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RF Circuit Fundamentals

RF Circuit Fundamentals. Contents. Passive Components. Resonator Divider Coupler. Active Components. Low Noise Amplifier Power Amplifier Mixer Oscillator. Conclusion. Passive Components. Resonator Divider Coupler. Microwave Resonator Basic Theory. Contents. Fundamental

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RF Circuit Fundamentals

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  1. RF Circuit Fundamentals

  2. Contents • Passive Components • Resonator • Divider • Coupler • Active Components • Low Noise Amplifier • Power Amplifier • Mixer • Oscillator • Conclusion

  3. Passive Components • Resonator • Divider • Coupler

  4. Microwave Resonator Basic Theory

  5. Contents • Fundamental • Transmission Line Resonator • Dielectric Resonator • Ring Resonator • Conclusion

  6. Fundamental (1) • 직렬, 병렬 공진 기에 대한 이해 • Series Resonator Series Resonator Circuit Frequency Response • 설계 주파수에 Band pass Type

  7. Fundamental (2) • Parallel Resonator Parallel Resonator Circuit Frequency Response • 설계 주파수에 Band Rejection Type

  8. Transmission Line Resonator (1) * Short-Circuited Lamda/2 Line* Short-Circuited Lamda/4 Line* Open-Circuited Lamda/2 Line 1] LAMDA/2의 선로 길이와 종단이 Short로 구성된 공진 기 설계 • 설계 주파수에 대한 Band Pass Type

  9. Transmission Line Resonator (2) 2] LAMDA/2의 선로 길이와 종단이 Open으로 구성된 공진기 설계 • 설계 주파수에 대한 Band Rejection Type

  10. Dielectric Resonator • Dielectric Resonator • MIC 불가능 • Hair Pin Resonator • MIC 가능

  11. Ring의 반지름 Mode 수 Ring Resonator (1)

  12. Ring Resonator (2) • Coupling에 의한 변화 Coupling Gap이 작아질 수록 삽입 손실은 적어지고, 반대로 선택도 는 악화된다.

  13. Microwave Divider/Coupler Basic Theory

  14. Contents • Divider • Coupled Line Coupler • Branch Line Coupler

  15. Divider (1) • Resistive Divider • 모든 Port에 대해 50 Ohm 매칭 실현 • Isolation 능력 부재 • Isolation ?

  16. Divider (2) • Wilkinson Divider • 모든 Port에 대해 50 Ohm 매칭 실현 • Isolation 능력을 가지고 있음 • Even and Odd Mode를 이용한 해석이 가능함

  17. Coupled Line Coupler S : Coupling Gap

  18. Branch Line Coupler

  19. BALUN (1) • BALUN 정의 • BALUN (Balanced to Unbalanced) 은 Balanced transmission line 과 Unbalance transmission line 회로간을 연결하는 Transformer - Unbalanced Transmission Line - Balanced Transmission Line • BALUN 응용 Mixer, push pull amplifier, multiplier

  20. BALUN (2) • BALUN Type - 전송 선로의 길이를 이용한 BALUN - Transformer

  21. Active Components • Low Noise Amplifier • Power Amplifier • Mixer • Oscillator

  22. Microwave Mixer Basic Theory

  23. Contents • Introduction • Design Basic • Specification • Diode Mixer • FET Mixer • Balanced Mixer • Conclusion

  24. Introduction • Three Ports Device RF (Radio Frequency) IF (Intermediate Frequency) LO (Local Oscillator Frequency) • Mixer is multiplier

  25. Mixer Basic (1) • To understand the mixer • Using Power Expansion Series

  26. Mixer Basic (2) • Analyzing Power Expansion Series

  27. Specification (1) • Image frequency • Conversion Gain (loss) • Port Return loss • Gain Compression • 3th-order IM Distortion

  28. Specification (2) • Port Isolation - LO to RF Port Isolation - LO to IF Port Isolation - RF to IF Port Isolation - Inter-port Isolation (Dissipate Ant) - Inter Mixer Isolation • Noise Figure

  29. Diode Mixer (1) Specification 결정 Diode 선택 • GaAs : - High Cutoff Frequency - High Breakdown Voltage - Low Temperature Noise • Silicon : Low cost Matching 회로 설계

  30. Diode Mixer (2) DC Bias와 Image Filter를 삽입한다. Diode Mixer Testing (Using Spectrum Analyzer) • Summary

  31. Advantage • Conversion Gain • Consideration of Noise Figure • Lower LO Power FET Mixer (1) • Configuration

  32. FET Mixer (2) Nonlinear Generation

  33. Balanced Mixer • Coupling Structure

  34. Single Balanced Mixer • Double Balanced Mixer • Double-Double Balanced Mixer • Sub-Harmonic Pumped Mixer • Image Rejection Mixer Balanced Mixer

  35. Single Balanced Mixer • Advantage 1. Port Isolation LO 신호는 RF 와 IF Port에서 완전히 제거되어진다.

  36. Single Balanced Mixer • Advantage (Cont….) 2. Spurious Performance 3. Lower LO Power • Disadvantage 1.High conversion loss 2. Perfect Balance 필요

  37. Single Balanced Mixer • Configuration • 상대적으로 매우 큰 LO 신호에 대한 Isolation이 가능하다.

  38. IF 신호 Double Balanced Mixer • Configuration • Advantages • Excellent all Ports Isolation • Application of broadband RF system • Very low LO noise • NO RF Signal • NO LO Signal

  39. Advantages • Good Linearity • Disadvantages • Complex • High Cost • Difficulty Design Double-Double Balanced Mixer • Configuration

  40. Microwave Oscillator Basic Theory

  41. Contents • Introduction • Specification • Diode Oscillator • FET Oscillator • Dielectric Resonator Oscillator • Conclusion

  42. Introduction • RF System에서 매우 중요한 부품 • Oscillator의 성능에 따라 전체 시스템의 Noise 특성이 결정되어 짐

  43. Specification (1) • Stability of the Center Frequency • Oscillator’s Noise - 출력되는 주파수와 위상의 변화에 의해 발생하는 잡음 Perfect Oscillator Change in the oscillator’s phase and amplitude over time

  44. Noise Vector - In-Phase Component (AM) - Out of Phase Component (PM) Specification (2) • Oscillator’s PhaseNoise

  45. Diode Oscillator • One Port Negative Resistance Oscillator • Negative Resistor로 발생되는 에너지를 이용하여 발진 기 설계.

  46. FET Oscillator (1) • Configuration • Negative Resistor로 발생시키기 위해 Termination 회로를 이용하여 FET를 불안정 영역에서 동작하도록 한다. • 발생된 에너지를 Load Network을 통해 출력한다.

  47. FET Oscillator (2) • Stability and Un-stability Region • Stability circle를 이용하여 쉽게 Unstable 영역을 찾을 수 있음 • Unstable 영역에 Load Network 구현

  48. FET Oscillator (3) • Procedure

  49. DRO (1) • Stabilized DRO 발진 주파수를 안정시키기 위해 출력 단에 DR를 위치시킨 것으로, 이 때의 유전체 공진 기는 대역 통과 필터로써 역할 한다. • 단점 Phase Noise가 나쁘고, Tunning 범위가 좁다.

  50. DRO (2) • Parallel Feedback DRO FET의 Gate와 Source 또는, Drain 과 Gate 사이에 DR를 위치시킨 것으로, 이 때의 유전체 공진 기는 Feedback 요소로써 사용한다. • 단점 Tunning 범위가 좁고, 상대적으로 Output Power 가 작다.

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