41:
27:
647:
One application of spiral antennas is wide-band communications. Another application of spiral antennas is monitoring of the frequency spectrum. One antenna can receive over a wide bandwidth, for example a ratio 5:1 between the maximum and minimum frequency. Usually a pair of spiral antennas are used
607:
The antenna usually has two conductive spiral arms, extending from the center outwards. The direction of rotation of the spiral defines the direction of antenna polarization. Additional spirals may be included as well, to form a multi-spiral structure. The antenna may be a flat disc, with conductors
630:
The spiral can be printed or etched over a specifically chosen dielectric medium, whose permittivity can be used to alter the frequency for a given size. Dielectric mediums like Rogers RT Duroid help in reducing the physical size of antenna. Thin substrates with higher permittivity can achieve the
626:
Usually the spiral is cavity-backed – that is, there is a cavity of air or non-conductive material or vacuum, surrounded by conductive walls behind the spiral. A cavity with the proper shape and size changes the antenna pattern to receive and transmit in a single direction, away from the cavity.
643:
radio waves, and will receive linearly polarized waves in any orientation, but will drastically attenuate circularly polarized signals received with the opposite-rotation. A spiral antenna will reject circularly polarized waves of one type, while receiving perfectly well waves having the other
598:
Different designs of spiral antenna can be obtained by varying number of turns for each arm, the number of arms, the type of spiral, the spacing between its turns, the variation of the width of its arm(s), and the material(s) that surround it, such as the substrate it lies on.
118:
The traveling wave, formed on spiral arms, allows for broadband performance. Fast wave is due to mutual coupling phenomenon occurring between arms of spiral. Leaky wave “leaks” the energy during propagation through the spiral arms to produce radiation.
228:. The inner radius is measured from center of the spiral to center of the first turn while the outer radius is measured from center of the spiral to center of the outermost turn. Other than these design parameters, spiral antennas have lowest (
102:
are usually placed at the back to eliminate back lobes, because a unidirectional pattern is usually preferred in such antennas. Spiral antennas are classified into different configurations: Archimedean spiral, logarithmic spiral,
544:
corresponds to multiplication factor. The consequence is equal spacing between successive turns, which limits the width of the spiral arms, which is usually kept constant. Other choices of spiral shape can also be used, such as
648:
in this application, having identical parameters except the polarization, which is opposite (one is right-hand, the other left-hand oriented). Spiral antennas are useful for microwave direction-finding.
387:
343:
283:
83:
are independent of frequency: the driving point impedance, radiation pattern and polarization of such antennas remain unchanged over a large bandwidth. Spiral antennas are inherently
593:
502:
426:
466:
226:
199:
542:
522:
446:
172:
152:
991:
134:
Different design parameters are to be considered while designing a square spiral antenna. The parameters include spacing between the turns
631:
same result as thick substrates with lower permittivity. The only problem with such materials is their less availability and high costs.
1099:
115:
In general, antennas may operate in three different modes: traveling wave, fast wave, and leaky wave. Spiral antennas use all three.
595:; the resulting spiral arms are more widely spaced in the outer turns, which can better accommodate arms that widen significantly.
122:
Ring theory (band theory) explains the working principle of spiral antenna. The theory states that spiral antenna radiate from an
902:
95:
can be used to increase the gain. Spiral antennas are reduced in size with its windings making it an extremely small structure.
608:
resembling a pair of loosely nested clock springs, or the spirals may extend in a three-dimensional shape like a screw thread.
765:
795:
Mehta, A.; Mirshekar-Syahkal, D.; Nakano, H. (2006). "Beam adaptive single arm rectangular spiral antenna with switches".
348:
1331:
1149:
850:
713:
673:
288:
764:
Hill, David A.; Ma, M. T.; Ondrejka, Arthur; Riddle, Billy F.; Crawford, M. L.; Johnk, Robert T. (September 1993).
