1409:
188:
156:
43:
140:
1447:
Grating lobes are a special case of a sidelobe. In such a case, the sidelobes should be considered all the lobes lying between the main lobe and the first grating lobe, or between grating lobes. It is conceptually useful to distinguish between sidelobes and grating lobes because grating lobes have
1232:
796:, or if the antenna is so small as to have no sidelobes in the visible space. Larger antennas have narrower main beams, as well as narrower sidelobes. Hence, larger antennas have more sidelobes in the visible space (as the antenna size is increased, sidelobes move from the
889:
761:
relative to the peak of the main beam. The main lobe and sidelobes occur for both transmitting and receiving. The concepts of main and sidelobes, radiation pattern, aperture shapes, and aperture weighting, apply to
1388:
for a given aperture size, but it also produces the maximum sidelobe level. Sidelobe levels can be reduced by tapering the edges of the aperture distribution (changing from uniformity) at the expense of reduced
1143:
1111:
1020:
825:
1062:
971:
1287:
757:
The power density in the sidelobes is generally much less than that in the main beam. It is generally desirable to minimize the sidelobe level (SLL), which is measured in
724:
in which the objective is to emit the radio waves in one direction, the lobe in that direction is designed to have a larger field strength than the others; this is the "
404:
1480:
410:
1519:
607:
399:
1227:{\displaystyle \displaystyle {\text{Radiation pattern (in units of dB)}}\propto 10\log _{10}\left|2\cdot {\frac {J_{1}(X)}{X}}\right|^{2}}
422:
1438:
effect causes some sidelobes to become substantially larger in amplitude, and approaching the level of the main lobe; these are called
669:
1290:
126:
1076:
985:
734:", and usually represent unwanted radiation in undesired directions. The sidelobe directly behind the main lobe is called the
884:{\displaystyle \displaystyle {\text{Radiation pattern (in units of dB)}}\propto 20\log _{10}\left|{\frac {\sin X}{X}}\right|}
64:
533:
285:
1448:
larger amplitudes than most, if not all, of the other sidelobes. The mathematics of grating lobes is the same as that of
808:
For a rectangular aperture antenna having a uniform amplitude distribution (or uniform weighting), the first sidelobe is
750:
to other equipment. Another disadvantage is that confidential information may be picked up by unintended receivers. In
747:
270:
107:
523:
160:
79:
360:
60:
1408:
53:
792:
of its aperture distribution, most antennas will generally have sidelobes, unless the aperture distribution is a
513:
86:
1036:
948:
1420:
whose inter-element spacing is greater than half a wavelength, hence the radiation pattern has grating lobes
1254:
148:
1126:
For a circular aperture antenna, also having a uniform amplitude distribution, the first sidelobe level is
93:
662:
624:
370:
558:
415:
1444:, and they are either identical, or nearly identical as shown in the figure, copies of the main beams.
75:
543:
710:" at various angles, directions where the radiated signal strength reaches a maximum, separated by "
1384:
A uniform aperture distribution, as provided in the two examples above, gives the maximum possible
793:
754:
antennas, sidelobes may pick up interfering signals, and increase the noise level in the receiver.
721:
144:
187:
151:
representation, showing sidelobes. The radial distance from the center represents signal strength.
691:
503:
463:
305:
230:
1396:
The nulls between sidelobes occur when the radiation patterns passes through the origin in the
1514:
1476:
1449:
1413:
789:
785:
694:
655:
563:
548:
538:
508:
443:
260:
171:
350:
295:
290:
220:
797:
716:", angles at which the radiated signal strength falls to zero. This can be viewed as the
683:
629:
355:
300:
210:
179:
155:
1131:
813:
751:
553:
518:
473:
225:
205:
100:
1499:
1508:
1440:
1425:
1397:
812:
relative to the peak of the main beam. For such antennas the radiation pattern has a
583:
345:
315:
265:
197:
1431:
1417:
712:
528:
453:
340:
275:
235:
215:
1470:
1130:
relative to the peak of the main beam. In this case, the radiation pattern has a
1390:
1385:
771:
743:
717:
593:
498:
448:
310:
42:
1434:) in which the element spacing is greater than a half wavelength, the spatial
739:
598:
493:
1294:
782:
767:
726:
699:
588:
468:
458:
320:
280:
31:
1400:. Hence, adjacent sidelobes are generally 180° out of phase to each other.
139:
1435:
380:
17:
758:
763:
746:
antennas, excessive sidelobe radiation wastes energy and may cause
775:
638:
375:
365:
255:
138:
616:
36:
1106:{\displaystyle \displaystyle 7.72\approx {\frac {5\pi }{2}}}
1015:{\displaystyle \displaystyle 4.49\approx {\frac {3\pi }{2}}}
706:
The radiation pattern of most antennas shows a pattern of "
697:
of an antenna or other radiation source, that are not the
1301:
into the canonical equation yield the following results:
912:
into the canonical equation yield the following results:
1258:
1257:
1147:
1146:
1080:
1079:
1040:
1039:
989:
988:
952:
951:
829:
828:
804:
Sidelobes for case of uniformly-illuminated aperture
67:. Unsourced material may be challenged and removed.
