A Single-Feed Dual-Band Circularly Polarized Four-Arm Curl ... · Archimedean Spiral Antenna Four-armconfigurationgenerally requiresafeedthathasfour outputlineswithequalamplitudes

A Single-Feed Dual-Band Circularly Polarized

Four-Arm Curl Antenna

Son Xuat Ta and Ikmo ParkDepartment of Electrical and Computer Engineering

Ajou UniversityRepublic of Korea

Asia-Pacific Conference on Antennas and PropagationJuly 2, 2015

Bali Island, Indonesia

Ikmo Park received the B.S. degree in Electrical

Engineering from the State University of New York

at Stony Brook, and M.S. and Ph.D. degrees in

Electrical Engineering from the University of

Illinois at Urbana-Champaign. He joined the

Department of Electrical and Computer Engineering

at Ajou University in March 1996. Prior to joining

Ajou University, he has been working with the

Device & Materials Laboratory of LG Corporate

Institute of Technology, Seoul, Korea, where he had

been engaged in research and development of various antennas for personal

communication systems, wireless local area networks, and direct broadcasting

systems.

He has authored and co-authored over 250 technical journal and conference

papers. He also holds over 30 patents. He served as a Chair of the Department of

Electrical and Computer Engineering at Ajou University. He is a member of

Board of Directors at the Korea Institute of Electromagnetic Engineering and

Science (KIEES). He serves as chairs, organizers, and members of the program

committees for various conferences, workshops, and short courses in

electromagnetic related topics. His current research interests include the design

and analysis of microwave, millimeter-wave, terahertz wave, and nano-

structured antennas. He is also a member of Eta Kappa Nu and Tau Betta Pi.

*This use of this work is restricted solely for academic purposes. The author of

this work owns the copyright and no reproduction in any form is permitted

without written permission by the author.*

Abstract

This paper presents a single-feed dual-band circularlypolarized composite cavity-backed four-arm curl antenna.A pair of vacant-quarter printed rings is utilized in thefeeding structure to produce good impedance matchingand circular polarization (CP). A cavity-backed reflector isemployed to improve the CP radiation characteristics,such as 3-dB axial ratio beamwidth and broadside gain.Dual-band operation is obtained with different armlengths in the four-arm curl structure. The proposedantenna can be very useful in dual-band applications witha small frequency ratio.

Keywords—Curl antenna; dual-band operation; vacant-quarter printed ring; global positioning system

Contents

Introduction on spiral and curl antennas

Design method for a single-feed four-armcurl antenna

Dual-band operation of a curl antennawith an asymmetric arm-length

Simulation and measurement results

Conclusions

Congratulations

Professor

Nakano’s

70th Birthday

Spiral Antenna: Prof. Nakano

Numerical analysis of 4-arm spiral antenna, EL, 1983.

A spiral antenna on a reflector, IEEE TAP, 1986.

Dual-spiral antenna, IEE Proc.-H, 1991.

A 2-arm spiral antenna on finite dielectric substrate,

IEEE TAP, 2002.

A spiral antenna sandwiched by dielectric layers,

IEEE TAP, 2004.

Equiangular spiral antenna backed by a shallow cavity,

IEEE TAP, 2008.

Equiangular spiral antenna backed by an EBG reflector,

IEEE TAP, 2009.

Single-arm spiral antenna, IEEE TAP, 2010.

A two-arm spiral antenna, IEEE TAP, 2011.

A HIS-based spiral antenna, AWPL, 2009.

Metamaterial spiral antenna, IEEE AWPL, 2011.

Single-arm metamaterial-based spiral antenna,

IEEE TAP, 2013.

Spiral Antenna: Prof. Nakano

Archimedean Spiral Antenna

Their primary radiating elements can be single-, two-, or four-arm configurations with a large number of turns.

Archimedean spiral antennas are belong to the class oftraveling-wave wideband antennas radiating a circularlypolarized wave with a wide axial ratio beamwidth.

Single-arm Two-arm Four-arm

In practice, four-arm spiral antennas are superior inperformance to their single- and two-arm counterparts.

Archimedean Spiral Antenna

Four-arm configuration generallyrequires a feed that has fouroutput lines with equal amplitudesand a sequentially rotated phase.It usually contains a 1-to-4 powerdivider or combiner.

