Bonfring International Journal of Research in Communication Engineering, Vol. 5, No. 3, October Hare Ram Jha and Shiva Nand Singh

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1 Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol. 5, No. 3, October 05 Study of Scatterng Parameters and Gan of two Longtudnal Slots of Same Electrcal Lengths lled on two Wavegudes for Seres and Shunt Slot Array Planar Antenna Hare Ram Jha and Shva Nand Sngh Abstract--- Ths paper presents a study of two longtudnal slots of same electrcal lengths mlled on two wavegudes for seres and shunt slot array planar antenna. Intally sngle longtudnal slot element s mlled on wavegude whch s called sngle element wavegude slot antenna (WSA). Two same or dfferent structures of sngle element WSA are kept ether n seres or shunt for makng of two element longtudnal wavegude seres slot array and shunt slot array planar antenna respectvely. Theoretcal data for the reflecton coeffcent and transmsson coeffcent due to mutual mpedance have been obtaned for two element seres and shunt planar WSA. The theoretcal data have been compared wth smulated data for valdaton the proposed desgn structures. The almost outstandng agreement obtaned between the results valdates the nvestgaton of proposed desgn structure. After the reflecton and transmsson coeffcents valdaton, the total gan of the proposed desgn structures s smulated. The result found n seres slot array planar antenna behaves as a mult band wthn n X-band for the applcaton of the mult frequency selectve devce for communcaton and shunt slot array planar antenna behaves as n sngle band entre coverage of X-band for the applcaton of long dstance data communcaton. Keywords--- Array, Desgn, ethod of oments, ultple Cavty odelng Technque, Slot, Wavegude S I. INTRODUCTION TUDIES on wavegude slot antennas are very common due to ther unque features such as lower loss n comparson wth mcro strp antennas, and smpler structure n comparson wth reflector antennas[], []. A large no. of lteratures s avalable n ths feld. ost of them are about fndng the equvalent crcut, resonant length and the radaton pattern of the sngle solated slot antenna usng dfferent methodologes lke varaton, transmsson lne matrx method, Fnte Dfference ethod Tme Doman, ethod of oment etc [3]. A few work were Hare Ram Jha, Research Scholar, Department of Electroncs & Communcaton Engneerng, Natonal Insttute of Technology, Jamshedpur, Jharkhand, Inda. E-mal:hrjha.ece@ntjsr.ac.n Shva Nand Sngh, Professor, Department of Electroncs & Communcaton Engneerng, Natonal Insttute of Technology, Jamshedpur, Jharkhand, Inda. E-mal:snsngh.ece@ntjsr.ac.n DOI: /BIJRCE.047 also studed out n two or more than two slot are used as radated element wth mutual couplng for calculatng the scatterng parameters [4], [5], [6], [7], [8], [9], [0]. A. J. Sangstar et al., [] employed moment method to analyze a longtudnal slot doublet n both ar-flled and delectrc-flled rectangular wavegudes, n whch the slot radators are located n the opposng broad faces of the wavegude. Later they also presented an entre doman moment method analyss of an Omn drectonal lnear array antenna []. Then after, A. Bastan et al., [3] presented analyss of planar slotted-wavegude array antennas wth longtudnal slots usng the method of moments. The effects of varous mutual couplngs, thckness of the wavegude walls, and wavegude proxmty were taken nto account n ths analyss. After two year P. ondal et al., [4] reported the analyss of an solated slot doublet n a rectangular wavegude usng agnetc Feld Integral Equaton (FIE). The equaton was solved usng Galerkn specalzaton of ethod of oment (O) and reflecton and transmsson coeffcents were obtaned. Equvalent crcut of the wavegude slot doublet was represented on the bass of these coeffcents. Later they also presented the desgn of a lnear array antenna havng two radaton nulls and otherwse Omn drectonal radaton pattern usng slot doublet. Ths type of doublet produces two