Research Article Yagi Array of Microstrip Quarter-Wave ...downloads.hindawi.com/journals/ijap/2014/102362.pdf · Yagi Array of Microstrip Quarter-Wave Patch Antennas with Microstrip

Research ArticleYagi Array of Microstrip Quarter-Wave PatchAntennas with Microstrip Lines Coupling

Juhua Liu12 Yue Kang12 Jie Chen12 and Yunliang Long12

1 Department of Electronics and Communication Engineering Sun Yat-sen University Guangzhou 510006 China2 SYSU-CMU Shunde International Joint Research Institute Shunde 528300 China

Correspondence should be addressed to Juhua Liu liujh33mailsysueducn

Received 28 March 2014 Revised 29 June 2014 Accepted 14 July 2014 Published 22 July 2014

Academic Editor Z N Chen

Copyright copy 2014 Juhua Liu et alThis is an open access article distributed under theCreativeCommonsAttribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A new kind of Yagi array of quarter-wave patch antennas is presented The Yagi array has a low profile a wide bandwidth and ahigh gain A main beam close to endfire is produced with a vertical polarization in the horizontal plane A set of microstrip linesare introduced between the driven element and the first director element to enhance the coupling between them and therefore thebandwidth could be increased and the back lobes could be suppressed Measured results show that the Yagi array with 4 elementsgenerates a peak gain of about 97 dBi a front-to-back ratio higher than 10 dB and a 10 dB return loss band from 468GHz to524GHz with a profile of 15mm and an overall size of 80 times 100mm2 An increase of the number of director elements wouldenhance the gain and have the main beam pointing closer to endfire

1 Introduction

YAGI-UDA arrays of classical electric dipole antennas arefamous and widely used [1ndash3] because they provide a highgain and have a simple structure with only one drivenelement However the classical Yagi array of dipole antennashas a high profile (about half wavelength) if it is set forgenerating vertical polarization Yagi array of monopoleantennas [4] is also developed that produces a beam closeto endfire and with a vertical polarization in the horizontalplane Nonetheless the Yagi array of monopole antennas hasa high profile of 025120582

0(where 120582

0is the wavelength in free

space) In mobile communications vertical polarization isusually preferred since transmitter and receiver can keepthe same vertical polarization for good connection no matterhow transmitter or receiver rotates on a horizontal platform

Recently Yagi arrays of printed antennas [5ndash12] havebeen studied since printed antennas have a low profilelight weight and easy fabrication The microstrip Yagi arrayof half-wave patch antennas [5ndash9] provides a high gainand has its main beam tilted away from the broadsideThis type of antenna can generate a vertical polarization

in the horizontal plane The quasi Yagi array based onclassical dipole antennas [10ndash12] has a high gain a widebandwidth and a main beam pointing exactly at endfirebut this type of Yagi arrays could only generate horizontalpolarization

In this paper we propose a new type of microstrip Yagiarray based on quarter-wave patch antennas The microstripYagi array has advantages of low profile and simple struc-ture and can easily be fabricated on a PCB with shortingvias A set of microstrip lines are introduced between thedriven element and the first director element to enhancethe coupling between them and therefore the bandwidthcould be increased and the back lobes could be suppressedAn increase of the number of director elements wouldenhance the gain and have the main beam pointing closerto endfire The front-to-back ratio of the presented Yagiarray is higher than 10 dB Compared with a half-wave patchantenna a quarter-wave patch antenna has half the length ofthe half-wave patch and therefore the Yagi array of quarter-wave patch antennas has a smaller length compared withthe conventional Yagi array of half-wave patch antennasThe comparison between the Yagi array of half-wave patch

Hindawi Publishing CorporationInternational Journal of Antennas and PropagationVolume 2014 Article ID 102362 7 pageshttpdxdoiorg1011552014102362

2 International Journal of Antennas and Propagation

h

b

x

y

x

z

R D D1 D2

W

d

p

sd sd s998400d2s998400g s998400r

L998400rL998400d Lm

sm

sm

L998400d1 L998400d2

d998400

Lg

Wg

120576r

Figure 1 Top view and cross-section of the microstrip Yagi array ofquarter-wave patch antennas

Figure 2 Photo for the 4-element Yagi array of quarter-wave patchantennas with the geometry shown in Figure 1

antennas and the Yagi array of quarter-wave patch antennaswill be discussed in the paper