231:
971:
996:
895:
552:
1362:
1357:
1234:
471:
1229:
1139:
1129:
938:
399:
390:
1311:
1249:
986:
888:
869:
966:
640:
451:
729:
Mayes, Paul E. (1992). "Frequency-independent antennas and broad-band derivatives thereof".
468:-axis simultaneously. Often-used Archemedian spirals satisfy a particularly simple equation
1274:
1174:
1046:
1021:
777:
738:
204:
177:
84:
8:
1194:
1086:
1041:
781:
742:
1336:
1184:
1124:
1119:
1016:
928:
546:
527:
507:
431:
157:
137:
78:
71:
46:
32:
1321:
1214:
1134:
1056:
951:
846:
709:
669:
389:
corresponds to speed of light in the metal of the antenna, mainly determined by the
1295:
1109:
1071:
1036:
804:
746:
99:
1301:
1264:
1239:
1164:
1154:
1011:
981:
961:
946:
911:
62:
59:
20:
1259:
1244:
1219:
1094:
1051:
1026:
976:
808:
1351:
1306:
1199:
1189:
1144:
1031:
616:
612:
104:
92:
40:
1254:
1224:
1209:
1204:
1179:
1169:
1076:
1061:
1006:
1001:
96:
88:
1104:
956:
26:
794:
821:
615:. If a single input or output line is desired – for example a grounded
822:
Asad, M.; Gilani, J.; Khalid, A.; Iqbal, M.S. (2010). "Optimizing the
1159:
1066:
750:
623:
or other transformer is added to alter the signal's electrical mode.
393:
of the substrate the spiral lies on, and its over-coating (if any).
1316:
1114:
920:
880:
1290:
66:
1269:
620:
126:
where the circumference of the spiral equals the wavelength.
862:
766:"Aperture-excitation of electrically-large, lossy cavities"
611:
The output of a two-arm or four-arm spiral antenna is a
797:
693:(5th ed.). Radio Publications. pp. 185–186.
555:
530:
510:
474:
454:
434:
402:
351:
291:
234:
207:
180:
160:
140:
763:
587:
536:
516:
496:
460:
440:
420:
381:
337:
277:
220:
193:
166:
146:
1349:
664:Johnson, Richard C.; Jasik, Henry, eds. (1961).
382:{\displaystyle c\leq 299.79{\text{ Mm/s}}=c_{0}}
657:
428:coordinate system, the spiral grows along the
338:{\displaystyle (f_{\text{high}}=c/2\pi r_{1})}
896:
663:
278:{\displaystyle f_{\text{low}}=c/2\pi r_{2})}
903:
889:
571:
490:
708:(2 ed.). McGraw-Hill. p. 697.
39:
25:
1350:
840:
884:
728:
703:
826:factor of a square spiral antenna".
843:Microwave Passive Direction Finding
688:
588:{\displaystyle r=a+b\,e^{m\theta }}
13:
845:. SciTech Publishing. p. 40.
14:
1374:
1332:Circularly disposed antenna array
1150:Folded inverted conformal antenna
910:
770:NASA STI/Recon Technical Report N
524:corresponds to growth factor and
634:
863:"Practical antenna" references
834:
815:
788:
757:
722:
697:
682:
497:{\displaystyle r=a+b\,\theta }
415:
403:
332:
292:
272:
1:
651:
972:Dielectric resonator antenna
666:Antenna Engineering Handbook
345:operating frequencies. Here
110:
76:are the most popular, while
7:
841:Lipsky, Stephen E. (2004).
602:
421:{\displaystyle (r,\theta )}
69:, first described in 1956.
10:
1379:
31:Two-arm, tightly-wrapped,
18:
1283:
1235:Regenerative loop antenna
1085:
937:
919:
639:Spiral antennas transmit
129:
45:Two-arm, widely-wrapped,
1230:Reflective array antenna
1140:Corner reflector antenna
689:Orr, William I. (1976).
