Multi GNSS ieee

1910 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 62, NO. 4, APRIL 2014
Multiband Monopole Mobile Phone Antenna With
Circular Polarization for GNSS Application Zhixi Liang, Yuanxin Li , Member, IEEE , and Yunliang Long , Senior Member, IEEE
Abstract— A novel design of a multiband monopolemobile phone
antenna with circular polarization for GNSS application is pre-
sented. The proposed antenna generates four resonant frequencies
with branch lines and a shorted parasitic strip to obtain a wide op-
erating band. With the definition of 2.5:1 VSWR, the bandwidth
covers several wireless communication systems, including GSM
(880 960 MHz), DCS (1710 1880 MHz), PCS (1850 1990
MHz), UMTS (1920 2170 MHz), WiBro (2300 2390 MHz)
and ISM (2400 2483 MHz), and also covers GNSS, including
COMPASS (1559.052 1591.788 MHz), GPS (1575.42 5 MHz),
GLONASS (1602 1615.5 MHz). A tuning stub is added to the
ground plane and the feeding strip is mounted 45 at the corner
to achieve circular polarization for GNSS application. The 3 dB
axial ratio (AR)bandwidth (AR-BW) is obtained from 1540to 1630
MHz, covering the L1 band of GNSS, including COMPASS, GPS
and GLONASS. In the 3 dB axial ratio bandwidth, right hand and
left hand circularly polarizations are obtained in different broad-
side directions, with the peak circularly polarized gain of more
than 2.7 dBic. An equivalent circuit network is used to analyze
the mechanism of circular polarization. Details of the proposed an-
tenna parameters, including return loss, radiation characteristics,
and AR spectrum are presented and discussed.
Index Terms— Circular polarization, GNSS antenna, mobile phone antenna, monopole antenna.
I. I NTRODUCTION
communication systems, including the GSM (880 960
MHz), DCS (1710 1880 MHz), PCS (1850 1990 MHz),
UMTS (1920 2170 MHz), and ISM (2400 2483 MHz). As
navigation has become indispensable for smart mobile phone,
global navigation satellite system (GNSS) also becomes one
of the most important applications. The well known naviga-
tion system is the global positioning system (GPS), when the
Russian GLONASS and Chinese COMPASS are catching up
[1]. Bands of GNSS are in the neighborhoods of 1575 and
1227 MHz, which are referred as L1 and L2. Single-frequency
receivers for civil use work at L1 frequency and dual-frequency
Manuscript received June 07, 2013; revised October 22, 2013; accepted De-
cember 17, 2013. Date of publication January 13, 2014; date of current version
April 03, 2014. This work was supported by the Natural Science Foundation of China under Grants 61172026 and 41376041.
The authors are with the Department of Electronics and Communication Engineering, Sun Yat-sen University, Guangzhou, China. They are also with
SYSU-CMU Shunde International Joint Research Institute, Shunde, China (e-mail: [email protected]; [email protected]).
Color versions of one or more of the figures in this paper are available online
at http://ieeexplore.ieee.org.
in the ionosphere. When the linearly-polarized antenna receives
the circularly-polarized satellite signals, the received signals
attenuate 3 dB [2]. Therefore, most of the GNSS reception
antennas are circularly polarized.
tion such as patch antennas, helical antennas and slot antennas.
With slots or corner truncated, patch antennas [3], [4] can
achieve high circularly polarized gain. However, the size o f
patch antennas is quite large, even with solid geometry [5].
Broad circularly polarized bandwidth can be seen in many slot
antenna designs [6]–[8], but their ground planes are too small
to be a circuit broad. Helical antennas [9], [10] in the form of a
straight rod are conventional in some GPS handset. Reference
[11] developed the helical antenna into plan ar structure, but a
three-dimensional space was still needed. These conventional
circularly polarized antennas are dif ficult to be integrated,
because of the limited design space for mobile phone antenna.
It is more dif ficult for a multiband mobile phone antenna to
cover both the communication system bands and positioning
system bands. As a result, most mobile phone GNSS antennas
are linearly polarized and designed separately. A mobile phone
antenna with broad bandwidth and circular polarization has
great practical value in im proving the performance and minia-
turization of mobile phone.