2 Quarter-Wave Patch Antenna Yagi Array

21 Operation Principles The structure of the Yagi arraybased four quarter-wave patch antennas is shown in Figure 1Four quarter-wave patch antennas [13ndash15] and a set ofcouplingmicrostrip lines are fabricated on a substrate backedwith a ground plane The substrate could be air or dielectricsubstrate The four quarter-wave patch antennas include adriven element (D) two director elements (D1 and D2) anda reflector element (R) Only the driven element is excitedwith a 50Ω coaxial probe and the other patches are parasiticradiators

Radiation is mainly generated from the open apertures ofthe four quarter-wave patches (the open apertures opposite

44 46 48 5 52 54 56Frequency (GHz)

4E (not coupled) HFSS4E (coupled) HFSS

4E (coupled) measure12E (coupled) measure

minus45

minus40

minus35

minus30

minus25

minus20

minus15

minus10

minus5

0

|S11|

(dB)

Figure 3 Reflection coefficients for the 4-element Yagi array ofquarter-wave patch antennas without microstrip lines coupling the4-element Yagi array with microstrip lines coupling (Figure 2) andthe 12-element Yagi array with microsrip lines coupling (Figure 7)

to the shorting vias) Since the tangential electric field at eachopen aperture can be considered as a magnetic current theYagi array can be considered as a Yagi array of magneticelements With respect to the principle of duality to theclassical electric dipole Yagi array the parasitic magneticelement would act as a reflector when it has an additionalcapacitive component and it would act as a director whenit has an additional inductive component The reactivecomponent of each magnetic element can be controlled byadjusting the length of the quarter-wave patch (the distancefrom the open edge to the shorting vias of the quarter-wavepatch) Therefore a quarter-wave patch must have a smallerlength in order to have an additional inductive component(in view at the open aperture) when it acts as a directorOtherwise a quarter-wave patchwould act as a reflectorwhenit has a larger lengthThe lengths of the directors and reflectorneed to be tuned with simulation tools (such HFSS) to haveoptimum values and to have the array radiating in forwarddirection

In order to make more power coupled into the firstdirector from the driven element three parallel microstriplines with equal widths (119882 minus 2119904

119898)3 are introduced between

them Actually the three coupling microstrip lines can beconsidered as a wide microstrip line with width119882 that is cutwith two slits with width 119904

119898 as shown in Figure 1 The two

slits cutting the wide microstrip line are to avoid the widemicrostrip line resonating as a radiating patch Thereforethe coupling effect between the driven element and the firstdirector element is mainly through a guided wave underthe microstrip transmission lines On the other hand thecoupling between the driven and the reflector elements andthat between the first and the second elements are throughspace wave

International Journal of Antennas and Propagation 3

0

030

60

90

120

150

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180minus150

minus120

minus90

minus60

minus30

E120579 measureE120579 HFSS


(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10



(b)

Figure 4 Elevation (a) and azimuth (b) radiation patterns for the Yagi array (Figure 2) working at 51 GHz

030

60

90

120

1500

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180

minus150

minus120

minus90

minus60

minus30

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(b)

Figure 5 Measured elevation (a) and azimuth (b) radiation patterns for the Yagi array (Figure 2)

The width 119904119889of the gaps between the coupling microstrip

lines and the quarter-wave patches controls the couplingstrength which is usually less than the thickness ℎ of thesubstrate

The length119871119898of the couplingmicrostrip lineswould have

an effect on the directivity and front-to-back (FB) ratio Thelength 119871

119898is usually between 01 120582

0and 015 120582

0 We let all

these elements have the same width 119882 and then we tunethe length of each element to control its resonant frequencyOptimized values for the parameters of the Yagi array aregiven in Table 1

22 4-Element Yagi Array Simulated and measured resultsfor the reflection coefficient are shown in Figure 3 The arrayhas an overall size of 100 times 80mm2 and a profile of 15mmIt shows that the simulated results agree very well with themeasured ones Measured results show that the array worksin the band from 468GHz to 524GHz for the reflectioncoefficient being less thanminus10 dBwith a fractional bandwidthof 113 The profile of the antenna is about 0026120582

0(where

1205820is the wavelength in free space)Also shown in Figure 3 is the reflection coefficient for

the Yagi array without microstrip lines coupling between the


44 46 48 5 52 54 560

2

4

6

8

10

12

Frequency (GHz)

Gai

n (d

B)