19:Not to be confused with
1130:Collinear antenna array
809:10.1049/ip-map:20050045
731:Proceedings of the IEEE
461:{\displaystyle \theta }
391:electrical permittivity
1312:Reconfigurable antenna
1275:Yagi–Uda antenna
1250:Short backfire antenna
987:Folded unipole antenna
589:
538:
518:
498:
462:
442:
422:
383:
339:
279:
222:
195:
168:
148:
51:
37:
967:Crossed field antenna
691:Beam Antenna Handbook
590:
539:
519:
499:
463:
443:
423:
384:
340:
280:
223:
221:{\displaystyle r_{2}}
196:
194:{\displaystyle r_{1}}
169:
149:
43:
29:
1284:Application-specific
1175:Log-periodic antenna
1047:Rubber ducky antenna
1022:Inverted vee antenna
997:Ground-plane antenna
704:Kraus, John (1988).
641:circularly polarized
553:
528:
508:
472:
452:
432:
400:
349:
289:
232:
205:
178:
158:
138:
85:circularly polarized
1195:Offset dish antenna
1042:Random wire antenna
782:1993STIN...9431683H
743:1992IEEEP..80..103M
668:(Second ed.).
547:logarithmic spirals
1337:Television antenna
1185:Microstrip antenna
1125:Choke ring antenna
1120:Cassegrain antenna
1017:Inverted-F antenna
929:Isotropic radiator
585:
534:
514:
494:
458:
438:
418:
379:
335:
275:
218:
191:
164:
144:
79:logarithmic spiral
72:Archimedean spiral
52:
47:logarithmic spiral
38:
33:logarithmic spiral
16:Type of RF antenna
1363:Radio electronics
1345:
1344:
1322:Reference antenna
1215:Parabolic antenna
1135:Conformal antenna
1057:Turnstile antenna
952:Biconical antenna
537:{\displaystyle b}
517:{\displaystyle a}
441:{\displaystyle r}
364:
302:
242:
201:and outer radius
167:{\displaystyle w}
147:{\displaystyle s}
1370:
1358:Antennas (radio)
1296:Corner reflector
1110:Beverage antenna
1072:Umbrella antenna
1037:Monopole antenna
992:Franklin antenna
905:
898:
891:
882:
881:
877:
870:"Spiral Antenna"
857:
856:
838:
832:
831:
819:
813:
812:
792:
786:
785:
761:
755:
754:
751:10.1109/5.119570
726:
720:
719:
701:
695:
694:
686:
680:
679:
661:
594:
592:
591:
586:
584:
583:
543:
541:
540:
535:
523:
521:
520:
515:
503:
501:
500:
495:
467:
465:
464:
459:
447:
445:
444:
439:
427:
425:
424:
419:
388:
386:
385:
380:
378:
377:
365:
362:
344:
342:
341:
336:
331:
330:
315:
304:
303:
300:
284:
282:
281:
276:
271:
270:
255:
244:
243:
240:
227:
225:
224:
219:
217:
216:
200:
198:
197:
192:
190:
189:
173:
171:
170:
165:
153:
151:
150:
145:
1378:
1377:
1373:
1372:
1371:
1369:
1368:
1367:
1348:
1347:
1346:
1341:
1302:Evolved antenna
1279:
1265:Vivaldi antenna
1240:Rhombic antenna
1165:Helical antenna
1155:Fractal antenna
1100:AS-2259 Antenna
1081:
1012:Helical antenna
982:Discone antenna
962:Coaxial antenna
947:Batwing antenna
939:Omnidirectional
933:
915:
909:
868:
865:
860:
853:
839:
835:
820:
816:
793:
789:
762:
758:
727:
723:
716:
702:
698:
687:
683:
676:
662:
658:
654:
637:
605:
576:
572:
554:
551:
550:
529:
526:
525:
509:
506:
505:
473:
470:
469:
453:
450:
449:
433:
430:
429:
401:
398:
397:
373:
369:
361:
350:
347:
346:
326:
322:
311:
299:
295:
290:
287:
286:
266:
262:
251:
239:
235:
233:
230:
229:
212:
208:
206:
203:
202:
185:
181:
179:
176:
175:
174:, inner radius
159:
156:
155:
154:, width of arm
139:
136:
135:
132:
113:
60:radio frequency
50:
36:
24:
21:Helical antenna
17:
12:
11:
5:
1376:
1366:
1365:
1360:
1343:
1342:
1340:
1339:
1334:
1329:
1327:Spiral antenna
1324:
1319:
1314:
1309:
1304:
1299:
1293:
1287:
1285:
1281:
1280:
1278:
1277:
1272:
1267:
1262:
1260:Sterba antenna
1257:
1252:
1247:
1245:Sector antenna
1242:
1237:
1232:
1227:
1222:
1220:Plasma antenna
1217:
1212:
1207:
1202:
1197:
1192:
1187:
1182:
1177:
1172:
1167:
1162:
1157:
1152:
1147:
1142:
1137:
1132:
1127:
1122:
1117:
1112:
1107:
1102:
1097:
1095:Adcock antenna
1091:
1089:
1083:
1082:
1080:
1079:
1074:
1069:
1064:
1059:
1054:
1052:Sloper antenna
1049:
1044:
1039:
1034:
1029:
1027:J-pole antenna
1024:
1019:
1014:
1009:
1004:
999:
994:
989:
984:
979:
977:Dipole antenna
974:
969:
964:
959:
954:
949:
943:
941:
935:
934:
932:
931:
925:
923:
917:
916:
908:
907:
900:
893:
885:
879:
878:
874:Antenna Theory
864:
861:
859:
858:
851:
833:
814:
787:
756:
737:(1): 103–112.
721:
714:
696:
681:
674:
655:
653:
650:
644:polarization.
636:
633:
604:
601:
582:
579:
575:
570:
567:
564:
561:
558:
533:
513:
493:
489:
486:
483:
480:
477:
457:
437:
417:
414:
411:
408:
405:
376:
372:
368:
360:
357:
354:
334:
329:
325:
321:
318:
314:
310:
307:
298:
294:
274:
269:
265:
261:
258:
254:
250:
247:
238:
215:
211:
188:
184:
163:
143:
131:
128:
112:
109:
93:antenna arrays
56:spiral antenna
44:
30:
15:
9:
6:
4:
3:
2:
1375:
1364:
1361:
1359:
1356:
1355:
1353:
1338:
1335:
1333:
1330:
1328:
1325:
1323:
1320:
1318:
1315:
1313:
1310:
1308:
1307:Ground dipole
1305:
1303:
1300:
1297:
1294:
1292:
1289:
1288:
1286:
1282:
1276:
1273:
1271:
1268:
1266:
1263:
1261:
1258:
1256:
1253:
1251:
1248:
1246:
1243:
1241:
1238:
1236:
1233:
1231:
1228:
1226:
1223:
1221:
1218:
1216:
1213:
1211:
1208:
1206:
1203:
1201:
1200:Patch antenna
1198:
1196:
1193:
1191:
1190:Moxon antenna
1188:
1186:
1183:
1181:
1178:
1176:
1173:
1171:
1168:
1166:
1163:
1161:
1158:
1156:
1153:
1151:
1148:
1146:
1145:Curtain array
1143:
1141:
1138:
1136:
1133:
1131:
1128:
1126:
1123:
1121:
1118:
1116:
1113:
1111:
1108:
1106:
1103:
1101:
1098:
1096:
1093:
1092:
1090:
1088:
1084:
1078:
1075:
1073:
1070:
1068:
1065:
1063:
1060:
1058:
1055:
1053:
1050:
1048:
1045:
1043:
1040:
1038:
1035:
1033:
1032:Mast radiator
