Lecture Loop Antenna
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Transcript of Lecture Loop Antenna
Lecture 8
EE‐871: Antennas and Wave Propagation DR. RASHID AHMAD BHATTI
LOOP ANTENNASINTRODUCTIONINTRODUCTION
Loop antennas feature simplicity, low cost and versatility. They may have various shapes:circular, triangular, square, elliptical, etc. They are widely used in communication links upto the microwave bands (up to 3 GHz) They are also used as electromagnetic (EM) fieldto the microwave bands (up to ‐ 3 GHz). They are also used as electromagnetic (EM) fieldprobes in the microwave bands.Loop antennas are usually classified as electrically small (C < 0.1 λ ) and electrically large(C ~ λ ). Here, C denotes the loop’s circumference. Electrically small loops of a single turn
( )have very small radiation resistance (comparable to their loss resistance). Their radiationresistance can be substantially improved by adding more turns. Multi‐turn loops havebetter radiation resistance although their efficiency is still poor. That is why they are usedmostly as receiving antennas where losses are not so important. The radiationmostly as receiving antennas where losses are not so important. The radiationcharacteristics of a small loop antenna can be additionally improved by inserting aferromagnetic core. Radio‐receivers of AM broadcast are usually equipped with ferrite‐loop antennas.The small loops regardless of their shape have a far field pattern very similar to that of aThe small loops, regardless of their shape, have a far‐field pattern very similar to that of asmall electric dipole (normal to the plane of the loop). This is expected because they areequivalent to a magnetic dipole. Note, however, that the field polarization is orthogonal tothat of the electric dipole. As the circumference of the loop increases, the pattern maximum
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
shifts towards the loop’s normal, and when C � � , the maximum of the pattern is at the loop’snormal.
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
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EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNASNON‐UNIFORM CURRENT LOOP
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis
LOOP ANTENNAS
EE‐871: Antennas and Wave Propagation Ref. Antenna Theory by C. A. Balanis