Planar monopole antennas have been widely used in mobile
phone for lots of advantages, such as small size, low profile, low
cost. In the recent years, many researches are working on the
miniaturization and multiband for monopole mobile phone an-
tenna [12]–[17]. Most of these researches focus on the commu-
nication system bands or cover the GNSS bands with linear po-
larization. Currently, circularly polarized planar monopole an-
tennas have been achieved in some studies, which create the
possibility for achieving circular polarization in mobile phone.
With slots or falcate-shaped monopole, [18] and [19] produce
dual frequencies circularly polarized operation. But the radia-
tors of these designs are quite large, about , as
they are based on rectangle or circular monopoles. Another way
to achieve circular polarization is adding parasitic elements to
the ground plane, such as slits [20], stubs [21]–[24] or couplers
[25]. However, these antennas are designed for WLAN or UWB
application, with a limited ground length less than 40 mm. These
designs are not suitable for mobile phone application, as mobile
phone antenna should be working in multiband and composed
of a small radiator and a large ground plane, in order to place
more electronics components.
See http://www.ieee.org/publications_standards/publications/rights/index.html for more information.

LIANG et al.: MULTIBAND MONOPOLE MOBILE PHONE ANTENNA WITH CIRCULAR POLARIZATION FOR GNSS APPLICAT ION 1911
Fig. 1. Geometry of the proposed antenna.
In this paper, we present a novel multiband monopole an-
tenna that operating in communication systems with linear po-
larization and global positioning systems with circular polar-
ization. The proposed antenna occupies about 22 50 mm2
with a larger ground (about 88 50 mm2), which is suitable
for mobile phone application. With branch lines and a shorted
parasitic strip, the proposed antenna generates four resonant fre-
quencies to obtain a wide operating band. The bandwidth (2.5:1
VSWR) covers GSM (880 960 MHz), DCS (1710 1880
MHz), PCS (1850 1990 MHz), UMTS (1920 2170 MHz),
WiBro (2300 2390 MHz) and ISM (2400 2483 MHz),
and also covers COMPASS (1559.052 1591.788 MHz), GPS
(1575.42 5 MHz), GLONASS (1602 1615.5 MHz). The
feeding strip and a tuning stub are constructed at different cor-
ners to achieve circular polarization. The 3 dB axial ratio (AR)
bandwidth (AR-BW) is obtained from 1540 to 1630 MHz, with
the peak circularly polarized gain of more than 2.7 dBic. In
the 3 dB axial ratio bandwidth, right hand and left hand circu-
larly polarizations are obtained in different broadside directions.
The generation of circular polarization has been studied with
an equivalent circuit network. Effects of various parameters on
the circular polarization performances are analyzed. A practical
structure was constructed for test and results are presented and
discussed.
II. A NTENNA CONFIGURATION
Fig. 1 shows the proposed antenna, which is printed on a FR4
substrate with a thickness of 1.6 mm and a relative permittivity
of 4.4. The whole substrate occupies an area of 110 50 mm2,
when the antenna and the ground plane are printed on different
sides. The ground plane is not designed as a conventional rec-
tangle, in order to achieve circular polarization.
Details of the proposed antenna are shown in Fig. 2. Point
A is the feeding point and point B is a shorting point via to
the ground plane. A 50 strip line is mounted at the corner
of the ground and feeds a tribranch monopole directly. In the
fabricated prototype, a 50 coaxial connector is attached to
point A from the back of the ground. At the other side of the
ground plane, a tuning stub is extended from the corner. The
Fig. 2. Detail size parameters of the antenna.
radiator consists of two parts, a strip being shorted by a via-hole
(point B)to the ground plane and a strip being fed bya 50 strip
line. There are total 4 resonant paths, including AE, AF, AG
and BD, which generate 4 resonant frequencies with the
mode.
With the proposed structure, it is easy to cover wide op-
erating bands. To demonstrate the multiband mechanism of
the proposed antenna, the antenna is constructed step by step.
