, Circularly Polarized Patch Antennas Combining Different Shaped Linealy Polarized Elements Takanori NORO,, Yasuhiro KAZAMA, Masaharu TAKAHASHI, and Koichi ITO 1. GPS LAN 10% [1] Graduate School of Science and Technology, Chiba University, Chiba-shi, 263 8522 Japan Japan Radio Co., Ltd., Mitaka-shi, 181 8510 Japan Japan Aerospace Exploration Agency, Sagamihara-shi, 229 8510 Japan Research Center for Frontier Medical Engineering, Chiba University, Chiba-shi, 263 8522 Japan Graduate School of Engineering, Chiba University, Chibashi, 263 8522 Japan [2] 2 90 [3] 10% [4][6] [7][9] [4], [5] 0.5λ [6] 90 2 8% 2dB 90 G/T B Vol. J91 B No. 5 pp. 595 604 c 2008 595
2008/5 Vol. J91 B No. 5 [7], [8] [10] [9] % [11] % 10% 2. 3. 4. 5. 3. 6. 2. 1 1 AL 1 1 AL 2 (Pcut) ε r=1 Ensemble [12] 1 3. 3. 1 [11] (a) Top view (b) Side view 1 Fig. 1 Geometry of proposed circularly polarized patch antenna. 1 Table 1 Fundamental antenna parameters. Length and width of excited patch AL 1 89 mm Length and width of parasitic patch AL 2 73 mm Chamfered depth Pcut 35 mm Distance between excited patch and GND TL 8mm Distance between excited and parasitic patch TH 10 mm 596
(a) Top view (b) Side view 2 Fig. 2 Geometry of conventional corner-truncated patch antenna. 2 2 I 1I 2 I 1I 2 f 1 f 2f 1f 2 f o f 2 f 1 /f o Q f o Q Q 2050 25% 2 1 (TL = 8 mm) 1.6 GHz Q 10 ΔS/S Q =0.5 ΔS/S =5% [11] ΔS/S =15.5% 3. 2 1 1 3 3 Fig. 3 Calculated frequency response of axial ratio. 1 3 3dB 12% 1.55 GHz (f alower ) 1.66 GHz (f aupper) 1.6 GHz (f acenter) 0.17 db0.20 db f alower f aupper f acenter 4. 2 1 4. 1 4 12.5 GHz 1.46 GHz1.98 GHz 30% 597
2008/5 Vol. J91 B No. 5 (a) t =0 (b)t = T/4 4 Fig. 4 Frequency response of return loss. (excited patch only) (c) t = T/2 (d) t =3T/4 6 Fig. 6 Time variation of currents on excited patch. (excited patch only) (a) Frequency: 1.46 GHz (b) Frequency: 1.55 GHz (c) Frequency: 1.60 GHz (d) Frequency: 1.66 GHz (e) Frequency: 1.76 GHz (f) Frequency: 1.98 GHz 5 Fig. 5 Current distributions on excited patch. (excited patch only) 4. 2 5 4 1.46 GHz1.98 GHz 3 1.55 GHz 1.66 GHz 1.6 GHz 1.66 GHz 1.98 GHz 1.76 GHz 5(a) (f) 1.46 GHz 1.98 GHz 1.46 GHz 2 I 1 1.98 GHz I 2 5(b)(e) (b)(d) 1.6 GHz 6 3 1.6 GHz 11 db 4. 3 7 I 1 I 4 [11] P 1 598
7 Fig. 7 Schematic of currents on proposed patch antenna. (a) Amplitude (a) Amplitude (b) Phase difference 9 P1P2 I1-I4 Fig. 9 Calculated frequency response of current I1-I4 at observation point P1 and P2. (b) Phase difference 8 P1 I1I2 Fig. 8 Calculated frequency response of current I1, I2 at observation point P1. P 2 P 1 7 8 9(a) I 2 8(a) I 1 f 1 =1.44 GHz I 2 f 2 =1.9GHz f 1 f 2 4.2 I 2 1.4 GHz I 1 1.44 GHz I 1 8(b) I 1 I 2 3 3dB 1.51.7 GHz 150 TH 9 8 9(a) I 2 I 1 I 4 7 I 1 1.4 GHz 1.7 GHz I 2 1.9 GHz 2.1 GHz I 1 I 2 I 1 1.51.7 GHz I 1I 2 1.54 GHz I 1 I 2 107 599
