Radiating Slot in the Coaxial Cable Shield: Measurement Based Characterization

Transcription

1 136 JOURNAL OF COMMUNICATIONS SOFTWARE AND SYSTEMS, VOL. 11, NO. 3, SEPTEMBER 215 Radatng Slot n the Coaxal Cable Sheld: Meaurement Baed Characterzaton Antono Šarolć, Zlatko Žvkovć, Damr Senć, and Nko Ištuk Orgnal centfc paper Abtract: The paper preent the comprehenve expermental tudy of radaton charactertc of a ngle lot n a coaxal cable held. The lot wa realzed n four dfferent embodment, whch vared by lot orentaton and length. Three orthogonal polarzaton of radated electrc feld were analyzed along the ax perpendcular to cable, broadde to the lot, n a broadband frequency range (- MHz). The analy wa baed on thorough meaurement of the couplng lo, whch the common parameter for the leaky cable characterzaton. The obtaned reult howed that the electrc feld component longtudnal to the cable ax conderably domnate over other two orthogonal component, for all four lot type. Doublng the length of the lot caued a ca. 2 db ncreae of the radated feld. Dfferent lot orentaton, havng the ame length n the croecton projecton, yelded approxmately equal feld trength. The reult of th expermental tudy clearly and vbly demontrate the radatng lot feld dependence on polarzaton and lot geometry n a wde frequency range. Thu they are ueful for plannng of wrele communcaton ytem baed on radatng cable, a well a for undertandng polarzaton related ue n uch ytem. Index term: leaky radatng coaxal cable held, lot length and orentaton, couplng lo meaurement, polarzaton I. INTRODUCTION A lot n an nfnte PEC (perfect electrc conductor) plane a well-known theoretcally analyzed radaton ource [1]. A lot may alo be cut n a coaxal cable held, preentng a radatng element n a leaky or radatng cable ytem [2-5]. Leaky cable are lotted coaxal tructure ued a radaton ource for ndoor wrele communcaton (buldng, tunnel, mne, ubway, etc. [6-1]), where ordnary antenna preent a le utable oluton. The comprehenve theoretcal tudy of leaky cable [2-5], [11-13], accompaned wth numercal and meaurement reult [14-2], can be found n lterature. However, the rgorou analytcal approach for a ngle lot manly deal wth electrc feld dtrbuton on the lot [2, 4], wthout a clear nght nto the electromagnetc (EM) feld radated from a ngle lot. Thee feld could be of nteret, a a ngle lot can ubequently be treated a an antenna array element on a coaxal cable wth a large number of perodcally arranged Manucrpt receved June 4, 215; reved September 11, 215. Author are wth the Unverty of Splt, Faculty of Electrcal Engneerng, Mechancal Engneerng and Naval Archtecture (FESB), Croata and Unverty of Colorado Boulder, Colorado, USA (E-mal: {antono.arolc, zlatko.zvkovc, nko.tuk}@feb.hr, damr.enc@nt.gov). lot. The radated feld calculated by ung cylndrcal harmonc expanon [12], mode matchng technque combned wth qua tatc [11] or ntegral [17] method, a well a numercal procedure [3, 5, 16] requre elf-developed code, and ther applcaton n practce not traghtforward. On the other hand, a few expermental tude that can be found n lterature [6, 7, 15], manly deal wth domnatng polarzaton component that meaured at everal cable-torecever dtance, n a narrow frequency range. Therefore, th paper preent a meaurement-baed comprehenve tudy of the radaton charactertc of a ngle lot n a coaxal cable held. The tudy baed on extenve meaurement reult for four dfferent lot, havng dfferent length and orentaton,.e. nclnaton angle wth repect to the cable ax. Couplng lo wa meaured along the ax perpendcular to cable, broadde to the lot, for three orthogonal electrc feld polarzaton, n a broadband frequency range from MHz to MHz. The expermental reult preented n th paper can be appled by communcaton engneer whle plannng leakage cable wrele ytem, epecally regardng gnal coverage ue. The paper tructured a follow the econd chapter preent the detaled explanaton of the materal and method that were ued to characterze radaton properte of a radatng lot, a well a detaled decrpton of the meaurement etup. At the end of the chapter the couplng lo calculaton, baed on the meaured quantte, ha been preented. The meaurement reult for the elected lot embodment and recevng antenna poton were preented and dcued n the thrd chapter. The concludng remark are gven at the fourth chapter. II. MATERIALS AND METHODS A. Slot embodment Each ngle lot wa potoned n the mdpont of a 1 m long RG213 5 Ω coaxal cable wth polyethylene delectrc (εr=2.25). The lot wa realzed n four dfferent embodment (Table 1), whch vared by orentaton (º and 3º to the cable ax), and length (2% and 4% of the cable crcumference, meaured n the cro-ecton projecton of the lot). Embodment and relevant dmenon are hown n Fg. 1, where a and b are tandard dmenon of the RG213 5 Ω coaxal cable, whle the crcumference C of the outer conductor calculated a C=πb. The lot were made a narrow a poble, to acheve w << l and w << l /9/ CCIS

