Research Article Study on Horizontally Polarized ...A horizontally polarized omnidirectional microstrip antenna is proposed in this paper. e structure of designed antenna is with two

Research ArticleStudy on Horizontally Polarized OmnidirectionalMicrostrip Antenna

Kun Wei Jian-ying Li Ling Wang Zi-jian Xing and Rui Xu

School of Electronics and Information Northwestern Polytechnical University Xirsquoan 710072 China

Correspondence should be addressed to Kun Wei weikun916163com

Received 27 October 2015 Revised 11 December 2015 Accepted 17 December 2015

Academic Editor Giuseppe Mazzarella

Copyright copy 2016 Kun Wei et alThis is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A horizontally polarized omnidirectional microstrip antenna is proposed in this paper The structure of designed antenna iswith two back-to-back horizontally polarized microstrip antenna elements Gain variation on main radiation plane of this newantenna is analyzed and radiation theory is deduced formula of directivity onmain radiation plane is given Better omnidirectionalcharacteristic of this antenna can be obtained by decreasing patch physical length Both simulated and measured results verify theomnidirectional radiation patterns and input impedance characteristics Good omnidirectional radiation patterns (gain variationin 119864-plane less than plusmn04 dBi) and input impedance characteristics are obtained moreover cross polarization less than minus20 dBi isachieved

1 Introduction

Omnidirectional antenna has been widely used in mobilecommunication indoor radio and wireless LAN systemsbecause of their better performance in multiple paths envi-ronment It is well known that an omnidirectional antennacan be easily realized by a vertical dipole [1ndash4] Howeververtical dipole works in vertical polarization mode ratherthan horizontal polarization mode

Microstrip antennas are also designed with omnidirec-tional radiation pattern Microstrip antenna array mountedon a circular cylinder is presented in [5] it needs morethan eleven patches to achieve good omnidirectional patternThe drawbacks of those cylindrical conformal microstripantennas are difficult to fabricate and they need more thanthree patches to obtain omnidirectional radiation patternBack-to-back omnidirectional microstrip antennas in [6ndash9] are with omnidirectional radiation patterns howeverthose antennas are either vertically polarized or circularlypolarized none of the antennas in [5ndash9] are working inhorizontal polarization mode

Horizontally polarized (HP) omnidirectional antennascan be realized by printed antenna and slot antenna In [10]

there are four notches cut out from the bottom conductorlayer and fourmicrostrip lines feed them respectively on theupper layer to obtain HP omnidirectional radiation patternA horizontally polarized omnidirectional planar antenna in[11] is developed for mobile communications the proposedantenna consists of four printed arc dipoles that form a circu-lar loop forHP omnidirectional radiation but antenna size in[10 11] is bigger than that of antenna proposed in this paperIn [12] a HP omnidirectional planar printed antenna forWLAN applications is presented The printed Alford-loop-structure antenna consists of two Z-shaped strips printed onthe top and bottom plane of the FR-4 printed-circuit-boardsubstrate but average antenna gain (horizontal-polarizationfield) is only minus53 dBi

Slot antenna or array may also obtain omnidirectionalradiation pattern [13ndash15] A three-element CPW-fed leakywave folded slot antenna array is presented in [13] By usingthe columnar structure the gain variation in the azimuthalplane is less than 11 dB A planar slot array antenna withomnidirectional radiation pattern in the horizontal plane isproposed in [14] the antenna with eight back-to-back slots isdesigned by employing the genetic algorithm implementedon a cluster system to achieve omnidirectional radiation

Hindawi Publishing CorporationInternational Journal of Antennas and PropagationVolume 2016 Article ID 8214153 8 pageshttpdxdoiorg10115520168214153

2 International Journal of Antennas and Propagation

characteristics Drawbacks of slot antennas or arrays obtainedhorizontally polarized omnidirectional radiation pattern arelarge in size heavy in weight and difficult to fabricate

A horizontally polarized omnidirectional microstripantenna is described in [16] the antenna consists of threemain components a probe-fed main patch and two parasiticpatches placed conformally on a cylindrical structure Theantenna structure is designed in the form of a belt forhorizontally polarized applications But the minus10 dB antennabandwidth is about 146 and the antenna is hard to fabricate

A new horizontally polarized omnidirectional microstripantenna is proposed in this paper The designed antennawhich has a pair of patches is with back-to-back structureThe patches are symmetrically placed along vertical planeso fields from the two patches of the designed antenna areinterfered constructively (add) in the horizontal directionand interfered destructively (cancel each other) in verticaldirection Due to that omnidirectional radiation pattern isachieved Adding that patches are horizontally polarized sodesigned antenna is with horizontally polarized omnidirec-tional radiation pattern Wilkinson power divider is used forfeeding the patches because it is with the useful property ofappearing lossless when the output ports are matched Thischaracteristic provides good impedance matching and goodefficiency performances of designed antenna in this paper

