4. CONCLUSION We investigated the design of a microstrip patch antenna with improved low-elevation gain for CRPA applications. The pro- posed antenna is composed of the main patch and a subpatch, and the two patches were designed to be electromagnetically coupled for the same direction current by adjusting the size of the subpatch and the substrate height. The proposed antenna was fabricated and mounted on a 140-mm circular ground platform to measure its antenna characteristics. The measured reflection coefficient was 211.2 dB at 1575 MHz with a bore-sight gain of 5.1 dBic, and the average gain at h 5 758 was 21.7 dBic with an average HPBW of 1658. The results proved that the proposed antenna is suitable to enhance the low-elevation gain and can be used as the individual element of CRPA arrays. ACKNOWLEDGMENTS This research was supported by Civil Military Technology Coop- eration (CMTC) and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2014R1A1A2055813). REFERENCES 1. J.R. Lambert, C.A. Balanis, and D. DeCarlo, Spherical cap adaptive antennas for GPS, IEEE Antennas Propag Mag 57 (2009), 406–413. 2. P. Enge, T. Walter, S. Pullen, C. Kee, Y.C. Chao, and Y.J. Tsai, Wide area augmentation of the global positioning system, IEEE Proc Mag 84 (1996), 1063–1088. 3. S. Datta-Barua, J. Lee, S. Pullen, M. Luo, A. Ene, D. Qiu, G. Zhang, and P. Enge, Ionospheric threat parameterization for local area global-positioning- system-based aircraft landing systems, J Air 47 (2010), 1141–1151. 4. F.S. Chang, K.L. Wong, and T.W. Chiou, Low-cost broadband circu- larly polarized patch antenna, IEEE Antennas Propag Mag 51 (2003), 3006–3009. 5. T.N. Chang and J.M. Lin, Circularly polarized antenna having two linked slot-rings, IEEE Antennas Propag Mag 59 (2011), 3057–3060. 6. K.L. Wong and Y.F. Lin, Circularly polarised microstrip antenna with a tuning stub, IEEE Electron Lett 34 (1998), 831–832. 7. H.M. Chen and K.L. Wong, On the circular polarization operation of annular-ring microstrip patch antennas, IEEE Antennas Propag Mag 47 (1999), 1289–1292. 8. W.S. Chen, C.K. Wu, and K.L. Wong, Single-feed square-ring microstrip antenna with truncated corners for compact circular polar- isation operation, Electron Lett 34 (1998), 1045–1047. 9. G. Byun, S. Kim, and H. Choo, Design of a dual-band GPS antenna using a coupled feeding structure for high isolation in a small array, Microwave Opt Technol Lett 56 (2014), 359–361. 10. G. Byun, S.M. Seo, I. Park, and H. Choo, Design of small CRPA arrays for dual-band GPS applications, IEICE Trans Commun E97B (2014), 1130–1138. 11. Y. Rahmat-samii and E. Michielssen, Electromagnetic optimization by genetic algorithms, Wiley, New York, 1999. 12. FEKO Suite 7.0, EM software and systems, Available at: http:// www.feko.info, 2014. V C 2016 Wiley Periodicals, Inc. 8-ANTENNA AND 16-ANTENNA ARRAYS USING THE QUAD-ANTENNA LINEAR ARRAY AS A BUILDING BLOCK FOR THE 3.5-GHz LTE MIMO OPERATION IN THE SMARTPHONE Kin-Lu Wong, 1 Jun-Yu Lu, 1 Li-Yu Chen, 1 Wei-Yu Li, 2 and Yong-Ling Ban 3 1 Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan; Corresponding author: [email protected]2 Information and Communications Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan 3 Institute of Electromagnetics and School of Electrical Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China Received 19 May 2015 ABSTRACT: Using the quad-antenna linear (QAL) array as a building block, the 8-antenna and 16-antenna arrays for the 3.5-GHz long term evolution multiple-input multiple-output (MIMO) operation in the smart- phone are demonstrated. The QAL array has a planar structure of narrow width 3 mm (0.035k) and short length 50 mm (0.58k), with k being the wavelength at 3.5 GHz. For the 8-antenna array, two QAL arrays are dis- posed along two opposite side edges (denoted as Array A) or the same side edge (denoted as Array B) of the system circuit board of the smart- phone. The obtained envelope correlation coefficient values of the anten- nas in Array A and B are shown. The