Input impedance is usually high.Approximately 190-Ω for a self-complementary spiral antenna infree space

Need an impedance transformer inthe feed for matching with a 50-Ωcoaxial cable.

Four-arm Archimedean spiral antenna

One of the main design challenges of a four-arm spiral antennais the design of a simple feeding structure.

Single-Arm Curl Antenna

Single-arm short Archimedeanspiral or curl antenna with a smallnumber of turn.

Simple structure and can producecircularly polarized radiation witha single-feed.

Axial ratio bandwidth ~ 10%.

Require a large ground plane.

Operate only on a single-band.

Radiation patterns are not verysymmetric due to the single-armconfiguration.

Curl Antenna, Prof. Nakano et. al, IEE Proc. Micow. AP, 1997.

Curl Antenna, Prof. Nakano et. al, IEEE TAP, 2011.

To improve the performance of a conventional curl antenna, weproposed a single feed dual-band four-arm curl antenna.

-300

-200

-100

0

100

200

300

Frequency (GHz)0.0 0.5 1.0 1.5 2.0 2.5 3.0

ImaginaryReal

0

3

6

9

12

15

18

Axi

al ra

tio (d

B)

Frequency (GHz)0.0 0.5 1.0 1.5 2.0 2.5 3.0

2.85-GHz

AR < 3-dB

RO4003: εr = 3.38, d = 0.508 mm

Starting radius: R0 = 9 mm Ending radius: Rc = 25 mm Number of turns: n = 1 Stripline width: Ws = 3 mm

Two-Arm Curl Antenna

ANSYS HFSS modeling

Starting point: R0 = 9 mm Ending radius: Rc = 25 mm Number of turns: n = 1 Stripline width: Ws = 3 mm

arm #2arm #1

arm #4arm #3

(-)(-) (+)

(+)

Port-1

Port-2

The input impedance of the antenna depends on the numberof turns, the spacing between turns, and the width of arm, aswell as the dielectric substrate.

Four-Arm Curl Antenna

HFSS modeling

RO4003: εr = 3.38, d = 0.508 mm

A four-arm curl antenna is created by inserting two otherarms on the other side of the substrate.

Comparison of Curl Antenna

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-200

-100

0

100

200

300

Frequency (GHz)0.0 0.5 1.0 1.5 2.0 2.5 3.0

ImaginaryReal

Inpu

t im

peda

nce

(Ω)

The antenna should be excitedwith equal amplitudes and a90o phase difference to producea circularly polarized wave.

Four-Arm Curl Antenna

Sequentially rotated feed

|S11

| (dB

)

Axi

al ra

tio (d

B)

Rsub=35 mm

Vacant-quarter printed ring

To achieve the condition for agood CP radiation and impedancematching, a pair of vacant-quarter printed rings was used tofeed the four-arm curl antenna.

|S11| BW: 1.50–1.72 GHz AR BW: 1.54–1.60 GHz

|S11

| (dB

)

Axi

al ra

tio (d

B)

Gain: 7.4 dBicRadiation efficiency: 92%

Impedance BW: 1.515–1.640 GHzAR BW: 1.555–1.590 GHz90 × 90 × 25 mm3

Curl radiator

Hc Air-gap

Metallic Cavity

SMA

H

Antenna on Cavity Reflector

Asymmetric Curl Antenna

-300

-200

-100

0

100

200

300

Frequency (GHz)0.0 0.5 1.0 1.5 2.0 2.5 3.0

ImaginaryReal

Arms #1 and #2 were variedArms #3 and #4 were fixed

n1 = n2 = 1.0, n3 = n4 = 1.0

-300

-200

-100

0

100

200

300

Inpu

t im

peda

nce

(Ω)

Frequency (GHz)0.0 0.5 1.0 1.5 2.0 2.5 3.0

n1 = n2 = 0.9, n3 = n4 = 1.0

-300

-200

-100

0

100

200

300

Inpu

t im

peda

nce

(Ω)

Frequency (GHz)0.0 0.5 1.0 1.5 2.0 2.5 3.0

n1 = n2 = 1.1, n3 = n4 = 1.0

Varied

Fixed

A dual-band operation of curl antenna

Asymmetric Curl Antenna

Vary number of turn (nt)

