In this Letter, an investigation is performed on the utilization of nematic liquid crystal (NLC) cells in the design of leaky-wave antennas (LWAs) for millimeter-wave (mm-wave) radiation in order to dynamically control its beam scanning capability at a single frequency. A NLC compound is sandwiched between two single-sided copper-plated substrates allowing a traveling wave to be guided through a substrate-integrated waveguide. The tuning capabilities of the structure, based on the use of K15 or GT7-29001 as the middle layer, were evaluated for different biasing conditions demonstrating the associated dynamic scanning of the main beam. A quasi-periodic LWA was designed to operate in the 5G mm-wave band, thus supporting a fast-wave propagation with tunable phase constant and dynamic beam steering at a single frequency. The simulated results clearly illustrate a dynamic beam scanning range of 45° through the use of an external bias voltage ranging between 0 and 40 V. These results are quite promising creating a fertile ground for the utilization of NLCs in the design and fabrication of LWAs for 5G wireless communication networks.

1.
D. R.
Jackson
and
A. A.
Oliner
, “
Leaky-wave antennas
,” in
Modern Antenna Handbook
, edited by
C. A.
Balanis
(
Wiley
,
New York, NY
,
2008
), Chap. 7.
2.
A. A.
Oliner
and
D. R.
Jackson
, “
Leaky-wave antennas
,” in
Antenna Engineering Handbook
, 4th ed., edited by
J. L.
Volakis
(
McGraw-Hill
,
New York, NY
,
2007
), Chap. 11.
3.
D.
Deslandes
and
K.
Wu
, “
Substrate integrated waveguide leaky-wave antenna: Concept and design considerations
,” in
Proceedings of Asia-Pacific Microwave Conference
(
IEEE
,
2005
), pp.
346
349
.
4.
F.
Xu
,
K.
Wu
, and
X.
Zhang
, “
Periodic leaky-wave antenna for millimeter wave applications based on substrate integrated waveguide
,”
IEEE Trans. Antennas Propag.
58
,
340
347
(
2010
).
5.
Y. J.
Cheng
,
W.
Hong
,
K.
Wu
, and
Y.
Fan
, “
Millimeter-wave substrate integrated waveguide long slot leaky-wave antennas and two-dimensional multibeam applications
,”
IEEE Trans. Antennas Propag.
59
,
40
47
(
2011
).
6.
J.
Liu
,
D. R.
Jackson
, and
Y.
Long
, “
Substrate integrated waveguide (SIW) leaky-wave antenna with transverse slots
,”
IEEE Trans. Antennas Propag.
60
,
20
29
(
2012
).
7.
S.
Lim
,
C.
Caloz
, and
T.
Itoh
, “
Metamaterial-based electronically controlled transmission-line structure as a novel leaky-wave antenna with tunable radiation angle and beamwidth
,”
IEEE Trans. Microwave Theory Tech.
53
,
161
173
(
2005
).
8.
J.-H.
Fu
,
A.
Li
,
W.
Chen
,
Z. J.
Wang
, and
Q.
Wu
, “
An electrically controlled CRLH-inspired circularly polarized leaky-wave antenna
,”
IEEE Antennas Wireless Propag. Lett.
16
,
760
763
(
2017
).
9.
M.
Wang
,
H. F.
Ma
,
H. C.
Zhang
,
W. X.
Tang
,
X. R.
Zhang
, and
T. J.
Cui
, “
Frequency-fixed beam-scanning leaky-wave antenna using electronically controllable corrugated microstrip line
,”
IEEE Trans. Antennas Propag.
66
,
4449
4456
(
2018
).
10.
Z.
Li
,
Y. J.
Guo
,
S. L.
Chen
, and
J.
Wang
, “
A period-reconfigurable leaky-wave antenna with fixed-frequency and wide-angle beam scanning
,”
IEEE Trans. Antennas Propag.
67
,
3720
3731
(
2019
).
11.
D.
Deslandes
, “
Design equations for tapered microstrip-to-substrate integrated waveguide transitions
,” in
2010 IEEE MTT-S International Microwave Symposium
(
IEEE
,
2010
), pp.
704
707
.
12.
R.
Jakoby
,
A.
Gaebler
, and
C.
Weickhmann
, “
Microwave liquid crystal enabling technology for electronically steerable antennas in SATCOM and 5G millimeter-wave systems
,”
Crystals
10
,
514
(
2020
).
13.
C.
Fritzsch
,
B.
Snow
,
J.
Sargent
,
D.
Klass
,
S.
Kaur
, and
O.
Parri
, “
Liquid crystals beyond displays: Smart antennas and digital optics
,” in
SID Symposium Digest of Technical Papers
(
SID
,
2019
), Vol.
50
, pp.
1098
1101
.
14.
V.
Fréedericksz
and
A.
Repiewa
, “
Theoretisches und experimentelles zur frage nach der natur der anisotropen flüssigkeiten
,”
Z. Phys. Soc.
42
,
532
546
(
1927
).
15.
C. W.
Oseen
, “
The theory of liquid crystals
,”
Trans. Faraday Soc.
29
,
883
898
(
1933
).
16.
F. C.
Frank
, “
On the theory of liquid crystals
,”
Discuss. Faraday Soc.
25
,
19
28
(
1958
).
17.
S.
Bulja
,
D.
Mirshekar-Syahkal
,
R.
James
,
S. E.
Day
, and
F. A.
Fernández
, “
Measurement of dielectric properties of nematic liquid crystals at millimeter wavelength
,”
IEEE Trans. Microwave Theory Tech.
58
,
3493
3501
(
2010
).
18.
R. B.
Tchema
and
A. C.
Polycarpou
, “
Quasi-periodic leaky-wave antenna based on substrate integrated waveguide and liquid crystal technologies
,” in
14th European Conference on Antennas and Propagation (EuCAP 2020)
(
IEEE
,
2020
), pp.
1
5
.
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