RF Circuit Fundamentals

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)

• ??, ?? ?? ?? ?? ??

• Series Resonator

Series Resonator Circuit
Frequency Response

• ?? ???? Band pass Type

7
Fundamental (2)

• Parallel Resonator

Parallel Resonator Circuit
Frequency Response

• ?? ???? 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/2? ?? ??? ??? Short? ??? ?? ? ??

• ?? ???? ?? Band Pass Type

9
Transmission Line Resonator (2)
2 LAMDA/2? ?? ??? ??? Open?? ??? ??? ??

• ?? ???? ?? Band Rejection Type

10
Dielectric Resonator

• Dielectric Resonator
• MIC ???

• Hair Pin Resonator
• MIC ??

11
Ring Resonator (1)
12
Ring Resonator (2)

• Coupling? ?? ??

Coupling Gap? ??? ?? ?? ??? ????, ??? ??? ?
????.
13
Microwave Divider/Coupler Basic Theory
14
Contents

• Divider
• Coupled Line Coupler
• Branch Line Coupler

15
Divider (1)

• Resistive Divider

• ?? Port? ?? 50 Ohm ?? ??

• Isolation ?? ??

• Isolation ?

16
Divider (2)

• Wilkinson Divider

• ?? Port? ?? 50 Ohm ?? ??

• Isolation ??? ??? ??

• Even and Odd Mode? ??? ??? ???

17
Coupled Line Coupler
S Coupling Gap
18
Branch Line Coupler
19
BALUN (1)

• BALUN ??

• BALUN (Balanced to Unbalanced) ? Balanced
  transmission line ?
• Unbalance transmission line ???? ????
  Transformer

- Unbalanced Transmission Line
- Balanced Transmission Line

• BALUN ??

Mixer, push pull amplifier, multiplier
20
BALUN (2)

• BALUN Type

- Transformer
- ?? ??? ??? ??? BALUN
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 ??
Diode ??

• GaAs - High Cutoff Frequency

- High Breakdown Voltage
- Low Temperature Noise

• Silicon Low cost

Matching ?? ??
30
Diode Mixer (2)
DC Bias? Image Filter? ????.
Diode Mixer Testing (Using Spectrum Analyzer)

• Summary

31
FET Mixer (1)

• Configuration

32
FET Mixer (2)
Nonlinear Generation
33
Balanced Mixer

• Coupling Structure

34
Balanced Mixer
35
Single Balanced Mixer

• Advantage

1. Port Isolation
LO ??? RF ? IF Port?? ??? ??????.
36
Single Balanced Mixer

• Advantage (Cont.)

2. Spurious Performance
3. Lower LO Power

• Disadvantage

1. High conversion loss
2. Perfect Balance ??
37
Single Balanced Mixer

• Configuration

• ????? ?? ? LO ??? ?? Isolation? ????.

38
Double Balanced Mixer

• Configuration

• Advantages

1. Excellent all Ports Isolation
2. Application of broadband RF system
3. Very low LO noise

• NO RF Signal
• NO LO Signal

39
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 System?? ?? ??? ??

• Oscillator? ??? ?? ?? ???? Noise ??? ???? ?

43
Specification (1)

• Stability of the Center Frequency

• Oscillators Noise

- ???? ???? ??? ??? ?? ???? ??
Perfect Oscillator
Change in the oscillators phase and amplitude
over time
44
Specification (2)

• Oscillators Phase Noise

45
Diode Oscillator

• One Port Negative Resistance Oscillator

• Negative Resistor? ????
• ???? ???? ?? ? ??.

46
FET Oscillator (1)

• Configuration

• Negative Resistor? ????? ??
• Termination ??? ???? FET? ???
• ???? ????? ??.
• ??? ???? Load Network? ??
• ????.

47
FET Oscillator (2)

• Stability and Un-stability Region

• Stability circle? ???? ?? Unstable
• ??? ?? ? ??
• Unstable ??? Load Network ??

48
FET Oscillator (3)

• Procedure

49
DRO (1)

• Stabilized DRO

?? ???? ????? ?? ?? ?? DR? ???? ???, ? ?? ??? ??
?? ?? ?? ???? ?? ??.

• ??

