Design of Compact Dual-Band Microstrip Patch Antenna

Design of Compact Dual-Band Microstrip Patch Antenna for GPSK-PCS Operation Ho-yong Kim', Yong-nn Lee, Chung-ho Won, Hong-min Lcc Department of Electronics [email  protected] Univerrily hi-Dong, Yeongtong-Cu, Suwon-Si, Kyonggi-do, Korea email: [email  protected] com lnlraduetion In recent years, with the advance o f technology, the demand for an antenna operating a1 mutibands i s increasing rapidly. Such as GPS and K-PCS, The multi-hand antennas with one feeding pon use the multiple resonance technolagy[l] such antennal are difficult lo provide a good polarization efficiency for GPS signal reception. So the integrated GPSIK-PCS dual-band antenna using two feeding pan has been proposed in this paper. Referenced dual-band antenna using two feeding pon has matched poiariration of integrated system. [2] but it has large size. Proposed antenna uses miniafurizalion technique that is to insect ilits. This technique is to increase elecVlcal surface length by slits. [3-5] Operating frequency o f proposed Bntenna is greatly lowered by slit^. Meander line patch and square ring patch with four diu o f proposed antenna are about 70% and 50% ofreferenced antenna size. The proposed antenna composed of a low-profile cylindrical monopole with a top-loaded meander line patch for K-PCS Operation, and a comer-truncated square-ring microstrip patch antenna with four-slits for GPS ooeration. Pmposed Antenna Design The geometry and design parameter of the proposed antenna for compact GPSIK-PCS operation i s presented in Figure I. The proposed antenna has the common ground plane, but i s fed by separate feeding pon. The antenns for GPS-hand i s realized by using a corner-truncated square-ring microstrip patch with four slits. The outer side length and inner ride length are40mm(L,)and IZmm(&) ~ ~ p % t i d printed on a rubrtrale o f thickness 1. 6mm(h) and y, relative peminiviry (e, :4. 4). The middle ofthe substrate is removed for inner rectangular d i t area ( b x b ) of patch. Feed position for right-hand circularly polarized (RHCP) wave operation is placed along x-axis. and the distance of the probe feed away fram the patch center i s denoted as 6 . 6 m m ( / ) . The four-rlitr at the comers are of equal length I3. 5mm(S)and width Imm(w). Fig 2(a) shows simulated reNm loss of the proposed anlenna for GPS receiving antenna with various d i t lengths(S). It i s noted that the reSonant frequency rapidly lowered with increasingdesign parameter(S). In f h i ~ way, the excited surface current paths are lengthened in the propo~ed designs, and the operating frequency is greatly lowered. 0-7803-8302-8/04/$20. 00 IEEE 3529 02004 Also, the shorted meander line patch antenna with low-profile cylindrical monopole top is loaded at the center of square ring patch for K-PCS operation. For brbadband characteristic, cylindrical monopole has a large diameter of 6. 2mm(d,) and l e n ~ h 10. 7mm(h2). The eander line patch has a ride lengh Z l m m ( p ) and is connected to the common ground by two same shorting posh, which have a diameter of 2. 