1281:
1226:
1105:
1056:
1014:
965:
883:
742:, the more lobes its radiation pattern has. In
738:. The longer the antenna relative to the radio
27:Lobes of far field radiation pattern of antenna
1500:Sidelobes and Beamwidths - An Antenna Tutorial
663:
8:
1297:. Simple substitutions of various values of
766:(another branch of electromagnetics) and in
1303:
914:
908:Simple substitutions of various values of
670:
656:
166:
1263:
1256:
1217:
1191:
1184:
1163:
1148:
1145:
1087:
1078:
1038:
996:
987:
950:
858:
845:
830:
827:
127:Learn how and when to remove this message
1472:Introduction to Radar Target Recognition
1430:For discrete aperture antennas (such as
1407:
1057:{\displaystyle \displaystyle 6.28=2\pi }
154:
1461:
966:{\displaystyle \displaystyle 3.14=\pi }
178:
159:A typical antenna radiation pattern in
1282:{\displaystyle \displaystyle J_{1}(x)}
405:Wireless electronic devices and health
617:Multiple-input multiple-output (MIMO)
411:International Telecommunication Union
7:
1136:
818:
690:are the lobes (local maxima) of the
436:Radiation sources / regions
400:Wireless device radiation and health
65:adding citations to reliable sources
778:design, as well as antenna design.
423:World Radiocommunication Conference
1150:Radiation pattern (in units of dB)
832:Radiation pattern (in units of dB)
25:
1293:of order 1. This is known as the
1291:Bessel function of the first kind
186:
163:representation showing sidelobes
41:
730:". The other lobes are called "
52:needs additional citations for
1275:
1269:
1203:
1197:
1:
286:Low-noise block downconverter
271:Counterpoise (ground system)
1520:Radio frequency propagation
524:Friis transmission equation
161:cartesian coordinate system
1536:
1423:
361:Municipal wireless network
29:
608:Bell Laboratories Layered
1378:peak of second sidelobe
1120:peak of second sidelobe
30:Not to be confused with
1362:−∞ dB
1354:peak of first sidelobe
1338:−∞ dB
1066:−∞ dB
1029:peak of first sidelobe
975:−∞ dB
800:to the visible space).
641:Multiple Access (WSDMA)
639:Wideband Space Division
149:polar coordinate system
1421:
1283:
1228:
1107:
1058:
1016:
967:
885:
371:Radio masts and towers
164:
152:
1411:
1284:
1229:
1108:
1059:
1017:
968:
886:
781:Because an antenna's
720:of the antenna. In a
559:Signal-to-noise ratio
394:Safety and regulation
158:
147:radiation pattern in
142:
1475:. IET. p. 126.
1255:
1144:
1077:
1037:
986:
949:
826:
544:Radiation resistance
61:improve this article
722:directional antenna
718:diffraction pattern
145:directional antenna
1422:
1330:peak of main beam
1314:Radiation pattern
1279:
1278:
1224:
1223:
1103:
1102:
1054:
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963:
962:
941:peak of main beam
925:Radiation pattern
881:
880:
610:Space-Time (BLAST)
464:Near and far field
165:
153:
1482:978-0-86341-501-2
1469:Tait, P. (2005).
1450:X-ray diffraction
1414:radiation pattern
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1123:
1100:
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906:
905:
874:
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790:Fourier Transform
786:radiation pattern
695:radiation pattern
680:
679:
564:Spurious emission
549:Radio propagation
539:Radiation pattern
514:Equivalent radius
509:Electrical length
416:Radio Regulations
261:Block upconverter
137:
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16:(Redirected from
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834:
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819:
811:
798:evanescent space
672:
665:
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437:
351:Cellular network
291:Passive radiator
190:
167:
132:
125:
121:
118:
112:
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45:
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21:
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841:
824:
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770:fields such as
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643:
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634:
630:Spread spectrum
625:Reconfiguration
612:
609:
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578:
570:
569:
568:
488:
487:Characteristics
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438:
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335:
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70:
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58:
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35:
28:
23:
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15:
12:
11:
5:
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1517:
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1502:
1495:
1494:External links
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1460:
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1457:
1454:
1424:Main article:
1405:
1402:
1380:
1379:
1376:
1374:−23.81 dB
1371:
1367:
1366:
1363:
1360:
1356:
1355:
1352:
1350:−17.57 dB
1347:
1343:
1342:
1339:
1336:
1332:
1331:
1328:
1323:
1319:
1318:
1315:
1312:
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1266:
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1247:
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1237:
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1220:
1215:
1209:
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1202:
1199:
1194:
1190:
1183:
1180:
1176:
1171:
1166:
1162:
1158:
1155:
1132:canonical form
1128:−17.57 dB
1122:
1121:
1118:
1116:−17.83 dB
1113:
1099:
1095:
1092:
1086:
1083:
1071:
1070:
1067:
1064:
1052:
1049:
1046:
1043:
1031:
1030:
1027:
1025:−13.26 dB
1022:
1008:
1004:
1001:
995:
992:
980:
979:
976:
973:
961:
958:
955:
943:
942:
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869:
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844:
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837:
814:canonical form
810:−13.26 dB
805:
802:
678:
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637:
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554:Radio spectrum
551:
546:
541:
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531:
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474:Vertical plane
471:
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318:
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288:
283:
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273:
268:
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239:
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233:
228:
226:Satellite dish
223:
218:
213:
208:
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201:
196:
195:
192:
191:
183:
182:
176:
175:
135:
134:
49:
47:
40:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
1532:
1521:
1518:
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1513:
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1510:
1501:
1498:
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1478:
1474:
1473:
1465:
1462:
1455:
1453:
1451:
1445:
1443:
1442:
1441:grating lobes
1437:
1433:
1432:phased arrays
1427:
1426:Grating lobes
1419:
1418:phased arrays
1415:
1410:
1404:Grating lobes
1403:
1401:
1399:
1398:complex plane
1394:
1392:
1387:
1377:
1372:
1369:
1368:
1364:
1361:
1358:
1357:
1353:
1348:
1345:
1344:
1340:
1337:
1334:
1333:
1329:
1324:
1321:
1320:
1316:
1313:
1306:
1305:
1302:
1296:
1292:
1272:
1264:
1260:
1245:
1238:
1236:
1234:
1218:
1213:
1207:
1200:
1192:
1188:
1181:
1178:
1174:
1169:
1164:
1160:
1156:
1153:
1139:
1138:
1135:
1133:
1119:
1114:
1097:
1093:
1090:
1084:
1081:
1073:
1072:
1068:
1065:
1050:
1047:
1044:
1041:
1033:
1032:
1028:
1023:
1006:
1002:
999:
993:
990:
982:
981:
977:
974:
959:
956:
953:
945:
944:
940:
935:
932:
931:
927:
924:
917:
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913:
902:
895:
893:
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773:
769:
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749:
745:
741:
737:
733:
729:
728:
723:
719:
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714:
709:
704:
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701:
696:
693:
689:
686:engineering,
685:
673:
668:
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623:
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584:Beam steering
582:
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346:Amateur radio
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266:Coaxial cable
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117:February 2024
109:
106:
102:
99:
95:
92:
88:
85:
81:
78: –
77:
73:
72:Find sources:
66:
62:
56:
55:
50:This article
48:
44:
39:
38:
33:
19:
1471:
1464:
1446:
1439:
1429:
1395:
1383:
1365:second null
1317:Explanation
1295:Airy pattern
1250:
1239:
1140:
1125:
1069:second null
928:Explanation
907:
896:
822:
807:
780:
756:
748:interference
744:transmitting
735:
731:
725:
711:
707:
705:
698:
687:
681:
454:Ground plane
341:Antenna farm
198:Common types
123:
114:
104:
97:
90:
83:
71:
59:Please help
54:verification
51:
1391:directivity
1386:directivity
1341:first null
978:first null
772:loudspeaker
594:Beamforming
499:Directivity
449:Focal cloud
311:Transmitter
76:"Sidelobes"
1509:Categories
1456:References
1412:A typical
740:wavelength
599:Small cell
577:Techniques
504:Efficiency
494:Array gain
249:Components
231:Television
143:A typical
87:newspapers
1326:0 dB
1182:⋅
1170:
1154:∝
1094:π
1085:≈
1051:π
1003:π
994:≈
960:π
937:0 dB
865:
852:
836:∝
783:far field
768:acoustics
752:receiving
736:back lobe
732:sidelobes
727:main lobe
700:main lobe
692:far field
688:sidelobes
589:Beam tilt
469:Side lobe
459:Main lobe
444:Boresight
321:Twin-lead
281:Feed line
32:Sidebands
18:Side lobe
1515:Antennas
1436:aliasing
794:Gaussian
759:decibels
615:Massive
381:Wireless
296:Receiver
221:Monopole
180:Antennas
172:a series
170:Part of
1289:is the
684:antenna
356:Hotspot
334:Systems
301:Rotator
211:Fractal
101:scholar
1479:
1251:where
764:optics
534:Height
519:Factor
206:Dipole
103:
96:
89:
82:
74:
1370:8.42
1359:7.02
1346:5.14
1335:3.83
788:is a
776:sonar
713:nulls
708:lobes
376:Wi-Fi
366:Radio
316:Tuner
256:Balun
108:JSTOR
94:books
1477:ISBN
1082:7.72
1042:6.28
991:4.49
954:3.14
774:and
703:.
529:Gain
306:Stub
276:Feed
236:Whip
216:Loop
80:news
1416:of
1161:log
1134:of
862:sin
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105:·
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