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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 64, NO. 3,
MARCH 2016 953
Single-Feed Quad-Beam TransmitarrayAntenna Design
Ahmed H. Abdelrahman, Member, IEEE, Payam Nayeri, Member, IEEE,
Atef Z. Elsherbeni, Fellow, IEEE,and Fan Yang, Senior Member,
IEEE
Abstract—We present a design methodology for
single-feedmultibeam transmitarray antennas through case studies of
quad-beam designs. Different far-field pattern masks and fitness
func-tions are studied for multibeam designs, and the particle
swarmoptimization (PSO) technique is implemented for aperture
phasesynthesis. A quad-layer configuration of double square loops
isused for the transmitarray elements, and a quad-beam
transmi-tarray prototype is fabricated and tested. The effects of
variousapproximations in unit-cell analysis are also investigated
in detail.The Ku-band prototype generates four symmetric beams with
50◦
elevation separation between the beams and gains around 23
dB.
Index Terms—Multibeam, particle swarm optimization (PSO),phase
synthesis, transmitarray antenna.
I. INTRODUCTION
P LANAR transmitarray antennas have attracted a grow-ing
interest in the area of high-gain antennas due to theirnumerous
advantages [1], [2]. They combine the favorable fea-tures of
optical lens and array antennas leading to a low-profileaperture
and light weight design, which is well appropriatefor long distance
communications and space applications [3].One of the main
advantages of transmitarray antennas com-pared to dielectric lens
is the individual phase control of eachtransmitarray element, which
provides flexibility in array phasesynthesis, and hence is suitable
for various applications thatrequire radiation pattern control
[4]–[6].
Multibeam antennas receive considerable attention in
space[7]–[8], radar [9]–[10], SAR [11], millimeter wave [12],
andMIMO [13] applications. High-gain antennas with
multiplesimultaneous beams are usually implemented using
reflec-tors or lenses with feed-horn clusters, or large phased
arrays.The main disadvantages of these structures are cost, size,
andweight, mainly for space applications. Similar to
reflectarrayantennas [14], [15], a transmitarray antenna with a
single feed
Manuscript received June 08, 2015; revised October 29, 2015;
acceptedDecember 31, 2015. Date of publication January 13, 2016;
date of current ver-sion March 01, 2016. This work is supported by
NSF Award # ECCS-1413863.
A. H. Abdelrahman is with the Millimeter Wave Circuits and
AntennasLaboratory, Electrical and Computer Engineering Department,
University ofArizona, Tucson, AZ 85721 USA (e-mail:
[email protected]).
P. Nayeri and A. Z. Elsherbeni are with the Department of
ElectricalEngineering and Computer Science, Colorado School of
Mines, Golden, CO80401 USA (e-mail: [email protected];
[email protected]).
F. Yang is with the Microwave and Antenna Institute, Department
ofElectronic Engineering, Tsinghua University, Beijing 100084,
China (e-mail:[email protected]).
Color versions of one or more of the figures in this paper are
available onlineat http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TAP.2016.2517660
can achieve multiple simultaneous beams with the added
advan-tages of light weight and low-profile aperture [16], [17].
Incomparison to a multibeam reflectarray, the main advantageof a
multibeam transmitarray is the inherent ability to avoidfeed
blockage, which is typically a concern for simultaneousmultibeam
patterns [15].
In this paper, we present a general design methodologyfor
multibeam transmitarray antennas using a single sourcefeed, through
case studies of several quad-beam designs. Itshould be noted that
since all beam are generated with a sin-gle source, they carry the
same signal. The particle swarmoptimization (PSO) technique is
implemented to synthesize thetransmission phase of the
transmitarray elements [18], and var-ious pattern masks and fitness
functions are implemented formultibeam designs. A Ku-band quad-beam
transmitarray pro-totype is fabricated and tested using quad-layer
double squareloop (QLDSL) elements. Effects of oblique incidence
andlocal periodicity approximation in the element design are
alsoinvestigated in detail to determine their impacts on the
ele-ment transmission coefficients and the overall antenna
radiationpattern.
