Book contents
- Frontmatter
- Contents
- Preface
- List of contributors
- List of abbreviations
- Part I General concepts
- Part II Microwave instrumentation
- 3 Microwave synthesizers
- 4 Real-time spectrum analysis and time-correlated measurements applied to nonlinear system characterization
- 5 Vector network analyzers
- 6 Microwave power measurements
- 7 Modular systems for RF and microwave measurements
- Part III Linear measurements
- Part IV Nonlinear measurements
- Index
- References
6 - Microwave power measurements
from Part II - Microwave instrumentation
Published online by Cambridge University Press: 05 June 2013
- Frontmatter
- Contents
- Preface
- List of contributors
- List of abbreviations
- Part I General concepts
- Part II Microwave instrumentation
- 3 Microwave synthesizers
- 4 Real-time spectrum analysis and time-correlated measurements applied to nonlinear system characterization
- 5 Vector network analyzers
- 6 Microwave power measurements
- 7 Modular systems for RF and microwave measurements
- Part III Linear measurements
- Part IV Nonlinear measurements
- Index
- References
Summary
Introduction
In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts – the more wattage, the more power, or equivalently the more electrical energy is used per unit time [1]. Energy transfer can be used to do work, so power is also the rate at which this work is performed [2].
For systems or circuits that operate at microwave frequencies, the output power is usually the critical factor in the design and performance of that circuit or system. Measurement of the power (signal level) is critical in understanding everything from the basic circuit element up to the overall system performance. The large number of signal measurements that can be made and their importance to system performance means that the power-measurement equipment and techniques must be accurate, repeatable, traceable, and convenient.
In a system, each component in a signal chain must receive the proper signal level from the previous component and pass the proper signal level on to the succeeding component. If the output signal level becomes too low, the signal becomes obscured in noise. If the signal level becomes too high, though, the performance becomes nonlinear and distortion can result. The uncertainties associated with the measurement of power also play a very important role in the development and application of microwave circuits. For example, a 10 W transmitter costs more than a 5 W transmitter.
- Type
- Chapter
- Information
- Modern RF and Microwave Measurement Techniques , pp. 130 - 159Publisher: Cambridge University PressPrint publication year: 2013