1030:
1028:
1025:
1023:
1020:
1018:
1015:
1013:
1010:
1008:
1005:
1003:
1000:
998:
995:
993:
990:
988:
985:
983:
980:
978:
975:
973:
970:
968:
965:
963:
960:
958:
955:
953:
950:
948:
945:
944:
942:
940:
936:
930:
927:
926:
924:
922:
918:
913:
906:
901:
899:
894:
892:
887:
886:
883:
875:
871:
867:
866:
854:
852:1-891121-23-5
848:
844:
837:
829:
825:
818:
810:
806:
802:
798:
791:
783:
779:
775:
771:
767:
760:
752:
748:
744:
740:
736:
732:
725:
717:
715:0-07-035422-7
711:
707:
700:
692:
685:
677:
675:0-07-032291-0
671:
667:
660:
656:
649:
645:
642:
632:
628:
624:
622:
618:
614:
613:balanced line
609:
600:
596:
580:
577:
573:
568:
565:
562:
559:
556:
549:that satisfy
548:
531:
511:
491:
487:
484:
481:
478:
475:
455:
435:
412:
409:
406:
394:
392:
374:
370:
366:
358:
355:
352:
327:
323:
319:
316:
312:
308:
305:
296:
267:
263:
259:
256:
252:
248:
245:
236:
213:
209:
186:
182:
161:
141:
127:
125:
124:active region
120:
116:
108:
106:
105:square spiral
101:
98:
94:
90:
86:
82:
80:
75:
73:
68:
64:
61:
58:is a type of
57:
48:
42:
34:
28:
22:
1326:
1255:Slot antenna
1225:Quad antenna
1210:Planar array
1205:Phased array
1180:Loop antenna
1170:Horn antenna
1077:Whip antenna
1062:T2FD antenna
1007:Halo antenna
1002:G5RV antenna
873:
842:
836:
827:
823:
817:
800:
796:
790:
773:
769:
759:
734:
730:
724:
705:
699:
690:
684:
665:
659:
646:
638:
635:Applications
629:
625:
617:coaxial line
610:
606:
597:
395:
285:and highest
133:
123:
121:
117:
114:
77:
70:
65:shaped as a
55:
53:
1105:AWX antenna
1087:Directional
957:Cage aerial
396:In a polar
1352:Categories
830:: 227–230.
803:(1): –18.
652:References
448:-axis and
363: Mm/s
1298:(passive)
1160:Gizmotchy
1067:T-antenna
921:Isotropic
776:: 31683.
619:– then a
581:θ
492:θ
456:θ
413:θ
356:≤
320:π
260:π
111:Principle
87:with low
1317:Rectenna
1115:Cantenna
706:Antennas
603:Elements
100:cavities
81:antennas
74:antennas
912:Antenna
778:Bibcode
739:Bibcode
107:, etc.
63:antenna
49:antenna
35:antenna
1291:ALLISS
849:
712:
672:
504:where
359:299.79
130:Design
67:spiral
1270:WokFi
914:types
828:PACCS
621:balun
97:Lossy
847:ISBN
774:1361
710:ISBN
670:ISBN
301:high
89:gain
805:doi
801:153
747:doi
241:low
1354::
872:.
799:.
772:.
768:.
745:.
735:80
733:.
91:;
54:A
904:e
897:t
890:v
876:.
855:.
824:Q
811:.
807::
784:.
780::
753:.
749::
741::
718:.
678:.
578:m
574:e
569:b
566:+
563:a
560:=
557:r
532:b
512:a
488:b
485:+
482:a
479:=
476:r
436:r
416:)
410:,
407:r
404:(
375:0
371:c
367:=
353:c
333:)
328:1
324:r
317:2
313:/
309:c
306:=
297:f
293:(
273:)
268:2
264:r
257:2
253:/
249:c
246:=
237:f
214:2
210:r
187:1
183:r
162:w
142:s
23:.
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