2 A. ŠAROLIĆ et al.: RADIATING SLOT IN THE COAXIAL CABLE SHIELD: MEASUREMENT BASED CHARACTERIZATION 1 Inclnaton angle wth repect to cable ax normal, º 2 normal, º l=.4c 3 nclned, 3º h=.2c 4 nclned, 3º h=.4c Embodment Slot length l=.2c Fg. 1. Left: normal lot; Rght: nclned lot B. Meaurement etup The radaton charactertc of a leaky (radatng) cable, havng a large number of lot along a conderable cable length, are commonly meaured n accordance wth IEC tandard [21]. The tandard decrbe couplng lo meaurement along the cable ax, at a ngle predefned radal (broadde drecton) dtance of 2 m. Relyng on the meaurement method decrbed n the tandard, the ntenton of th tudy wa to meaure the couplng lo along the ax perpendcular to cable, broadde to the lot, varyng the dtance (.e. heght, accordng to Fg. 2) from.2 m to 2 m wth a 1 cm tep. Bacally, th reulted wth the radal couplng lo profle n front of the lot, meaured for three orthogonal polarzaton hown n Fg. 2. a) b) c) Fg. 2. Three antenna orentaton: a) radal; b) tranveral; c) longtudnal The IEC tandard [21] ugget two type of meaurement method: the free pace method and the ground level method. In the free pace method the radatng cable hould be potoned on the non-metallc pot at a heght of 1.5 to 2 m. The montorng antenna hould be potoned at the ame heght a that of the examned cable, on the horzontal dtance of 2 m from the cable. In the ground level method the cable hould be potoned on the non-metallc pot, at a dtance of 1-12 cm from the concrete floor. The couplng lo then meaured at the heght of 2 m drectly above the cable. Conderng the avalable meaurement urroundng, the meaurement n th tudy were carred out accordng to the ground level method. Even though the gven tandard recommend the uage of half-wave dpole antenna for meaurement purpoe, other type of antenna can alo be ued, provded that ther gan known. For th broadband tudy, a bconcal dpole wa ued (Fg. 3), a a more convenent broadband antenna. The meaured couplng lo wa then expreed wth repect to the half-wave dpole antenna. The meaurement were performed n the frequency range from MHz to 1 GHz n 1 dcrete frequency pont. The couplng lo wa meaured ung a vector network analyzer Aglent FeldFox N9912A RF Combnaton Analyzer n CAT (Cable and Antenna Tet) mode, meaurng the 2-port nerton lo between the output and the nput port of the devce. Takng nto account all the gan and loe n the ytem, the couplng lo wa ealy obtaned. The analyzer telf ha a nomnal output power of +6 dbm, and the prelmnary meaurement ung only that amount of nput power howed that the lot generated very weak radaton,.e. the reultng couplng lo, n addton to the ytem loe n the connecton cable, wa rather hgh compared to the ytem dynamc range. Therefore, the dynamc range had to be ncreaed by addtonal gan acheved by a 15W broadband RF amplfer (Amplfer Reearch AR15W). The chematc layout of the meaurement etup hown n Fg. 4a. G [db] TABLE I SLOT EMBODIMENTS Fg. 3. Gan of the calbrated broadband bconcal dpole The output gnal from the analyzer wa amplfed and fed to the lotted coaxal cable that wa termnated by a hgh power 3 db attenuator and a 5 Ω dummy load. The electrc feld radated by the lot (DUT), wa meaured by a calbrated broadband bconcal dpole antenna PCD 825 placed drectly above the DUT, mounted on the adjutable wooden trpod (Fg. 4b). The RX antenna heght wa vared from.2 m to 2 m wth a 1 cm tep. Bede the VNA' own lmted dynamc range, the overall meaurement ytem dynamc range wa lmted by two addtonal factor. The RX antenna (broadband bconcal dpole) gan hown n Fg. 3, howng a evere defcency n the lower part of t frequency range, that eventually tranform to the ytem dynamc lmtaton. Alo, conderng the frequency range of nteret (from MHz to 1 GHz), the dynamc range wa compromed by the background noe and nterference arng from varou rado ytem preent n that range. After a comprehenve EM te urvey, the meaurement locaton wa choen n the faculty baement where no nterference problem had been oberved.

