Progress In Electromagnetics Research, Vol. 137, , 2013

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1 Progress In Elecromagneics Research, Vol. 137, , 213 BROADBAND MODIFIED RECTANGULAR MICRO- STRIP PATCH ANTENNA USING STEPPED CUT AT FOUR CORNERS METHOD Alishir MoradiKordalivand * and Tharek A. Rahman Wireless Communicaion Cenre, Faculy of Elecrical Engineering, Universii Teknologi Malaysia, Skudai, Johor 8131, Malaysia Absrac In his paper, a new mehod ha called he Sepped Cu a Four Corners is inroduced o design a muli-mode/broadband modified recangular microsrip pach anennas (MRMPAs). In order o become acquained wih he new mehod, he design process of a monopole broadband MRMPA suiable for mulifuncional wireless communicaion bands is explained. The mehodology of he proposed broadband MRMPA design is presened in six sages. The firs sage is designing a single-mode RMPA. Subsequenly, by creaing a sep a he corners using he proposed mehod a dual-mode anenna is obained a he second sage, while he riple-mode and muli-mode anennas are designed, a he hird and fourh sages respecively. Two ypes of broadband anennas are obained, he sepped line and sraigh line anennas. By increasing he number of seps, he anenna s operaing bandwidh (BW), wih reurn loss less han 1 db, covers he frequency range from 9 MHz o 2.6 GHZ, which is suiable for GSM (9 MHz and 1.5 GHz), WiFi (2.4 GHz) and LTE (2.6 GHz) applicaions. In addiion, he anenna prooype has been fabricaed and measured in he all sages, in order o validae he simulaion resuls, and here is a close agreemen beween he simulaed and measured resuls. 1. INTRODUCTION Anennas are very significan in he area of wireless communicaions, and he microsrip pach anenna (MPA) is one of he mos popular and widely used in his field. Indeed, he MPAs have araced so much research ineres, due o heir ligh weigh, compaibiliy, Received 17 January 213, Acceped 28 February 213, Scheduled 7 March 213 * Corresponding auhor: Alishir Moradikordalivand (alimoradi22@gmail.com).

2 6 MoradiKordalivand and Rahman low-profile, ease of fabricaion, and low cos. Oher meris include ease of inegraion wih oher kinds of microwave inegraed circuis (MICs) on he same subsrae and capabiliy of being deployed for boh linear and circular polarizaions. However, MPAs have such disadvanages as low power handling capabiliy, low gain, and narrow BW. MPAs comprise narrow BW ha is approximaely 1 5%, which is he mos major limiing facor for is widespread applicaions. Mos of he previous conribuions in his research area were o increase he BW of MPAs [1, 2], and herefore, several measures have been inroduced o achieve his objecive, including modified shape paches, which is a mehod of modifying he shape of pach [3 8], uilizaion of sloed ground srucure [9 13], modificaion of recangular and circular paches o recangular [14] and circular rings [15, 16]. Anoher mehod includes an impedance maching nework mehod proposed o enhance he MPAs BW [17 19]. Several parasiic paches, such as shored quarer-wavelengh, recangular paches and narrow srips, are used as gap-couple o he cenral-fed recangular pach in planar muliresonaor srucure [2 26]. Wih differen layers of he dielecric subsrae, wo or more paches are sacked on one anoher in he mulilayer configuraion, which is caegorized as elecromagneically aperure-coupled or coupled MPAs as regards o he coupling mechanism [27 3]. The sacked and planar muliresonaor echniques are combined wih he proposed mehod o increase he BW and he gain of he sacked muliresonaor MPAs. A circular pach on he boom layer or probe-fed single recangular pach has been used o excie circular paches on he op layer or muliple recangular, respecively [31 33]. Anoher mehod o enhance he BW is LC mehod, which disribues LC circui on he backside of he convenional pach anenna [34]. In his paper, he Sepped Cu a Four Corners mehod for designing a monopole muli-mode/broadband MRMPA has been proposed based on modifying he pach shape. In order o become acquained wih he new mehod, we will describe he design procedure, simulaion, and fabricaion of a broadband MRMPA wih operaing frequency from 9 MHZ o 2.6 GHz. The proposed MRMPA covers GSM (9 MHz and 1.5 GHz), Wi-Fi (2.4 GHz) and LTE (2.6 GHz) applicaions. 2. RMPAs MODEL Figure 1 shows he RMPA configuraion, including a dielecric subsrae locaed beween a radiaing pach and a ground plane. Generally, he pach is prepared of conducing maerial such as gold

