1、 ITU-R RECMN*fl= $091 74 4855212 0523667 TI0 66 RC ITU-R M.1091 RECOMMENDATION ITU-R M.1091 REFERENCE OFT-AXIS RADIATION PATTERNS FOR MOBILE EARTH STATION ANTENNAS OPERATING IN THE LAND MOBILESATELLITJC SERVICE IN THE FREQUENCY RANGE 1 TO 3 GHz (Question ITU-R 88/8) (1994) The ITU Radiocommunication
2、 Assembly, considering a) that, for statistical assessment of interference and for use in coordination between land mobile earth stations and the space stations of different satellite systems sharing the same frequency bands, it is appropriate to use a single radiation pattern for each type of land
3、mobile earth station antenna; b) that the reference radiation patterns for mobile earth station antennas operating in the land mobile-satellite service depend on the type of antenna and the earth station system performance requirements, in particular the gain and the associated beamwidth for differe
4、nt LMSS services; c) that the types of antennas to be considered should include a: i) ii) transportable or vehicle-mounted antenna producing an axis-symmetric or near-symmetric beam; vehicle-mounted vertical array antenna producing a toroidal antenna pattern (360“ in azimuth, narrow in elevation); i
5、ii) vehicle-mounted array antenna having a horizontal profile and producing a vertical fan-beam pattern (narrow in azimuth, wide in elevation); iv) vehicle-mounted near-omnidirectional antenna; d) that the reference radiation pattern should result in achievable side-lobe limits for each type of ante
6、nna; e) particularly at low elevation angles, and that this effect will vary from vehicle to vehicle; that the vehicle structure upon which these antennas will be mounted will distort the radiation pattern, f) that in the mobile environment, other non-electrical factors, such as size, wind profile,
7、mechanical stability, consumer acceptance, and cost, must be taken into account in the antenna design, and will limit the choice of available designs; g) boresight; that the interference to other systems is related to the absolute level of radiation in directions other than the h) and f) will lead t
8、o the most efficient use of the radio-frequency spectrum and the geostationary orbit; that the use of an antenna with a good radiation pattern, i.e. one with the lowest side-lobe levels within 5 d), e) j) to cause interference may occur along planes other than the principal planes, that an antenna o
9、f type iii) produces a pattern with minimum symmetry and that side lobes of a level sufficient recommends 1. that the reference radiation pattern in Annex 1 should be used for transportable or vehicle-mounted antennas producing an axis-symmetric or near-symmetric beam and operating in the frequency
10、range allocated for mobile-satellite systems between about 1 and 3 GHz; COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services ITU-R RECMN*M. LO7L 74 S 4855232 0523bb8 777 W Rw. ITU-R M.1091 67 2. that the reference radiation pattern in Anne
11、x 2 should be used for vehicle-mounted vertical array antennas which produce a toroidal antenna pattern, and operate in the frequency range allocated for mobile-satellite systems between about 1 and 3 GHz; 3. that the reference radiation pattern in Annex 3 should be used for vehicle-mounted tracking
12、 array antennas which have a horizontal profile, produce a vertical fan-beam pattern, and operate in the frequency range allocated for mobile-satellite systems between about 1 and 3 GHz, and that the measurement principle given in Annex 5 should be used for such antennas; 4. antennas operating in th
13、e frequency range allocated for mobile-satellite systems between about 1 and 3 GE; that the reference radiation pattern in Annex 4 should be used for vehicle-mounted near-omnidirectional 5. that when these reference radiation patterns are used for interference calculations, allowances must be made t
14、o the values derived to take account of the variances introduced by the vehicle movement and tolerances in the pointing accuracy and the tracking mechanism; 6. that the following Notes should be regarded as part of this Recommendation. Note 1 - The reference radiation patterns given in the Annexes a
15、pply for all beam positions. Note 2 - In addition to antennas of type iii), it may be appropriate to use the measurement principle of Annex 5 for other antennas which have a non-symmetric radiation pattern either intrinsically or due to the effect of a ground plane. Note 3 - For vehicle-mounted ante
16、nnas, the proximity of the vehicle acts as a .ground plane and may have a significant effect on the radiation pattern of the antenna. Note 4 - Antennas for handheld terminals are expected to have nearly omnidirectional patterns which provide very little angular discrimination and are not specified i
17、n this Recommendation. Note.5-Other antenna types than the four described above may be developed for mobile earth station use; administrations are requested to supply information as it becomes available. ANNEX 1 Reference radiation pattern for transportable or vehicle-mounted near-axis symmetric ear
18、th station antennas with a gain of 12 to 18 dBi and with an operating frequency within the range of about 1 to 3 GHz for use in the land mobiie-satellite service 0 : angle (degrees) between the direction of maximum gain and the side-lobe direction G : absolute gain relative to an isotropic antenna.
