Analysis of Hertzian Dipole

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A Hertzian dipole is a starting point of antenna theory. Since most of antennas can be understood with a Hertzian dipole, we need to thoroughly study this kind of an infinitesimal antenna that is not real in practical applications.

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Analysis of Hertzian Dipole

  1. 1. Antenna Engineering CHO, Yong Heui Analysis of Hertzian Dipole
  2. 2. E and H fields 1. Field analysis Vector potential <ul><li>Vector potential approach </li></ul>
  3. 3. Hertzian dipole 1. Field analysis <ul><li>Current density approximation </li></ul>
  4. 4. Vector potential 1. Field analysis <ul><li>Current vs. vector potential </li></ul>
  5. 5. H field 1. Field analysis 
  6. 6. E field 1. Field analysis 
  7. 7. Electric dipole moment 1. Field analysis  <ul><li>Current vs. electric dipole moment </li></ul>
  8. 8. Far-field 1. Field analysis 
  9. 9. Radiated power 1. Field analysis 
  10. 10. Radiation resistance 1. Field analysis   <ul><li>Open transmission line </li></ul>
  11. 11. Simple calculation 1. Field analysis  <ul><li>Far-field calculation </li></ul>
  12. 12. Radiation pattern 1. Field analysis  <ul><li>Power and field pattern </li></ul><ul><li>dB scale: </li></ul><ul><li>Half-power beamwidth: </li></ul><ul><li>Main beam: </li></ul>Far-field condition : phase condition
  13. 13. Antenna gain 1. Field analysis  <ul><li>Directivity: 3/2 for Hertzian dipole </li></ul><ul><li>Gain and efficiency </li></ul><ul><li>Isotropic radiation </li></ul><ul><li>dBi </li></ul>
  14. 14. (Lorentz) Reciprocity theorem 1. Field analysis  <ul><li>The same propagation characteristics: Tx and Rx </li></ul><ul><li>Antenna measurement </li></ul>
  15. 15. Antenna characteristics  <ul><li>Antenna gain: anisotropic radiation (G > 1) </li></ul><ul><li>isotropic radiation (G = 1) </li></ul><ul><li>Directivity and efficiency: </li></ul><ul><li>Angular beamwidth: 3dB </li></ul>Radiation pattern [dBi]: dB isotropic 1. Field analysis
  16. 16. Friis power transmission formula  <ul><li>Microwave radio link </li></ul>2. Microwave link
  17. 17. Transmitted power  <ul><li>Power density: </li></ul><ul><li>EIRP (Effective Isotropic Radiated Power) </li></ul>Radiation pattern [dBi]: dB isotropic 2. Microwave link
  18. 18. Received power  <ul><li>Received power: </li></ul><ul><li>Effective area </li></ul>Friis transmission formula  2. Microwave link
  19. 19. Effective area  <ul><li>Reciprocity theorem: </li></ul><ul><li>Effective area: </li></ul>2. Microwave link  
  20. 20. Free space loss  <ul><li>Free space loss: </li></ul><ul><li>Received power </li></ul>2. Microwave link
  21. 21.   Uplink and downlink 2. Microwave link
  22. 22.   Uplink calculation 2. Microwave link
  23. 23.   Downlink calculation 2. Microwave link
  24. 24. Noise power  <ul><li>Thermal noise: white noise, Nyquist formula </li></ul> Thermal noise Noise temperature  2. Microwave link
  25. 25. Carrier to noise ratio <ul><li>C/No: related to carrier to noise ratio </li></ul><ul><li>G/T: Figure of merit </li></ul> Carrier to noise ratio  G/T: sensitivity of receiver  2. Microwave link

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