3 Progress In Elecromagneics Research, Vol. 137, Figure 1. Srucure of RMPA. or copper in any shape. On he dielecric subsrae, he feed lines and radiaing pach are usually phoo-eched [35, 36]. The microsrip pach anenna analysis is represened by some models such as he ransmission line model, caviy model, full wave model and characerisic mode. The caviy model is more accurae and gives a good physical insigh hus very complex compared o he ransmission line model ha is he simples of all models and less accurae. The characerisic mode is ypically performed on elecrically small o inermediae size anennas for simpliciy [37, 38]. However, he full wave model is he mos accurae and complex of he models and can analyze single elemens, arbirary shaped elemens and infinie anenna arrays. The ransmission line model is used in his work because of is simpliciy o implemen and is oupu good performance in anenna designs in erms of efficiency and reurn loss and also i is well suied for RMPAs design. By choosing operaing frequency f r and a subsrae wih he required permiiviy ε r, and also defining he subsrae hickness h, he design sars. Based on he ransmission line model, he lengh L and widh W of he pach are calculaed as: W = v 2 (1) 2f r ε r + 1 v L = 2 L (2) 2f r εreff where, v is he speed of ligh in free space, ε reff he effecive permiiviy, and 2 L he exension in lengh due o fringing effecs: [ h ] 1/2 (3) W ε reff = ε r ε r 1 2 L =.412h (ε reff +.3) (W/h +.264) (ε reff.258) (W/h +.8) (4)

4 62 MoradiKordalivand and Rahman Alhough he pach design is simple, feeding design mechanism is no direc. There are four main mehods used o design he feed, which are probe feed, microsrip-line feed, Proximiy-coupled feed and aperurecoupled feed. However, we used a microsrip-line feed because of he simpliciy of he model, fabricaion and mach [35, 36]. 3. CONCEPT OF STEPPED CUT AT FOUR CORNERS METHOD The proposed mehod, called he Sepped Cu a Four Corners (SCFC) is used o design of Mulimode/Broadband MRMPAs. As he name implies, four corners of he recangular pach are cu o creae he desired BW by he sepped approach which will be explained in he following ex. Firsly, in he proposed mehod, he lower cuoff frequency (FL) and upper cuoff frequency (FH) mus be deermined in order o specify he BW range. Nex, he values of he pach s lengh and widh will be deermined for he excied frequencies of FH and FL, using Transmission Line equaions, given in Equaions (1) (4). According o obained pach s dimensions, he pach of FL is bigger han ha of FH. Therefore, he coordinae posiions of FH pach are insered wihin coordinae posiions of ha of he FL. Considering he nesed srucure of he paches, i can be seen ha hey are all concenric, for example, he poin (, ); and hey are placed on he x-y plane of he coordinae sysem. As menioned earlier, he pach obained from FL is he larges in erms of dimensions; herefore i is considered as he main pach. As can be seen in Figure 2, he recangles wih red and green colour lines are he paches designed for he FL and FH respecively. W L and L L denoe he FL pach lengh and widh, respecively. Also he corresponding FH pach widh and lengh are W H and L H. Each design covers only one operaing frequency, hus if a broadband design is expeced from FL o FH frequency range, all of he frequencies wihin he BW mus be covered. Therefore, he lengh and widh of he paches mus be from L L o L H and W L o W H, respecively. As shown in Figure 2, he pach obained from FH is shown in whie colour; however he pach colour becomes darker as i moves oward FL. In Figure 2, by drawing he lines from inernal pach corners (designed for FH pach and displayed in green colour) oward exernal pach lines (designed for FL pach and displayed in red colour), sep cuing posiion is specified in each corner, which are shown in blue colour. The widh and lengh of he paches wihin he given BW, denoed by F1 o Fn-1 are drawn from W 1 o W n 1 and L 1 o L n 1, respecively. In order o connec F1-Fn-1 paches o FL pach for creaing he seps

5 Progress In Elecromagneics Research, Vol. 137, Y L L W L L L L L n-1 F F2 F3 F n-1 FL W1 W2W3W n-1 FH W H X 1 L H R 1 W 1 L 1 Figure 2. Configuraion posiion of he paches in he SCFC mehod. a he corners, a process similar o he one menioned above is followed. By referring o Figure 2, i is shown ha a grid plane wih 1/n spacing is creaed a he corners, where n is he number of he paches designed inside he main pach. Figure 3 shows geomeric deails of he corners in his mehod. In order o calculae he dimensions of he firs sep a he corners, he lengh and widh relae o L 1 and spacing beween he coordinae posiion of W F L and W F 1. Second sep widh is considered from he disance beween he coordinae posiion of W F 1 and W F 2, and lengh is relaed o he disance beween he coordinae posiion of L F L and L F n 1 and oher seps creaed in he same process. The sep pah creaed using his mehod is shown in whie colour. By creaing each sep, in fac an excied resonan frequency is creaed over he BW herefore by increasing he number of seps; he excied resonan frequencies are increased as long as he BW is covered. Whereas he pach heigh () is exremely hin compared o is widh and lengh, z-axis are ignored in coordinaing sysem and all calculaions are done on he x-y plane. To obain he dimensions and coordinae posiion of he paches lengh and widh over he BW, following equaions are used in accordance wih Figure 3. W 1 = W L W H 2 n=n = W Rn (5) n=1