The radiation theory of the back-to-back structure isstudied Software Ansoft HFSS is applied to design andsimulate the antenna for the purpose of optimizing theomnidirectional characteristic drawing the best technicalparameters The new proposed antenna is fabricated andmeasured Measured results are shown to make the compar-ison with the simulated ones The proposed HP omnidirec-tionalmicrostrip antenna enjoys the following advantages (1)it has a small and compact size (2) it is easy to fabricate (3)the radiation pattern and input impedance characteristic aresatisfactory (4) the cross polarization level is low

2 Antenna Design

The geometry of designed antenna is shown in Figure 1(a)Outline size of the antenna is as follows length 119887 = 32mmwidth 119886 = 10mm and height ℎ = 65mm For better illustra-tion of the designed antenna structure the model is dividedinto four parts as shown in Figure 1(b) namely two externallayers and two internal layers There is no gap between eachlayer in practical design Both external layers are single-fed rectangular-patchmicrostrip antennas with back-to-backstructure And the internal layers constitute a classic stripline-type Wilkinson power divider where port 1 is input portand port 2 and port 3 are two output ports with the samesignal amplitude and phase Two patches are connected withoutput ports of the power divider differently by probes whichare inner core of coaxial line with length 5mm and radius045mm Port 2 is used to excite the right patch shownin Figure 1(b) and port 3 feeds the left patch Figure 1(c)demonstrates the front view of the designed antenna where 119888denotes the distance between the center of the patch and theupper edge of the substrate 119890 is distance between the feeding

Table 1 Design dimensions of designed antenna

Dimension name Dimension value119886 10mm119887 32mmℎ 65mm119888 16mm119890 935mm1198971015840 227mm119908 227mmℎ1 105mmℎ2 29mmℎ3 10mm1199081 25mm1199082 12mm1199083 25mm

point and the patch edge and 1198971015840 and 119908 represent the physical

length and physical width of patch respectivelyFigure 1(d) illustrates the dimension of equal-split

Wilkinson power divider which is for 50Ω systemimpedance in working band Width of the 50Ω transmissionlines is 1199081 = 25mm And the width of the quarter-wavelength transmission lines is 1199082 = 12mm which have acharacteristic impedance of 707Ω The dielectric constantof the external layer substrate is 16 with its thickness being4mm while the dielectric constant of the internal layersubstrate is 265 with its thickness being 1mm Designdimensions of the proposed antenna are shown in Table 1

3 Analysis of the Antenna Structure

For main TM01mode the 119864-field radiation is given by [17]

119864120579= 119895

4119896011988001

120582119903119890minus1198951198960119903119890119895((119906+V)2) sin(

119906

2) cos(V

2)

sdot [1199082

1199062+

1198972

V2 minus 1205872] sin 120579 sin120593 cos120593

119864120593= 119895

4119896011988001

120582119903119890minus1198951198960119903119890119895((119906+V)2) sin(

119906

2) cos( V

2)

sdot [1199082cos21205931199062

+1198972sin2120593V2 minus 1205872

] sin 120579 cos 120579

(1)

where 119906 = 1198960119908 sin 120579 cos120593 V = 119896

0119897 sin 120579 cos120593 119896

0= 2120587120582 119908

is the effective width of the patch 119897 is the effective length ofthe patch and119880

01denotes the voltage of mode TM

01at patch

corner point

International Journal of Antennas and Propagation 3

Patch

ab

h

(a)

External layers

Internal layers

Power divider

Ground plane

(b)

Feedingpoint

Patch

Substrate

b

h

e

c

l998400

w

x

y

(c)

Port 3 Port 2

Port 1

b

h

h2

h3

h1

w2

w3

w1

R = 100Ω

(d)

Figure 1 Model of the designed antenna

In 119864-plane (120593 = 90∘) 119906 = 0 and V = 119896

0119897 sin 120579 (1) can be

simplified as

119864120579= 119895

211990811988001

120582119903119890minus1198951198960119903119890119895(11989601198972) sin 120579 cos(

1198960119897

2sin 120579)

119864120593= 0

(2)

The designed antenna under investigation can be treatedas an array with two horizontally polarized microstripantenna elements lying along the 119911-axis as shown in Figure 2Element 1 is placed on the positive 119911-axis while element 2is on the negative 119911-axis Both of the elements are fed bytwo signals with the same amplitude and phase The totalfield radiated by two elements assuming no coupling and nodifference in excitation between the elements is equal to thesum of the two antenna elements And the radiation field ofelement 1 in the 119910-119911 plane is given by

1198641120579

= 119895211990811988001

1205821199031119890minus11989511989601199031119890

119895(11989601198972) sin 120579 cos(1198960119897

2sin 120579) (3)

Since element 2 rotates 180∘ around 119909-axis and facesnegative 119911-axis compared to element 1 far field radiationpattern of element 2 in 119910-119911 plane is given by

1198642120579

= 119895211990811988001

1205821199032119890minus11989511989601199032119890

119895(11989601198972) sin(120587+120579) cos(1198960119897

2sin (120587 + 120579))

(4)

Note that element 1 and element 2 share one commonground in this case 119889 = 0 and 1199031 = 1199032 = 119903 The total fieldradiated by the elements is given by