Fig. 3 shows the design process of the proposed antenna and
the corresponding results of simulated return loss are shown in
Fig. 4. Fig. 3(a) shows the basic design of monopole antenna,
which resonates at 1600 MHz in Fig. 4. When another branch
AF is added in Fig. 3(b), a new resonant frequency appears
at 1900 MHz, but the bandwidth near 1600 MHz decreases.
With an additional branch AG, the antenna 3 in Fig. 3(c) ex-
pands the upper bandwidth to cover the UMTS, WiBro and
ISM operating bands. Although the path AG is longer than the
path AF, it generates a higher resonant frequency at about 2200
MHz. Because most of the path AG is at the edge of the sub-
strate, the effect of the FR4 substrate is weaker. In Fig. 3(d), a
shorted strip is added for the GSM application. As the resonant
path BD is the longest path, which is excited by the coupling
between the shorted strip and the fed strip, it generates a reso-
nant frequency at 900 MHz. Good return loss of the proposed
antenna is shown in Fig. 4.
III. GENERATION OF CIRCULAR POLARIZATION
In general, circular polarization is generated by two orthog-
onal E vectors with equal amplitudes and a 90 phase difference.
It is defined as
vertical planes, and is the phase difference. If the amplitudes
of and are equal and , the polarized wave
is right hand circularly polarized (RHCP) or left hand circularly

Fig. 3. The antennas with different bands. (a) Antenna 1, the basic design monopole antenna. (b) Antenna 2, the dual-band monopole antenna. (c) An-
tenna 3, the tri-band monopole antenna. (d) The proposed antenna.
Fig. 4. Simulated return loss for the antennas with different bands shown in Fig. 3.
can be used to represent the characteristic of the polarization. It
is expressed as
(2)
where
(3)
For a perfect circularly polarized wave, the AR value is 0 dB.
In practice, circular polarization is typically defined based on an
axial ratio value of less than 3 dB.
Typically, mobile phone antenna is placed on the top of the
ground plane and fed by a vertical stip. Therefore, the copo-
larization of the mobile phone antenna is vertical. To achieve
circular polarization, the resonant path AE and the tuning stub
BC are placed at different corners to generate two orthogonal E
vectors. In Fig. 5, simulated axial ratio results of the antennas in
Fig. 3 are shown to evaluate the effect of the resonant paths AF,
AG and BD. The proposed antenna achieves circular polariza-
tion near 1600 MHz, and slight difference can be seen when the
paths AF, AG and BD are removed from the proposed design. As
Fig. 5. Simulated axial ratio for the antennas in Fig. 3.
Fig. 6. Simulated current distributions at 1600 MHz.
Fig. 7. Simplified schematic diagram for the antenna in Fig. 3(a) at 1600 MHz.
can be observed from Fig. 6, strong surface current distributes
in the tuning stub BC and path AE at 1600 MHz, which means
BC and AE are the key resonant elements.
For analysis convenience, we take antenna 1 in Fig. 3(a) as
a basic configuration to study the cause of circular polarization
at 1600 MHz. The configuration is simplified as a schematic di-
agram in Fig. 7. In the simplified schematic diagram, a driven
element is used to represent path AE and a shorted parasitic el-
ement is used to represent the tuning stub BC. The length of
parasitic stub, , and the distance between two elements, d,
are considered as the key parameters to be discussed in the fol-
lowing analysis.
In Fig. 8, an equivalent circuit network given by Kraus [26] is
used to study the reciprocity of two antenna elements. The case
of a driven element with a single parasitic element has also been

Fig. 8. Equivalent circuit network for the simplified schematic diagram in Fig. 7.
space between them are replaced with equivalent components.
and are the self impedance of the driven element and
parasitic element, or is the mutual impedance, which
represents the mutual coupling between two elements. and
are the current in the driven element and the parasitic element.
According to Kirchhoff’s law, the circuit relations for the ele-
ments are
(6)
Where
(7)
(8)
Let
(9)
(10)
is the amplitude ratio of to and is the phase dif-
ference between and . They are determined by the self
impedance of the parasitic stub and the mutual impedance
of the two elements. and , respectively, represent the
effect contributed by coupling and the parasitic stub on phase
difference.
