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Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
Microwave Systems
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Microwave Systems

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  • 1. Microwave Systems Microwave Engineering CHO, Yong Heui
  • 2. Microwave Engineering1. Microwave SystemsTransmission  Information - Channel bandwidth - Base band - Inefficient wave radiation  Modulation – center frequency 출처: RFDH.com Time domain Frequency domain 2 전자파연구실
  • 3. Microwave Engineering1. Microwave SystemsWhy’s modulation need?  Transmission efficiency - Multiplexing - Antenna length: wavelength - Wave radiation: comparison with DC Battery: DC Antenna: AC 3 전자파연구실
  • 4. Microwave Engineering1. Microwave SystemsFriis power transmission formula  Microwave radio link R Pt Pr 4 전자파연구실
  • 5. Microwave Engineering1. Microwave SystemsFriis power transmission formula Pt  Power density: S 2 Gt W / m 2 4 R  Antenna gain: anisotropic radiation (G > 1) isotropic radiation (G = 1) Radiation pattern [dBi]: dB isotropic 5 전자파연구실
  • 6. Microwave Engineering1. Microwave SystemsFriis power transmission formula  Received power: Pr SAe  Effective area 2 Gr - Ae 4 2 Pr Gt Gr W Pt 4 R  Friis transmission formula 6 전자파연구실
  • 7. Microwave Engineering1. Microwave SystemsMicrowave transmitter (Tx)  Up-conversion: frequency f BB f LO f BB f LO f BB 출처: RFDH.com 1  cos(x) cos(y) 2 cos(x y ) cos(x y) 7 전자파연구실
  • 8. Microwave Engineering1. Microwave SystemsMicrowave receiver (Rx)  Down-conversion: frequency 출처: RFDH.com f f LO f IF f f IF f LO f BB f IF f BB f BB 1  cos(x) cos(y) 2 cos(x y ) cos(x y) 8 전자파연구실
  • 9. Microwave Engineering1. Microwave SystemsMicrowave transceiver  Duplexer: bandpass filter or switch - Loss, tx suppression, channel selection 출처: RFDH.com IF: superheterodyne No IF: direct conversion 9 전자파연구실
  • 10. Microwave Engineering1. Microwave SystemsUplink and downlink Pt 10[ W ] R 40,000[km]  fd 12[GHz ] θ3dB 2 0.55 Pt 100[ W ] fu 14[GHz ] 4m diameter dish 0.6 10 전자파연구실
  • 11. Microwave Engineering1. Microwave SystemsUplink calculation 4 DrPr EIRP LFS Gr [dB]  1 2 Gr Dr EIRP Pt Gt 4 2 Dt Ae 4 R 2 LFS Gt Dt 11 전자파연구실
  • 12. Microwave Engineering1. Microwave SystemsDownlink calculation EIRP Pt GtPr EIRP LFS Gr [dB]  4 Dt 1 2 Gt Dt Dr 4 Am ax 2 2 4 R LFS Gr Dr 12 전자파연구실
  • 13. Microwave Engineering1. Microwave SystemsThermal Noise or Johnson Noise  Thermal noise: white noise, Nyquist formula Pn kTB N T N N0 B kB  Noise power  Noise temperature 13 전자파연구실
  • 14. Microwave Engineering1. Microwave SystemsCarrier to noise ratio  C/No: related to carrier to noise ratio  G/T: Figure of merit  Carrier to noise ratio C C C N N0 B TkB  G/T: sensitivity of receiver C EIRP LFS Gr [dB] 14 전자파연구실
  • 15. Microwave Engineering1. Microwave SystemsMultiplexing: resources  FDM (Frequency Division Multiplexing)  TDM (Time Division Multiplexing)  CDM (Code Division Multiplexing) Communication 15 전자파연구실
  • 16. Microwave Engineering1. Microwave SystemsFDMA (FDM Access)   Resource: frequency  Guard band  Simple transceiver  Interference 16 전자파연구실
  • 17. Microwave Engineering1. Microwave SystemsTDMA (TDM Access)  Resource: time  Guard time  Complicated transceiver GSM: Global System for Mobile commo 17 전자파연구실
  • 18. Microwave Engineering1. Microwave SystemsFH(Frequency Hopping)-CDMA   Resource: code  Precise clock  Very complicated transceiver  Bluetooth, military applications 18 전자파연구실
  • 19. Microwave Engineering1. Microwave SystemsDS(Direct Sequence)-CDMA QPSK: Quadrature Phase Shift Keying 19 전자파연구실
  • 20. Microwave Engineering2. ApplicationsFrequency spectrum Name Frequency[Hz] Wavelength Application EHF 30G-300G 1cm-1mm Car radar SHF 3G-30G 10cm-1cm Radar, satellite UHF 300M-3G 1m-10cm TV, PCS, IMT2000 VHF 30M-300M 10m-1m FM, TV HF 3M-30M 100m-10m Shortwave AM, HAM MF 300k-3M 1km-100m AM LF 30k-300k 10km-1km Navigation VLF 3k-30k 100km-10km Submarine, navigation ELF 30-300 10000km-1000km Submarine 20 전자파연구실
  • 21. Microwave Engineering2. ApplicationsAttenuation  HF application  Attenuation by water and oxygen 21 전자파연구실
  • 22. Microwave Engineering2. ApplicationsELF application  Skin depth: long wavelength  Long antenna: 104km at USA  Unidirectional communication  Slow bit rate: redundancy  Information: code table 2 1 22 전자파연구실
  • 23. Microwave Engineering2. ApplicationsEHF application  Short antenna  Absorption: air, water(60 GHz)  Anti-collision radar: 76 GHz  ITS: Intelligent Transport System Radar ITS 23 전자파연구실

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