4E HFSS

12E measure4E measure

Figure 6 Gains for the 4-element Yagi array (Figure 2) and the 12-element Yagi array (Figure 7)

Figure 7 Photo of the 12-element Yagi array of quarter-wave patchantennas

driven element and the first director element It shows thatthe bandwidth could be greatly improved when the couplingmicrostrip lines are introduced

Figure 4 shows radiation patterns in the elevation planeand in the azimuth plane for the Yagi array working at51 GHz It shows that simulated results agree very well withmeasured ones While not shown here the main beamwouldpoint exactly at endfirewhen the array is on an infinite groundplane Due to the finite ground plane diffraction effects themain beam does not point exactly at endfire but at an angleof about 45ndash50∘ from the normal direction when the array isin a finite ground plane Measured results show that the crosspolarization is less than minus17 dB in the main elevation planeand less than minus10 dB in the horizontal (azimuth) plane Thefront-to-back (FB) ratio that is used to represent the mainlobe in the front quadrant over that of the reflected lobe inthe back quadrant is higher than 10 dB

Figure 5 shows radiation patterns for other frequenciesfor the Yagi array It shows that the beam directions are stableat an angle of about 45ndash50∘ from the normal directionWhilenot shown here the cross polarization is also less than minus10 dBfor these frequenciesThe back lobes for these frequencies areless than minus10 dB as shown in the horizontal plane in Figure 5

Table 1 Parameters for the Yagi arrays

Yagi array of quarter-wavepatch antennas (Figure 1)

Yagi array of half-wavepatch antennas (Figure 9)

Variable Values Variable Values120576119903

233 120576119903

233ℎ 157mm ℎ 157mm1198711015840

1198898926mm 119871

119889176mm

1198711015840

1199039026mm 119871

11990319mm

1198711015840

11988917826mm 119871

119889115mm

1198711015840

11988927626mm 119871

119889215mm

119882 40mm 119882 25mm119887 14mm 119887 13mm119904119889

08mm 119904 08mm119904119898

08mm 119871119892 115mm

119871119898

84mm 119882119892 80mm

1199041015840

119903337mm

1199041015840

1198892337mm

119904119892 2367mm119871119892 100mm119882119892 80mm119889 06mm119901 15mm

Figure 6 shows the gains for the Yagi array in finite groundplane Figure 6 shows thatmeasured gains (dashed line) agreevery well with simulated ones (dotted line) Measured resultsshow that the array has a gain of about 95 dBi in the bandfrom 468GHz to 524GHz

23 12-Element Yagi Array The photo of the designed Yagiarray is shown in Figure 7The substrate the first four patchesand the coupling microstrip lines are the same as the Yagiarray shown in Figure 2 The added eight director elementsare the same as the second director element that has a lengthof 11987110158401198892= 7626mm and the apertures of the added eight

director elements have the same size as that of the secondelement The ground plane has a length of 119871

119892= 180mm and

a width of119882119892= 80mm

The reflection coefficient for the Yagi array with 12radiators is shown in black dashed line in Figure 2 It showsthat the 12-element Yagi array works in the band from464GHz to 522GHz for the reflection coefficient beingless than minus10 dB with a fractional bandwidth of 118 Thebandwidth of the Yagi array with 12 radiators is very close tothat of the Yagi array with 4 radiators As a matter of factthe driven and the first director elements play a much moreimportant role in the bandwidth than other elements sincethe coupling through a guided wave under the microstriplines between the driven and the first director elementsis much stronger than the coupling through space wavesbetween other elements Therefore adding more directorelements would not help to enhance the bandwidth in thistype of Yagi array


030

60

90

120

1500

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180

minus150

minus120

minus90

minus60

minus30

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(b)

Figure 8 Measured radiation patterns in the elevation (a) plane and in the azimuth (b) plane for the 12-element Yagi array (Figure 7)

W

b

s

x

y

Lr Ld1 Ld1Ld

Wg

Lg

D

Figure 9 Geometry of the Yagi array of half-wave patch antennas

The gain of the antenna with 12 elements is shown in redline in Figure 6 Measured results show that the peak gain ofthe 12-element Yagi array is about 105 dBi in the band from464GHz to 522GHz which is about 1 dB higher than that ofthe 4-element Yagi array Measured radiation patterns for the12-element Yagi array are shown in Figure 8 It shows that themain beam of the 12-element Yagi array would point closerto endfire compared with the 4-element Yagi arrayThe beamdirection is 65ndash75∘ entitled from the normal direction