II. DESIGN OF SINGLE-FEED MULTIBEAMTRANSMITARRAY ANTENNAS
A. Design Methodologies
In transmitarray antennas, the element amplitudes are fixedby
the properties of the feed and the element locations.However, the
elements of a transmitarray antenna have the flex-ibility to
achieve any value of phase shift. Utilizing this directcontrol of
phase shift for every element, the phase distribu-tion on the array
aperture can be synthesized to achieve anydesired pattern shape,
such as multibeam patterns. Accordingly,the design procedure of the
proposed transmitarray antennastarts with synthesis of the
transmission phase distribution ofthe array aperture using PSO
technique. Once the requiredtransmission phase is determined for
each element, the corre-sponding element dimension is obtained
using the transmis-sion phase versus element dimension curve, which
is usuallyobtained from the unit-cell full EM wave analysis.
Two different synthesis approaches are available for single-feed
multibeam space-fed arrays, i.e., direct analytical solutionsor
optimization methods. While analytical solutions are typ-ically
simple to implement, recent studies [14] have shownthat the
performance of these methods is not satisfactory inmany cases.
Optimization methods on the other hand have the
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954 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 64, NO.
3, MARCH 2016
Fig. 1. Quad-layer unit-cell configuration of a double square
loop element.(a) Top view. (b) Side view.
potential to find a solution to the synthesis problem;
however,they typically require long computational time to converge
[15].
In this study, we use the PSO global search method to
syn-thesize the aperture phase distribution of transmitarray
antennasfor multibeam performance. Far-field pattern masks are
definedbased on the design requirements, and different fitness
func-tions are studied to achieve optimal beam performance
andsidelobe level. Pattern computation is conducted
efficientlyusing an in-house code, which is based on the array
theoryformulation with spectral transformations for
computationalspeedup [19].
B. Design of Single-Feed Quad-Beam Transmitarray Antennasat
Ku-Band
To demonstrate the feasibility of the proposed design tech-nique
for single-feed multibeam transmitarray antennas, westudy a
symmetric quad-beam system. The elevation separa-tion between the
four beams is designed to be 50◦, such thatthe four beams are
pointing at ϑ1,2,3,4 = 25◦, ϕ1 = 0◦, ϕ2 =90◦, ϕ3 = 180◦, and ϕ4 =
270◦. The transmitarray is designedfor the center operating
frequency of 13.5 GHz.
A linearly polarized corrugated conical horn with a gainequal to
16.3 dB at 13.5 GHz is used as the feed antenna. Thephase center of
the horn is placed at a distance of 275 mm fromthe transmitarray
antenna aperture. For the simulation model,the radiation pattern of
this feed is approximated with a cosq (θ)model with q = 9.25.
The array has a circular aperture with a diameter of 311
mmconsisting of 648 elements. The elements are QLDSL asdescribed in
[20]. The element configuration and design param-eters are shown in
Fig. 1.
The unit-cell simulations were carried out using CSTMicrowave
Studio software [21]. The optimum dimensions ofthe separation
between the two loops (S) and the loop width(W) were determined
through parametric analysis aiming toachieve an optimal linear
slope of the transmission phase, undernormal incidence excitation.
These dimensions were deter-mined to be S = 0.2 L1 and W = 4.2 mm,
and phase tuningis achieved by varying the length L1 from 6.6 to
10.4 mm.L1 is the only variable parameter, S and L2 are
dependentparameters of L1. The four-layers of the unit-cell are
identical.The elements are printed on a Taconic TLX-8 dielectric
sub-strate with permittivity �r = 2.574 and thickness T = 0.5
mm.The periodicity of the unit-cell element is P = 11.1 mm, and
Fig. 2. Transmission coefficient of the QLDSL element with
normal incidenceat 13.5 GHz.
the separation between layers is equal to H = 5 mm, whichcan
achieve a 360◦ transmission phase range with transmissionmagnitudes
better than −1.2 dB at 13.5 GHz [2], as shown inFig. 2.