Simulation has been carried out with the con figuration in
Fig. 3(a) to study and for different stub length and
coupling distance. Fig. 9 shows the simulated self impedance
of the parasitic stub for a fixed distance and
varied length . When is short,
the parasitic stub is capacitive and the reactance is negative. As
Fig. 9. Simulated self impedance of the parasitic stub in Fig. 3(a) for fixed
distance and varied length.
Fig. 10. Calculated and according to the simulated self impedance in
Fig. 9.
Fig. 11. Simulated mutual impedance of two resonant elements in Fig. 3(a) for
fixed length and varied distance.
increases, the parasitic stub becomes inductive and the re-
actance rises to positive. As can be seen in Fig. 10, drops
from 80 to because the reactance of the parasitic stub
changes rapidly. As approach to the resonant length (
mode), the resonant current on the stub become stronger and
increases. Fig. 11 shows the simulated mutual impedance of two
elements for a fixed length and varied distance
. When d increases from 20 mm to
40 mm, the mutual resistance falls slowly and the mutual reac-

Fig. 12. Calculated and according to the simulated mutual impedance in
Fig. 11.
Fig. 13. Simulated axial ratio for different stub width.
Fig. 14. Simulated axial ratio for different stub length.
phase difference and the ratio are more sensitive to the size
of the parasitic stub. When the parasitic stub is capacitive, the
phase difference is in the interval of (180 , 360 ). In this case,
leads and right hand circular polarization may be obtained
in the direction along X axis.
To achieve perfect circular polarization, and d are adjusted
to control the amplitude ratio and phase difference . When
and , the best axial ratio is obtained. Although
the configuration of the proposed antenna is more complicated,
circular polarization can also be realized by adjusting the size
of tuning stub and coupling distance. This method is often sim-
pler in practice but more dif ficult of analysis. In Fig. 13, it can
Fig. 15. Simulated 3D LHCP and RHCP gain patterns of the proposed antenna
at 1600 MHz. (a) LHCP gain pattern. (b) RHCP gain pattern.
be seen that the circularly polarized frequency falls when the
width of the tuning stub decreases. In Fig. 14, when the
length of the tuning stub increases, the circularly polarized
frequency falls. Both the decrease of the width and the increase
of the length make the stub less capacitive. Thus, the corre-
sponding changes of the circular polarized frequency are in con-
sistency with each other. When the values of and are set
as 16 mm and 8 mm, the best axial ratio values are obtained
in the L1 band of GNSS (COMPASS/GPS/GLONASS). As the
resonant frequency and the circularly polarized frequency can
be adjusted separately, the circular polarization can be achieved
in two steps: adjusting the length of the resonant path AE and
adjusting the size of the stub. This property makes the antenna
easy to design and manufacture.
In Fig. 15, the simulated 3D LHCP and RHCP gain patterns
are shown in the form of contour plot. In the simulated results,
the maximal gains of LHCP and RHCP are more than 3 dBic. As
the proposed antenna is designed in a low pro file planar struc-
ture, the radiation is mirror symmetric with respect to YZ plane.
Therefore, LHCP and RHCP coexist at different sides like an
image to each other.
The proposed antenna prototype has been fabricated and
shown in Fig. 16. Good agreement between the measured result
and simulated data is shown in Fig. 17. With the definition
of 7.5 dB return loss or 2.5:1 VSWR, the obtained band-
width covers the operating bands of GSM, COMPASS, GPS,

Fig. 16. Fabricated prototype of the proposed antenna.
Fig. 17. Measured and simulated return loss of the proposed antenna.
Fig. 18. Measured and simulated axial ratio of the proposed antenna.
the axial ratio (AR) for the broadside direction (along X axis)
in simulation and measurement. The 3 dB axial ratio bandwidth
(AR-BW) is from 1540 MHz to 1630 MHz, which covers the
L1 band of GNSS (COMPASS, GPS and GLONASS).