3 Comparisons with Yagi Array ofHalf-Wave Patch Antennas

In this section the Yagi array of quarter-wave patch antennasis compared with the conventional Yagi array of half-wavepatch antennas The geometry of the Yagi array of half-wavepatch antennas is shown in Figure 9 To have a reasonable

48 49 5 51 52 53 54 55 56

0

10

560

3

6

9

12

Frequency (GHz)

Gai

n (d

Bi)

minus30

minus20

minus10

|S11|

(dB)

Figure 10 Reflection coefficient and gain for the 4-element Yagiarray of half-wave patch antennas

compassion the two kinds of Yagi arrays are fabricated onthe same substrate The length of the driven half-wave patchantenna is twice the effective length [16] of the quarter-wavepatch antenna To prevent higher modes of the half-wavepatch antenna to be excited the width 119882 of the half-wavepatch antennas is 25mm which is smaller than the width ofthe quarter-wave patch antennasThe parameters for the Yagiarray half-wave patch antennas and those for the Yagi arraysof quarter-wave patch antennas are given in Table 1

Simulated results for the reflection coefficient and gainfor the 4-element Yagi array of half-wave patch antennasare shown in Figure 10 Simulated results for the radiationpatterns in the elevation and azimuth planes for the Yagi arrayare shown in Figure 11 Table 2 gives data for the comparisonsbetween the Yagi array of half-wave patch antennas and theYagi array of quarter-wave patch antennas


030

60

90

120

150plusmn180

minus150

minus120

minus90

minus60

minus30

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(b)

Figure 11 Elevation radiation patterns (a) in the 119909119911 plane and azimuth radiation patterns (b) in the 119909119910 plane for the 4-element Yagi array ofhalf-wave patch antennas

Table 2 Comparisons between the Yagi array of quarter-wave patchAntennas and the Yagi array of half-wave patch antennas

CharacterYagi array of

quarter-wave patchantennas (Figure 1)

Yagi array ofhalf-wave patch

antennas (Figure 9)Band 468ndash524GHz 50ndash543GHzFractionalbandwidth 113 825

Beamwidth(elevation plane) 56ndash58∘ 42ndash46∘

Beamwidth(azimuth plane) 44ndash60∘ 80ndash87∘

Gain 865ndash99 dBi 828ndash1019 dBiFront-to-back ratio gt10 dB gt74 dBRadiation angle(from broadside) 45ndash50∘ 35ndash40∘

Radiationefficiency 91ndash98 95ndash99

Size of driven patch 8926 times 40mm2 176 times 25mm2

Size of groundplane 100 times 80mm2 115 times 80mm2

From Table 2 it is seen that the bandwidth of theYagi array of quarter-wave patch antennas is slightly widerthan the Yagi array of half-wave patch antenna The size ofthe ground plane for the Yagi array of quarter-wave patchantenna is smaller than that for the Yagi array of half-wave patch antenna because the length of each quarter-wavepatch antenna is only half the length of the correspondinghalf-wave patch antenna The main beam of the Yagi arrayof quarter-wave patch antennas points closer to endfirethan that of the Yagi array of half-wave patch antennas

because a single quarter-wave patch antenna has an almostomnidirectional pattern in upper half-space (when in infiniteground plane) while a single half-wave patch antenna hasits main beam point at broadside [6] The FB ratio for theYagi array of quarter-wave patch antennas is higher than thatfor the Yagi array of half-wave patch antennas The gainsare almost the same for the two kinds of Yagi arrays Theefficiency for the Yagi array of quarter-wave patch antennas isnot as high as that for the Yagi array of quarter-wave antennasdue to the conducting loss of the shorting vias in the quarter-wave patch antennas Actually the shorting-vias may alsoresult in a sloppy fabrication so the period of the shorting-vias should not be too small (the period of the shorting-viasis about 2ndash25 times the diameter of the shorting-vias [16])

4 Conclusion

A new type of Yagi array of quarter-wave patch antennas hasbeen presented and studied The Yagi array has a wide band-width and a high gain and provides a vertical polarization inthe horizontal plane A Yagi array with 4 microstrip quarter-wave patch antennas is designed and measured Measuredresults show that the Yagi array generates a gain of about95 dBi and a bandwidth of 113 with an overall size of100times80mm2 and a profile of 15mm An increase of directorradiators of the Yagi array would enhance the gain and hasthe main beam pointing closer to endfire