radaton nulls [5]. After four year, Rntu Kumar Gyan et al., [6] paper presented, method of moments based analyss of broad-wall longtudnal slots array antenna usng ultple Cavty odelng Technque (CT) for calculatng resonance and scatterng parameters two element planar slot array antenna for X-band. Later, they also presented a method of moments based analyss of hgh-gan broad-band wavegude broad-wall longtudnal slot array antenna for eghteen element slot for calculatng scatterng parameters and gan for entre coverage of X-band [7]. After that Hare Ram Jha et al., [8] presented a paper desgn and analyss of wavegude-fed broad-wall longtudnal log perodc slotted array antenna for X-band for calculatng the scatterng parameters and gan smultaneously. Agan, more recently Rntu Kumar Gyan et al., [9] also presented a method of moments based analyss of standard and reduced heght a broad-wall longtudnal slot doublets antenna usng ultple Cavty odelng Technque (CT) for sngle doublet calculatng scatterng parameters. Above reported lterature survey no one author studed the behavor of scatterng parameters and gan smultaneously of two element ISSN Bonfrng

2 Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol. 5, No. 3, October 05 3 seres and shunt planar wavegude slot array antenna. So, ths s the great opportunty to study on two element seres and shunt planar wavegude slot array antenna. In ths paper we have analyzed scatterng parameter due to mutual mpedance between two slots of same electrcal lengths mlled on two wavegudes, kept sde-by-sde, keepng ther polarzaton parallel otherwse arbtrarly located. The confguraton s shown n Fgure (Total 4 confguraton). As the name suggests wavegude slot antenna (WSA) conssts wth two thngs slot antenna and wavegude. Any slot has ts complementary form n wres or strps, so that the pattern and mpedance data of these forms can be used to predct the patterns and mpedances of the correspondng slot [0]. Wavegude has been often appled for hgh power handlng capablty and low losses []. Generally, wavegude s a hollow metallc box that comprses wth two broad walls and two narrow walls shown n Fgure. Slots mlled on ether the broad wall or on the narrow wall of a rectangular wavegude have found wde applcaton n naval radars. A slot s capable of gvng vertcal and horzontal polarzaton, dependng on ts locaton and orentaton of the broad wall and narrow wall of a rectangular wavegude. Front-fed reflector or Cassegran antenna systems suffer from the drawback. oreover, such arrays can be fabrcated wth mnmum power loss compared to the case of reflector antennas. Due to these characterstcs the wavegude-fed slots have found an mportant place n the array antennas as radatng elements. For desgn of lnear and planar slot arrays, t s frst essental to characterze a sngle slot element. The equvalent network representaton of such element s necessary for desgnng such arrays. However, when two or more array elements are near to each other, some of the energy that s radated by one element gets sgnfcantly coupled to the other elements. The amount of couplng depends on the radaton characterstcs of the elements, separaton and orentaton between them. Ths couplng of energy between array elements s known as mutual couplng and n many cases t complcates the analyss and desgn of antenna. For most practcal antenna confguraton, mutual couplng s dffcult to predct analytcally, but must be taken nto account because of ts sgnfcant effects on antenna performance. The effect of mutual couplng performance of an array depends upon the antenna type, ts desgn parameters, relatve postonng of the elements, feed and on the scan volume. Fgure represents that a slot s cut on four separate standard wavegude (WR-90) wth same electrcal lengths. Here, four combnatons can be made by Fgure (a) & (b) for case-i: two port two element seres slot array planar antenna, Fgure (a) & (d) for case-ii: two port two element seres slot array planar antenna, Fgure (a) & (c) case-iii : four port two element shunt slot array planar antenna, and Fgure (b) & (d) for case-iv: four port two element shunt slot array planar antenna, for measurng the scatterng parameters between two slots of same electrcal length. Fgure (a), (b) and (c) are dentcal n shape, sze and offset poston of the slot, but Fgure (d) mrror mage of Fgure (c). The dmenson of standard WR-90 wavegude, slot and slot poston are shown n Table. 