In Fig. 19(a), the simulated results show that good circular
polarization radiation patterns are excited at 1600 MHz. The
antenna achieves right-hand circular polarization (RHCP) along
the X axis and left-hand circular polarization (LHCP) in the op-
posite direction. In the XY plane, the max right-hand circular
polarization and left-hand circular polarization directions are
slightly rotated to the Y axis, because the tuning stub beside the
antenna works as a director. Theexperiment results in Fig. 19(b)
are basically consistent with the simulated results, except some
back lobes. These back lobes are mainly caused by the excited
current in resonant paths AF, AG and BD, as the coupling effect
Fig. 19. Simulated and measured radiation pattern of the proposed antenna in
the XY and XZ plane at 1600 MHz. (a) Simulated. (b) Measured.
becomes more complicated in the fabricated prototype and the
testing environment.
Fig. 20 shows the simulated and measured radiation patterns
at 900, 1900, 2050 and 2450 MHz of the proposed antenna
for wireless communication systems. Fig. 20(a) describes the
radiation pattern at 900 MHz, as good as those of conventional
simple monopole antennas. When the frequency goes higher,
the cross polarization becomes stronger and difference between
the simulated and measured patterns turns more obvious in
Fig. 20(b), (c), (d). In general, good omni directional radiation
patterns are achieved for the communication system bands.
The ef ficiency and gain results are shown in Fig. 21. Within
all the operating bands, the ef ficiency is near 80%. Over the
GSM band, the measured antenna gain is about 1.8 2.4 dBi.
For the upper band including DCS, PCS, UMTS, WiBro, ISM,
the measured antenna gain is varied from 2 to 4.2 dBi. The mea-
sured radiation gain of the GSM band is lower than the upper
band, because the shorted strip works as a reflector and enhances
the directivity in the upper band. As can be seen in Fig. 21(b),
the measured LHCP gain and RHCP gain are a little lower than
the simulated result, because the measured axial ratio is higher
than simulation and slight deviation is observed in the measured
radiation pattern at 1600 MHz. The measured maximal LHCP
and RHCP gain is more than 2.7 dBic in the 3 dB axial ratio
bandwidth.
In this paper, a multiband monopole antenna with circular po-
larization is presented. Branch lines and a shorted parasitic strip
are exploited to obtain a broad bandwidth, which covers sev-
eral wireless communication systems, including the GSM (880
960 MHz), DCS (1710 1880 MHz), PCS (1850 1990
MHz), UMTS (1920 2170 MHz), WiBro (2300 2390 MHz)
and ISM (2400 2483 MHz), and also covers GNSS, including
COMPASS (1559.052 1591.788 MHz), GPS (1575.42 5
MHz), GLONASS (1602 1615.5 MHz). The feeding strip and

Fig. 20. Radiation patterns for the proposed antenna in the XY, XZ and YZ plane. (a) 900 MHz. (b) 1900 MHz. (c) 2050 MHz. (d) 2450 MHz.
Fig. 21. Antenna gain and radiation ef ficiency of the proposed antenna. (a) Operating bands of GSM/DCS/PCS/UMTS/WiBro/ISM. (b) L1 bands of COM-
PASS/GPS/GLONASS.
a tuning stub are constructed at different corners to achieve a cir-
cularly polarized bandwidth about 90 MHz, from 1540 to 1630
MHz. Broadside circularly polarized radiation is provided for
GNSS operation, with the measured maximal LHCP and RHCP
gain of more than 2.7 dBic. Within all the operating bands, the
ef ficiency is near 80%. Good omni directional radiation is pro-
vided within the communication system bands. The way to gen-
erate circular polarization in the proposed antenna is easy to
manufacture. The antenna is very promising for personal com-
munication applications, such as smart mobile phone.
R EFERENCES
[1] C. J. Hegarty and E. Chatre, “Evolution of the global navigation satellite system,” Proc. IEEE , vol. 96, no. 12, pp. 1902–1917, Dec. 2008.
[2] M. A. Jensen, “Alternative antenna polarization schemes for satellite-
handset links including operator tissue,” in Proc. Antennas Propag. Soc. Int. Sym. Digest , Jul. 13–18, 1997, vol. 2, pp. 1336–1339.