119864120579= 1198641120579

+ 1198642120579

= 119895211990811988001

120582119903119890minus1198951198960119903 cos(

1198960119897

2sin 120579)

sdot [119890119895(11989601198972) sin 120579 + 119890

minus119895(11989601198972) sin 120579] = 119895411990811988001

120582119903119890minus1198951198960119903

sdot cos2 (1198960119897

2sin 120579)

(5)


1

2

r1

r2

r

120579

120579

120579

d2

d2

z

y

Figure 2 Geometry of a two-element array lying along the 119911-axis

Table 2 Roundness and gain variation against physical length 1198971015840

119892 Physical length 1198971015840 (mm) Roundness Gain variation (dBi)

2 1205822 0 infin

4 1205824 025 606 1205826 056 248 1205828 073 1410 12058210 082 0816 12058216 093 0320 12058220 095 02

Since effective length 119897 is a little bit longer than physicallength 119897

1015840 and effective length 119897 is in proportion to physicallength 119897

1015840 it is tenable using physical length 1198971015840 to replace

effective length 119897 in (5) Thus for the two-element array ofconstant amplitude approximate formula for directivity as afunction of the directional angles in 119910-119911 plane is representedby

119863 = 1198630cos4 (

11989601198971015840

2sin 120579) (6)

where1198630is the maximum directivity

Suggest that physical length 1198971015840= 120582119892 where119892 represents a

parameter Roundness of radiation pattern is 119877 = 119863min119863maxand gain variation around the 119864-plane is 119881 = |10 sdot log119877| dBi

Table 2 shows the formula calculated roundness and gainvariation against physical length 119897

1015840 Taking 1198971015840 equal to 1205824 for

example 119863min = 0251198630and 119863max = 119863

0 roundness 119877 =

119863min119863max = 025 and gain variation is 119881 = |10 sdot log(05)| asymp6 dBi Roundness and gain variationwith some other physicallength 119897

1015840 are calculated by using the same procedure shownin Table 2 Roundness and gain variation against physicallength 119897

1015840 are plotted in Figure 3 It is clearly seen that asphysical length 119897

1015840 decreases the roundness increases and gainvariation decreases

From Table 2 and Figure 3 the following results are clear(a) the back-to-back microstrip antenna radiates omnidi-rectional pattern (b) by decreasing the physical length 119897

1015840

6

6 8 10 12 14 16 18 20

5

4

4

3

2

2

1

0

10

08

06

04

02

00

Gai

n va

riatio

n (d

B)

Roun

dnes

s

RoundnessGain variation

g(l998400 = 120582g)

Figure 3 Roundness and gain variation against 1198971015840

g = 2g = 4g = 6

g = 10

g = 16

0

30

60

90

120

150

180

210

240

270

300

330

10

10

08

08

06

06

04

04

02

02

00

Figure 4 Formula calculated normalized radiation pattern on 119910-119911plane against 1198971015840

roundness increases and gain variation decreases In generalphysical length 119897

1015840 of patch is less than 1205822 and it can bedecreased by increasing dielectric constant of substrate Inthis way gain variation of the omnidirectional pattern will bedecreased and better omnidirectional radiation pattern willbe achieved by using higher permittivity material as shownin Figure 4 However it is well known that such patch sizereduction often brings decreased bandwidth increased losses(lower efficiency) and matching problems so selecting aproper substrate dielectric constant and physical length 119897

1015840 isquit important to achieve better antenna performance Thereare three ways to increase antenna impedance bandwidth(1) increasing substrate thickness (2) using U-slot wideband


Table 3 Comparison of gain variations

Physical length 1198971015840 By formula (dBi) By HFSS (dBi)

Patch number 1 615mm 0323 120582 111 70Patch number 2 441mm 0232 120582 5 31Patch number 3 314mm 0165 120582 24 10Patch number 4 252mm 0132 120582 154 08

0 25 50

(mm)

X

YZ

Figure 5 Model of simplified antenna structure

patch to replace rectangular patch and (3) using H-shapedpatch to decrease patch physical length without increasingsubstrate dielectric constant

In order to verify the accuracy of formula (6) calculateddirectivity in 119910-119911 plane of the proposed antenna gainvariation comparisons between formula calculated andHFSSsimulated are made For simplifying the simulation process-ing power divider is removed from designed antenna twopatches are excited by two ports with the same amplitude andphase as shown in Figure 5 By choosing different substratedielectric constant different physical length 119897

1015840 is got anddifferent gain variation on main radiation plane is obtained

There are total of four different patches whose physicallength is shown in Table 3 physical length 119897

10158401 of patch

number 1 is 615mm with substrate dielectric constant 120576119903

that is 2 11989710158402 of patch number 2 is 441mm with substrate 120576119903


that is 8 11989710158404 of patch number 4 is 252mm with substrate120576119903 that is 12 Four antennas from number 1 to number

4 are working in the same center frequency 235GHzNormalized simulated radiation patterns (by Ansoft HFSS)in 119910-119911 plane with different patches length are indicated inFigure 6 It is clearly seen that as physical length decreasesbetter omnidirectional performance is obtained which hasthe same variation tendency as formula (6) calculated results