3 138 JOURNAL OF COMMUNICATIONS SOFTWARE AND SYSTEMS, VOL. 11, NO. 3, SEPTEMBER 215 Pout dbm Pn dbm L4 db PA dbm L2 db ATT db (3) Gamp db L3 db L4 db. Lkewe, Prec can be expreed ung PB: Prec dbm PB dbm L1 db. (4) Hence the couplng lo can be calculated ung (1), (3) and (4): CL db PA dbm L2 db ATT db Gamp db a) L3 db L4 db PB dbm L1 db. (5) All the loe and gan were known, nce they had been prevouly meaured n the frequency range of nteret. The dfference (PA - PB) wa actually meaured by the analyzer a the nerton lo IL (Fg.4): IL db PA dbm PB dbm. (6) Thereby, the couplng lo CLbcon (meaured by the bconcal dpole) wa fnally deducted a: CL db IL db L2 db ATT db Gamp db b) Fg. 4. Meaurement etup (DUT denote the radatng lot) a) chematc layout, b) bconcal dpole antenna above DUT (radal orentaton) C. Couplng lo calculaton Couplng lo CL defned a the dfference (n db) between the power Pout n the radatng cable at the locaton of the lot, and the avalable power Prec meaured at the recevng antenna (Fg.4), placed broadde to the lot, at a certan dtance: CL db Pout dbm Prec, dbm. (1) Index tand for -th polarzaton of the meaured electrc feld. Accordng to Fg. 2, and wth repect to the cable ax, polarzaton can be meaured a radal, tranveral and longtudnal. Accordng to [21], the recevng antenna preferably a half-wave dpole, however, other type of antenna can be ued, and t type and gan hould be gven wth the reult. If the cable attenuaton contant α known, a well a the power Pn at the cable nput termnal, Pout can be calculated a: Pout dbm Pn dbm db/m x m Pn dbm L4 db, (2) where x the dtance from the cable nput termnal to the lot, and L4 denote the cable lo calculated ung the attenuaton contant α prevouly meaured n the frequency range of nteret. The dtrbuton of gnal power (Prec, PA, PB, Pn, Pout) and cable loe (L1, L2, L3, L4), at the pont of nteret along the ytem, alo ndcated n Fg. 4. Takng nto account the attenuaton ATT of 6 db, amplfer gan Gamp, cable loe L2 and L3, Pout can be expreed ung PA: L3 db L4 db L1 db. (7) The couplng lo obtaned by the bconcal dpole can be ealy converted to the couplng lo wth repect to half-wave dpole. Ung the Fr equaton, Prec can be expreed a a functon of the RX antenna gan (all quantte n db): CLbcon db Pout Prec_bcon Pout ( Pout Glot Gbcon 2log Glot Gbcon 2log, 2 r ) 2 r (8) CLλ/2 db Pout Pλ/2 Pout ( Pout Glot Gλ/2 2log Glot Gλ/2 2log, 2 r ) 2 r (9) for the bconcal and half-wave dpole, repectvely. Gbcon had been prevouly meaured (hown n Fg.3), and Gλ/2 equal 2.15 db, the tandard gan of the half-wave dpole. After ubtractng (8) from (9), CLλ/2 can be calculated (n db): CL /2, db CLbcon, db Gbcon, db G /2 db. (1) Snce the couplng lo wa meaured eparately for each of the three orthogonal polarzaton (Fg. 2), ndex hown n (1). Therefore, the tandard [21] defne the mean couplng lo calculated by: 1 3 CL CLmean db 1log (11)

4 A. ŠAROLIĆ et al.: RADIATING SLOT IN THE COAXIAL CABLE SHIELD: MEASUREMENT BASED CHARACTERIZATION III. RESULTS AND DISCUSSION A. The meaurement dynamc wa lmted by the ntrument noe level. In order to oberve th lmtaton, the noe level wa meaured n term of nerton lo, by cuttng off the power tranmon. Th wa acheved by turnng off the power amplfer, however keepng all the connecton, ncludng the RX antenna, to oberve eventual background noe and nterference receved by the antenna. The meaured nerton lo noe, averaged over 3 frequency weep, hown n Fg. 5, howng no background gnal, thu approvng the choce of meaurement locaton n a quet envronment. The noe level remaned practcally unchanged for all polarzaton. The meaured nerton lo noe level wa then converted to the couplng lo noe level (alo dplayed n Fg. 5) ung equaton (7) and (1), to oberve the actual lmtaton of the meaurement ytem for the quantty of nteret. The dynamc tart to dratcally decreae below 3 MHz, a a conequence of a very low RX antenna gan (obervable n Fg. 3). Couplng lo noe level Inerton lo noe level [db] couplng lo defned by (11), th ha no major conequence, nce the major part of the mean