[3] S. Shekhawat, P. Sekra, D. Bhatnagar, V. K. Saxena, and J. Saini, “Stacked arrangement of rectangular microstrip patches for circularly
polarized broadband performance,” IEEE Antennas Wireless Propag. Lett., vol. 9, pp. 910–913, Sep. 2010.
[4] W. Chen, Y. Li, H. Jiang, and Y. Long, “Design of novel tri-frequency
microstrip antenna with arc slots,” Electron. Lett., vol. 48, no. 11, pp. 609–611, May 2012.
[5] X. H. Tang, K. L. Lau, Q. Xue, and Y. L. Long, “Miniature circularly polarized patch antenna,” Electron Lett., vol. 46, no. 6, pp. 391–392,
Mar. 2010.

[6] J. Y. Sze, C. I. Hsu, Z. W. Chen, and C. C. Chang, “Broad- band CPW-fed circularly polarized square slot antenna with light-
ening-shaped feed line and inverted-L grounded strips,” IEEE Trans.
Antennas Propag., vol. 58, no. 3, pp. 973–977, Mar. 2010. [7] W. T. Hsieh, T. H.Chang, and J. F.Kiang, “Dual-band circularly polar-
ized cavity-backed annularslot antennafor GPSreceiver,” IEEE Trans. Antennas Propag., vol. 60, no. 4, pp. 2076–2080, Apr. 2012.
[8] S. L. S. Yang, A. A. Kishk, and K. F. Lee, “Wideband circularly polarized antenna with L-shaped slot,” IEEE Trans. Antennas Propag., vol.
56, no. 6, pp. 1780–1783, Jun. 2008. [9] Y. S. Wang and S. J. Chung, “A Miniature quadrifilar helix antenna for
global positioning satellite reception,” IEEE Trans. Antennas Propag.,
vol. 57, no. 12, pp. 3736–3751, Dec. 2009. [10] Z.H. Wu,W. Q.Che, B.Fu,P. Y.Lau, and E.K. N.Yung,“Axial mode
ellipticalhelical antennawith parasitic wire for CP bandwidth enhance- ment,” IET Microw. Antennas Propag., vol. 1, no.4, pp.943–948, Aug.
2007. [11] S. H. Chang and W. J. Liao, “A novel dual band circularly polarized
GNSS antenna for handheld devices,” IEEE Trans. Antennas Propag.,
vol. 61, no. 2, pp. 555–562, Feb. 2013. [12] D. B. Lin, H. P. Lin, I. T. Tang, and P. S. Chen, “Printed inverted-F
monopole antenna for internal multi-band mobile phone antenna,” in Proc. VTC , May 15–18, 2011, pp. 1–5.
[13] Z. W. Zhong, Y. X. Li, Z. X. Liang, and Y. L. Long, “Biplanar monopole with DSPSL feed and coupling line for broadband mo-
bile phone,” IEEE Antennas Wireless Propag. Lett., vol. 11, pp.
1326–1329, 2012. [14] C. L. Liu, Y. F. Lin, C. M. Liang, S. C. Pan, and H. M. Chen, “Minia-
ture internal penta-band monopole antenna for mobile phones,” IEEE Trans. Antennas Propag., vol. 58, no. 3, pp. 1008–1011, Mar. 2010.
[15] C. T. Lee and K. L. Wong, “Internal WWAN clamshell mobile phone antenna using a current trap for reduced ground plane effects,” IEEE
Trans. Antennas Propag., vol. 57, no. 10, pp. 3303–3308, Oct. 2009.
[16] C. H. Wu and K. L. Wong, “Ultra wideband PIFA with a capacitive feed for penta-band folder-type mobile phone antenna,” IEEE Trans.
Antennas Propag., vol. 57, no. 8, pp. 2461–2464, Aug. 2009. [17] K. G. Kangand Y. Sung, “Compact hexaband PIFA antenna formobile
handset applications,” IEEE Antennas Wireless Propag. Letters, vol. 9, pp. 1127–1130, 2010.