Table 3 summarizes the specified numeric comparison offormula (6) calculated gain variation and HFSS simulatedgain variation by given different patches physical lengthPhysical length 119897

1015840 of patch number 4 is 252mm which isnearly 119897

1015840asymp 0132 120582 thus 119863min = 1426119863

0and 119863max = 119863

0

0

30

60

90

120

150

180

210

240

270

300

330

10

10

08

08

06

06

04

04

02

02

00

Number 1Number 2

Number 3Number 4

Figure 6 HFSS simulated normalized radiation pattern in 119910-119911plane

so roundness 119877 = 119863min119863max = 1426 and calculated gainvariation is119881 = |10sdotlog(0078)| asymp 154 dBi By using the sameprocedure gain variation of other patches physical length canbe calculated as shown in Table 3

Gain variation difference between formula calculated andHFSS simulated results is shown in Figure 6 Gain variationdifference of patch number 1 is 41 dBi and those of patchnumber 2 patch number 3 and patch number 4 are 19 dBi14 dBi and 074 dBi respectively (Figure 7) As physicallength is getting smaller less difference between formulacalculated result and HFSS simulated result is achievedBoth results show that better gain variation performance isobtained as patch physical length is getting shorter

4 Simulated and Measured Results

In this section several numerical simulations are conductedusing Ansoft HFSS to validate the performance of the pro-posed algorithm Better omnidirectional performance of thisantenna can be obtained by increasing substrate dielectricconstant to reduce patch physical length However suchpatch length reduction often brings decreased bandwidthincreased losses (lower efficiency) and matching problems


12

10

8

6

4

2

00 1 2 3 4 5

Patch_Number

By formulaBy HFSS

Gai

n_Va

riatio

n (d

B)

Figure 7 Gain variation difference in 119910-119911 plane

Figure 8 Designed antenna

Therefore we set the substrate dielectric constant as 120576119903

=

16 to optimize antenna performance And the optimizedparameters of the antenna are as follows 119886 = 6mm 119887 =32mm 119888 = 16mm 119890 = 935mm 119908 = 221mm 1198971015840 = 221mmℎ = 65mm ℎ1 = 105mm ℎ2 = 29mm ℎ3 = 10mm 1199081 =25mm 1199082 = 12mm and 1199083 = 25mm

Figure 8 illustrates the realization of the designed hori-zontally polarized omnidirectionalmicrostrip antenna with aSMA connector Both the simulated and measured values ofthe designed antennarsquos 119878

11parameter are shown in Figure 9 It

is clear that the band-width of the antenna is about 16 (from1562GHz to 1587GHz) with center frequency 1575GHzand measured result agrees well with the simulated one Notethat bandwidth of designed antenna is narrow one feasibleway to overcome narrow bandwidth performance is to usewideband U-slot patch to replace square patch

Simulated three-dimensional radiation pattern of thedesigned antenna is shown in Figure 10 Peak gain of thedesigned antenna is about 22 dBi It is obvious that theradiation pattern is omnidirectional in 119910-119911 plane and thegain variation in 119910-119911 plane is less than plusmn04 dBi

0

minus5

minus10

minus15

minus20

minus25

S 11

(dB)

1530 1545 1560 1575 1590 1605 1620

Frequency (GHz)

Measured_S11Simulated_S11

Figure 9 Simulated and measured 11987811


Y

X

dB (g

ain

tota

l)

22557e + 00035204e minus 001minus15516e + 000minus34552e + 000minus53588e + 000minus72624e + 000minus91660e + 000minus11070e + 001minus12973e + 001minus14877e + 001minus16780e + 001minus18684e + 001minus20588e + 001minus22491e + 001minus24395e + 001minus26299e + 001minus28202e + 001

Phi

Figure 10 Three-dimensional radiation pattern

0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30

Simulated_Cross polarizationMeasured_Cross polarization

Simulated_E-planeMeasured_E-plane

(a)

0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus40


Simulated_H-planeMeasured_H-plane

(b)

Figure 11 Simulated and measured radiation pattern (a) 119864-plane (b)119867-plane

Figures 11(a) and 11(b) depict the simulated andmeasuredmain polarization pattern and cross polarization pattern in119864-plane and119867-plane respectively Peak gain of the designedantenna is about 22 dBi antenna efficiency is higher than90 in the operating band According to the simulationresults the gain variation in119864-plane pattern is about 058 dBiwhile the measured gain variation is about 08 dBi andcross polarization level is minus20 dBi lower than that of mainpolarization

Figure 12 shows the simulated radiation patterns ofdesigned antenna in this paper and dipole antenna in119864-planeand 119867-plane Both designed antenna and dipole antennacan obtain omnidirectional radiation pattern Peak gainsof those two antennas are almost the same but antennain this paper is with better omnidirectional performance

Moreover designed antenna is horizontally polarized ratherthan vertically polarized