Three different design models are investigated for
quad-beamtransmitarray antennas. First, we consider two different
patternmasks: a constant sidelobe level of −30 dB (Design 1), and
atapered mask with −25 dB SLL at the first sidelobe to −40 dBat ϑ =
90◦ (Design 2). A two term fitness function is defined,which
evaluates the radiation performance of the array in termsof the
peak gain for each beam and sidelobe level in the entireangular
space based on the mask requirements as described in[15]. The
fitness function to be minimized is
Cost =W1∑
(u,v)/∈mainbeamand |F (u,v)|>MU (u,v)
∑(|F (u, v)| −MU (u, v))2
+W2∑
(u,v)∈mainbeamand |F (u,v)|
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ABDELRAHMAN et al.: SINGLE-FEED QUAD-BEAM TRANSMITARRAY ANTENNA
DESIGN 955
TABLE ICOMPARISON OF THREE DIFFERENT DESIGN MODELS FOR
SINGLE-FEED
QUAD-BEAM TRANSMITARRAY ANTENNAS
Fig. 3. (a) Synthesized phase distribution. (b) Radiation
pattern mask.(c) Simulated radiation patterns for the quad-beam
transmitarray antenna at13.5 GHz.
space, and thus was selected for fabrication. The
synthesizedphase distribution on the aperture, the pattern mask,
and theradiation patterns for this design are given in Fig. 3.
III. PROTOTYPE FABRICATION AND MEASUREMENTS
The optimized quad-beam prototype is fabricated using
acommercial PCB etching process. The mask and photographof one
layer of the fabricated array with 648 QLDSL elementsare shown in
Fig. 4. The fabricated prototype is tested using theNSI planar
near-field measurement system at the University ofMississippi. An
image of the test setup is shown in Fig. 5.
The far-field radiation patterns for y-polarized feed-horn
aredepicted in Fig. 6, which show a good quad-beam performance.The
four beams are located at elevation angle θ1,2,3,4 = 25◦,
Fig. 4. One layer of the fabricated quad-beam transmitarray
prototype.(a) Mask. (b) Photograph.
Fig. 5. Measurement setup of the quad-beam transmitarray antenna
in the NSIplanar near-field system.
Fig. 6. Far-field patterns. (a) xz-plane. (b) yz-plane. (c) 3-D
pattern.
except a 1◦ shift in one beam, and azimuth angles φ1 =0◦,φ2 =
90◦,φ3 = 180◦, and φ4 = 270◦ as desired. The mea-sured gain of the
two beams along the yz-plane are the sameand equal to 23.8 dB, and
those along the xz-plane are equal to22.3 dB and 22.6 dB. Note that
the simulated gain is 24.77 dBfor each beam. The sidelobe and cross
polarized levels are lessthan −14 dB and −30 dB, respectively.
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956 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 64, NO.
3, MARCH 2016
Fig. 7. Transmission coefficients of the QLDSL element versus
element dimen-sion L1. (a) Magnitude of elements along x-axis. (b)
Phase of elements alongx-axis. (c) Magnitude of elements along
y-axis. (b) Phase of elements alongy-axis.
The gain reduction of 1.5 and 1.2 dB observed for the twobeams
along the xz-plane in comparison with the other twobeams along the
yz-plane is primarily attributed to polarizationeffects [3].
Additionally, the higher sidelobe levels observedin the measured
results are attributed to fabrication toler-ances, and
approximation errors in the unit-cell analysis, whichinclude normal
incidence and local periodicity approximations.Detailed
investigations on these sources of error are conductedand presented
in the following sections.
IV. EFFECTS OF VARIOUS APPROXIMATIONS
A. Oblique Incidence Effects on the Element Performance
In this section, we study the transmission performance of
thephasing elements under oblique incidence excitation. The aimof
this study is to investigate the potential errors due to
normalincidence approximation in the element design. Fig. 7
depictsthe variations in the transmission magnitude and phase of
theQLDSL element at different oblique incidence angles and
fory-polarized incidence wave. The parameters θ and ϕ are
theelevation and azimuth angles of the incident wave,
respectively.
The results shown here indicate that despite some minor
dif-ferences, the transmission magnitude and phase of the
elementsdo not differ significantly with the normal incidence case
forelevation angles up to 30◦. It should be noted, however, thatfor
the case of L1 = 9.4 mm, when placed along the x-axis(ϕ = 0◦), the
element does exhibit a resonance for obliqueexcitation angles that
significantly degrades its performance.However, the fabricated
prototype only has four elements withthis dimension, which are not
along the x-axis, and are close tothe aperture edge, thus they also
exhibit a weaker taper. In sum-mary, the errors arising from the
normal incident approximationare relatively small, and the
discrepancies between measuredand simulated results are not
attributed to this approximation.