6 64 MoradiKordalivand and Rahman L R3 W R1 L R2 W R2 R R2 W R3 R R3 L R1WFH R R1 WFn-1 WFn-2 R 1 W 1 L Rn-1 WRn-1 L Rn R Rn-1 WRn Rn R L LFH LFn-1 Fn-2 WF3 WF2 WF1 W LF3 L F2 LF1 L FL FL L 1 Figure 3. Geomeric deails of seps a he corners. L 1 = L L L H 2 When he seps dimension are same: n=n = L Rn (6) n=1 W R = W R1 =W R2 =...=W Rn and L R =L R1 =L R2 =...=L Rn W R = W 1 n (7) L R = L1 n (8) R 1 = n L 2 R + W R 2 (9) where, n is he number of seps, R 1 he sepped pah, and W R and L R are he widh and lengh of sep, respecively. Oherwise: { } W 1 n = 1 {W Rn (n)} = (1) W F n 1 W F n 2 n < where, W F H = W F n, W F L = W F, W F 1 o W F n 1 are paches widh posiion on he y-axis and W R1 W Rn are sep widh. { } L1 n = 1 {L Rn (n)} = (11) L F n 1 L F n 2 n < where L F H = L F n and L F L = L F. R Rn = L 2 Rn + W Rn 2 (12)

7 Progress In Elecromagneics Research, Vol. 137, n=n R 1 = R Rn = n=1 n=n = n=1 L 2R1 + W 2R1 + L 2R2 + W 2R2...+ L 2 Rn +W 2 Rn L 2 Rn + W 2 Rn (13) where, L F 1 o L F n 1 are paches lengh posiion on he x-axis, and L R1 L Rn are seps lengh. When n is larger, he number of seps creaed a he corners is more, and R 1 becomes almos linear and acs somehow as hypoenuse of a righ riangle wih sides of W 1 and L 1. The values of R 1 can be obained by he following equaion: R 1 = L W 1 2 (14) As explained in his secion, muli-mode/broadband MRMPAs can be designed very quickly using simple equaions. 4. DESIGN PROCESS OF PROPOSED BROADBAND MRMPA USING SCFC METHOD In order o become familiar wih SCFC mehod, he design process of monopole broadband MRMPA wih frequency range from 9 MHz o 2.6 GHz is explained. This design can be used for GSM (9 MHz/1.5 GHz), WiFi (2.4 GHz) and LTE (2.6 GHz) applicaions. All designs and simulaions of he RMPAs wih he proposed mehod are done using CST Microwave Sudio sofware. FR-4 dielecric subsrae wih relaive permiiviy ε r = 4.3, hickness h = 1.6 mm, Lengh L s =9 mm and widh W S = 13 mm is used. Radiaing pach and ground plane are on he op and boom of he dielecric subsrae, respecively and made of copper maerial wih hickness =.35 mm and conduciviy σ = 5.96e 7 s/m. The ground plane lengh and widh are L G = 18 mm and W G = 9 mm, respecively and remain consan in all sages of he design process. To achieve 5 Ω oupu impedance maching wih he SMA connecor, a ransmission line fed wih widh W F = 3 mm and lengh L F = 2 mm was used. The following explains he design process of he proposed broadband MRMPA Sage I: Single-mode RMPA As explained in Secion 3, dimensions of paches a he lowes frequency (FL = 9 MHz), he highes frequency (FH = 2.6 GHz) as well as desired frequencies beween FL and FH mus be obained from Equaions (1) (4). Table 1 gives he dimensions for paches in