Phase Noise? ???, Tunning ??? ??.
50
DRO (2)

• Parallel Feedback DRO

FET? Gate? Source ??, Drain ? Gate ??? DR? ????
???, ? ?? ??? ?? ?? Feedback ???? ????.

• ??

Tunning ??? ??, ????? Output Power ? ??.
51
DRO (3)

• Series Feedback DRO

FET? ?? ?? ??? ???? ???? ??? ?? ??? ???? ????
??? ?? ??? ??? ???? ??? ????, ? ? ??? FET ???
???? FET? ?????? ??? ???? ??.
52
Microwave Low Noise Amplifier Basic Theory
53
Contents

• Design Basic
• Gain Consideration
• Noise Consideration
• Broadband Design
• Conclusion

54
Design Basic (1)

• Selection of the Transistor

- Technical note
55
Design Basic (2)

• Selection of the Transistor (Cont)

Noise Parameters
1) Minimum noise figure2) Noise resistance3)
Optimum noise admittance
56
Design Basic (3)

• Stability ??

Unconditionally Stable Condition

• Power Gain ? Noise Figure ?? Optimization

57
Design Basic (4)

• Summary

58
Gain Consideration (1)

• LNA Design Circuit

Input Reflection Coefficient
Output Reflection Coefficient
59
Gain Consideration (2)

• Available Power Gain

• Operating Power Gain

60
Noise Consideration (1)

• Noise Power Input Noise PowerGain Self
  Noise Power

Optimization
White Noise
Flicker Noise
Thermal Noise
61
Broadband Design
1) Compensated Matching Network
2) Negative Feedback Network
3) Balanced Type Network

• TIP

Broadband? ????? ?? ???? 10 ??? ???? ???? ???
??.
62
Microwave Power Amplifier Basic Theory
63
Contents

• Fundamental
• Design Basic
• Nonlinear Effects
• Conclusion

64
Fundamental (1)

• FET ?? ?? ??

Transconductance
Voltage Controlled Current Generate

• FET ?? ??? ?? FET? ??? ??? ??????,
• Power Amplifier? ????.

65
Fundamental (2)

• Transconductance ??

• Gate ? Drain Voltage? ?? ??? ?? ??

• ?? Gate Voltage? ?? ? ??? ?? ??

• Transconductance ? ??????, Class A, B, C, AB ??
  ??? ? ? ??

66
Fundamental (3)

• Transconductance Time Delay

• Gate-Source Capacitance

• Cgs

• Channel Resistance

• Rds

67
Fundamental (4)

• Class A

68
Fundamental (5)

• Class B

69
Fundamental (6)

• Class AB

70
Fundamental (7)

• Class C

71
Design Basic (1)

• FET? Impedance ?

How to matching ?
72
Design Basic (2)

• Output matching Circuit ?? ?? ?

• Load-Pull Method

• Slide Tuner ?? Stub Tuner? ???? ??? Spec? ?? ??
• ???? ?? ???.
• ??? ???? ?? PCB? ??? ?, Input Matching ??? ????.
• Optimization? ?? ?? Tuning ??? ????.

73
Design Basic (3)
74
Design Basic (4)

• Load Line Method

• Using Transformer

• Using Lumped Components

• ?? Resistance ?? ??? ?? ?? ???
• ?? ?? ????? ???? ???. ???? ?? Load Line? ??? ?

75
Design Basic (5)

• Practice Load Line

76
Design Basic (6)

• Load-Line? Matching? ??
• PA? ??? ???? ???
• ? ??.
• Nonlinear ??? PAE? ??
• ??? ? ? ??.

77
Nonlinear Effect (1)

• Gain Compression Point

• Third Order Intercept Point

Gain Compression Point
78
Nonlinear Effect (2)

• Inter-modulation Distortion (IMD)

- Nonlinear ??? ???? ?? Power Series? ???? ??,
- ???? Two Tone Signal? ????,
???? ?? Harmonics
79
Conclusion

• ???? RF Components? ?? ?? ?? ??? ?? ??
• RF System? ?? ?? ??? ?? ?? ? ??.
• ?? ?? ? ? ??? ?? ??? RF ??? ?? ??? RF Testing?
  ??
• ? ?? ?? ?? ??? ?? ?? ??? ??.