B. Variations in Dimensions of Neighbor Elements
In multibeam space-fed arrays, the aperture phase distri-bution
is considerably different than traditional single-beam
Fig. 8. Large unit-cell analysis.
designs. For the latter, the elements exhibit a smooth
phasevariation between their neighboring elements and phase
wraps(element dimension jumping from a maximum to minimum orvice
versa) are only observed at the edge of the Fresnel zones.As such,
local periodicity is generally considered to be a reason-able
approximation. For multibeam designs, however, the
phasedistribution on the aperture is quite complex and significant
dif-ferences between each element and its surrounding
neighborelements are observed (see Fig. 4). Accordingly, the
approxi-mations in the traditional unit-cell analysis, which
consider allelements to be identical, could lead to noticeable
error in thetransmission coefficient values.
In order to investigate the accuracy of the unit-cell
elementapproximations, a large unit-cell consisting of nine
neighborelements is studied, which is known as the surrounded
ele-ment approach [22]. Three different cases, as shown in Fig.
8,are simulated using CST Microwave Studio software [21].
Thedimensions L1 of the center element for the three cases are7.2,
7.75, and 8.85 mm, respectively. The dimensions of theother
neighbor elements are selected according to their actualdimensions
in the designed quad-beam transmitarray prototype.
The transmission coefficients of the three cases are com-pared
with those of the conventional unit-cell element in Fig. 9.Due to
the asymmetry of the large unit-cell, the transmis-sion
coefficients for both perpendicular (TE) and parallel
(TM)polarizations are considered [3]. It can be seen that Case 1)
andCase 2) both show large phase error and magnitude loss
whencompared with the conventional unit-cell element. Case 3) onthe
other hand shows almost no significant change in the trans-mission
coefficient values. This is due to the fact that thedimensional
difference between the elements in this case issmall compared to
the other two cases. This study shows thatthe local periodicity
approximation appears to be the primaryreason for the transmission
coefficient errors of the elements.
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ABDELRAHMAN et al.: SINGLE-FEED QUAD-BEAM TRANSMITARRAY ANTENNA
DESIGN 957
Fig. 9. Transmission coefficients of the large unit-cell
compared with theconventional unit-cell. (a) Magnitude. (b)
Phase.
Fig. 10. Average radiation patterns of 20 trials for different
standard deviationsof the random phase error distribution.
Fig. 11. Average radiation patterns of 20 trials for different
standard deviationsof the random magnitude loss distribution.
C. Impact of Element Phase Error and Magnitude Loss onAntenna
Radiation Pattern
The potential sources of error were investigated in the
previ-ous two sections and it was shown that approximation of
localperiodicity led to significant inaccuracies in the
transmissioncoefficients values of the elements. Here, we study the
effectof both transmission phase error and loss of the elements
onthe radiation pattern of the quad-beam transmitarray
prototype.For phase error analysis, a random phase is added to the
actualphase of each element using a normal distribution with
meanvalue of 0◦. The standard deviation for this normal
distribu-tion ranges from 0◦ to 60◦. For each standard deviation
value,the average normalized radiation pattern of 20 trials is
demon-strated in Fig. 10. In the same way, the effects of
elementloss is analyzed, by adding a random loss to the actual
mag-nitude of each element using a normal distribution with
meanvalue of 0 dB and with different standard deviation values
thatrange from 0 to −15 dB. Because the magnitude loss leads to
areduction in the transmission magnitude, the random
magnitudelosses must be negative values. Similar to the phase error
anal-ysis, for each standard deviation value, the average
normalizedradiation pattern of 20 trials is presented in Fig.
11.
The results given in Figs. 10 and 11 reveal that while bothphase
error and magnitude loss of the transmitarray elements
have little effect on the direction of the main beams, they
signif-icantly increase the sidelobe levels. In particular, the
sidelobesin the area between the four beams increases by 20 dB
witha 40◦ mean random phase error. Moreover, when analyzingeach of
the 20 trials individually, we noticed that a very smallbeam-shift
could occur due to the local periodicity approxima-tion. Based on
the studies presented in Sections IV-A and IV-B,the authors believe
that the primary reasons for the discrepan-cies between measured
and simulated gain values are attributedto phase and magnitude
errors of the elements arising from thelocal periodicity
approximation, as well as fabrication errors.