5 Conclusion

A new horizontally polarized omnidirectional microstripantenna is presented in this paper Formula of directivity asa function of the directional angles in main lobe radiationplane of designed antenna is deduced Better omnidirectionalcharacteristic of this antenna can be obtained by increasingsubstrate dielectric constant or decreasing patch physicallength Both simulated andmeasured experiments are carriedout to verify the performance of the proposed antenna archi-tecture It has been shown that the peak gain is about 22 dBithe antenna efficiency is higher than 90 in operating band


0

30

60

90

120

150

180

210

240

270

300

3305

5

0

0

minus5

minus5

minus10

minus10

minus15

minus15

minus20

minus20

minus25

Designed antenna_H-planeDesigned antenna_E-plane

Dipole antenna_H-planeDipole antenna_E-plane

Figure 12 Simulated radiation patterns of designed antenna anddipole antenna

and the cross polarization level is minus20 dBi lower than that ofmain polarization Moreover the 119864-plane gain variation ofthe designed antenna is less than plusmn04 dBi which indicates asatisfactory omnidirectional radiation pattern

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was supported in part by the National NaturalScience Foundation of China (no 61271416 no 61301093and no 61501376) the Fundamental Research Funds forthe Central Universities (no 3102014KYJD027) and NPUFoundation for Fundamental Research (no JCY20130132)

References

[1] A Chen T Jiang Z Chen and D Su ldquoA novel low-profilewideband UHF antennardquo Progress in Electromagnetics Researchvol 121 pp 75ndash88 2011

[2] T J Judasz and B B Balsley ldquoImproved theoretical andexperimental models for the coaxial colinear antennardquo IEEETransactions on Antennas and Propagation vol 37 no 3 pp289ndash296 1989

[3] M Sierra-Perez F L Heras-Andres and J A G de LopeldquoLow-cost printed collinear array antennardquo IEEE Antennas andPropagation Magazine vol 43 no 5 pp 23ndash30 2001

[4] H-Y Xu H Zhang K Lu and X-F Zeng ldquoA holly-leaf-shapedmonopole antenna with low RCS for UWB applicationrdquoProgress in Electromagnetics Research vol 117 pp 35ndash50 2011

[5] P Li K M Luk and K L Lau ldquoAn omnidirectional highgain microstrip antenna array mounted on a circular cylinderrdquoin Proceedings of the IEEE Antennas and Propagation SocietyInternational Symposium vol 4 pp 698ndash701 Columbus OhioUSA June 2003

[6] A Narbudowicz X Bao M Ammann H Shakhtour and DHeberling ldquoCircularly polarized antenna with steerable dipole-like radiation patternrdquo IEEE Transactions on Antennas andPropagation vol 62 no 2 pp 519ndash526 2014

[7] H Iwasaki ldquoA back-to-back rectangular-patch antenna fed by aCPWrdquo IEEE Transactions on Antennas and Propagation vol 46no 10 pp 1527ndash1530 1998

[8] D I Wu ldquoOmnidirectional circularly-polarized conformalmicrostrip array for telemetry applicationsrdquo in Proceedings ofthe Antennas and Propagation Society International Symposiumvol 2 pp 998ndash1001 Newport Beach Calif USA June 1995

[9] K Wei J-Y Li L Wang and Z Xing ldquoA new omnidirectionalcircular polarization microstip antennardquo Progress in Electro-magnetics Research Letters vol 53 pp 45ndash50 2015

[10] S Wang and H Arai ldquoA horizontally polarized notch arrayantenna with good radiation identity in horizontal plane andits characteristic modes analysisrdquo in Proceedings of the IEEEAntennas and Propagation Society International Symposium pp1073ndash1074 IEEE Memphis Tenn USA July 2014

[11] X L Quan R L Li J Y Wang and Y H Cui ldquoDevelopmentof a broadband horizontally polarized omnidirectional planarantenna and its array for base stationsrdquo Progress in Electromag-netics Research vol 128 pp 441ndash456 2012

[12] C-C Lin L-C Kuo and H-R Chuang ldquoA horizontally polar-ized omnidirectional printed antenna for WLAN applicationsrdquoIEEE Transactions on Antennas and Propagation vol 54 no 11pp 3551ndash3556 2006

[13] Y Li Z Zhang and Z Feng ldquoA leaky wave slot antennaarray using single metal layer with azimuthally omnidirectionalpatternrdquo Progress in Electromagnetics Research vol 140 pp 199ndash212 2013

[14] X Chen K Huang and X-B Xu ldquoA novel planar slot arrayantenna with omnidirectional patternrdquo IEEE Transactions onAntennas and Propagation vol 59 no 12 pp 4853ndash4857 2011

[15] Y Li Z Zhang Z Feng and M F Iskander ldquoDesign of penta-band omnidirectional slot antenna with slender columnarstructurerdquo IEEE Transactions on Antennas and Propagation vol62 no 2 pp 594ndash601 2014

[16] A Y Svezhentsev P J Soh S Yan V Volskiy and G A E Van-denbosch ldquoOmnidirectional horizontally-polarized cylindricalmicrostrip antenna with two parasitic patchesrdquo in Proceedingsof the IEEE Antennas and Propagation Society InternationalSymposium (APSURSI rsquo14) pp 1863ndash1864 IEEE MemphisTenn USA July 2014