calculated channel capacities for Array A and B applied in an 8 3 8 MIMO system are also analyzed. The 16-antenna array formed by four QAL arrays disposed along two opposite side edges (denoted as Array C) is then studied. For operating in a 16 3 16 MIMO system, the calculated channel capacity of Array C can reach about 66–70 bps/Hz with a 20-dB signal-to-noise ratio. The obtained channel capacity is about 5.7–6.1 times that (11.5 bps/Hz) of the upper limit of an ideal 2 3 2 MIMO system with 100% antenna efficiency for Figure 9 Analysis of gain enhancement at low-elevation angles (a) amplitude and phase of the induced current and (b) gain enhancement at h 5 758 174 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 58, No. 1, January 2016 DOI 10.1002/mop
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4. CONCLUSION
We investigated the design of a microstrip patch antenna with
improved low-elevation gain for CRPA applications. The pro-
posed antenna is composed of the main patch and a subpatch, and
the two patches were designed to be electromagnetically coupled
for the same direction current by adjusting the size of the subpatch
and the substrate height. The proposed antenna was fabricated and
mounted on a 140-mm circular ground platform to measure its
antenna characteristics. The measured reflection coefficient was
211.2 dB at 1575 MHz with a bore-sight gain of 5.1 dBic, and the
average gain at h 5 758 was 21.7 dBic with an average HPBW of
1658. The results proved that the proposed antenna is suitable to
enhance the low-elevation gain and can be used as the individual
element of CRPA arrays.
ACKNOWLEDGMENTS
This research was supported by Civil Military Technology Coop-
eration (CMTC) and the Basic Science Research Program through
the National Research Foundation of Korea (NRF) funded by the
Ministry of Education (NRF-2014R1A1A2055813).
REFERENCES
1. J.R. Lambert, C.A. Balanis, and D. DeCarlo, Spherical cap adaptive
antennas for GPS, IEEE Antennas Propag Mag 57 (2009), 406–413.
2. P. Enge, T. Walter, S. Pullen, C. Kee, Y.C. Chao, and Y.J. Tsai,
Wide area augmentation of the global positioning system, IEEE Proc
Mag 84 (1996), 1063–1088.
3. S. Datta-Barua, J. Lee, S. Pullen, M. Luo, A. Ene, D. Qiu, G. Zhang, and P.
Enge, Ionospheric threat parameterization for local area global-positioning-
system-based aircraft landing systems, J Air 47 (2010), 1141–1151.
1 Department of Electrical Engineering, National Sun Yat-SenUniversity, Kaohsiung 80424, Taiwan; Corresponding author:[email protected] Information and Communications Research Laboratories, IndustrialTechnology Research Institute, Hsinchu 31040, Taiwan3 Institute of Electromagnetics and School of Electrical Engineering,University of Electronic Science and Technology of China, Chengdu611731, China
Received 19 May 2015
ABSTRACT: Using the quad-antenna linear (QAL) array as a buildingblock, the 8-antenna and 16-antenna arrays for the 3.5-GHz long termevolution multiple-input multiple-output (MIMO) operation in the smart-
phone are demonstrated. The QAL array has a planar structure of narrowwidth 3 mm (0.035k) and short length 50 mm (0.58k), with k being thewavelength at 3.5 GHz. For the 8-antenna array, two QAL arrays are dis-
posed along two opposite side edges (denoted as Array A) or the sameside edge (denoted as Array B) of the system circuit board of the smart-
phone. The obtained envelope correlation coefficient values of the anten-nas in Array A and B are shown. The calculated channel capacities forArray A and B applied in an 8 3 8 MIMO system are also analyzed. The
16-antenna array formed by four QAL arrays disposed along two oppositeside edges (denoted as Array C) is then studied. For operating in a 16 3
16 MIMO system, the calculated channel capacity of Array C can reachabout 66–70 bps/Hz with a 20-dB signal-to-noise ratio. The obtainedchannel capacity is about 5.7–6.1 times that (11.5 bps/Hz) of the upper
limit of an ideal 2 3 2 MIMO system with 100% antenna efficiency for