V. CONCLUSION
The feasibility of designing single-feed multibeam
transmi-tarray antennas is demonstrated through the design of
quad-beam patterns. The PSO method is used to synthesize the
aper-ture phase distribution of the transmitarray, and various
patternmasks and fitness functions are studied for multibeam
designs.A Ku-band single-feed quad-beam transmitarray antenna
with50◦ elevation separation between the beams is designed,
fabri-cated, and tested at 13.5 GHz by using QLDSL elements.
Thearray has a circular aperture with a diameter of 311 mm.
Themeasured gains of four beams are 23.8, 23.8, 22.3, and 22.6
dB,respectively. Furthermore, the impact of unit-cell
approxima-tions during simulation process is studied, and then the
effectsof phase error and magnitude loss of the unit-cell element
onthe antenna patterns are demonstrated.
REFERENCES
[1] A. Yu, F. Yang, A. Z. Elsherbeni, and J. Huang,
“Transmitarray antennas:An overview,” in Proc. IEEE Antennas
Propag. Soc. (APS/URSI) Symp.,Jul. 2011.
[2] A. H. Abdelrahman, F. Yang, and A. Z. Elsherbeni
“Transmissionphase limit of multilayer frequency selective surfaces
for transmitarraydesigns,” IEEE Trans. Antennas Propag., vol. 62,
no. 2, pp. 690–697,Feb. 2014.
[3] A. H. Abdelrahman, A. Z. Elsherbeni, and F. Yang,
“Transmitarrayantenna design using cross slot elements with no
dielectric substrate,”IEEE Antennas Wireless Propag. Lett., vol.
13, pp. 177–180, Feb. 2014.
[4] P. Nayeri, F. Yang, and A. Z. Elsherbeni, “Design of
multifocal transmi-tarray antennas for beamforming applications,”
in Proc. IEEE AntennasPropag. Soc. Int. Symp. (AP-S), Jul. 2013,
pp. 1672–1673.
[5] A. Clemente, L. Dussopt, R. Sauleau, P. Potier, and P.
Pouliguen,“Wideband 400-element electronically reconfigurable
transmitarray in X-band,” IEEE Trans. Antennas Propag., vol. 61,
no. 10, pp. 5017–5027,Oct. 2013.
[6] J. Y. Lau and S. V. Hum, “A wideband reconfigurable
transmitarray ele-ment,” IEEE Trans. Antennas Propag., vol. 60, no.
3, pp. 1303–1311,Mar. 2012.
[7] G. Zheng, S. Chatzinotas, and B. Ottersten, “Generic
optimization oflinear precoding in multibeam satellite systems”,
IEEE Trans. WirelessCommun., vol. 11, no. 6, pp. 2308–2320, Jun.
2012.
[8] S. A. Hasan, “Highly reliable & wideband digital multi
beamforminghorn array antenna with gain adjustment capabilities for
space applica-tions,” in Proc. China-Japan Joint Microw. Conf.
(CJMW), Apr. 2011.
[9] I. Slomian, P. Kaminski, J. Sorocki, I. Piekarz, K. Wincza,
andS. Gruszczynski, “Multi-beam and multi-range antenna array for
24 GHzradar applications,” in Proc. IEEE 20th Int. Conf. Microw.
RadarsWireless Commun. (MIKON), Jun. 2014.
[10] B. Schoenlinner and G. M. Rebeiz, “Compact multibeam
imagingantenna for automotive radars,” in Proc. IEEE MTT-S Int.
Microw. Symp.Dig., Seattle, WA, USA, Jun. 2002, vol. 2, pp.
1373–1376.
[11] G. Wen-jun and L. Xiao-meng, “Amplitude-only optimizing
methodof multi-subaperture multi-beam antenna for SAR
applications,” inProc. IEEE Int. Conf. Electron. Commun. Control
(ICECC), Sep. 2011,pp. 117–120.
-
958 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 64, NO.
3, MARCH 2016
[12] M. Ettorre, R. Sauleau, and L. Le Coq, “Multi-beam
multi-layer leaky-wave siw pillbox antenna for millimeter-wave
applications,” IEEE Trans.Antennas Propag., vol. 59, no. 4, pp.
