Path-Loss Exponents of Ultra Wideband Signals in Line-of-Sight Environments

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1 480 F UWB UWB shunsuke@grace.c.enai.ac.jp UWBultra wieban UWB 2 UWB 2 (1)UWB 2 (2)UWB 2 4 (3) UWB 2 Path-Loss Exponents o Ultra Wieban Signals in Line-o-Sight Environments Shunsuke SATO an Takehiko KOBAYASHI Grauate school, Tokyo enki University 2-2 Kana-nishiki-cho, Chiyoa-ku, Tokyo , Japan UWB Technology Institute, Communications Research Laboratory shunsuke@grace.c.enai.ac.jp Abstract Ultra wieban (UWB) technology is expecte to realize high-spee communication, high-resolution raars, precise geolocation, an other applications. It is also to expect evelop substantially new spectrums resource, i the UWB evices can share the requency spectra with the incumbent narrowban wireless systems. Whereas inoor an short-range propagation characteristics o UWB signals have been intensively stuie, the longer range UWB propagation neee to investigate the electromagnetic compatibility between the narrowban an UWB systems has not yet been precisely characterize. This report proposes a new UWB line-o-sight path loss ormula base on the conventional narrowban two-path (irect an groun relecte waves) moel, taking into account the banwith o signals. The ollowing results are erive rom numerical calculations: (1) UWB signals suer less intererence aing then narrowban signals; (2) UWB path loss exponents change 2 to 4 aroun a breakpoint; an (3) the breakpoint istance epens on the transmitting an receiving heights, the arithmetic average by wavelength o lowest an highest requency, an banwith. Inoor experimental results veriie the valiity o this new ormula. Keywors Ultra wieban, path-loss exponent, two-path moel, breakpoint

2 1. Transmitting Receiving irect wave UWB(ultra wieban) Relecte wave UWB WPAN(wireless personal Plane groun area network) 1 2 UWB Fig. 1. Two-path moel. 1 UWB 2 2 2π l L = 10 log 1 + γ + 2γ cos + φ (1) 4π ITU-R Task Group 1/8 EMC UWB ITU-R SG3 [1] UWB (1) l = 2 >> h T,h R ITU-R TG1/8 2 m UWB 2hT l (2) 2 m 2, 4 >> h T,h R γ 1φ π [2] ITU-R Rec. P.1411[3] UHF SHF 2 UWB 1 km 2 [4] UWB UWB 2 [6] 4hT = (3), 1020 B [7] [B] [8] πhT 2 1 b = (4) 1 m FCC L [B] UWB [9] h T h R 3.1GHz 10.6 GHz (CW)2 γ exp(jφ) (1) [5][6]

3 Path loss [B] Two-path moel (3.1 GHz) irect wave only (3.1 GHz) Two-path moel (10.6 GHz) irect wave only (10.6 GHz) h T, Lbp = 20 log 8πh T h T =h R =1 m =3.1 GHz 10.6 GHz Fig. 2. Path loss vs. istance calculate with the (6) > two-path moel an irect wave only. h T =h R =1 m, > requency=3.1 an 10.6 GHz. 1 2 b Table 1 an b calculate with the two-path moel. 3. UWB 2 Frequency b 3.1 GHz 41.6 m 64.9 m 3.1. UWB GHz 142 m 222 m UWB (1) 2 b = 10 log L π l L 1 + γ + 2γ cos + φ (7) UHF SHF L H H 4π [10]ITU-R [3] SHF γ γ =1φ =π, (7) 1 m FCC UWB GHz 3 ( ht h)( h) = 4 (5) GHz m h m m [GHz] [3][10] m 2.2. UWB 2 [2] 2 m UWB 2m 2, 4 2 m [4] = 2 4 Path Loss = L 20 log + 40 log > bp (6) 4