[17] S S Zhong ldquoSlot antenna and microstrip antennardquo in Proceed-ings of the 8th International Conference on Antenna Theory andTechniques (ICATT rsquo11) Section 1 pp 272ndash274 Beijing ChinaSeptember 2011

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Active and Passive Electronic Components

Control Scienceand Engineering

Journal of



RotatingMachinery


Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



Electrical and Computer Engineering

Journal of

Advances inOptoElectronics


Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



characteristics Drawbacks of slot antennas or arrays obtainedhorizontally polarized omnidirectional radiation pattern arelarge in size heavy in weight and difficult to fabricate

A horizontally polarized omnidirectional microstripantenna is described in [16] the antenna consists of threemain components a probe-fed main patch and two parasiticpatches placed conformally on a cylindrical structure Theantenna structure is designed in the form of a belt forhorizontally polarized applications But the minus10 dB antennabandwidth is about 146 and the antenna is hard to fabricate

A new horizontally polarized omnidirectional microstripantenna is proposed in this paper The designed antennawhich has a pair of patches is with back-to-back structureThe patches are symmetrically placed along vertical planeso fields from the two patches of the designed antenna areinterfered constructively (add) in the horizontal directionand interfered destructively (cancel each other) in verticaldirection Due to that omnidirectional radiation pattern isachieved Adding that patches are horizontally polarized sodesigned antenna is with horizontally polarized omnidirec-tional radiation pattern Wilkinson power divider is used forfeeding the patches because it is with the useful property ofappearing lossless when the output ports are matched Thischaracteristic provides good impedance matching and goodefficiency performances of designed antenna in this paper

The radiation theory of the back-to-back structure isstudied Software Ansoft HFSS is applied to design andsimulate the antenna for the purpose of optimizing theomnidirectional characteristic drawing the best technicalparameters The new proposed antenna is fabricated andmeasured Measured results are shown to make the compar-ison with the simulated ones The proposed HP omnidirec-tionalmicrostrip antenna enjoys the following advantages (1)it has a small and compact size (2) it is easy to fabricate (3)the radiation pattern and input impedance characteristic aresatisfactory (4) the cross polarization level is low

2 Antenna Design

The geometry of designed antenna is shown in Figure 1(a)Outline size of the antenna is as follows length 119887 = 32mmwidth 119886 = 10mm and height ℎ = 65mm For better illustra-tion of the designed antenna structure the model is dividedinto four parts as shown in Figure 1(b) namely two externallayers and two internal layers There is no gap between eachlayer in practical design Both external layers are single-fed rectangular-patchmicrostrip antennas with back-to-backstructure And the internal layers constitute a classic stripline-type Wilkinson power divider where port 1 is input portand port 2 and port 3 are two output ports with the samesignal amplitude and phase Two patches are connected withoutput ports of the power divider differently by probes whichare inner core of coaxial line with length 5mm and radius045mm Port 2 is used to excite the right patch shownin Figure 1(b) and port 3 feeds the left patch Figure 1(c)demonstrates the front view of the designed antenna where 119888denotes the distance between the center of the patch and theupper edge of the substrate 119890 is distance between the feeding

Table 1 Design dimensions of designed antenna

Dimension name Dimension value119886 10mm119887 32mmℎ 65mm119888 16mm119890 935mm1198971015840 227mm119908 227mmℎ1 105mmℎ2 29mmℎ3 10mm1199081 25mm1199082 12mm1199083 25mm

point and the patch edge and 1198971015840 and 119908 represent the physical

length and physical width of patch respectivelyFigure 1(d) illustrates the dimension of equal-split

Wilkinson power divider which is for 50Ω systemimpedance in working band Width of the 50Ω transmissionlines is 1199081 = 25mm And the width of the quarter-wavelength transmission lines is 1199082 = 12mm which have acharacteristic impedance of 707Ω The dielectric constantof the external layer substrate is 16 with its thickness being4mm while the dielectric constant of the internal layersubstrate is 265 with its thickness being 1mm Designdimensions of the proposed antenna are shown in Table 1

3 Analysis of the Antenna Structure

For main TM01mode the 119864-field radiation is given by [17]

119864120579= 119895

4119896011988001

120582119903119890minus1198951198960119903119890119895((119906+V)2) sin(

119906

2) cos(V

2)

sdot [1199082

1199062+

1198972

V2 minus 1205872] sin 120579 sin120593 cos120593

119864120593= 119895

4119896011988001

120582119903119890minus1198951198960119903119890119895((119906+V)2) sin(

119906

2) cos( V

2)

sdot [1199082cos21205931199062

+1198972sin2120593V2 minus 1205872

] sin 120579 cos 120579

(1)

where 119906 = 1198960119908 sin 120579 cos120593 V = 119896

0119897 sin 120579 cos120593 119896

0= 2120587120582 119908

is the effective width of the patch 119897 is the effective length ofthe patch and119880