1093–1100, Apr. 2011.
[13] K. Kagoshima, S. Takeda, and K. Itou, “Array excitation
coefficients ofa compact multi-beam antenna for MIMO applications,”
in Proc. IEEE-APS Topical Conf. Antennas Propag. Wireless Commun.
(APWC), Aug.2014, pp. 195–198.
[14] P. Nayeri, F. Yang, and A. Z. Elsherbeni, “Design and
experiment ofa single-feed quad-beam reflectarray antenna,” IEEE
Trans. AntennasPropag., vol. 60, no. 2, pp. 1166–1171, Feb.
2012.
[15] P. Nayeri, F. Yang, and A. Z. Elsherbeni, “Design of
single-feed reflectar-ray antennas with asymmetric multiple beams
using the particle swarmoptimization method,” IEEE Trans. Antennas
Propag., vol. 61, no. 9,pp. 4598–4605, Sep. 2013.
[16] A. H. Abdelrahman, P. Nayeri, A. Z. Elsherbeni, and F.
Yang, “Design ofsingle-feed multi-beam transmitarray antennas,” in
Proc. IEEE AntennasPropag. Soc. Int. Symp., Jul. 2014, pp.
1264–1265.
[17] S. H. Zainud-Deen, S. M. Gaber, H. A. Malhat, and K. H.
Awadalla,“Perforated transmitarray-enhanced circularly polarized
antennas forhigh-gain multi-beam radiation,” in Proc. IEEE Int.
Symp. AntennasPropag. (ISAP), Oct. 2013, pp. 484–487.
[18] D. W. Boeringer and D. H. Werner, “Particle swarm
optimization ver-sus genetic algorithms for phased array
synthesis,” IEEE Trans. AntennasPropag., vol. 52, no. 3, pp.
771–779, Mar. 2004.
[19] P. Nayeri, A. Z. Elsherbeni, and F. Yang, “Radiation
analysis approachesfor reflectarray antennas,” IEEE Antennas
Propag. Mag., vol. 55, no. 1,pp. 127–134, Feb. 2013.
[20] A. H. Abdelrahman, P. Nayeri, A. Z. Elsherbeni, and F.
Yang, “Analysisand design of wideband quad-layer transmitarray
antennas,” IEEE Trans.Antennas Propag., vol. 63, no. 7, pp.
2946–2854, Jul. 2015.
[21] CST Microwave Studio, version 2012.01, Feb. 24, 2012.[22]
M-A. Milon, D. Cadoret, R. Gillard, and H. Legay,
“Surrounded-element
approach for the simulation of reflectarray radiating cells,”
IET Microw.Antennas Propag., vol. 1, no. 2, pp. 289–293, Apr.
2007.
Ahmed H. Abdelrahman (S’13–M’15) receivedthe B.S. degree in
electrical engineering and theM.S. degree in electronics and
communications fromAin Shams University, Cairo, Egypt, and the
Ph.D.degree in engineering sciences from the University
ofMississippi, University, MS, USA, in 2001, 2010, and2014,
respectively.
He is currently a Postdoctoral Research Associatewith the
Department of Electrical and ComputerEngineering, University of
Arizona, Tucson, AZ,USA. He also possesses over eight years of
expe-
rience in Satellite Communications industry. He worked as a RF
DesignEngineer and a Communication System Engineer in building the
low earth orbitsatellite Egyptsat-1. His research interests include
transmitarray/reflectarrayantennas, mobile antennas, 3-D printed
antennas, and thermoacoustic andmillimeter-wave imaging.
Dr. Abdelrahman was the recipient of the several prestigious
awards, includ-ing the third place Winner Student Paper Competition
Award at the 2013 ACESAnnual Conference, and the Honorable Mention
Student Paper Competition atthe 2014 IEEE AP-S International
Symposium on Antennas and Propagation.
Payam Nayeri (S’09–M’12) received the B.Sc.degree in applied
physics from Shahid BeheshtiUniversity, Tehran, Iran, the M.Sc.
degree in elec-trical engineering from Iran University of
Scienceand Technology, Tehran, Iran, and the Ph.D. degreein
electrical engineering from the University ofMississippi,
University, MS, USA, in 2004, 2007, and2012, respectively.