Compared with the classical Yagi array of half-wavepatch antennas the presented Yagi array of quarter-waveantennas has a smaller length a slightly wider bandwidth abeam closer to endfire and a higher FB ratio However theefficiency of the Yagi array of quarter-wave patch antennasis not as high as that of the Yagi array of half-wave patch


antennas Both types of Yagi arrays have almost the samegains

Conflict of Interests

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

Acknowledgment

This work was supported in part by the Research Project ofGuangdong Province (2012B090600009)

References

[1] H Yagi ldquoBeam transmission of the ultra short wavesrdquo Proceed-ings of the IEEE vol 16 pp 715ndash741 1928

[2] J D Kraus and R J Marhefka Antennas For All Applicationschapter 8 McGraw-Hill New York NY USA 2002

[3] T A Milligan ldquoTraveling-wave antennasrdquo in Modern AntennaDesign chaper 10 John Wiley amp Sons Hoboken NJ USA 2ndedition 2005

[4] A Blalanis Modern Antenna Handbook John Wiley amp SonsNew York NY USA 2008

[5] J Huang ldquoPlanar microstrip Yagi array antennardquo in Proceedingsof the Digest Antennas and Propagation Society InternationalSymposium vol 2 pp 894ndash897 San Jose Calif USA June 1989

[6] J Huang and A C Densmore ldquoMicrostrip Yagi array antennafor mobile satellite vehicle applicationrdquo IEEE Transactions onAntennas and Propagation vol 39 no 7 pp 1024ndash1030 1991

[7] G R DeJean andMM Tentzeris ldquoA new high-gain microstripYagi array antenna with a high front-to-back (FB) ratio forWLAN and millimeter-wave applicationsrdquo IEEE Transactionson Antennas and Propagation vol 55 no 2 pp 298ndash304 2007

[8] G R DeJean T T Thai S Nikolaou and M M TentzerisldquoDesign and analysis of microstrip bi-yagi and quad-yagiantenna arrays for WLAN applicationsrdquo IEEE Antennas andWireless Propagation Letters vol 6 pp 244ndash248 2007

[9] T T Thai G R DeJean and M M Tentzeris ldquoDesign anddevelopment of a novel compact soft-surface structure forthe front-to-back ratio improvement and size reduction of amicrostrip Yagi array antennardquo IEEE Antennas and WirelessPropagation Letters vol 7 pp 369ndash373 2008

[10] W R Deal N Kaneda J Sor Y Qian and T Itoh ldquoA newquasi-yagi antenna for planar active antenna arraysrdquo IEEETransactions on Microwave Theory and Techniques vol 48 no6 pp 910ndash918 2000

[11] N Kaneda W R Deal Y Qian R Waterhouse and T Itoh ldquoAbroad-band planar quasi-Yagi antennardquo IEEE Transactions onAntennas and Propagation vol 50 no 8 pp 1158ndash1160 2002

[12] P R Grajek B Schoenlinner and G M Rebeiz ldquoA 24-GHz high-gain Yagi-Uda antenna arrayrdquo IEEE Transactions onAntennas and Propagation vol 52 no 5 pp 1257ndash1261 2004

[13] R A Sainati CAD of Microstrip Antennas for Wireless Applica-tion Artech House Norwood Mass USA 1996

[14] S Pinhas and S Shtrikman ldquoComparison between computedandmeasured bandwidth of quarter-wavemicrostrip radiatorsrdquoIEEE Transactions on Antennas and Propagation vol 36 no 11pp 1615ndash1616 1988

[15] Y X Guo K M Luk and K F Lee ldquoL-probe proximity-fedshort-circuited patch antennasrdquo Electronics Letters vol 35 no24 pp 2069ndash2070 1999

[16] Y Cassivi L Perregrini P Arcioni M Bressan K Wu and GConciauro ldquoDispersion characteristics of substrate integratedrectangular waveguiderdquo IEEE Microwave and Wireless Compo-nents Letters vol 12 no 9 pp 333ndash335 2002

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VLSI Design



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Civil EngineeringAdvances in

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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



h

b

x

y

x

z

R D D1 D2

W

d

p

sd sd s998400d2s998400g s998400r

L998400rL998400d Lm

sm

sm

L998400d1 L998400d2

d998400

Lg

Wg

120576r

Figure 1 Top view and cross-section of the microstrip Yagi array ofquarter-wave patch antennas