4 Path loss [B] Propose two-path moel irect wave only Path loss [B] Banwith = 75 GHz Banwith = 7.5 GHz Banwith = 750 MHz Banwith = 75 MHz CW 3 UWB 2 ((7)) UWB h T =h R =1 m = GHz Fig. 3. Path loss vs. istance calculate with the UWB two-path moel (Eq. (7)), h T =h R =1 m, requency = 3.1 to 10.6 GHz UWB 2 ((7)) 3.1 GHz UWB h T =h R =1 m Fig. 4. Path loss vs. istance or various banwiths starting rom 3.1 GHz calculate with the UWB two-path moel (Eq. (7)), h T =h R =1 m. (7) 3.1 GHz 2 b 1 Table 2 Breakpoint istance an path loss exponents 4 Banwith Breakpoint Path loss exponent [GHz] istance [m] < b >> b = 75 MHz CW Lowest requency = 3.1 GHz. (3) 1.6 (4) UWB (3) (4) 1.4 L ( [8] 4 L + H )/2 1.2 ( 4 L H ) 1/2 1 Η GHz 0.6 1GHz (4) ( Breakpoint istance 2π h T h R ) Banwith[GHz] Fig. 5. breakpoint istance vs. banwith. The lowest FCC requency = 3.1 GHz 3.1 GHz 6.0 GHz

5 0.1 m 0.1 m Breakpoint istance 2π h T h R ( L + H )/ Banwith[GHz] 6 8 UWB UWB 2 ( (7)) Fig. 8. Comparison o the UWB path loss Fig. 6. breakpoint istance vs. banwith. The lowest measurements an the UWB two-path moel. (Eq. (7)). requency = 3.1, 6.0 an 22.0 GHz Transmitting L = 3.1 GHz L = 6.0 GHz L =22.0 GHz VNA Receiving Path loss [B] UWB (Eq. (7)) CW (3.1GHz) CW (10.6 GHz) Measurements 0.5 m >0.5 m m b =0.97 m UWB UWB 2 8 b = 0.97 m b =0.97 m 4 UWB 2. Fig UWB 5. Ultra wieban path loss measurement setup. 3 Table 3 Parameters o UWB path-loss measurements. Frequency GHz Polarization Vertical Transmitting an receiving ouble-rige waveguie s horn s Transmitting an receiving heights 0.1 m (h T an h R ) 4. UWB 2 (1)UWB 2 (2)UWB 2 4 (3) 7 (VNA) S 21 UWB [1] ITU-R oc. 3K/66-E, Liaison statement to working 3 parties 3K an 3M Propagation moels or UWB compatibility stuies, Jan. 30, mm85 mm [2] ITU-R oc. 1-8/047-E, Chairman, ITU-R Task Group 1-8, Report o the irst meeting Task group R=2 2 / [11]1-8, Geneva, January 2003, March 28, 2003.

6 [3] ITU-R Rec. P , Propagation ata an preiction methos or the planning o short-range outoor raiocommunication systems an raio local area networks in the requency range 300 MHz to 100 GHz, [4] ITU-R oc, 1-8/32-E, Protection istance or UWB intererence, Jan 16, [5] K. Bullington, Raio propagation or vehicular communications, IEEE Trans. Veh. Tech., vol. VT-26, no. 4, pp , Nov [6] W. C. Y. Lee, Mobile Communications Engineering, pp , New York, McGraw Hill, [7] K. Siwiak, Raiowave Propagation an Antennas or Personal Communications, pp , Boston, Artech House, [8], pp ,, [9] FCC News, New public saety applications an broaban internet access among uses envisione by FCC authorization o ultra-wieban technology, Feb. 14, [10] H. Masui, T. Kobayashi, an M. Akaike, Microwave path-loss moeling in urban line-o-sight environments, IEEE J. Select. Areas Commun., vol. 20, no. 6, pp , August, [11], pp ,, 1980.

Experimental Evaluation Scheme of UWB Antenna Performance

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