9.8mm Slot Wavegude 9.8mm Slot Wavegude Offset Centre Offset Centre Wavegude length=79.5mm Wavegude length=79.5mm (a) (b) 9.8mm Slot Wavegude Wavegude Slot 9.8mm Offset Centre Offset Centre Wavegude length=79.5mm (c) Wavegude length=79.5mm (d) Fgure : Confguraton of Standard WR-90 Wavegude wth Sngle Slot wth slot offset = -3.5mm For desgn of lnear and planar slot arrays, t s frst essental to characterze a sngle slot element. The equvalent network representaton of such element s necessary for desgnng such arrays. However, when two or more array elements are near to each other, some of the energy that s radated by one element gets sgnfcantly coupled to the other elements. The amount of couplng depends on the radaton characterstcs of the elements, separaton and orentaton between them. Ths couplng of energy between array elements s known as mutual couplng and n many cases t ISSN Bonfrng

3 Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol. 5, No. 3, October 05 4 complcates the analyss and desgn of antenna. For most practcal antenna confguraton, mutual couplng s dffcult to predct analytcally, but must be taken nto account because of ts sgnfcant effects on antenna performance. The effect of mutual couplng performance of an array depends upon the antenna type, ts desgn parameters, relatve postonng of the elements, feed and on the scan volume. Fgure represents that a slot s cut on four separate standard wavegude (WR-90) wth same electrcal lengths. Here, four combnatons can be made by Fgure (a) & (b) for case-i: two port two element seres slot array planar antenna, Fgure (a) & (d) for case-ii: two port two element seres slot array planar antenna, Fgure (a) & (c) case-iii : four port two element shunt slot array planar antenna, and Fgure (b) & (d) for case-iv: four port two element shunt slot array planar antenna, for measurng the scatterng parameters between two slots of same electrcal length. Fgure (a), (b) and (c) are dentcal n shape, sze and offset poston of the slot, but Fgure (d) mrror mage of Fgure (c). The dmenson of standard WR-90 wavegude, slot and slot poston are shown n Table. Table : Desgn Specfcaton of Wavegude Slot Antenna Wavegude metal used Perfect conductor project metal (Thckness of metal:.7 mm) Wde sde wall.86 mm (nsde measurement) 5.40 mm (outer sde measurement) Short sde wall 0.6 mm (nsde measurement).70 mm (outer sde measurement Wavegude length 79.5 mm (left to rght) Fgure (a) Fgure (b) Slot length (L): 6mm, wdth (W): mm Offset: -3.5mm (from centre to slot centre) Left to slot dstance: 9.8 mm (centre of slot to left plate) Fgure (c) Fgure (d) Slot length (L): 6mm, wdth (W): mm Offset: -3.5mm(from centre to slot centre) Rght to slot dstance: 9.8 mm (centre of slot to rght plate) Y L X W X s Z Slot a Broad Wall b a b Narrow wall (a) Fgure : (a) Desgn parameter of Longtudnal Slot on the Broad wall of a Rectangular Wavegude, (b) HFSS Desgn Standard WR-90 Wavegude lled on a Sngle Slot (Length L =6mm and Wdth W =mm) wth Slot Offset = -3.5mm. Port (b) ISSN Bonfrng