Fix (nb = 1)

Curl antenna with actual feed structure

Asymmetric Curl Antenna

1.4-GHz6.9 dBic, 93%90 x 90 x 25 mm3

1.8-GHz7.5 dBic, 99%

Top side Bottom side

n1=1.17

n4 = 1n3 = 1

n2=1.17

|S11| BW: 1.36–1.41 GHz, 1.72–1.85 GHzAR BW: 1.39–1.41 GHz, 1.78–1.83 GHz

Optimized antenna for dual band operation

Dual-band GPS Antenna

Top side Bottom side

n1=1.198

n4=1.035n3=1.044

n2=1.185

90 x 90 x 30 mm3

GPS-L26.7 dBic, 91%

GPS-L16.9 dBic, 97%

|S11| BW: 1.220–1.235 GHz, 1.510–1.600 GHzAR BW: 1.222–1.232 GHz, 1.560–1.600 GHz

Optimized antenna for GPS L1 and L2

Dual-band GPS Antenna

|S11

| (dB

)

90 x 90 x 30 mm3

|S11| BW: 1.225–1.235 GHz, 1.500–1.585 GHzAR BW: 1.220–1.230 GHz, 1.570–1.605 GHz

Axi

al ra

tio (d

B)

Dual-band GPS Antenna

GPS-L17.0 dBic, 95%

-20

-10

0

10

-30

-20

-10

0

10

270

300

3300

30

60

90

120

150210

240

(dBic)

y-z plane

RHCP (sim.)RHCP (mea.)

LHCP (mea.)LHCP (sim.)

GPS-L26.0 dBic, 87%

Conclusions

We have presented the design of compact low-profilefour-arm curl antennas.

Dual-band operation was achieved by creating anasymmetric arm structure.

Good circularly polarized radiation with high gain, widebeamwidth, high front-to-back ratio, and high radiationefficiency is obtained.

The proposed antenna can be very useful in dual-bandapplications with a small frequency ratio such as GPS.

References• H. Nakano, S. Okuzawa, K. Ohishi, H. Mimaki, and J. Yamauchi, “A curl antenna,” IEEE Trans.

Antennas Propag., vol. 41, no. 11, pp. 1570–1575, Nov. 1993.• H. Nakano and H. Mimaki, “Axial ratio of a curl antenna,” IEE Proc.-Microw. Antennas Propag.,

vol. 144, no. 6, pp. 1570–1575, Dec. 1997.• F. Yang and Y. Rahmat-Samii, “A low profile circularly polarized curl antenna over electromagnetic

band-gap (EBG) surface,” Microwave Optical Tech. Lett., vol. 31, no. 4, pp. 264–267, 2001.• J. Baracco, M. Paquay, and P. de Maagt, “An electromagnetic bandgap curl antenna for phased

array applications,” IEEE Trans. Antennas Propag., vol. 53, no. 1, pp. 173–180, Jan. 2005.• H. Nakano, S. Kirita, N. Mizobe, and J. Yamauchi, “External-excitation curl antenna,” IEEE Trans.

Antennas Propag., vol. 59, no. 11, pp. 3969–3977, Nov. 2011.• S. H. Zainud-Deen, M. M. Badaway, H. A. Malhat, K. H. Awadalla, “Circularly polarized plasma

curl antenna for 2.45 GHz portable RFID reader,” National Radio Science Conference, pp. 1–8,Cairo, Egypt, Apr. 2014,

• S. X. Ta and I. Park, “Single-feed four-arm curl antenna for circularly polarized radiation,” IEEEInternational Conference on Computational Electromagnetics, pp. 232–234, Hong Kong, China, Feb.2015.

• S. X. Ta and I. Park, “Single-feed composite cavity-backed four-arm curl antenna,” J. Electromag.Eng. Sci., vol. 14, no. 4, pp. 360–366, Dec. 2014.

• S. X. Ta and I. Park, “A multiarm curl antenna for GPS applications,” Journal of ElectromagneticWaves and Applications, vol. 29, no. 1, 80–91, 2015.

• “HFSS: High Frequency Structure Simulator Based on the Finite Element Method,” Ansoft Corp.