2008/5 Vol. J91 B No. 5 10 t Fig. 10 Loci of elliptical waves radiated from excited and parasitic patch and of their superposition. I 3 I 1 1.7 GHz I 4 1.7 GHz I 3 I 2 1.54 GHz I 3 I 4 114 P1 I 1I 2 P2 I 3I 4 9 P1 3 1.54 GHz 10 2.7 db 4.4 db P2 P1 βth 3 11 Fig. 11 Schematic of currents on proposed patch antenna. 11 I ai b I ci d I ci d I ai b 9(a) I 1I 2 I ci d I 3I 4 I a I b I a I b I ci d I ci d I ci d I ci d (I a + I c)(i b + I d) 7 I 1 (I a + I c) 1.44 GHz 1.7 GHz I 2 (I b + I d) 1.7 GHz 1.9 GHz 2.1 GHz 1.7 GHz (I a + I c) I a I b I c I d I ci d 600
I a I c I b I d f a f b f a >f b 2(f a f b )/(f a + f b ) 9 I 1 I 3 C 13I 2 I 4 C 24 C 13 =0.19C 24 =0.21 I 1 I 2 I 3( C 13I 1) I 4( C 24I 2) I a I c I b I d 5. 12 2 2 1 0.5 mm 200 mm 12 Fig. 12 Photograph of fabricated antenna. 2 Table 2 Fabricated antenna parameters. Length and width of excited patch AL 1 87 mm Length and width of parasitic patch AL 2 71 mm Chamfered depth Pcut 35 mm Distance between excite patch and GND TL 8mm Distance between excite and parasitic patch TH 10 mm 13 VSWR Fig. 13 Measured and simulated VSWR. VSWR 13 1.51.7 GHz VSWR 90 180 1.51.7 GHz VSWR 601
2008/5 Vol. J91 B No. 5 (a) Measured and simulated gain (a) φ =0 (b) Measured and simulated axial ratio 14 Fig. 14 Measured and simulated antenna gain and axial ratio. 14 3dB8.9 dbi 1.66 GHz φ =0 φ =90 15 θ =90 270 θ =0 3dB φ =0 59 φ =90 60 φ =0 67 φ =90 68 3dB φ =0 96 φ =90 71 φ =0 109 φ =90 93 3dB 3dB (b) φ =90 15 Fig. 15 Measured and simulated radiation patterns. 6. 12% 3dB 602
[1] (http://www.jrc.co.jp/) Fleet F77 Maritime Satellite Communication Terminal. [2] J.D. Kraus, Antennas, McGraw-Hill, N.Y., 1959. [3] J.Q. Howel, Microstrip antennas, IEEE Trans. Antennas Propag., vol.ap-23, no.1, pp.90 93, Jan. 1975. [4] 4 Bvol.J65-B, no.10, pp.1267 1274, Oct. 1982. [5] H. Nakano, H. Tanaka, T. Honma, H. Mimaki, and J. Yamaguchi, Low-profile helical array antenna fed from a radial waveguide, IEEE Trans. Antennas Propag., vol.40, no.3, pp.279 284, March 1992. [6] Bvol.J68-B, no.4, pp.515 522, April 1985. [7] A P81-102, Nov. 1981. [8] T. Teshirogi, M. Tanaka, and W. Chujo, Wideband circularly polarized array antennas with sequential rotations and phase shift of elements, Proc. Int. Symp. on Antennas and Propagat., vol.i, pp.117 120, Japan, Aug. 1985. [9] 2 Bvol.J65-B, no.2, pp.238 243, Feb. 1982. [10] J.R. James and P.S. Hall, eds., Handbook of microstrip antennas, Peter Peregrinus, Ltd., London, 1989. [11] Bvol.J63-B, no.6, pp.559 565, June 1980. [12] Ansoft, Ansoft Ensemble user s Manual. A 1 TL Fig. A 1 Simulated axial ratio vs. spacing between excited patch and ground plane, TL. A 2 TH Fig. A 2 Simulated axial ratio vs. spacing between excited patch and parasitic patch, TH. 1 A 1 A 5 1 TL f alower 2 TH f aupper 3 Pcut f acenter 4 AL 1 A 3 Pcut Fig. A 3 Simulated axial ratio vs. chamfered length of excited patch, Pcut. 5 AL 2 603
2008/5 Vol. J91 B No. 5 51 53 11 55 19 IEEE A 4 AL 2 (AL 1 = 89 mm) Fig.A 4 Simulated axial ratio vs. length and width of parasitic patch, AL 2 (AL 1 = 89 mm). 6 12 16 16 RLSA IEEE A 5 AL 2 (AL 1 = 95 mm) Fig.A 5 Simulated axial ratio vs. length and width of parasitic patch AL 2 (AL 1 = 95 mm). A 1 A 5 19 9 4 12 17 49 51 54 9 15 17 18 19 IEEE AP-S Distinguished Lecturer AdCom IEEE FellowAAAS 8 10 10 IEEE 604