01denotes the voltage of mode TM

01at patch

corner point


Patch

ab

h

(a)

External layers

Internal layers

Power divider

Ground plane

(b)

Feedingpoint

Patch

Substrate

b

h

e

c

l998400

w

x

y

(c)

Port 3 Port 2

Port 1

b

h

h2

h3

h1

w2

w3

w1

R = 100Ω

(d)


In 119864-plane (120593 = 90∘) 119906 = 0 and V = 119896

0119897 sin 120579 (1) can be

simplified as

119864120579= 119895

211990811988001

120582119903119890minus1198951198960119903119890119895(11989601198972) sin 120579 cos(

1198960119897

2sin 120579)

119864120593= 0

(2)


1198641120579

= 119895211990811988001

1205821199031119890minus11989511989601199031119890

119895(11989601198972) sin 120579 cos(1198960119897

2sin 120579) (3)


1198642120579

= 119895211990811988001

1205821199032119890minus11989511989601199032119890

119895(11989601198972) sin(120587+120579) cos(1198960119897

2sin (120587 + 120579))

(4)


119864120579= 1198641120579

+ 1198642120579

= 119895211990811988001

120582119903119890minus1198951198960119903 cos(

1198960119897

2sin 120579)

sdot [119890119895(11989601198972) sin 120579 + 119890

minus119895(11989601198972) sin 120579] = 119895411990811988001

120582119903119890minus1198951198960119903

sdot cos2 (1198960119897

2sin 120579)

(5)


1

2

r1

r2

r

120579

120579

120579

d2

d2

z

y




2 1205822 0 infin

4 1205824 025 606 1205826 056 248 1205828 073 1410 12058210 082 0816 12058216 093 0320 12058220 095 02





119863 = 1198630cos4 (

11989601198971015840

2sin 120579) (6)













1015840

6

6 8 10 12 14 16 18 20

5

4

4

3

2

2

1

0

10

08

06

04

02

00

Gai

n va

riatio

n (d

B)

Roun

dnes

s


g(l998400 = 120582g)


g = 2g = 4g = 6

g = 10

g = 16

0

30

60

90

120

150

180

210

240

270

300

330

10

10

08

08

06

06

04

04

02

02

00









0 25 50

(mm)

X

YZ






10158401 of patch








1015840asymp 0132 120582 thus 119863min = 1426119863

0and 119863max = 119863

0

0

30

60

90

120

150

180

210

240

270

300

330

10

10

08

08

06

06

04

04

02

02

00

Number 1Number 2

Number 3Number 4







12

10

8

6

4

2

00 1 2 3 4 5

Patch_Number

By formulaBy HFSS

Gai

n_Va

riatio

n (d

B)




=






0

minus5

minus10

minus15

minus20

minus25

S 11

(dB)

1530 1545 1560 1575 1590 1605 1620

Frequency (GHz)




Y

X

dB (g

ain

tota

l)


Phi


0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30



(a)

0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus40



(b)





5 Conclusion



0

30

60

90

120

150

180

210

240

270

300

3305

5

0

0

minus5

minus5

minus10

minus10

minus15

minus15

minus20

minus20

minus25







Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Patch

ab

h

(a)

External layers

Internal layers

Power divider

Ground plane

(b)

Feedingpoint

Patch

Substrate

b

h

e

c

l998400

w

x

y

(c)

Port 3 Port 2

Port 1

b

h

h2

h3

h1

w2

w3

w1

R = 100Ω

(d)


In 119864-plane (120593 = 90∘) 119906 = 0 and V = 119896

0119897 sin 120579 (1) can be

simplified as

119864120579= 119895

211990811988001

120582119903119890minus1198951198960119903119890119895(11989601198972) sin 120579 cos(

1198960119897

2sin 120579)

119864120593= 0

(2)


1198641120579

= 119895211990811988001

1205821199031119890minus11989511989601199031119890

119895(11989601198972) sin 120579 cos(1198960119897

2sin 120579) (3)


1198642120579

= 119895211990811988001

1205821199032119890minus11989511989601199032119890

119895(11989601198972) sin(120587+120579) cos(1198960119897

2sin (120587 + 120579))

(4)


119864120579= 1198641120579

+ 1198642120579

= 119895211990811988001

120582119903119890minus1198951198960119903 cos(

1198960119897

2sin 120579)

sdot [119890119895(11989601198972) sin 120579 + 119890

minus119895(11989601198972) sin 120579] = 119895411990811988001

120582119903119890minus1198951198960119903

sdot cos2 (1198960119897

2sin 120579)

(5)


1

2

r1

r2

r

120579

120579

120579

d2

d2

z

y




2 1205822 0 infin

4 1205824 025 606 1205826 056 248 1205828 073 1410 12058210 082 0816 12058216 093 0320 12058220 095 02





119863 = 1198630cos4 (

11989601198971015840

2sin 120579) (6)













1015840

6

6 8 10 12 14 16 18 20

5

4

4

3

2

2

1

0

10

08

06

04

02

00

Gai

n va

riatio

n (d

B)

