is increased in demand. Accordingly, various studies
on array antenna calibration are being conducted [1][2][3].
In this paper, we study new array antenna calibration method
by measurement electric field of array antenna element using
non-resonant probe. In this method, the electric field of array
antenna element is measured in the reactive-near-field by
moving the probe closer to the measured element. In this
paper, as a fundamental study of this method, we describe
element electric field of the array antenna measurement
using an infinitesimal dipole antenna and an infinitesimal
loop antenna [4].
2. Non-Resonant Probe
Non-resonant probe is a probe that does not have
characteristic as an antenna, because it does not resonate in
a frequency band. Therefore, the effect of re-radiation of the
antenna is reduced by moving the probe closer to the
measuring antenna. This section discusses about the probe
characteristic.
(1) Characteristics of Non-Resonant Probe
The characteristic of the antenna is examined using an
infinitesimal dipole antenna and an infinitesimal loop
antenna as non-resonant probe. Fig.1 (a) shows the probe
arrangement whose positioned closer to the patch antenna in
the reactive-near-field(0.1λ). Fig.1 (b) shows the s-
parameters results for the arrangement confirming that non-
resonant probe has less impact on the patch antenna and the
coupling between patch antenna and the probe. The S11 is
very low and measured antenna’s characteristics are not
affected non-resonant probe’s characteristics.
(2) Antenna Factor of Non-Resonant Probe
The antenna factor of the probe is necessary for
measurement. Measurements of complex antenna factor by
the near field 3-antenna method is used as probe antenna
factor [5]. The probe and half-length dipole antenna is used,
complex antenna factor (F) is shown as, equation (1).
𝐹𝑖 = √𝑗𝜂0𝑒−𝑗𝛽𝑟 𝐴𝑗𝑘(𝑟)
𝑍0𝜆𝑟𝐴𝑖𝑘(𝑟)𝐴𝑗𝑖(𝑟) (1)
(𝑖, 𝑗, 𝑘 = 1,2,3, 𝑖 ≠ 𝑗 ≠ 𝑘)
Fig.2 shows the antenna factor of the probe in
measurement and calculation. Experimental values are
relatively close to simulation values. It is assumed that there
is an error due to experimental environment.
3. Element Electrical Field Measurement
We measure coupling level between the probe and each
element of the array antenna. Fig.3 shows the measurement
structure of 4×4 dipole array antenna and the probe. The
array antenna structure consists of sub arrays (SA) in which
four elements of the dipole antenna tilted by 45 degrees
arranged in four rows. Non-resonant probe is used as an
infinitesimal dipole antenna and an infinitesimal loop
antenna. Since the all result is close, I post the result only
probe 2. Where the coupling level results are shown in Fig.4
and Fig.5, respectively. The coupling level between both
probes and measured element are about 20 dB or more apart
from other element coupling level.
Fig.6 shows measurement result of probe 2, when input
signal at SA2. The input amplitude variation confirmed that
the amplitude and the phase of input signal variation
approximately equal to the amplitude and the phase of the
measurement result variation on the probe. We confirmed
that variation of the input signal amplitude and phase is equal
to variation of the measurement results amplitude and phase
on each probe 2 as shown in Fig.6. The variation
2018 International Symposium on Antennas and Propagation (ISAP 2018)October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea
[ThP-57]
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characteristics of loop is better than that of dipole. It is
conceivable that cause is because of the antenna
directionality.
4. Conclusion
In this paper, we propose a new calibration method for
array antenna using non-resonant probe by using a technique
of measuring the electric field of array antenna element using
non-resonant probe in reactive-near-field. We confirmed that
this technique can measure the element electric field using
non-resonant probe. Additionally, the characteristics of the
loop is better than that of the dipole, because the loop
directionality is facing the measured antenna element. Based
on this result, we design and produce a non-resonant probe
that also operate in the millimeter-wave band.
References
[1] S. Mano, et al., IEICE Trans. B., vol. J65-B, no. 5, pp. 555-560, May
1982.
[2] Y.V. Korotetskiy, et al., IEEE APM., pp.1161-1162, Jun. 2016.
[3] R. Long, et al., IEEE Trans. Elec, Vol. 65, no. 6, pp. 2931-2939, Jun.
2017.
[4] H. Whiteside, et al., IEEE Trans. Elec, Vol. 12, no.33, pp. 291-297,
May. 1964.
[5] S. Ishigami, et al., IEEE Trans. Elec, Vol. 36, no. 3, pp. 424-432,
Aug. 1996.
(a) (b)
Fig. 1 Non-resonant probe characteristics (a) structure
(b) S11 of the patch antenna.
Fig. 2 Measured and calculated antenna factor.
Fig. 3 Element E-field measurement structure.
xA = 1 λ, yA = 1 λ.
Fig. 4 Coupling level using infinitesimal dipole.
Fig. 5 Coupling level using infinitesimal loop.
(a) (b)
Fig. 6 E-field measured using each probe (a) variation
amplitude (b) variation phase of input signal.
2018 International Symposium on Antennas and Propagation (ISAP 2018)October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea
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