4 Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol. 5, No. 3, October 05 5 In case-i and case-ii both port s excted n Ansoft Hgh Frequency Smulaton Structure (HFSS) envronment but n case-iii and case-iv two ports are excted and rest two ports are connected wth matched load. Fgure (a) s desgn of sngle element longtudnal slot mlled on one sde broad face of standard wavegude WR-90. Fgure (b) s a desgn vew of a sngle slot wavegude fed antenna. II. PROBLE FORULATION A. Dervaton of the Scattered Feld nsde a Wavegude due to a Longtudnal Slot on the Broad Wall of the Wavegude Fgure (b) shows a longtudnal slot of dmenson L W cut on the broad wall of a rectangular wavegude of cross secton a b and the thckness of the wavegude s t. The slot s offset from the broad wall center lne by X s. If the slot s narrow, the electrc feld E s exstng n the aperture can be approxmated as: E s = u x E x () new structure two element seres slot array planar antenna that reformed case-ii for two element longtudnal slot array wavegude fed antenna. Fgure (a) and (c) kept sde-bysde n shunt, ultmately combned make a new structure two element shunt slot array planar antenna, whch s consdered as a case-iii for two element longtudnal slot array wavegude fed antenna. Fgure (b) and (d) kept sde-bysde n shunt, ultmately combned make a new structure two element shunt slot array planar antenna, that s performed case-iv for two element longtudnal slot array wavegude fed antenna. Fgure 3: Combne Fgure (a) and (b) antenna, kept sdeby-sde n seres wth the help of HFSS of two longtudnal slots of same electrcal lengths mlled on two wavegudes for seres slot array planar antenna. and the equvalent magnetc current s s gven by: s = u x E x u y = u z E x for feld radated nto free space u x E x u y () = u z E x for feld scattered nto free space The electromagnetc feld radated by the slot nto the wavegude therefore has to satsfy the scalar Helmholtz equaton, wth source. In other words, F z + k F z = (3) The green s functon s defned by the solvng of the dfferental equaton (3), The Green s functon G x, y, z/ x, y, z s for the electrc vector potental functon of the nternal scattered feld due to longtudnal slot on the broad wall of a rectangular wavegude []. G x, y, z/x, y, z = m =0 n=0 ϵ m ϵ n 8γ mn ab + a cos nπ b y cos mπ a + b x y z e γ mn z z dx dy dz (4) B. Dervaton of reflecton Coeffcent and Transmsson coeffcent formula usng ultple Cavty odelng Technque (CT) Fgure (a) and (b) are kept sde-by-sde n the seres, ultmately combned make a new structure two element seres slot array planar antenna, consdered case-i for two element longtudnal slot array wavegude fed antenna. Fgure (a) and (d) kept sde-by-sde n seres; at last combned make a x Fgure 4: Combne Fgure (a) and (d) antenna, kept sdeby-sde n seres wth the help of HFSS, of two longtudnal slots of same electrcal lengths mlled on two wavegudes for seres slot array planar antenna. Fgure 5: Combne Fgure (a) and (c) antenna, kept sdeby-sde n parallel wth the help of HFSS of two longtudnal slots of same electrcal lengths mlled on two wavegudes for shunt slot array planar antenna. Fgure 6: Combne Fgure (b) and (d) antenna, kept sdeby-sde n parallel wth the help of HFSS of two longtudnal slots of same electrcal lengths mlled on two wavegudes for shunt slot array planar antenna. The 3D vew of a wavegude fed planar two element broad-wall longtudnal slot array antenna for case- I, case -II, case-iii, and case-iv are shown n Fgure 3, Fgure 4, Fgure 5, and Fgure 6 respectvely. Whereas the top vew of the wavegude slot antenna s shown n Fgure 7. The correspondng cavty modelng and detals of magnetc current ISSN Bonfrng

5 Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol. 5, No. 3, October 05 6 at the apertures s shown n Fgure 8. The electrc feld at the slot may be assumed to be X- drected can be expressed n terms of a sum of weghted snusodal bass functon e p,z defned over the entre length of the slot as follows: Z E x, y, z = u x p= E p,z e p,z (5) L X XW Cavty- Where, e p,z s defned as: e p,z x, y, z pπ sn z W = l + L δ y b on aperture "" 0 Elsewere (6) X W XW d Wavegude- X Where, L the length of the th slot, b the gude heght, and Z the offset of the th slot along the z-drecton of propagaton dstance It s seen from the above expresson for the electrc feld, that the feld exsts only n the y=b plane, and that s no varaton of the electrc feld n the x-drecton,.e. n the drecton of the slot wdth. The equvalent magnetc current for computng the