value the domnant (longtudnal) polarzaton, for both lot nclnaton. However, th may be mportant for communcaton wth an antenna polarzed orthogonally to the longtudnal polarzaton, ncreang t recepton by a few db. Generally, at lower heght, the radal component domnated over the tranveral component. The certan concluon about ther relaton at hgher dtance cannot be made nce ther value progrevely ocllated wth frequency cloe to the couplng lo noe lmt. Fg. 1 how only the domnant (longtudnal) polarzaton, at the heght of 2 m (mot nteretng both for communcaton and wth repect to [21]), for dfferent type of lot. It can be ealy notced that the couplng lo wa almot 2 db lower for the longer lot, l=.4c and h=.4c, than for the horter lot, l=.2c and h=.2c. On the other hand, there wa no major dfference between the lot of the ame length, regardle of ther nclnaton. Fg. 11 how only the domnant (longtudnal) polarzaton, at three dfferent heght of.2 m, 1 m and 2 m. The graph hown for the longer lot only, to acheve better vblty (lower couplng lo). Theoretcally, a the dtance ncreae from.2 m to 1 m by a factor of 5, the couplng lo hould ncreae by 14 db. Smlar, a the dtance ncreae from 1 m to 2 m by a factor of 2, the couplng lo hould ncreae by 6 db. The meaurement reult approxmately followed th conderaton. The graph hown only for the normal lot, nce Fg. 1 howed that the reult for the nclned lot were very mlar. C. Couplng lo profle Fg. 5. Inerton lo and couplng lo noe level B. Couplng lo frequency dependence Fg. 6 and Fg. 7 how the couplng lo n front of the normal lot, for l=.2c and l=.4c repectvely, a a functon of frequency, at three dcrete dtance: 2 cm, 1 m and 2 m. The fgure how three orthogonal polarzaton (accordng to Fg. 2), along wth the noe level. Several obervaton can be made. The longtudnal polarzaton conderably domnated over the other two n all cae, by 1 to 2 db. For the horter lot and greater dtance, the le pronounced polarzaton approached the noe level. The couplng lo for the longer lot (.4C) wa conderably lower than for the horter lot (.2C) mot ealy obervable for the domnant polarzaton (the lowet curve). Fg. 8 and Fg. 9 how the couplng lo n front of the nclned lot, for h=.2c and h=.4c repectvely, a a functon of frequency, at three dcrete dtance: 2 cm, 1 m and 2 m. The fgure how three orthogonal polarzaton (accordng to Fg. 2), along wth the noe level. It can be oberved that the couplng lo wa very mlar to the normal lot, for the domnant (longtudnal) polarzaton. Due to the lot nclnaton, the other two polarzaton had a lghtly lower couplng lo than wth the normal lot. For the mean Fg. 12 how the couplng lo profle for the domnant (longtudnal) polarzaton, at three dfferent frequence ( MHz, 5 MHz and 1 GHz) for the normal lot, l=.4c. It obervable that the couplng loe at thee three frequence dffered by le than 1 db n any gven pont. Fg. 13 and Fg. 14 how the couplng lo profle at three frequence ( MHz, 5 MHz and 1 GHz) along the ax perpendcular to the cable, n front of the lot, for the normal and the nclned lot, repectvely. Fgure refer to the longer lot, l=.4c and h=.4c, to acheve better vblty (lower couplng lo). All three polarzaton are hown, along wth the noe level aocated wth each frequency. In the radatng far feld of the ource (lot), a teady ncreae of the couplng lo expected a the dtance ncreae. However, graph how the decreae of the couplng lo for the domnant (longtudnal) polarzaton at MHz a the dtance ncreae above cm, uggetng that the RX antenna wa tll n the near feld of the ource, where uch varaton commonly occur. Th not trange nce the wavelength of 3 m (at MHz) greater than the dtance from the ource. At frequence of 5 MHz and epecally at 1 GHz, for the domnant (longtudnal) polarzaton, there were tll ome fluctuaton of the couplng lo wth the dtance, probably due to the meaurement uncertanty, but the trend acceptable. It worth repeatng that, theoretcally, the couplng lo hould ncreae by 14 db from 2 cm to 1 m, and by only 6 db from 1 m to 2 m. Th wa practcally acheved at 5 MHz.