Roun

dnes

s


g(l998400 = 120582g)


g = 2g = 4g = 6

g = 10

g = 16

0

30

60

90

120

150

180

210

240

270

300

330

10

10

08

08

06

06

04

04

02

02

00









0 25 50

(mm)

X

YZ






10158401 of patch








1015840asymp 0132 120582 thus 119863min = 1426119863

0and 119863max = 119863

0

0

30

60

90

120

150

180

210

240

270

300

330

10

10

08

08

06

06

04

04

02

02

00

Number 1Number 2

Number 3Number 4







12

10

8

6

4

2

00 1 2 3 4 5

Patch_Number

By formulaBy HFSS

Gai

n_Va

riatio

n (d

B)




=






0

minus5

minus10

minus15

minus20

minus25

S 11

(dB)

1530 1545 1560 1575 1590 1605 1620

Frequency (GHz)




Y

X

dB (g

ain

tota

l)


Phi


0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30



(a)

0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus40



(b)





5 Conclusion



0

30

60

90

120

150

180

210

240

270

300

3305

5

0

0

minus5

minus5

minus10

minus10

minus15

minus15

minus20

minus20

minus25







Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










1

2

r1

r2

r

120579

120579

120579

d2

d2

z

y




2 1205822 0 infin

4 1205824 025 606 1205826 056 248 1205828 073 1410 12058210 082 0816 12058216 093 0320 12058220 095 02





119863 = 1198630cos4 (

11989601198971015840

2sin 120579) (6)













1015840

6

6 8 10 12 14 16 18 20

5

4

4

3

2

2

1

0

10

08

06

04

02

00

Gai

n va

riatio

n (d

B)

Roun

dnes

s


g(l998400 = 120582g)


g = 2g = 4g = 6

g = 10

g = 16

0

30

60

90

120

150

180

210

240

270

300

330

10

10

08

08

06

06

04

04

02

02

00









0 25 50

(mm)

X

YZ






10158401 of patch








1015840asymp 0132 120582 thus 119863min = 1426119863

0and 119863max = 119863

0

0

30

60

90

120

150

180

210

240

270

300

330

10

10

08

08

06

06

04

04

02

02

00

Number 1Number 2

Number 3Number 4







12

10

8

6

4

2

00 1 2 3 4 5

Patch_Number

By formulaBy HFSS

Gai

n_Va

riatio

n (d

B)




=






0

minus5

minus10

minus15

minus20

minus25

S 11

(dB)

1530 1545 1560 1575 1590 1605 1620

Frequency (GHz)




Y

X

dB (g

ain

tota

l)


Phi


0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30



(a)

0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus40



(b)





5 Conclusion



0

30

60

90

120

150

180

210

240

270

300

3305

5

0

0

minus5

minus5

minus10

minus10

minus15

minus15

minus20

minus20

minus25







Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation













0 25 50

(mm)

X

YZ






10158401 of patch








1015840asymp 0132 120582 thus 119863min = 1426119863

0and 119863max = 119863

0

0

30

60

90

120

150

180

210

240

270

300

330

10

10

08

08

06

06

04

04

02

02

00

Number 1Number 2

Number 3Number 4







12

10

8

6

4

2

00 1 2 3 4 5

Patch_Number

By formulaBy HFSS

Gai

n_Va

riatio

n (d

B)




=






0

minus5

minus10

minus15

minus20

minus25

S 11

(dB)

1530 1545 1560 1575 1590 1605 1620

Frequency (GHz)




Y

X

dB (g

ain

tota

l)


Phi


0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30



(a)

0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus40



(b)





5 Conclusion



0

30

60

90

120

150

180

210

240

270

300

3305

5

0

0

minus5

minus5

minus10

minus10

minus15

minus15

minus20

minus20

minus25







Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










12

10

8

6

4

2

00 1 2 3 4 5

Patch_Number

By formulaBy HFSS

Gai

n_Va

riatio

n (d

B)




=






0

minus5

minus10

minus15

minus20

minus25

S 11

(dB)

1530 1545 1560 1575 1590 1605 1620

Frequency (GHz)




Y

X

dB (g

ain

tota

l)


Phi


0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30



(a)

0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus40



(b)





5 Conclusion



0

30

60

90

120

150

180

210

240

270

300

3305

5

0

0

minus5

minus5

minus10

minus10

minus15

minus15

minus20

minus20

minus25







Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Y

X

dB (g

ain

tota

l)


Phi


0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30



(a)

0

30

60

90

120

150

180

210

240

270

300

33010

10

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus40



(b)





5 Conclusion



0

30

60

90

120

150

180

210

240

270

300

3305

5

0

0

minus5

minus5

minus10

minus10

minus15

minus15

minus20

minus20

minus25







Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

30

60

90

120

150

180

210

240

270

300

3305

5

0

0

minus5

minus5

minus10

minus10

minus15

minus15

minus20

minus20

minus25







Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Documents

Research Article Study on Horizontally Polarized ...A horizontally polarized omnidirectional microstrip antenna is proposed in this paper. e structure of designed antenna is with two