2mm(d2). By varying ofthe shorting ports diameter(d2), good impedance matching can easily be obtained. Figure 2(b) shows simulated retum loss for the p r a p ~ ~ e d K-PCS antenna with various slit lengthr(m,) of meander line patch. Meander line patch size can be reduced by increasing inserted slit length. Becaus e of the antenna for K-PCS operation interfere the axial mtio of GPS receiving antenna, the miniatufimion of GPS antenna is limited. According to the experiment, the patch size of GPS antenna for circular polarized operation must he over about twice the size of KPCS antenna with meander line suunurc. In the proposed designs, the bandwidth of3-dB axial mtio is about 13 MHz, which is much larger than that required for GPS operation at 1575 MHz. The measured axial ratio ofthe antenna for GPS operation i s presented in Figure 3. Figure 4 shows measured re† 101 of proposed antenna. The impedance bandwidths (. lOdB retum larr) are about lZOMH~(1744MHr-1864MH~)far K-PCS band and 60MHr (IS46MHr-1606MHz) for GPS-band. The isolation between the two feeding pons of the PCS and GPS elemenls is less than -17dB. Measured radiation panems of the proposed antenna at l8OOMHz and ISROMHz are presented in Figure 5 and 6, respectively. The K-PCS antenna radiation panem at IROOMHz shows a monopole radiation panem, 10 this fype of antenna is suitable for applications on a vehicular communication system. For the GPS anfenna at ISROMHz, good broadside band radiation panem is obtained. Far K-PCS operation the measured pea* antenna gains is about 2. 4dBi and t h c gain variations are within O. JdBi, for GPS operation the measured peak antenna gains is about 7. dBi and the vanations of gain does not exist. Conclusion Proposed antenna has a integrated slmcturc of microitrip patch antenna with two feeds for dual-band oprmtion(GPSiK-PCS). A low-profile cylindrical monopole with a shorted meander line patch i s loaded for K-PCS operation, which rhowr a linearly polarized monopole patkm with broadband characterirlic. Th e radiating clement for GPS operation is a novel square-ring microstip path with truncated comers with four slits, which provide circularly polarized braadrids radiation panemr. size reduction of proposed antenna is achieved by using slits. Meander line patch and square ring patch with four . lib of proposed antenna are about 70% and SO% of referenced antenna sire. As the proposed antenna has a compact size for dual band operation, it will be suitable for practical vehicular mobile communication antenna applications. R&E†Ce [I] R. Kronberger, H. Lindenmcier, L. Reiter, J. Hapf, † Multi hand planar Invencd-F C r a Antenna for Mobile Phone andGPS,†2714p-Z717p,AP confer. 1999 3530 [2] I. Y. Wu and K. L. Wong, â€Å"Two inlegraled stacked shorted patchantennas for DCSiGPS operations,† Micra wave Opt. Techno1 . Len. , Vol. 30. July, 2001. I31 S. Reed, L. Desclar, C. Terref, and S. Toutain, â€Å"Patch Antenna Size Reduction By Means Oflnductive Slots,† Micro wave Opt. Teehnol. Len. ,Vol29. Apri, 2001. 1 [41 J. Y. Wu and K. L. Wong, â€Å"Single-feed Square-ring Microstip Antenna wilh lruncated comers for Compact ~ircularpolarization Operation,† Electronics lea. , Vol. 34, May,1998. [ 5 ] W. S. Chen, C. K. Wu, and K. L. wong. I' Novel Compact Circularly polarized Square Microstrip Antennq† IEEE Trans. ,Antennas Propagat. , Vol. 49, March, 2001, L, = 40mm, L, = 12mm, S = 13. 5mm, t = 5. 74mm. IY = I n † f = 6. 6†³. p = Zlmnr, m, =ZOmm, ml =3. mm, d) = 6. 2mm, d* = 2. 2†³. d, =9. 3mm h, = 1. 6mm. h2 =10. 7mm Fib. 1. Geomelly and dimiiiimi ofthe pmpanrd a n t m i l for CPSIK-PCS operation. (a) The variation against parameter S (b) The variation againsl parmnster m, Fig. 2. Simulated return loss wilh v~riour ImgthsiS) nnd vsriour slit lengthsim,). slit 3531 I E 4 , d B ! -2 1. 560 1. 565 1. 570 1. 575 1. 580 .† -15 FrequanollGHz , I . 1. 5 2. 0 ~r4†³enwffi~ 2. 5 Fig. 3. The measured arid ratio. Fig 1 Measured r t b m loss of antenna. . (a) x-2 plane @) x-Y plane Fig 6. Measured radiation panem for GPS operation; f=1580MHz 3532