19、G 5 44 - 25logO dBi G I -5 dBi COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesITU-R RECflNnfl. 1071 74 4855232 0523667 803 Antenna type Typical minimum Approximate antenna GIT Relative gain class peak gain (dB(K-9) (dBi) -18 LOW 9-1 1
20、 -14 Medium 11-13 -12 High 13-15 68 Width constant (4 Note 1 0.33 0.33 Rc. ITU-R M.1091 ANNEX 2 Reference radiation pattern for vehicle-mounted earth station antennas with a vertical profde and producing a toroidal pattern with gain in the range of 7 to 13 dBi and with an operating frequency within
21、the range of about 1 to 3 GHz for use in the land mobile-satellite service E: Eo : G-: peak gain of the antenna G : The antenna is omnidirectional in azimuth. elevation angle (degrees) of the side-lobe direction elevation angle (degrees) of the maximum gain absolute gain relative to an isotropic ant
22、enna G I G, -10 dBi for E - EO 45“ G I G, - 0.3 (E - Eo)/IO). G I G, - 0.3 (EO - E)/10)2.3 dBi dBi for 20“ I E - Eo I 45“ for 20“ 5 Eo - E I 50“ G I G, - 13 dBi for EO - E 50“ ANNEX 3 Reference radiation pattern for vehicle-mounted tracking earth station antennas with a low profde which typically ha
23、ve a fan-beam pattern and with an operating frequency within the range of about 1 to 3 GHz for use in the land mobile-satellite service Maximum gain is in the direction (AZMAX, ELMAX). The point in consideration is (AZ, EL). G is the absolute gain relative to an isotropic antenna. A = I AZ - AZMAX I
24、 O“ I EL I 60“ G(AZ, EL) I 4 dBi for 30“ + k(EL)“ I A I 180“ Note 1 - Further work is needed to develop appropriate values for low-gain fan-beam antennas. It has been suggested that a width constant of 0.67 might be appropriate. COPYRIGHT International Telecommunications Union/ITU Radiocommunication
25、sLicensed by Information Handling Services ITU-R RECMN*M* LO91 94 4855232 0523670 525 W Rec. ITU-R M.1091 ANNEX 4 69 Reference radiation pattern for vehicle-mounted near-omnidirectional antennas with an operating frequency within the range of about 1 to 3 GHz for use in the land mobile-satellite ser
26、vice E : elevation angle (degrees) G : absolute gain relative to an isotropic antenna. G I 5 dBi for E 2 - 20“ G I O dBi for E e - 20“ ANNEX 5 Recommended measurement principle for vehicle-mounted horizontal array antennas used in the land mobile-satellite service It is important to measure the ante
27、nna pattern with a method that samples the entire hemisphere surrounding the antenna, These antennas have a pattern which is, at best, symmetric across a vertical plane and which is not adequately sampled by measurements along the two principal planes. Side lobes of a level sufficient to cause inter
28、ference may not necessarily occur along the principal planes. One such method is to measure along a series of conical cuts, that is, through 360“ in azimuth at a constant elevation with respect to a horizontal plane (for example, the vehicle roof), as shown in Fig. 1. These conical cut measurements
29、should be made at a sufficient number of elevation angles to reasonably sample the pattern of the antenna. Alternatively, a series of elevation cuts through zenith at various azimuth angles could be used to characterize the pattern. A complete set of such measurements should be made for each differe
30、nt configuration (e.g. elevation settings, switched beams) of the antenna. Because the ground plane effect of the vehicle structure has a significant effect on the antenna pattern, an appropriate ground plane should be used when measuring the antenna. COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services70 ITU-R RECMN*M. 1091 9Y I Y855212 0523673 463 Rc. ITU-R M.1091 . . _I 2%. : .: ,. . .- , . . *. , * I ,. . L I. COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services