8 66 MoradiKordalivand and Rahman he frequency range GHz wih Sep 1 MHz. In his sage, a single-mode RMPA for an excied resonan frequency a FL = 9 MHz is proposed. Figure 4 shows he prooype phoographs and geomeric deails of he single-mode RMPA. By referring o Table 1, i is clear ha widh W L = 12 mm and lengh L L = 8 mm obained for his pach have he larges dimensions, hus his pach is considered as he main pach. Table 1. Dimensions of paches in frequencies range GHz wih sep1 MHz. Freq. (GHz) W (mm) L (mm) Freq. (GHz) W (mm) L (mm) L S L L W L W S L G L F W F Pach Subsrae h Ground plane (a) (b) (c) Figure 4. Phoographs of fabricaed prooype and Geomeric deails of single-mode RMPA. (a) Fron view. (b) Back view. (c) Top & side view Sage II: Dual-mode MRMPA According o Table 1, i can be seen ha he values of widh and lengh for he pach a F H = 2.6 GHz are he smalles. By referring o SCFC mehod, L H = 27 mm and W H = 35 mm in erm of coordinae

9 Progress In Elecromagneics Research, Vol. 137, posiions are wihin and concenric wih he main pach in x-y plane of he coordinae sysem. A his sage using Equaions (1) and (11), sep lengh and widh a each corner are found o specify he BW. Picures of fabricaed anenna and configuraion for arrangemen of paches as well as specificaions of he sep creaed a he corners (shown wih hachure) are indicaed in Figure 5. By removing he hachured secions from main pach, in fac wo excied resonan frequencies a FL = 9 MHz and FH = 2.6 GHz are obained, and he designed anenna acs as dual-mode, as expeced. L S L L L H W L W H 26.5 mm W S 33.5 mm L G L F WF Pach Subsrae h Ground plane (a) (b) (c) Figure 5. Picures of fabricaed prooype and configuraion deails of dual-mode MRMPA. (a) Fron view. (b) Back view. (c) Top & side view Sage III: Triple-mode MRMPA To design he riple-mode MRMPA according o he CSFC mehod, wo seps mus be creaed in each corner of he main pach. By creaing a pach wihin frequency range paches from F L o F H, in fac helps o creae he hird excied resonan frequency. The widh and lengh coordinae posiion of new pach is obained using Equaions (1) (4) ha wihin W L o W F and L L o L F, respecively. The middle pach, same as FL pach, is concenric wih he main pach in x-y plane of he coordinae sysem and relaed o frequency of 1.5 GHz according o Table 1. Figure 6 illusraes he phoos of fabricaed prooype of proposed anenna and srucural configuraion for he arrangemen of

10 68 MoradiKordalivand and Rahman L S L L L H W L W H mm mm L G W F Pach Subsrae h Ground plane (a) (b) (c) L F Figure 6. Phoos of manufacured prooype and srucural deails of Triple-mode MRMPA. (a) Fron view. (b) Back view. (c) Top & side view. he paches as well as specificaions of he seps creaed a he corners of he main pach. As shown in Figure 6, if he hachured secion is removed from he main pach, hree excied resonan frequencies will be resuled a F L =9 MHz, F 1 = 1.5 GHz and FH = 2.6 GHz Sage IV: Muli-mode MRMPA In order o show deails of he design owards achieving mulimode anenna, he number of seps a main pach corners are increased using CSFC mehod. Three paches are creaed in frequency ranges from FL o FH wih appropriae disances and concenric wih he main pach in x-y plane of he coordinae sysem. By increasing he seps, he number of excied resonan frequencies in he specified par of he BW are enhanced; herefore a mulimode anenna is obained. Figure 7 shows a deailed geomeric srucure and picures of fron and back view of fabricaed prooype obained a his sage. In he figure, some pars of he pach corners are specified by hachure which is removed from he main pach o achieve he muli-mode MRMPA. Considering he resuls obained from sage wo o four, i is shown ha broadband MRMPA is gradually realized in he expeced frequency range Sage V: Broadband MRMPA wih Sepped Line In he previous sage, i was observed ha using CSFC mehod, he designed MRMPA was ransformed ino muli-mode from single mode. As explained in Secion 3, n 1 paches can be creaed beween

11 Progress In Elecromagneics Research, Vol. 137, L S L L L H W L W H 6.6 mm W S 8.35mm L G L F W F Pach h Subsrae Ground plane (a) (b) (c) Figure 7. Phoographs of manufacured prooype and geomeric deails of mulimode MRMPA. (a) Fron view. (b) Back view. (c) Top & side view. L S L L L H W L W H WS WS WS W S 3.72 mm 2.95 mm L G L F WF Pach h Subsrae Ground plane (a) (b) (c) Figure 8. Phoographs of fabricaed prooype and geomeric deails of broadband MRMPA using sepped line. (a) Fron view. (b) Back view. (c) Top & side view. frequencies ranging from FL o FH, which creae n seps a each corner of main pach. For designing he expeced broadband MRMPA wih full coverage of he BW, he number of seps a he corners using he SCFC mehod has increased. As shown in Figure 8, en seps are creaed a he corners of he main pach for ensuring full coverage of