externally scattered feld s obtaned usng equaton () as follows: e = E x, y, z u y = u z E p,z e p,z 7 Wavegude- Cavty- Wavegude- Cavty- L X W Z (a) X p= In the regon of the slot, z-component of the magnetc feld wvg H z s related to the F z as follows: W L H z wvg = jkη k + z F z (8) Z X XW Z s: And that for the evaluaton of the nternally scattered feld Z d XW Z W = E x, y, z u y = u z p= E p,z e p,z (9) Z L X Z Wth respect to the cavty and free space coordnate the aperture s centered and hence x s = 0 n the expresson of e p,z. For the domnant mode TE 0 mode exctaton n the wavegude, the ncdent y-drected electrc feld can be descrbed as: E nc y πx a e jβz (0) H nc z = E y jkη x () Wavegude- (b) X Cavty- Fgure 7: Top vew of two element slot array wth (a) seres connecton and (b) shunt connecton of planar wavegude slot antenna for two wavegudes ISSN Bonfrng

6 Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol. 5, No. 3, October 05 7 Cavty- R3 Cavty R4 - R -4 - R5 R R5 Wavegude- Wavegude- Regon R : H z cav cav (4) Regon 3 R 3 : H z ext ext 3 (5) Regon 4 R 4 : H z cav 3 cav 4 (6) Regon 5 R 5 : H z wvg 4 (7) In the regon of the slot, the tangental components of the magnetc feld should be contnuous, whch results n the followng boundary condtons: Aperture (Regon = Regon ): H z wvg cav H z cav H z nc = 0 (8) Aperture (Regon = Regon 3): H z cav cav ext ext = 0 (9) (a) Aperture3 (Regon 3 = Regon 4): Cavty- Free Space Cavty- R - - R Wavegude- R R 4 4 R 5 Wavegude- (b) Fgure 8: Detals of dfferent regons and magnetc currents at the apertures of two element planar wavegude slot antenna for (a) seres connecton (b) shunt connecton for two wavegudes. Snce from the analyss, the ncdent electrc feld can be assumed to be of any strength. For the sake of convenence, we may assume the z component of ncdent magnetc feld to be: H z nc = jsn πx a e jβz () Usng equvalence prncple, electrc feld dstrbuton the fcttous magnetc currents exstng at apertures can be obtaned. For the proposed structure, the tangental components of magnetc feld exstng at dfferent regons can be expanded as: Regon R : H z wvg nc (3) - 4 H z ext ext 3 H z cav 3 cav 4 = 0 (0) Aperture4 (Regon4=Regon5): H z cav 3 cav 4 wvg 4 = 0 () The feld components of the equaton (8) - () are gven by []: ext H z = W L ηκπ p=0 E p,z. snc κ x w e j κ x x+κ z z H wvg z = E p,z p= + a sn c pπ L m =0 n=0 j m n W ηκγ mn mπ a W cos mπ a sn pπ L z + L κ κ κ x κ κ x κ z jsn κ z L f p s even cos κ z L f p s odd pπ L k z p cos nπ + S p x + a k Z f p even cos mπ a x () + γ mn S p e γ mn L snh γ mn nπ + cosh γ mn Z f p odd cos b y + b (3) When, z = 0: H z nc = j sn πx a e jβz (4) ISSN Bonfrng

7 Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol. 5, No. 3, October 05 8 Where a s the gude wdth, t the slot/wavegude wall thckness, and cav H z = jωε κ E k mπ p,z L sn mπ L p= m =p=. + L cos nπ x + W W Γ mn sn Γ mn cos Γ mn y t cos Γ mn y + t y > y. cos Γ mn y t cos Γ mn y + t y > y z For m = p and n = 0 0 Oterwse (5) The method of moments s appled to Galerkn s specalzaton [, 3] to obtan dfferent equaton from the boundary condtons to enable the determnaton of the E p,z. The weghtng functons w q,z x, y, z are defned as follows: w q,z x, y, z qπ sn z = W l + L δ y b on aperture "" 0 Elsewere (6) For all q (q=,, 3,, ) after takng moment of l each of the terms n boundary condtons (4)-(7), wth w q,z, we obtaned a set of smultaneous equaton whch upon solvng the unknown bass coeffcents. Here, we assume that the weghtng functon defnes over a slot havng a slot length L, slot wdth W. Where, d s the dstance between the slots. The (p, q) th element of the moment matrces can be derved as follows: H nc z, w q,z = j πw q sn πx w L a H wav z, w p,z = m =0 n=0 + a sn c +. sn c πw a j m n W ηκγ mn ab mπ a W e jβz d S p S q k + γ mn γ mn e γ mn + S q cos nπ + S p cos βl for q odd j sn βl for q even β qπ (7) L k pπ L snh γ mn Z f p,q both even cos mπ a δ pq L x w + cosh γ mn Z f p,q both odd 0 otherwse 8 H cav z, w p,z = jωεlw κ E p,z k mπ L p= m =p= sn mπ L + L cos nπ x + W W Γ mn sn Γ mn cos Γ mn y t cos Γ mn y + t y > y m = p = q cos Γ mn y t cos Γ mn y + t y > y and n = 0 0 Oterwse (9) ext H z e pz, w q,z vsble regon = 6W L λ η π/ θ=0 π φ=0 sn θ cos φ snc (Wk snθsnφ) sn Lksnθsnφ for p, q bot are even cos Lksnθsnφ for p, q bot are even 0 oterwse pπ qπ Lksnθsnφ Lksnθsnφ pπ qπ snθdθdφ (30) ext H z e pz, w q,z nvsble regon = 6W L λ η π/ θ=0 π φ=0 cosh θ cos φ snc (Wk cosh θ snφ) sn Lk cosh θ snφ for p, q bot are even cos Lk cosh θ snφ for p, q bot are even 0 oterwse pπ qπ Lk cosh θ snφ Lk cosh θ snφ pπ qπ cosh θ dθdφ (3) Rewrtng equaton n the matrx form, for all p and q: Y Y Y Y E E p, z p, z nc h z 0 z (3) Once the admttance matrx s calculated by equaton (3) then easly calculated the mpedance matrx because mpedance matrx s the recprocal of admttance matrx. After calculatng mpedance matrx, the reflecton coeffcent Γ or and Transmsson coeffcents T or S at z=0 plane are obtaned as []: Γ = π W sn πx 4 a 3 b ηκ β a snc πw a p= E p,z S p +S p jsnh βl f p even cosh βl f p odd (33) ISSN Bonfrng

8 agntude of Transmsson Coeffcent agntude of Reflecton Coeffcent Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol. 5, No. 3, October 05 9 T = + π W 4 a 3 b ηκβ sn πx a E p,z p= S p + S p Where, S p = III. pπ L γ mn snc πw a jsnh βl f p even cosh βl f p odd NUERICAL RESULT AND DISCUSSION (34) (35) On the pre bass of the problem formulaton, ATLAB codes have wrtten to compute the reflecton coeffcents and transmsson coeffcents of the dfferent case structures and compared wth HFSS smulated data n Fgure 9 (a) and Fgure 9 (b) over an entre X-band (.e. 8.GHz~.4GHz) operaton. Fgure 9 shows that excellent agreement between theoretcal CT data and Ansoft HFSS smulated data to valdate the proposed CT methodology. The result ndcates that proposed methodology able to solve reflecton and transmsson coeffcent for four dfferent cases of longtudnal slots of same electrcal lengths mlled on two wavegudes for seres and shunt slot array planar antenna. After valdatng the analyss, computed the total gan data over the range of 8.GHz~.4GHz by the usng Ansoft HFSS software when cut off frequency/ soluton frequency s 0GHz for four dfferent cases are shown n Fgure 0. In ths fgure case-iii and case-iv mantans a hgh gan (more than 5dB) n entre X-band and total gan s reached up to 7.7dB at 0 GHz n both cases. However case-i and case-ii does not mantan hgh gan n an entre X-band, but total gan s reached up to.5db at 0GHz frequency n both cases. In case-i total gan characterstcs shown n Fgure0 that at 8.GHz~8.4GHz, 8.8GHz~.GHz,.7GHz~.4GHz frequency band antenna s workng because of ths reason total gan consdered more than 0dB. Therefore, we can say that case-i antenna s workng n multband n nature wthn the X - band. In case-ii total gan graph characterstcs show that at 8.GHz~9.GHz, 9.GHz~0.8GHz and.ghz~.4ghz frequency band antenna s workng because of ths reason total gan s more than 0dB. Therefore, we can say that case II antenna s performed as multband n nature. In case-iii total gan graph characterstc shows that at 8.GHz~.4GHz frequency band antenna s workng because of ths reason total gan s more than 5dB and maxmum total gan s reached up to 8.dB at 9.4GHz frequency. Therefore, we can say that case-iii antenna s also workng n sngle band wth the entre coverage of X-band. In case-iv total gan graph characterstc shows that at 8.GHz~.4GHz frequency band antenna s workng because of ths reason total gan s more than 5dB and maxmum total gan s reached up to 7.9dB at.4ghz frequency. Therefore, we can say that case-iv antenna s also workng n sngle band wth the entre coverage of X-band Frequency [GHz] (a) (b) HFSS for case-iv CT for case-iv HFSS for case-iii CT for case-iii HFSS for case-ii CT for case-ii HFSS for case-i CT for case-i Frequency [GHz] S CT for case-iv S HFSS for case-iv S CT for case-iii S HFSS for case-iii S CT for case-ii S HFSS for case-ii S CT for case-i S HFSS for case-i Fgure 9: Theoretcal and smulated (a) agntude of Reflecton Coeffcent (b) agntude of Transmsson Coeffcent of scatterng parameter analyss of dfferent cases of seres and shunt slot array antenna n X-band frequency. ISSN Bonfrng