5 14 JOURNAL OF COMMUNICATIONS SOFTWARE AND SYSTEMS, VOL. 11, NO. 3, SEPTEMBER 215 Normal lot (l =.2C), h=2cm Normal lot (l =.4C), h=2cm Normal lot (l =.2C), h=cm 5 Normal lot (l =.4C), h=cm Normal lot (l =.2C), h=cm 5 Normal lot (l =.4C), h=cm Fg. 6. Couplng lo frequency dependence at pecfc heght, for normal lot, ls=.2c (lower couplng lo better, n all fgure) Fg. 7. Couplng lo frequency dependence at pecfc heght, for normal lot, ls=.4c

6 A. ŠAROLIĆ et al.: RADIATING SLOT IN THE COAXIAL CABLE SHIELD: MEASUREMENT BASED CHARACTERIZATION Inclned lot (h =.4C), h=2cm Inclned lot (h =.2C), h=2cm Inclned lot (h =.2C), h=cm 5 Inclned lot (h =.4C), h=cm Inclned lot (h =.2C), h=cm 4 5 Inclned lot (h =.4C), h=cm Fg. 8. Couplng lo frequency dependence at pecfc heght, for nclned lot, h=.2c Fg. 9. Couplng lo frequency dependence at pecfc heght, for nclned lot, h=.4c

7 142 JOURNAL OF COMMUNICATIONS SOFTWARE AND SYSTEMS, VOL. 11, NO. 3, SEPTEMBER 215 Normal lot (l =.4C), MHz polarzaton, h=cm normal lot (l =.2C) normal lot (l =.4C) nclned lot (h =.2C) nclned lot (h =.4C) MHz 2 4 Fg. 1. Couplng lo frequency dependence, longtudnal polarzaton, heght h=2 m, for dfferent lot Normal lot (l =.4C), 5 MHz Normal lot (l =.4C), polarzaton h=2cm h=cm h=cm -5 MHz Normal lot (l =.4C), MHz Fg. 11. Couplng lo frequency dependence, longtudnal polarzaton, normal lot, ls=.4c, for three dfferent heght Normal lot (l =.4C), polarzaton MHz 5 MHz MHz - MHz -5 MHz - MHz MHz 5 2 Fg. 12. Couplng lo profle for the longtudnal polarzaton, normal lot, l=.4c, for three dfferent frequence Fg. 13. Couplng lo profle for all three polarzaton, normal lot, ls=.4c, for three dfferent frequence

8 A. ŠAROLIĆ et al.: RADIATING SLOT IN THE COAXIAL CABLE SHIELD: MEASUREMENT BASED CHARACTERIZATION For the full nght nto the meaurement reult, the 3D graph of the mean couplng lo, calculated ung (11), for all frequence, heght and lot embodment, are preented n Fg. 15. Inclned lot (h =.4C), MHz Normal 65 - MHz 2 Normal Inclned lot (h=.4c), 5 MHz -5 MHz Inclned lot (h =.4C), MHz - MHz Fg. 15. Mean couplng lo for all lot type Fg. 14. Couplng lo profle for all three polarzaton, nclned lot, h=.4c, for three dfferent frequence

9 144 JOURNAL OF COMMUNICATIONS SOFTWARE AND SYSTEMS, VOL. 11, NO. 3, SEPTEMBER 215 IV. CONCLUDING REMARKS A ngle lot n a coaxal cable held a varaton of the lot antenna, and can be ued both for tranmttng EM wave from the cable, and recevng EM wave nto the cable. Cable havng a large number of perodcally arranged lot are commonly ued a dtrbuted antenna, o called "leaky cable". Undertandng of a ngle lot radaton therefore mportant for the undertandng of a leaky cable behavor. Th tudy conted of couplng lo meaurement for four dfferent embodment of a ngle lot n a coaxal cable held. The lot length and nclnaton wth repect to the cable ax were vared. Accordng to the reult, the tronget electrc feld polarzaton wa the one longtudnal to the cable ax. Th can be explaned by the fact that the lot wa orented normal to the cable ax, thu cuttng the longtudnal current flow, breakng the longtudnal current lne and creatng the potental dfference between the oppote edge of the narrower lot dmenon. Inclnng the lot wth