From 2008 to 2013, he was with the Centerfor Applied
Electromagnetic Systems Research(CAESR), University of Mississippi.
Prior to this,
he was a Visiting Researcher at the University of Queensland,
Brisbane,QLD, Australia. From August 2012 to December 2013, he was
a PostdoctoralResearch Associate and an Instructor with the
Department of ElectricalEngineering, University of Mississippi.
From January 2014 to June 2015, hewas a Postdoctoral Fellow with
the Department of Electrical Engineering andComputer Science,
Colorado School of Mines, Golden, CO, USA. He joinedthe Department
of Electrical Engineering and Computer Science, Colorado
School of Mines, as an Assistant Professor in July 2015. He has
authoredover sixty journal articles and conference papers. His
research interests includeantennas, arrays, and RF/microwave
devices and systems, with applications indeep space communications,
microwave imaging, and remote sensing.
Dr. Nayeri is a member of Sigma Xi, and Phi Kappa Phi. He was
the recipientof several prestigious awards, including the IEEE
Antennas and PropagationSociety Doctoral Research Award in 2010,
the University of MississippiGraduate Achievement Award in
Electrical Engineering in 2011, and the BestStudent Paper Award of
the 29th International Review of Progress in ACES.
Atef Z. Elsherbeni (S’84–M’86–SM’91–F’07)received the B.Sc.
degree (Hons.) in electronicsand communications, the B.Sc. degree
(Hons.) inapplied physics, and the M.Eng. degree in
electricalengineering, all from Cairo University, Cairo, Egypt,and
the Ph.D. degree in electrical engineering fromManitoba University,
Winnipeg, MB, Canada, in1976, 1979, 1982, and 1987,
respectively.
He joined as Faculty at the University ofMississippi,
University, MS, USA, in August 1987,as an Assistant Professor of
Electrical Engineering.
He advanced to the rank of Associate Professor in 1991, and to
the rank ofProfessor in 1997. He was appointed as an Associate Dean
of Engineeringfor Research and Graduate Programs in 2009. He became
the DobelmanDistinguished Chair and Professor of Electrical
Engineering with ColoradoSchool of Mines, Golden, CO, USA, in
August 2013. He was appointedas an Adjunct Professor with the
Department of Electrical Engineering andComputer Science, Syracuse
University, Syracuse, NY, USA, in 2004. Hespent a sabbatical term
in 1996 at the Electrical Engineering Department,University of
California at Los Angeles (UCLA), Los Angeles, CA, USA,and was a
Visiting Professor at Magdeburg University, Magdeburg, Germany,in
2005 and Tampere University of Technology, Tampere, Finland, in
2007.From 2009 to 2011, he was a Finland Distinguished Professor
selected bythe Academy of Finland and TEKES. He is the coauthor of
the booksAntenna Analysis and Design Using FEKO Electromagnetic
SimulationSoftware, ACES Series on Computational Electromagnetics
and Engineering,(SciTech, 2014), Double-Grid Finite-Difference
Frequency-Domain (DG-FDFD) Method for Scattering from Chiral
Objects (Morgan and Claypool,2013), Scattering Analysis of Periodic
Structures Using Finite-Difference Time-Domain Method (Morgan and
Claypool, 2012), Multiresolution FrequencyDomain Technique for
Electromagnetics (Morgan and Claypool, 2012), TheFinite Difference
Time Domain Method for Electromagnetics with MatlabSimulations,
(SciTech, 2009), Antenna Design and Visualization Using
Matlab(SciTech, 2006), MATLAB Simulations for Radar Systems Design
(CRCPress, 2003), Electromagnetic Scattering Using the Iterative
MultiregionTechnique (Morgan & Claypool, 2007),
Electromagnetics and AntennaOptimization using Taguchi’s Method,
(Morgan & Claypool, 2007), ScatteringAnalysis of Periodic
Structures Using Finite-Difference Time-Domain Method,(Morgan &
Claypool, 2012), Multiresolution Frequency Domain Technique
forElectromagnetics, (Morgan and Claypool, 2012), and the main
author of thechapters Handheld Antennas and The Finite Difference
Time Domain Techniquefor Microstrip Antennas in Handbook of
Antennas in Wireless Communications(CRC Press, 2001). He was the
advisor/coadvisor for 33 M.S. and 20 Ph.D.students.
