RF Circuit Fundamentals Contents Passive Components Resonator Divider

RF Circuit Fundamentals

Contents ë Passive Components - Resonator - Divider - Coupler ë Active Components - Low Noise Amplifier - Power Amplifier - Mixer - Oscillator ë Conclusion

ë Passive Components - Resonator - Divider - Coupler

Microwave Resonator Basic Theory

Contents l Fundamental l Transmission Line Resonator l Dielectric Resonator l Ring Resonator l Conclusion

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

Fundamental (2) Ø Parallel Resonator Circuit Frequency Response Ø 설계 주파수에 Band Rejection Type

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 Ø 설계 주파수에 대한 Band Pass Type

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

Dielectric Resonator ü MIC 불가능 ü Hair Pin Resonator ü MIC 가능

Ring Resonator (1) Ring의 반지름 Mode 수

Microwave Divider/Coupler Basic Theory

Contents l Divider l Coupled Line Coupler l Branch Line Coupler

Divider (1) l Resistive Divider ü 모든 Port에 대해 50 Ohm 매칭 실현 ü Isolation 능력 부재 Ø Isolation ?

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

Coupled Line Coupler S : Coupling Gap

Branch Line Coupler

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

BALUN (2) l BALUN Type - 전송 선로의 길이를 이용한 BALUN - Transformer

ëActive Components - Low Noise Amplifier - Power Amplifier - Mixer - Oscillator

Microwave Mixer Basic Theory

Contents l Introduction l Design Basic l Specification l Diode Mixer l FET Mixer l Balanced Mixer l Conclusion

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

Mixer Basic (1) l To understand the mixer l Using Power Expansion Series

Mixer Basic (2) l Analyzing Power Expansion Series

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

Specification (2) l 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 l Noise Figure

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

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

FET Mixer (1) Advantage l Conversion Gain l Consideration of Noise Figure l Lower LO Power Ø Configuration

FET Mixer (2) Nonlinear Generation

Balanced Mixer l Coupling Structure

Balanced Mixer Ø Single Balanced Mixer Ø Double-Double Balanced Mixer Ø Sub-Harmonic Pumped Mixer Ø Image Rejection Mixer

Single Balanced Mixer l Advantage 1. Port Isolation LO 신호는 RF 와 IF Port에 서 완전히 제거되어진다.

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

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

Double Balanced Mixer l Configuration IF 신호 l Advantages 1. Excellent all Ports Isolation 2. Application of broadband RF system 3. Very low LO noise l NO RF Signal l NO LO Signal

Double-Double Balanced Mixer l Configuration l Advantages 1. Good Linearity l Disadvantages 1. Complex 2. High Cost 3. Difficulty Design

Microwave Oscillator Basic Theory

Contents l Introduction l Specification l Diode Oscillator l FET Oscillator l Dielectric Resonator Oscillator l Conclusion

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

Specification (2) l Oscillator’s Phase Noise Vector - In-Phase Component (AM) - Out of Phase Component (PM)

Diode Oscillator l One Port Negative Resistance Oscillator Ø Negative Resistor로 발생되는 에너지를 이용하여 발진 기 설계.

FET Oscillator (2) l Stability and Un-stability Region Ø Stability circle를 이용하여 쉽게 Unstable 영역을 찾을 수 있음 ØUnstable 영역에 Load Network 구현

FET Oscillator (3) l Procedure

Microwave Low Noise Amplifier Basic Theory

Contents l Design Basic l Gain Consideration l Noise Consideration l Broadband Design l Conclusion

Design Basic (1) l Selection of the Transistor - Technical note

Design Basic (2) l Selection of the Transistor (Cont…) Noise Parameters 1) Minimum noise figure 2) Noise resistance 3) Optimum noise admittance

Design Basic (3) l Stability 판단 Unconditionally Stable Condition l Power Gain 과 Noise Figure 간의 Optimization

Design Basic (4) Ø Summary

Gain Consideration (1) l LNA Design Circuit Input Reflection Coefficient Output Reflection Coefficient

Gain Consideration (2) Transducer Power Gain Operating Power Gain Available Power Gain Ø Operating Power Gain

Noise Consideration (1) Ø Noise Power = Input Noise Power*Gain + Self Noise Power Optimization White Noise Flicker Noise Thermal Noise

Broadband Design 1) Compensated Matching Network 2) Negative Feedback Network 3) Balanced Type Network ü TIP Broadband는 일반적으로 설계 주파수의 10 % 이상의 대역폭을 의미하는 경우가 많다.

Microwave Power Amplifier Basic Theory

Contents l Fundamental l Design Basic l Nonlinear Effects l Conclusion

Fundamental (1) l FET 등가 회로 해석 Transconductance Voltage Controlled Current Generate l FET 등가 회로를 통해 FET의 비선형 특성을 이해함으로써, Power Amplifier를 이해한다.

Fundamental (2) l Transconductance 란? Ø Gate 와 Drain Voltage에 의한 영향을 받는 함수 Ø 특히 Gate Voltage에 의해 큰 영향을 받는 함수 l Transconductance 을 이해함으로써, Class A, B, C, AB 등의 의미를 알 수 있음

Fundamental (3) l Transconductance Time Delay l Gate-Source Capacitance ü Cgs l Channel Resistance ü Rds

Fundamental (4) l Class A

Fundamental (5) l Class B

Fundamental (6) l Class AB

Fundamental (7) l Class C

Design Basic (1) l FET의 Impedance ? How to matching ?

Design Basic (3) Ø Load Line Method (RL) ü The Ratio of the peak voltage to the peak current

Design Basic (4) Ø Load Line Method ü Using Transformer ü Using Lumped Components ü순수 Resistance 값을 가지고 있지 않기 때문에 위와 같은 방법으로는 충분하지 못하다. 그렇다면 실제 Load Line의 모습은 ?

Design Basic (5) Ø Practice Load Line

Nonlinear Effect (1) l Gain Compression Point l Third Order Intercept Point * IIP 3 와 OIP 3 계산하는 방법 Gain Compression Point

Nonlinear Effect (2) l Inter-modulation Distortion (IMD) - Nonlinear 특성을 나타내기 위해 Power Series를 이용하여 풀면, - 입력으로 Two Tone Signal를 입력하면, 제거되지 않는 Harmonics