12 61 MoradiKordalivand and Rahman he BW by he anenna. I is observed from he obained resuls ha specificaions of he anenna, such as reurn loss, gains, are improved by increasing he number of seps a he corners. Figure 8 also shows phoographs of manufacured prooype and geomeric deails relaed o creaed sepped pah and removed pars of he main pach Sage VI: Broadband MRMPA wih Sraigh Line By increasing he number of seps a he corners, in fac he number of he exied resonance frequencies over he impedance BW is invesigaed. There are infinie frequencies beween F L o F H. If he number of seps a he corners increases infiniely, he seps become smaller and reach a poin ha he sep pah (R 1 ) acs as a line wih infinie poins. By calculaing W 1 and L 1 using Equaions (1) and (11), R 1 acs as hypoenuse in a righ riangle wih W 1, L 1 sides, which can be calculaed using Equaion (14). Figure 9 shows he geomeric deails and phoos of fabricaed proposed broadband MRMPA. L S L L L H W L W H R 1 =42.7 mm WS L G L F WF Pach Subsrae h Ground plane (a) (b) (c) Figure 9. Phoos of fabricaed prooype and geomeric deails of Broadband MRMPA proposed using sraigh line. (a) Fron view. (b) Back view. (c) Top & side view. 5. SIMULATION AND MEASUREMENT RESULTS In order o validae he simulaed resuls obained from CST Microwave Sudio sofware, he prooype has been fabricaed and measured by Rohde and Schwarz ZVL Nework analyzer a all sages of

13 Progress In Elecromagneics Research, Vol. 137, he proposed RMPAs. Simulaed vecor surface curren disribuions in radiaing pach and simulaed and measured reurn losses are depiced in Table 2. Comparison beween he simulaion and measuremen reurn losses (RL) resuls is illusraed in Table 2, as i can be seen approximaely ha here is a good agreemen beween he resuls a all sages. The firs sage relaed o he proposed single-mode RMPA for operaing frequency a 9 MHz, whose approximae reurn loss 12-dB was obained from boh simulaion and measuremen. The second sage demonsraes a dual-mode MRMPA using CSFC mehod for wo exied resonance frequencies a FL = 9 MHz and FH = 2.6 GHz. Consequenly, reurn losses 27 db and 17 db for operaing frequencies a FL and FH were obained, respecively. Sage III proposes a riple-mode MRMPA. As expeced, hree exied resonance frequencies a 9 MHz, 1.5 GHz and 2.6 GHz were obained. For hese frequencies, i can be seen from Table 2 ha reurn loss values are 28 db, 27 db and 16 db for simulaion and 16 db, 25 db and 13 db for measuremen, respecively. In sage IV, by increasing he number of seps a he corners using SCFC mehod, a muli-mode MRMPA was obained. By referring o resuls, here are desired resuls based on he reurn loss less han 1 db across frequency bands from 9 MHz o 1.65 GHz and 2.25 GHz o 2.6 GHz. In sage V o cover enire BW by proposing MRMPA, he number of seps is enhanced and sepped line is creaed a he corners. Considering he resuls obained a sage V, i can be observed ha he designed MRMPA has a broadband performance from 9 MHz o 2.6 GHz based on RL < 1 db ha provides he approximaely sable omnidirecional/bidirecional radiaion paern over he BW; herefore he whole expeced BW using SCFC mehod was covered. In he las sage, assuming an infinie number of seps a he corners, he sepped line became a sraigh line. In his sage, he proposed MRMPA produced approximaely similar resuls as obained in sage V bu he difference is he sepped line model gives resuls ha are adjusable in he range of he BW by changing he dimensions of he seps whereas in he sraigh line model all resuls remains fixed. Figures 1 and 11, illusrae simulaed and measured reurn losses of RMPAs a all sages, respecively. According o he figures, he evoluion process from single-mode o broadband MRMPA can be seen. The desire frequency band is specified by highligh. Therefore, i is clear ha he diagrams of broadband MRMPAs have covered he enire BW. Sable omnidirecion a he lower frequencies and approximae bidirecion a he upper frequencies have been achieved for he far

14 612 MoradiKordalivand and Rahman Table 2. Simulaed and measured reurn loss and vecor surface curren disribuions of RMPAs. Srucure Surface curren Reurn loss Sage I: Single mode Simulaion Measuremen Freq. (Hz) Sage II: Dual mode Simulaion Measuremen Freq. (Hz) Sage III: Triple mode -1-2 Simulaion Measuremen Freq. (Hz) Sage IV: Muli mode Reurn Loss (db) -1-2 Simulaion Measuremen Freq. (Hz) Sage V: Broadband sepped line Sage VI: Broadband sraigh Line Reurn Loss (db) Reurn Loss (db) -1-2 Simulaion Measuremen Freq. (Hz) Simulaion Measuremen Freq. (Hz)

