VHF / UHF Filters and Multicouplers

Bernard Piette is a practicing engineer. After working in submarine acoustics, HF electronics, phase-locked loops and telecommunications, he has dedicated his efforts to the design of coaxial cavities and other narrow-band resonators for the last 20 years. He has been a technical manager in several companies specializing in this field, and has designed hundreds of prototypes for numerous French private mobile radio networks such as Radiocom 2000, Rubis and Acropol.

Preface xi

Introduction xvii

Chapter 1. Reminders and General Points 1

1.1. Lines 1

1.2. Adaptation and stationary waves 4

1.3. Smith chart 6

1.4. Power in a line 6

1.5. Line sections 7

1.6. Lines with losses 9

Chapter 2. Measurements in HF 11

2.1. Material 11

2.2. The power bench 11

2.3. Measurements on the network analyzer 14

Chapter 3. Resonant Cavities 25

3.1. Resonance 25

3.2. Coaxial cavities 28

3.3. Quarter-wave cavities 29

Chapter 4. Fabrication and Tuning of Cavities 47

4.1. Standard structures 47

4.2. Materials 53

4.3. Assembly 56

4.4. Temperature stability 58

4.5. Cavity tuning 70

Chapter 5. The Band-pass Filter 83

5.1. The band-pass function 83

5.2. Calculation of a Tchebycheff band-pass 85

5.3. Technologies 87

Chapter 6. The Combline Filter 97

6.1. Architecture 97

6.2. Dimension calculations. Dishal’s Method 105

6.3. Tuning of filters 114

Chapter 7. Channel Multiplexing 129

7.1. Definitions 129

7.2. The duplexer 129

7.3. The combiner 140

Chapter 8. Auxiliary Devices 157

8.1. Introduction 157

8.2. Circulators 157

8.3. The antenna alarms 165

8.4. Loads and attenuators 170

8.5. Reception amplifiers 177

8.6. The impedance adaptor 186

8.7. The 2nd harmonic rejecter 186

Chapter 9. Directive Couplers 189

9.1. Introduction 189

9.2. Technologies 191

9.3. The hybrid transformer 194

9.4. The 180° hybrid ring 196

9.5. The wireline 198

9.6. The “groundless” coupler 199

9.7. The “catnose” coupler 201

9.8. Discrete-elements coupler 202

9.9. Numerical data 204

9.10. Applications 210

Chapter 10. Helical Resonators 213

10.1. Introduction 213

10.2. Functioning 214

10.3. Structures 215

10.4. Tapping and coupling 219

10.5. Quality coefficient 220

10.6. Set-up rules 223

10.7. Applications 224

Chapter 11. Multicouplers 225

11.1. Transmitter multicouplers (TX) 225

11.2. Receiver multicouplers (RX) 235

11.3. TX/RX multicouplers 236

11.4. TMA 240

11.5. Power and intermodulations 243

11.6. Multiband coupling 254

Chapter 12. Utilities 257

12.1. BASIC programs 257

12.2. Varia 264

Chapter 13. Various Questions and Exploratory Ways 271

13.1. The coupler without intrinsic loss 271

13.2. Infinite rejection band-pass 275

13.3. Helix TX multicoupler 276

13.4. Conclusion 278

Bibliography 281

Index 283