repect to the cable ax dd not yeld any major change for the domnant longtudnal polarzaton, a long a the length of the lot (meaured n the cro-ecton projecton of the lot) remaned unchanged. On the other hand, the other two orthogonal polarzaton ganed everal db from the lot nclnaton, whch could be mportant for communcaton between the cable and an arbtrarly polarzed antenna. The mot dramatc effect occurred a the conequence of extendng the length of the lot by a factor of 2, from 2% to 4% of the held crcumference. Th yelded a 2 db ncreae of the radated feld, reultng wth 2 db lower couplng lo. Hence the lot length play a major factor n degnng the lot. REFERENCES [1] C. A. Balan: Antenna theory, Analy and Degn, John Wley & Son, New Jork, NY, USA, 3rd edton, 5. [2] Y. L, J. Wang, Z. Zhang, and M. Chen: Emprcal Formula for the Electrc Feld Calculaton n Rectangular Slot on Leaky Coaxal Cable, IEEE Tranacton on Antenna and Propagaton, vol., no. 12, pp , 212. [3] J. F. Kang: Radaton Properte of Crcumferental Slot on a Coaxal Cable, IEEE Tranacton on Mcrowave Theory and Technque, vol. 45, no. 1, pp , [4] J. H. Wang and S. S. Jan: Analy of the Feld Dtrbuton Stmulated on the Slot of the Leaky Coaxal Cable, n Proceedng of Antenna and Propagaton Socety Internatonal Sympoum, vol. 3, pp , July [5] J. H. Wang and K. K. Me: Theory and Analy of Leaky Coaxal Cable Wth Perodc Slot, IEEE Tranacton on Antenna and Propagaton, vol. 49, no. 12, pp , 1 [6] J. We, C. J, and Y. Yang: An ununform perodc lotted leaky coaxal cable ued n the pecfc wrele communcaton ytem of ubway, n Proceedng of 1th Internatonal Sympoum on Antenna, Propagaton & EM Theory, (ISAPE), pp , October 212. [7] J. Guo and X. Lu: Reearch on the Influence of Tunnel Wall on Radaton Feld Caued by the Leaky Antenna, n Proceedng of Internatonal Conference on Communcaton and Moble Computng, CMC 9, vol. 1, pp. 9-13, January 9. [8] M. Nakamura, H. Takag, K. Enaga, T. Nhkawa, N. Moryama, and K. Waak: Evaluaton of a Dual-band Long Leaky Coaxal Cable n the 2.4 and 5 GHz Frequency Band for Wrele Network Acce, n Proceedng of IEEE Rado and Wrele Sympoum, (RWS 9), pp , January 9. [9] H. Cao and Y. P. Zhang: Rado Propagaton along a Radated Mode Leaky Coaxal Cable n Tunnel, n Proceedng of Aa Pacfc Mcrowave Conference, vol. 2, pp , November [1] J. R. Wat and D. A. Hll: Propagaton Along a Braded Coaxal Cable n a Crcular Tunnel, IEEE Tranacton on Mcrowave Theory and Technque, vol. MTT-23, no. 5, pp , 19. [11] J. R. Wat: Electromagnetc Feld Analy for a Coaxal Cable wth Perodc Slot, IEEE Tranacton on Electromagnetc Compatblty, vol. EMC-19, no. 1, pp. 7-13, [12] P. P. Delogne and A. A. Laloux: Theory of the Slotted Coaxal Cable, IEEE Tranacton on Mcrowave Theory and Technque, vol. MTT-28, no. 1, pp. 2-7, 19. [13] D. H. Km and H. J. Eom: Radaton of a Leaky Coaxal Cable wth Narrow Tranvere Slot, IEEE Tranacton on Antenna and Propagaton, vol. 55, no. 1, pp. 17-, 7. [14] T. Baba, T. Nagao, N. Kurauch, and T. Nakahara: Leaky Coaxal Cable wth Slot Array, n Proceedng of Antenna and Propagaton Socety Internatonal Sympoum, vol. 6, pp , September [15] S. C. Da and J. C. Beal: Meaurement on Coupled Leaky Coaxal Cable, n Proceedng of Antenna and