9 Gan Total [db] Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol. 5, No. 3, October Fgure 0 : Smulated total gan of dfferent cases of two element seres and shunt slot array planar antenna n X-band frequency. IV. Gan total for case-iv Gan total for case-iii Gan total for case-ii Gan total for case-i Frequency [GHz] CONCLUSION Ths paper presents a study of scatterng parameters two longtudnal slots of same electrcal lengths mlled on two wavegudes for seres and shunt slot array planar antenna. The methodology has been verfed usng Ansoft HFFS smulated data. The antenna provdes gan hgh as.5db n both case-i and case-ii, 8.dB n case-iii, 7.9dB n case-iv. The case-i and case-ii antenna works n multple band wthn n X-band. The case-iii and case-iv antenna works n sngle band entre coverage of X-band. It could be noted that geometrcal parameters (.e. Length, wdth, poston and offset of the slots) are not optmzed. Here our am was only to show that two longtudnal slots of same electrcal lengths mlled on two wavegudes n seres create mult-band and two longtudnal slots of same electrcal lengths mlled on two wavegudes n shunt creates sngle band. At last, the case-i and case-ii s applcable for mult frequency selectve devce for communcaton whle, the case- III and case-iv s applcable for long dstance data communcaton. Conclusvely, ths paper ndcates that two longtudnal slots of same electrcal lengths wavegude shunt slot planar antenna behaves as a sngle band and two longtudnal slots of same electrcal lengths wavegude seres slot planar antenna behaves as a multple band characterstcs wthn X-band. ACKNOWLEDGENT The research and software support provded by the Department of Electroncs & Communcaton Engneerng, NIT, Jamshedpur, and Department of Electroncs Engneerng, IS, Dhanbad s gratefully acknowledged respectvely. REFERENCES [] R. S. Ellot and L. A. Kurtz, The Desgn of Small Slot Arrays, IEEE Transactons on Antennas and Propagaton, Vol. 6, Issue, Pp. 4 9, 978. [] R. S Ellott, Improved Desgn Procedure for Small Arrays of Shunt Slots, IEEE Trans. Antennas Propagaton, Vol. 3, Pp , 983. [3] S. Gupta, Electromagnetc Feld estmaton n Aperture and Slot Antennas wth ther Equvalent Network Representaton", Ph.D. Dssertaton, Department of Electroncs & Electrcal Communcaton Engneerng, I.I.T. Kharagpur, Inda, 996. [4] S. Edelberg and A. A. Olner, utual Couplng Effects n Large Antenna Arrays Part I Slot Arrays, IRE Transactons on Antennas and Propagaton, Vol. 8, Issue 3, Pp , 960. [5] B. N. Das and G. S. Sanyal, utual Impedance between two Resonant Slot Radators, Proceedngs of the Insttuton of Electrcal Engneers, Vol. 8, Issue, Pp , 97. [6] R. S. Ellot, On the Desgn of Travellng Wave Fed Longtudnal Shunt Slot Arrays, IEEE Transactons on Antennas and Propagaton, Vol. 7, Issue 5, Pp , 979. [7] R. S. Ellot and W. R. O Loughln, The Desgn of Slot Arrays, ncludng Internal utual Couplng, IEEE Transactons on Antennas and Propagaton, Vol. 34, Issue 9, Pp , 986. [8]. Grabowsk, Analyss of an Internal utual Couplngs nfluence on a Radaton Pattern of a non Resonant ult Slot Wavegude Array Antenna, IEEE Antenna and Propagaton Socety Internatonal Symposum, Vol. 4, Pp. 39 3, 986. [9] G. azzarella and G. Panareallo, On the Evaluaton of utual Couplng between Slots, IEEE Transactons on Antennas and Propagaton, Vol. 35, Issue, Pp.89 93, 987. [0] S. R. Rengarajan and E. Gabrelan, Effcent and Accurate Evaluaton of External utual Couplng between Broad Wall Compound Slots, IEEE Transactons on Antennas and Propagaton, Vol. 40, Issue 6, Pp , 99. [] A. J. Sangstar and H. Wang, Resonance Propertes of Omndrectonal Slot Doublet n Rectangular Wavegude, Electroncs Letters, Vol. 9, Issue -, Pp. 6-8, 993. [] A. J. Sangstar and H. Wang, oment ethod Analyss