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天線工程期中報告
論文研討: MinSeok Han and Jaehoon Choi
“Compact Multiband MIMO Antenna
for Next Generation USB Dongle Application”
報告人:
碩研電子一甲 MA130216 蘇暐倫
摘要
研究方向:
In this paper, we propose a compact printed strip
MIMO antenna with an embedded chip
inductor for next generation USB dongle application.
設計方法:
The proposed MIMO antenna consists of a chipinductor-embedded longer radiating strip and a
shorter radiating strip. Both the longer and shorter
strips can also be incorporated close to each other
to have a compact structure. The embedded chip
inductor contributes additional inductance to
compensate for the increased capacitance resulting
from the shortened radiating strip.
MIMO ANTENNA DESIGN
The geometry of the proposed MIMO antenna embedded with a chip inductor multiband
MIMO antenna for 4G system is shown in Fig. 1. Two same elements are placed at
the two corners of top edge of a FR4 (εr = 4.4) substrate having the volume of
25 mm× 66 mm× 0.8 mm, which simulates the ground plane of a practical USB dongle.
Figure 1. Geometry of the proposed MIMO antenna
EXPERIMENTAL RESULTS
The radiating portion of the antenna is a
simple two-strip PIFA. The shorter strip has a
length of about 12 mm, which is about 0.1
wavelength at about 2.0 GHz and can easily
generate a wide resonant mode to cover WCDMA
operation in the 2.05 GHz band. The longer
strip with an embedded chip inductor of 15 nH
has a total length of about 34 mm, which is
about 0.08 wavelength at about 0.77 GHz. Owing
to the embedded chip inductor, the resonant
mode contributed by the longer strip can be
effectively shifted to lower frequencies of
about 0.77 GHz, from an about 1.3 GHz. Effects
of the two radiating strips of the proposed
MIMO antenna are analyzed in Fig. 2. It is
clear that the antenna’s lower and upper bands
are contributed by the longer and shorter
strips, respectively.
Simulation was carried out with the aid of
the commercially available simulation
software MWS [6] to optimize the geometric
parameters of the proposed antenna. From
the measured S-parameter characteristics, the
two antenna elements have very narrow
bandwidth of 30 MHz at the LTE band 13 and
sufficient bandwidth at the
WCDMA/WiBro band, respectively. The
additional study is required to widen the
bandwidth at the LTE band 13 and to enhance
antenna gains and radiation efficiencies at
LTE band 13.
Figure 2. S-parameter characteristics for the proposed MIMO antenna
THE MEASURED RADIATION PATTERNS OF THE FABRICATED MIMO ANTENNA AT 0.77,
2.05, AND 2.35 GHZ
Although MIMO antenna elements usually have different directivity for each element, the radiation
patterns of the designed antennas resemble to each other.
Figure 3. Measured radiation patterns of the proposed multiband MIMO antennas
From the H (zx)-plane patterns, it is confirmed that monopole-like radiation
patterns at three frequencies are obtained, and omni-directional total power
radiation is generally seen, which is advantageous for practical
applications.
THE MEASURED ANTENNA GAINS AND EFFICIENCIES
Table 1. Measured antenna gains and antenna efficiencies
The measured peak gains of two antenna elements are -0.52 dBi and 0.64 dBi at the LTE band 13, 3.5 dBi and 2.9 dBi at the WCDMA band
and 3.4 dBi and 3.2 dBi at the WiBro band, respectively.
CONCLUSIONS
In this paper, a compact printed strip MIMO antenna with an embedded chip inductor for
LTE/WCDMA/WiBro applications was proposed. The proposed MIMO antenna consists
of a simple two-strip monopole and embedded chip inductor. The antenna’s lower and
upper bands are contributed by the longer and shorter strips, respectively. The fabricated
antenna has the isolation of about -18 dB at the lower band and lower than -12 dB at the
higher band. The measured peak gains of two antenna elements are -0.52 dBi and -0.64
dBi at the LTE band 13, 3.8 dBi and 3.5 dBi at the WCDMA band and 3.4 dBi and 3.2
dBi at the WiBro band, respectively. The simulated and measured results show that the
proposed multiband MIMO antenna could be a good candidate for 4G mobile systems.
REFERENCES
[1] G. J. Foschini and M. J. Gans, “On limits of wireless communications in a fading
environment when using multiple antennas,” Wireless Personal Comm., Vol. 6, No. 3,
311–335, Mar. 1998.
[2] D. S. Shiu, G. J. Foschini, M. J. Gans, and J. M. Kahn, “Fading correlation and its
effect on the capacity of multi element antenna systems,” IEEE Trans. on Comm.,
Vol. 48, No. 3, 502–513, Mar. 2000.
[3] Wikipedia, the free encyclopedia. Available at:
http://en.wikipedia.org/wiki/Universal_Serial_Bus
[4] C. Y. Chiu, J. B. Yan, and R. D. Murch, ‘‘Compact three-port orthogonally polarized
MIMO antennas,’’ IEEE Antennas Wireless Propag. Lett., vol. 6, pp. 619---622, 2007.
[5] C. Y. Chiu, J. B. Yan, and R. D. Murch, ‘‘24-port and 36-port antenna cubes suitable
for MIMO wireless communications,’’ IEEE Trans. Antennas Propag., vol. 56, no. 4,
pp. 1170---1176, Apr. 2008.
[6] Computer Simulation Technology (CST) Microwave Studio. Suite 2008 [Online].
Available: http://www.cst.com
[7] MinSeok Han and Jaehoon Choi “Compact Multiband MIMO Antenna
for Next Generation USB Dongle Application”