Figure 9 Analysis of gain enhancement at low-elevation angles (a)
amplitude and phase of the induced current and (b) gain enhancement at
h 5 758
174 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 58, No. 1, January 2016 DOI 10.1002/mop
the antennas therein. Details of the proposed Array A, B, and C are
described, and the obtained results are presented. VC 2016 Wiley
Periodicals, Inc. Microwave Opt Technol Lett 58:174–181, 2016; View
this article online at wileyonlinelibrary.com. DOI 10.1002/mop.29527
Key words: mobile antennas; multiple-input multiple-output antennas;8-antenna array; 16-antenna array; quad-antenna linear array; smart-
phone antennas; slot antennas
1. INTRODUCTION
For the 2 3 2 long term evolution (LTE) multiple-input multi-
ple-output (MIMO) mobile communication, two antennas with
acceptable isolation are needed to be embedded in the limited
space inside the smartphone [1–5]. It is also noted that for the 2
3 2 LTE MIMO operation, the upper limit of the ergodic chan-
nel capacity can reach about 11.5 bps/Hz with a 20-dB signal-
to-noise (SNR) ratio [6]. The channel capacity can further be
greatly increased by increasing the number of the antennas in
the MIMO system [7]. However, owing to the limited space
inside the smartphone, it is difficult to embed a large number of
LTE antennas operated in the 698–960 MHz and/or 1710–2690
MHz bands for the MIMO operation. Conversely, it has been
recently demonstrated that a 10-antenna array [6] operating in
the new LTE band of 3400–3800 MHz [8–10] is promising to
Figure 1 Geometry of the 8-antenna arrays formed by two QAL arrays. (a) Two QAL arrays disposed along two opposite side edges (Array A), (b)
two QAL arrays disposed along the same side edge (Array B) and (c) dimensions of the QAL array comprising Anta1 to Anta4. [Color figure can be
viewed in the online issue, which is available at wileyonlinelibrary.com]
DOI 10.1002/mop MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 58, No. 1, January 2016 175
slot antenna for penta-band WWAN operation in the mobile handset,
Microwave Opt Technol Lett 53 (2011), 1399–1404.
15. C.I. Lin and K.L. Wong, Printed monopole slot antenna for internal
multiband mobile phone antenna, IEEE Trans Antennas Propag 55
(2007), 3690–3697.
16. Y. Wang and Z. Du, A wideband printed dual-antenna with three
neutralization lines for mobile terminals, IEEE Trans Antennas
Propag 62 (2014), 1495–1500.
17. S.W. Su, C.T. Lee, and F.S. Chang, Printed MIMO-antenna system
using neutralization-line technique for wireless USB dongle applica-
tions, IEEE Trans Antennas Propag 60 (2012), 456–463.
VC 2016 Wiley Periodicals, Inc.
AN ULTRAWIDEBAND INVERTEDDOUBLE DISCONE ANTENNA WITH150:1 IMPEDANCE BANDWIDTH
Irfan Shahid,1 Fawad Hussain,1 Jehanzeb Burki,2 andM. Shoaib Arif11 College of Aeronautical Engineering, NUST, Risalpur, KhyberPakhtunkhwa, Pakistan; Corresponding author:[email protected] Institute of Avionics and Aeronautics, Air University E-9, Islamabad,Pakistan
Received 22 May 2015
ABSTRACT: In this article, an improved design of ultrawideband(UWB) inverted double discone (IDD) antenna is presented. Convention-ally, IDD antennas are designed using tapered cylindrical wires as
antenna elements. The tapering makes these antennas very fragile and theantennas suffer frequent damage during installation, transportation or
even, due to perching of birds during normal operation. In this work,curved metal sheets are used instead of tapered wires to improve antennarobustness with no compromise on antenna’s performance. Using this
approach, an IDD antenna with an ultrawide impedance bandwidth isdesigned, fabricated, and tested. The measurements show good conform-
ance with design and the measured antenna demonstrates an impedancebandwidth (for VSWR< 2) of 150:1 in frequency range of 120 MHz–18 GHz with omnidirectional radiation characteristics. VC 2016 Wiley
Periodicals, Inc. Microwave Opt Technol Lett 58:181–184, 2016; View
this article online at wileyonlinelibrary.com. DOI 10.1002/mop.29530