of a Horzontally Polarzed Omndrectonal Slot Antenna, IEE Proceedngs on crowaves, Antennas and Propagaton, Vol. 4, Issue, Pp. 6, 995. [3] A. Bastan and J. Rashed-ohassed, Analyss of Planar Slotted- Wavegude Array Antennas wth Longtudnal Slots usng the ethod of oments", IEEE Antennas and Propagaton Socety Internatonal Symposum, Vol., Pp.9-3, 004. [4] P. ondal and A. Chakraborty, Equvalent Crcut Representaton of Wavegude Slot Doublet, Natonal Symposum on Antennas and Propagaton, Pp. 4, 006. [5] P. ondal and A. Chakraborty, Slotted Wavegude Antenna wth two Radaton Nulls, IEEE Transactons on Antennas and Propagaton, Vol. 56, Issue 9, Pp , 008. [6] Rntu Kumar Gyan and Sushrut Das, Resonance and Parametrc Analyss of Planar Broad-Wall Longtudnal Slot Array Antennas, Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol., No.3, Pp.3-0, 0. [7] Rntu Kumar Gyan and Sushrut Das, A Hgh-Gan Broad-Band Wavegude Longtudnal Slot Array Antenna, Progress n Electromagnetcs Research C, Vol. 44, Pp.39-49, 03. [8] Hare Ram Jha and Shva Nand Sngh, Desgn and Analyss of Wavegude-Fed Broad-Wall Longtudnal Log Perodc Slotted Array Antenna for 8. ~. GHz Frequency Applcatons, Internatonal Journal of Advanced Engneerng Research and Scence, Vol., Issue.6, Pp.5-4 Nov. 04. [9] Rntu Kumar Gyan and Sushrut Das, oment ethod Analyss of Standard and Reduced Heght Broad-Wall Longtudnal Slot Doublets n Rectangular Wavegudes, Internatonal Journal of Electroncs & Communcaton Technology, Vol. 6, Issue, Spl-, Pp. -8, 05. [0] John D Kraus and Ronald J. arhefka, Slot, Patch and Horn Antenna, Antennas for all Applcaton TH 3 rd Edton, Pp-304, 003. [] Davd Pozar, crowave Engneerng, John Wley & Sons (Asa) Pte Ltd, nd Edton, Pp.-04, 998. [] S. Das, Analyss of Rectangular Wavegude Based Passve Devces and Antennas usng ultple Cavty odelng Technque, PhD Dssertaton, Department of Electroncs & Electrcal Communcaton Engneerng, I.I.T. Kharagpur, Inda, 007. ISSN Bonfrng

10 Bonfrng Internatonal Journal of Research n Communcaton Engneerng, Vol. 5, No. 3, October 05 [3] R. F. Harrngton, Feld Computaton by oment ethods, Roger E. Kreger Publshng Company, USA, Pp. 5-7, 993. Hare Ram Jha was born n Bara Vllage, Saharsa Dstrct, Bhar, Inda, n 980. He had completed hs B.Sc. Engneerng n Electroncs & Communcaton Engneerng at the R. P. Sharma Insttute of Technology, Patna, Bhar, Inda (afflated to agadh Unversty, Bodh-Gaya, Bhar, Inda) n 007. From 007 to 008 he was a Lecturer n Electroncs & Communcaton Engneerng at the R. P. Sharma Insttute of Technology, Patna, Bhar, Inda. After that, from 009 to 00 he was a Lecturer n Electroncs & Communcaton Engneerng at the Ram Govnd Insttute of Technology, Koderma, Jharkhand, Inda. Then after from 0 to 04, he has been a lecturer n Electroncs & Communcaton Engneerng Department at Natonal Insttute of Technology, Jamshedpur, and Jharkhand, Inda. Presently he s workng as a Research Scholar at Natonal Insttute of Technology, Jamshedpur, Jharkhand, Inda. In hs area of specalzaton, he s nterested n Electromagnetcs, crowave, Antenna and Wave Propagaton. He has publshed one artcle n natonal conference and three artcles n Internatonal Journal. (Emal:hrjha.ece@ntjsr.ac.n) Shva Nand Sngh obtaned hs Bachelor of Technology degree n Electroncs and Communcaton Engneerng from BIT esra (a Deemed unversty), Ranch, Jharkhand, Inda n 980 and the.sc. Engneerng degree n Electrcal Engneerng from Ranch Unversty, Jharkhand, Inda, n 99. After that he had receved PhD degree at the Department of electrcal engneerng, Natonal Insttute of Technology, Jamshedpur, Jharkhand, Inda. He has publshed more than 50 papers n Natonal and Internatonal journals based on hs research work. He has been Co-ordnator of Govt. of Inda sponsored VLSI SDP-II Project of Natonal Insttute of Technology, Jamshedpur, Jharkhand, Inda. Presently, he s the head of department of Electroncs and Communcaton Engneerng, Natonal Insttute of Technology, Jamshedpur, Inda. (E-mal:snsngh.ece@ntjsr.ac.n) ISSN Bonfrng