Dr. Elsherbeni is a Fellow Member of ACES. He is the
Editor-in-Chief for ACES Journal, and a past Associate Editor to
the Radio ScienceJournal. He was the Chair of the Engineering and
Physics Division of theMississippi Academy of Science and was the
Chair of the Educational ActivityCommittee for the IEEE Region 3
Section. He was the General Chair forthe APS-URSI 2014 Symposium.
He held the President position of ACESSociety from 2013 to 2015. He
was the recipient of the 2013 AppliedComputational Electromagnetics
Society (ACES) Technical AchievementsAward, the 2012 University of
Mississippi Distinguished Research andCreative Achievement Award,
the 2006 and 2011 School of EngineeringSenior Faculty Research
Award for Outstanding Performance in research,the 2005 School of
Engineering Faculty Service Award for OutstandingPerformance in
Service, the 2004 ACES Valued Service Award for OutstandingService
as 2003 ACES Symposium Chair, Mississippi Academy of Science2003
Outstanding Contribution to Science Award, the 2002 IEEE Region
3Outstanding Engineering Educator Award, the 2002 School of
EngineeringOutstanding Engineering Faculty Member of the Year
Award, the 2001 ACESExemplary Service Award for leadership and
contributions as an ElectronicPublishing Managing Editor 1999–2001,
the 2001 Researcher/Scholar ofthe Year Award in the Department of
Electrical Engineering, University ofMississippi, and 1996
Outstanding Engineering Educator of the IEEE MemphisSection.
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ABDELRAHMAN et al.: SINGLE-FEED QUAD-BEAM TRANSMITARRAY ANTENNA
DESIGN 959
Fan Yang (S’96–M’03–SM’08) received the B.S.and M.S. degrees
from Tsinghua University, Beijing,China, and the Ph.D. degree from
the University ofCalifornia at Los Angeles (UCLA), Los Angeles,
CA,USA, in 1997, 1999, and 2002, respectively.
From 1994 to 1999, he was a Research Assistantwith the State Key
Laboratory of Microwave andDigital Communications, Tsinghua
University. From1999 to 2002, he was a Graduate Student
Researcherwith the Antenna Laboratory, UCLA. From 2002 to2004, he
was a Postdoctoral Research Engineer and
Instructor with the Electrical Engineering Department, UCLA. In
2004, hejoined the Department of Electrical Engineering, University
of Mississippi,University, MS, USA, as an Assistant Professor, and
was promoted toan Associate Professor. In 2011, he joined the
Department of ElectronicEngineering, Tsinghua University, Beijing,
China, as a Professor, and hasserved as the Director of the
Microwave and Antenna Institute since then.He has authored over 200
journal articles and conference papers, five bookchapters, and
three books entitled Scattering Analysis of Periodic
StructuresUsing Finite-Difference Time-Domain Method (Morgan &
Claypool, 2012),Electromagnetic Band Gap Structures in Antenna
Engineering (CambridgeUniv. Press, 2009), and Electromagnetics and
Antenna Optimization UsingTaguchi’s Method (Morgan & Claypool,
2007). His research interests includeantennas, periodic structures,
computational electromagnetics, and appliedelectromagnetic
systems.
Dr. Yang served as an Associate Editor of the IEEE TRANSACTIONS
ONANTENNAS AND PROPAGATION (2010–2013) and an Associate
Editor-in-Chief of Applied Computational Electromagnetics Society
(ACES) Journal(2008–2014). He was the Technical Program Committee
(TPC) Chair ofthe 2014 IEEE International Symposium on Antennas and
Propagation andUSNC-URSI Radio Science Meeting. He was the
recipient of several pres-tigious awards and recognitions,
including the Young Scientist Award ofthe 2005 URSI General
Assembly and the 2007 International Symposiumon Electromagnetic
Theory, the 2008 Junior Faculty Research Award of theUniversity of
Mississippi, the 2009 inaugural IEEE Donald G. Dudley
Jr.Undergraduate Teaching Award, and the 2011 Recipient of Global
ExpertsProgram of China.