[18] S. A. Rezaeieh, “Dual band dual sense circularly polarized monopole antenna for GPS and WLAN applications,” Electron. Lett., vol. 47, no.
12, pp. 1212–1214, Oct. 2011.
[19] C. R. Huang, J. H. Huang, and C. F. Jou, “Dual-band circularly polarized slotted monopole antenna,” in Proc. APMC , Dec. 5–8, 2011, pp.
1866–1869. [20] J. W. Wu, J. Y. Ke, C. F. Jou, and C. J. Wang, “Microstrip-fed broad-
band circularly polarized monopole antenna,” IET Microw. Antennas Propag., vol. 4, pp. 518–525, Apr. 2010.
[21] J. W. Wu, C. F. Jou, and C. J. Wang, “Dual-band circularly polarized
monopole antenna,” in Proc. iWAT , Mar. 2–4, 2009, pp. 1–4. [22] S. Esfandiarpour, H. R. Hassani, and A. Frotanpour, “A dual-band cir-
cularly polarized monopole antenna for WLAN application,” in Proc. EUCAP , Apr. 11–15, 2011, pp. 346–349.
[23] T. Fujimoto and K. Jono, “Wideband printed rectangular monopole antenna for circularly polarization,” in Proc. Antennas andPropag. Soc.
Int. Sym., Jul. 8–14, 2012, pp. 1–2.
[24] L. Zhang, Y. C. Jiao, and Z. B. Weng, “CPW-Fed broadband circularly polarized planar monopole antenna with improved ground-plane struc-
ture,” IEEE Trans. Antennas Propag., vol. 61, no. 9, pp. 4824–4828, Sep. 2013.
[25] A. Ghobadi, “A printed circularly polarized y-shaped monopole an-
tenna,” IEEE Antennas Wireless Propag. Lett., vol.11,pp. 22–25,2012.
[26] J. D. Kraus and R. J. Marhefka , Antennas: For All Applications. New
York, NY, USA: McGraw-Hill, 2008, ch. 13, p. 441. [27] G. H. Brown, “Directional antennas,” in Proc. IRE , Jan. 1937, vol. 25,
pp. 78–145.
China, in 1989. He received the B.S. degree in elec-
tronics engineering from Sun Yat-sen University, Guangzhou, China, in 2011. He is currently working
toward the Ph.D. degree at Sun Yat-sen University, Guangzhou, China.
His current research interests include microstrip antenna theory, novel mobile phone antennas design,
and UWB antennas design.
Yuanxin Li (M’08) was born in Guangzhou, China.
He received the B.S. and Ph.D. degrees from the Sun Yat-sen University, China, in 2001 and 2006,
respectively. From 2006 to 2008 and 2010, he was a Senior Re-
search Assistant and Research Fellow with the State Key Laboratory of Millimeter Waves, City Univer-
sityof HongKong. From 2008, he joined Department of Electronics and Communication Engineering, Sun
Yat-sen University. He currently is an Associate Pro-
fessor of Department of Electronicsand Communica- tion Engineering, Sun Yat-sen University. His recently research interests include
microstrip leaky wave antenna and the applications of the periodic construction.
Yunliang Long (M’01–SM’02) was born in Chongqing, China. He received the B.Sc., M.Eng.,
and Ph.D. degrees from the University of Elec-
tronic Science and Technology of China (UESTC), Chengdu, in 1983, 1989, and 1992, respectively.
From 1992 to 1994, he was a Postdoctoral Research Fellow, then employed as an Associate
Professor, with the Department of Electronics, Sun Yat-sen University, Guangzhou, China. From 1998
to 1999, he was a Visiting Scholar in IHF, RWTH University of Aachen, Germany. From 2000 to 2001,
he was a Research Fellow with the Department of Electronics Engineering,
City University of Hong Kong, China. Currently, he is a full Professor and the Head of the Department of Electronics and Communication Engineering, Sun
Yat-sen University, China. He has authored and coauthored over 200 academic papers. His research interests include antennas and propagation theory, EM
theory in inhomogeneous lossy medium, computational electromagnetics, and wireless communication applications.

Documents

Multi GNSS ieee