15 Progress In Elecromagneics Research, Vol. 137, Reurn Loss (db) -1.9 GHz 2.6 GHz -2 Sage1 Sage2 Sage3 Sage4 Sage5 Sage Freq. (GHz) Figure 1. Simulaed reurn loss of he RMPAs. Reurn Loss (db) -1.9 GHz 2.6 GHz -2 Sage1 Sage2 Sage3 Sage4 Sage5 Sage6-3 5.x16 1.x x19 2.x19 2.5x x1 Freq. (Hz) Figure 11. Measured reurn loss of he RMPAs. field radiaion paern of proposed monopole broadband MRMPA over he BW. The maximum radiaed field direcs in he direcion of +z and z, for he desired direcion. Figure 12 shows he simulaed normalized E and H-plane radiaion paerns of proposed broadband MRMPA for resonan frequencies a 9 MHz, 1.5 GHz, 2.4 GHz and 2.6 GHz. Figure 12(a) shows, a linear polarizaion wih he broadside and bidirecional E-plane radiaion paern and almos omnidirecional H-plane radiaion paern a 9 MHz operaing frequency. Figure 12(b), (c) and (d), show boh E and H-plane radiaion paern of operaing frequencies a 1.5 GHz, 2.4 GHz and 2.6 GHz, ha polarizaion a hese frequencies from linear o circular and radiaion paerns approximaely bidirecional, respecively. I is found ha he radiaion paern in E-plane ils from z axis, and he main lobes spread o four direcions wih 45 degree from he z axis. As menioned in Secion 3, he lowes and highes frequencies over he BW belong o he bigges and smalles dimension of he pach, respecively. Therefore, by decreasing he dimension of he pach and he corners, he radiaion paern has changed a he upper frequencies. I is observed from Figure 13 ha axial raios of he proposed broadband MRMPA a upper frequencies of desire BW are below 3 db, hus polarizaion is circular. The vecor surface curren disribuions in he radiaion pach a he operaing frequency (sage I: 9 MHz, sages II VI: 2.6 GHz) are shown in Table 2. I can be seen ha a all sages excep sage I here is he mos surface curren disribuion on he sepped line pah. This means ha he maximum surface curren densiy a he corners is due o he operaing frequencies via he seps size. Furhermore o he radiaion characerisics, he realized gains of he proposed RMPAs are shown in Figure 14. In accordance wih he

16 614 MoradiKordalivand and Rahman H_plane E_plane (a) H_plane E_plane (c) H_plane E_plane (b) H_plane E_plane (d) Figure 12. Simulaed radiaion paerns of he broadband MRMPA. (a).9 GHz, (b) 1.5 GHz, (c) 2.4 GHz, and (d) 2.6 GHz. resuls, by increasing he number of seps a he corners he gains enhanced correspondingly, along he frequency band. Consequenly a he design sage of he proposed broadband MRMPA, gains of dbi are achieved a he desired direcion (θ = and ϕ = 9 ) over he BW. Figure 15 shows he radiaion efficiency simulaed of he proposed RMPAs a he all sages. By referring o he figure, i is observed ha he radiaion efficiency of proposed broadband MRMPAs is more

17 Progress In Elecromagneics Research, Vol. 137, Axial Raio (db) Freq. (GHz) Figure 13. Axial Raios of proposed broadband MRMPA. Gain (dbi) GHz GHz -4 Sage1 Sage2-6 Sage3 Sage4-8 Sage5 Sage Freq. (GHz) Figure 14. Simulaed realized gain of he RMPAs. Radiaion efficiency (%) GHZ 2.6 GHZ 4 Sage1 Sage2 Sage3 2 Sage4 Sage5 Sage Freq. (GHz) Figure 15. Simulaed Radiaion efficiency of he RMPAS. han 93% across he whole BW ha is highlighed and specified by blue and green colour diagrams ha are belonging o sages V and VI, respecively. 6. CONCLUSION A new mehod, Sepped Cu a Four Corners, for designing a muli-mode/broadband MRMPAs, has been proposed in his paper. In order o become familiar wih he proposed mehod, he process of designing a broadband MRMPA has been analyzed. The proposed broadband MRMPA is suiable for mulifuncional wireless communicaion sysems. The design process includes six sages, saring from designing a single-mode RMPA wih a resonan frequency of 9 MHz and developed o design a Dual-mode, Triple-mode, Mulimode and finally he expeced broadband MRMPA for operaing frequency band from 9 MHz o 2.6 GHz. Complee measuremens