Figure 2 Photo for the 4-element Yagi array of quarter-wave patchantennas with the geometry shown in Figure 1

antennas and the Yagi array of quarter-wave patch antennaswill be discussed in the paper

2 Quarter-Wave Patch Antenna Yagi Array

21 Operation Principles The structure of the Yagi arraybased four quarter-wave patch antennas is shown in Figure 1Four quarter-wave patch antennas [13ndash15] and a set ofcouplingmicrostrip lines are fabricated on a substrate backedwith a ground plane The substrate could be air or dielectricsubstrate The four quarter-wave patch antennas include adriven element (D) two director elements (D1 and D2) anda reflector element (R) Only the driven element is excitedwith a 50Ω coaxial probe and the other patches are parasiticradiators

Radiation is mainly generated from the open apertures ofthe four quarter-wave patches (the open apertures opposite

44 46 48 5 52 54 56Frequency (GHz)

4E (not coupled) HFSS4E (coupled) HFSS

4E (coupled) measure12E (coupled) measure

minus45

minus40

minus35

minus30

minus25

minus20

minus15

minus10

minus5

0

|S11|

(dB)

Figure 3 Reflection coefficients for the 4-element Yagi array ofquarter-wave patch antennas without microstrip lines coupling the4-element Yagi array with microstrip lines coupling (Figure 2) andthe 12-element Yagi array with microsrip lines coupling (Figure 7)

to the shorting vias) Since the tangential electric field at eachopen aperture can be considered as a magnetic current theYagi array can be considered as a Yagi array of magneticelements With respect to the principle of duality to theclassical electric dipole Yagi array the parasitic magneticelement would act as a reflector when it has an additionalcapacitive component and it would act as a director whenit has an additional inductive component The reactivecomponent of each magnetic element can be controlled byadjusting the length of the quarter-wave patch (the distancefrom the open edge to the shorting vias of the quarter-wavepatch) Therefore a quarter-wave patch must have a smallerlength in order to have an additional inductive component(in view at the open aperture) when it acts as a directorOtherwise a quarter-wave patchwould act as a reflectorwhenit has a larger lengthThe lengths of the directors and reflectorneed to be tuned with simulation tools (such HFSS) to haveoptimum values and to have the array radiating in forwarddirection

In order to make more power coupled into the firstdirector from the driven element three parallel microstriplines with equal widths (119882 minus 2119904

119898)3 are introduced between

them Actually the three coupling microstrip lines can beconsidered as a wide microstrip line with width119882 that is cutwith two slits with width 119904

119898 as shown in Figure 1 The two

slits cutting the wide microstrip line are to avoid the widemicrostrip line resonating as a radiating patch Thereforethe coupling effect between the driven element and the firstdirector element is mainly through a guided wave underthe microstrip transmission lines On the other hand thecoupling between the driven and the reflector elements andthat between the first and the second elements are throughspace wave


0

030

60

90

120

150

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180minus150

minus120

minus90

minus60

minus30



(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10



(b)


030

60

90

120

1500

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180

minus150

minus120

minus90

minus60

minus30

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(b)







0and 015 120582

0 We let all



0(where




44 46 48 5 52 54 560

2

4

6

8

10

12

Frequency (GHz)

Gai

n (d

B)

4E HFSS











233 120576119903

233ℎ 157mm ℎ 157mm1198711015840

1198898926mm 119871

119889176mm

1198711015840

1199039026mm 119871

11990319mm

1198711015840

11988917826mm 119871

119889115mm

1198711015840

11988927626mm 119871

119889215mm

119882 40mm 119882 25mm119887 14mm 119887 13mm119904119889

08mm 119904 08mm119904119898

08mm 119871119892 115mm

119871119898

84mm 119882119892 80mm

1199041015840

119903337mm

1199041015840

1198892337mm

119904119892 2367mm119871119892 100mm119882119892 80mm119889 06mm119901 15mm




119892= 180mm and

a width of119882119892= 80mm



030

60

90

120

1500

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180

minus150

minus120

minus90

minus60

minus30

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(b)


W

b

s

x

y

Lr Ld1 Ld1Ld

Wg

Lg

D





48 49 5 51 52 53 54 55 56

0

10

560

3

6

9

12

Frequency (GHz)

Gai

n (d

Bi)

minus30

minus20

minus10

|S11|

(dB)