Propagaton Socety Internatonal Sympoum, vol. 13, pp , June 19. [16] S. T. Km, G. H. Yun, and H. K. Park: Numercal Analy of the Propagaton Charactertc of Multangle Multlot Coaxal Cable Ung Moment Method, IEEE Tranacton on Mcrowave Theory and Technque, vol. 46, no. 3, pp , [17] C. W. Lee and H. Son: Radaton Charactertc of DelectrcCoated Coaxal Wavegude Perodc Slot wth Fnte and Zero Thckne, IEEE Tranacton on Antenna and Propagaton, vol. 47, no. 1, pp , [18] J. H. Wang and S. S. Jan: Radaton from Slot on the Leaky Coaxal Cable, n Proceedng on IEEE Antenna and Propagaton Socety Internatonal Sympoum, vol. 4, pp , 1. [19] L. Shu, J. Wang, H. Sh, and Z. L: Reearch on the Radaton Charactertc of the Leaky Coaxal Cable, n 6th Internatonal Sympoum on Antenna, Propagaton and EM Theory, pp , October 3. [2] Y. L and J. Wang: Polarzaton Property of Leaky Coaxal Cable Wth Overlapped Trangle Slot, IEEE Antenna and Wrele Propagaton Letter, vol. 9, pp , 21. [21] Internatonal Standard IEC : Coaxal Communcaton Cable, 2nd Edton, 4. Antono Šarolć receved the Dploma Engneer, MS and PhD degree n Electrcal Engneerng n 19, and 4 from the Unverty of Zagreb, Croata. He wa employed at the ame unverty from 19 to 5, at the Faculty of Electrcal Engneerng and Computng (FER), Dept. of Radocommuncaton. In 6 he joned the Unverty of Splt, FESB, Department of Electronc and now Aocate Profeor n Electrcal Engneerng. H area of nteret are electromagnetc meaurement, boeffect of EM feld, electromagnetc compatblty (EMC) and radocommuncaton.

10 A. ŠAROLIĆ et al.: RADIATING SLOT IN THE COAXIAL CABLE SHIELD: MEASUREMENT BASED CHARACTERIZATION Zlatko Žvkovć receved the Dploma Engneer and PhD degree n Electrcal Engneerng n 7 and 214 from the Faculty of Electrcal Engneerng, Mechancal Engneerng and Naval Archtecture, Unverty of Splt, Croata. He currently a potdoc atant at the Unverty of Splt, Faculty of Electrcal Engneerng, Mechancal Engneerng and Naval Archtecture (FESB), Department of Electronc. H reearch nteret are: electromagnetc meaurement, boeffect of EM feld, electromagnetc compatblty (EMC) and radocommuncaton. Damr Senć receved the M.Sc. degree n 8 and Ph.D. degree n 214, both from Unverty of Splt, Faculty of Electrcal Engneerng, Mechancal Engneerng and Naval Archtecture, Splt, Croata. He currently wth Unverty of Colorado Boulder workng at Natonal Inttute of Standard and Technology, Communcaton Technology Laboratory n Boulder a a Potdoctoral Reearch Aocate through Profeonal Reearch Experence Program. H reearch nteret nclude mllmeter wave radocommuncaton, electromagnetc meaurement, electromagnetc compatblty (EMC) and boeffect of EM feld. Dr. Senc receved Rchard E. Merwn Award of IEEE Computer Socety for exemplary nvolvement n IEEE actvte and excellent academc achevement n Nko Ištuk receved the M.Sc degree n Communcaton and Informaton Technology n 213 from Unverty of Splt, Faculty of Electrcal Engneerng, Mechancal Engneerng and Naval Archtecture, Splt, Croata. He an EMC Engneer wthn the STRIPmed project team (Strengthenng the capacty of Unverty of Splt for reearch, development and nnovaton n medcal neuroelectronc) at the Speech and Hearng Reearch Lab, School of Medcne, Unverty of Splt, Splt (Croata).