18 616 MoradiKordalivand and Rahman were carried ou a each sage of he design, in order o validae he simulaion resuls wih he measured ones. Each of he sages discussed in deails he mehodology of creaing he seps a he pach s corners o enhancing he impedance BW. The proposed broadband MRMPA can be used for GSM (9 MHz and 1.5 GHz), WiFi (2.4 GHz) and LTE (2.6 GHz) applicaions. The RMPAs have demonsraed good performance in erms of reurn loss, radiaion paern, gain and efficiency. The simulaed gains were obained as dbi a he desired direcion. In addiion, he radiaion efficiency was more han 93% wih a reurn loss below 1 db over he BW. I is found ha he measuremen and simulaion resuls are in close agreemen. I should be noed ha some reasons for using SCFC mehod are simpliciy of calculaing he seps dimensions for expeced resonance frequencies, he capabiliy o design all ypes of muli-mode/broadband MRMPAs and abiliy o change he polarizaion of he anenna from linear o circular. REFERENCES 1. Milligan, T. A., Modern Anenna Design, John Wiley & Sons, Inc., Hoboken, New Jersey, Kumar, G. and K. P. Ray, Broadband Microsrip Anennas, Arech House, Boson, Islam, M. T., M. N. Shakib, and N. Misran, Broadband E-H shaped microsrip pach anenna for wireless sysems, Progress In Elecromagneics Research, Vol. 98, , Pouyanfar, N. and S. A. Rezaeieh, Compac UWB anenna wih invered ha shaped resonaor and shorening via pins for filering properies, Progress In Elecromagneics Research Leers, Vol. 33, , Abbaspour, M. and H. R. Hassani Wideband sar-shaped microsrip pach anenna, Progress In Elecromagneics Research Leers, Vol. 1, 61 68, Xu, H.-Y., H. Zhang, K. Lu, and X.-F. Zeng, A holly-leaf-shaped monopole anenna wih low RCS for UWB applicaion, Progress In Elecromagneics Research, Vol. 117, 35 5, Kim, D.-O., N.-I. Jo, H.-A. Jang, and C.-Y. Kim, Design of he ulrawideband anenna wih a quadruple-band rejecion characerisics using a combinaion of he complemenary spli ring resonaors, Progress In Elecromagneics Research, Vol. 112, 93 17, Saleem, R. and A. K. Brown, Empirical miniaurizaion analysis

19 Progress In Elecromagneics Research, Vol. 137, of inverse parabolic sep sequence based UWB anennas, Progress In Elecromagneics Research, Vol. 114, , Chen, Z., Y. L. Ban, J. H. Chen, J. L. W. Li, and Y. J. Wu, Bandwidh enhancemen of LTE/WWAN prined mobile phone anenna using sloed ground srucure, Progress In Elecromagneics Research, Vol. 129, , Lin, D. B., I. T. Tang, and M. Z. Hong, A compac quad-band PIFA by uning he defeced ground srucure for mobile phones, Progress In Elecromagneics Research B, Vol. 24, , Li, C. M. and L. H. Ye, Improved dual band-noched UWB slo anenna wih conrollable noched bandwidhs, Progress In Elecromagneics Research, Vol. 115, , Zhou, D., S.-C. S. Gao, F. Zhu, R. A. Abd-Alhameed, and J.- D. Xu, A simple and compac planar ulra wideband anenna wih single or dual band-noched characerisics, Progress In Elecromagneics Research, Vol. 123, 47 65, Liu, J., K. P. Esselle, S. G. Hay, and S.-S. Zhong, Sudy of an exremely wideband monopole anenna wih riple band-noched characerisics, Progress In Elecromagneics Research, Vol. 123, , Lamulree, S. and C. Phongcharoenpanich, Bidirecional ulrawideband anenna using recangular ring fed by sepped monopole, Progress In Elecromagneics Research, Vol. 85, , Yu, A., F. Yang, and A. Elsherbeni, A dual band circularly polarized ring anenna based on composie righ and lef handed meamaerials, Progress In Elecromagneics Research, Vol. 78, 73 81, Chen, Y., S. Yang, and Z.-P. Nie, A novel wideband anenna array wih ighly coupled ocagonal ring elemens, Progress In Elecromagneics Research, Vol. 124, 55 7, Pues, H. G. and A. R. Van De Capelle, An impedance maching echnique for increasing he bandwidh of microsrip anennas, IEEE Trans. Anennas and Propagaion, Vol. 37, No. 11, , Wong, K. L. and T. W. Kang, GSM85/9/18/19/UMTS prined monopole anenna for mobile phone applicaion, Microwave Op. Technol. Le., Vol. 5, , Ban, Y. L., J. H. Chen, L. J. Ying, J. L. W. Li, and Y. J. Wu, Ulra wideband anenna for LTE/GSM/UMTS wireless USB dongle applicaions, IEEE Anennas and Wireless Propagaion