030

60

90

120

150plusmn180

minus150

minus120

minus90

minus60

minus30

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(b)















4 Conclusion







Acknowledgment


References



















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

030

60

90

120

150

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180minus150

minus120

minus90

minus60

minus30



(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10



(b)


030

60

90

120

1500

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180

minus150

minus120

minus90

minus60

minus30

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(b)







0and 015 120582

0 We let all



0(where




44 46 48 5 52 54 560

2

4

6

8

10

12

Frequency (GHz)

Gai

n (d

B)

4E HFSS











233 120576119903

233ℎ 157mm ℎ 157mm1198711015840

1198898926mm 119871

119889176mm

1198711015840

1199039026mm 119871

11990319mm

1198711015840

11988917826mm 119871

119889115mm

1198711015840

11988927626mm 119871

119889215mm

119882 40mm 119882 25mm119887 14mm 119887 13mm119904119889

08mm 119904 08mm119904119898

08mm 119871119892 115mm

119871119898

84mm 119882119892 80mm

1199041015840

119903337mm

1199041015840

1198892337mm

119904119892 2367mm119871119892 100mm119882119892 80mm119889 06mm119901 15mm




119892= 180mm and

a width of119882119892= 80mm



030

60

90

120

1500

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180

minus150

minus120

minus90

minus60

minus30

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(b)


W

b

s

x

y

Lr Ld1 Ld1Ld

Wg

Lg

D





48 49 5 51 52 53 54 55 56

0

10

560

3

6

9

12

Frequency (GHz)

Gai

n (d

Bi)

minus30

minus20

minus10

|S11|

(dB)





030

60

90

120

150plusmn180

minus150

minus120

minus90

minus60

minus30

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(b)















4 Conclusion







Acknowledgment


References



















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










44 46 48 5 52 54 560

2

4

6

8

10

12

Frequency (GHz)

Gai

n (d

B)

4E HFSS











233 120576119903

233ℎ 157mm ℎ 157mm1198711015840

1198898926mm 119871

119889176mm

1198711015840

1199039026mm 119871

11990319mm

1198711015840

11988917826mm 119871

119889115mm

1198711015840

11988927626mm 119871

119889215mm

119882 40mm 119882 25mm119887 14mm 119887 13mm119904119889

08mm 119904 08mm119904119898

08mm 119871119892 115mm

119871119898

84mm 119882119892 80mm

1199041015840

119903337mm

1199041015840

1198892337mm

119904119892 2367mm119871119892 100mm119882119892 80mm119889 06mm119901 15mm




119892= 180mm and

a width of119882119892= 80mm



030

60

90

120

1500

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180

minus150

minus120

minus90

minus60

minus30

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(b)


W

b

s

x

y

Lr Ld1 Ld1Ld

Wg

Lg

D





48 49 5 51 52 53 54 55 56

0

10

560

3

6

9

12

Frequency (GHz)

Gai

n (d

Bi)

minus30

minus20

minus10

|S11|

(dB)





030

60

90

120

150plusmn180

minus150

minus120

minus90

minus60

minus30

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(b)















4 Conclusion







Acknowledgment


References



















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










030

60

90

120

1500

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

plusmn180

minus150

minus120

minus90

minus60

minus30

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 48GHz)(f = 5GHz)(f = 52GHz)

(b)


W

b

s

x

y

Lr Ld1 Ld1Ld

Wg

Lg

D





48 49 5 51 52 53 54 55 56

0

10

560

3

6

9

12

Frequency (GHz)

Gai

n (d

Bi)

minus30

minus20

minus10

|S11|

(dB)





030

60

90

120

150plusmn180

minus150

minus120

minus90

minus60

minus30

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(b)















4 Conclusion







Acknowledgment


References



















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










030

60

90

120

150plusmn180

minus150

minus120

minus90

minus60

minus30

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(a)

0

30

6090

120

150

180

210

240270

300

330

0

(dB)

0

minus10

minus20

minus30

minus40

minus30

minus20

minus10

(f = 5GHz)

(f = 52GHz)(f = 51GHz) (f = 54GHz)

(f = 53GHz)

(b)















4 Conclusion







Acknowledgment


References



















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation













Acknowledgment


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 Yagi Array of Microstrip Quarter-Wave ...downloads.hindawi.com/journals/ijap/2014/102362.pdf · Yagi Array of Microstrip Quarter-Wave Patch Antennas with Microstrip