20 618 MoradiKordalivand and Rahman Leers, Vol. 11, 43 46, Islam, M. T., R. Azim, and A. T. Mobashsher, Triple bandnoched planar UWB anenna using parasiic srips, Progress In Elecromagneics Research, Vol. 129, , Gujra, M., J. L.-W. Li, T. Yuan, and C.-W. Qiu, Bandwidh improvemen of microsrip anenna array using dummy EBG paern on feedline, Progress In Elecromagneics Research, Vol. 127, 79 92, Deng, J., L. Guo, T. Fan, Z. Wu, Y. Hu, and J. Yang, Wideband circularly polarized suspended pach anenna wih indened edge and gap-coupled feed, Progress In Elecromagneics Research, Vol. 135, , Alvarez-Folgueiras, M., J. A. Rodriguez-Gonzalez, and F. Ares- Pena, Experimenal resuls on a planar array of parasiic dipoles fed by one acive elemen, Progress In Elecromagneics Research, Vol. 113, , Zhu, F., S.-C. S. Gao, A. T. S. Ho, C. H. See, R. A. Abd- Alhameed, J. Li, and J.-D. Xu, Design and analysis of planar ulra-wideb and anenna wih dual band-noched funcion, Progress In Elecromagneics Research, Vol. 127, , Chang, T. N. and J. H. Jiang, Enhance gain and bandwidh of circularly polarized microsrip pach anenna using gap-coupled mehod, Progress In Elecromagneics Research, Vol. 96, , Elsheakh, D. N., H. A. Elsadek, and E. A. Abdallah, Ulra-wide bandwidh microsrip monopole anenna by using elecromagneic band-gap srucures, Progress In Elecromagneics Research Leers, Vol. 23, , Zulkifli, F. Y., F. Narpai, and E. T. Rahardjo, S-shaped pach anenna fed by dual offse elecromagneically coupled for 5 6 GHz high speed nework, PIERS Online, Vol. 3, No. 2, , Zhou, B., H. Li, X. Zou, and T.-J. Cui, Broadband and high-gain planar Vivaldi anennas based on inhomogeneous anisoropic zeroindex meamaerials, Progress In Elecromagneics Research, Vol. 12, , Zhao, F., K. Xiao, W. J. Feng, S. L. Chai, and J. J. Mao, Design and manufacure of he wideband aperure-coupled sacked microsrip anenna, Progress In Elecromagneics Research C, Vol. 7, 37 5, Lai, C. H., Broadband aperure-coupled microsrip anennas wih low cross polarizaion and back radiaion, Progress In

21 Progress In Elecromagneics Research, Vol. 137, Elecromagneics Research Leers, Vol. 5, , Lien, H. C., H. C. Tsai, Y. Lee, and W. F. Lee, A circular polarizaion microsrip sacked srucure broadband anenna, PIERS Online, Vol. 4, No. 2, , Ollikainen, J., M. Fischer, and P. Vainikainen, Thin dualresonan sacked shored pach anenna for mobile communicaions, Elecronics Leers, Vol. 35, , Zaid, L., G. Kossiavas, J. Y. Dauvignac, J. Cazajous, and A. Papiernik, Dual-frequency and broad-band anennas wih sacked quarer wavelengh elemens, IEEE Trans. Anennas and Propagaion, Vol. 47, No. 4, , Chen, Y., S. Yang, and Z. Nie, Bandwidh enhancemen mehod for low profile E-shaped microsrip pach anennas, IEEE Trans. Anennas and Propagaion, Vol. 58, No. 7, , Bahal, I. J. and P. Bharia, Microsrip Anenna, Arech House, Massachuses, Pozar, D. M. and D. H. Schauber, Microsrip Anennas, he Analysis and Design of Microsrip Anennas and Arrays, IEEE Press, New York, Chen, Y. and C. F. Wang, Characerisic-mode-based improvemen of circularly polarized U-slo and E-shaped pach anennas, IEEE Anennas and Wireless Propagaion Leers, Vol. 11, , Wu, W. and Y. P. Zhang, Analysis of ulra-wideband prined planar quasi-monopole anennas using he heory of characerisic modes, IEEE Anennas Propag. Mag., Vol. 52, No. 6, 67 77, 21.