Understanding the role and implications of impedance in RF transmission lines and antennas is vital to successful system performance. The traditional matching approaches are still in wide use, but new application requirements and advances in components, modeling and simulation, and manufacturing precision have also provided new ways to address the matching problem. Q: What is […]
VSWR and impedance, Part 5: Making a match
Understanding the role and implications of impedance in RF transmission lines and antennas is vital to successful system performance. The importance of impedance matching, minimizing reflections, and keeping a low VSWR means these topics have been studied extensively, ranging from analytical perspectives through many physical designs and implementations. This section looks at some matching techniques. […]
VSWR and impedance, Part 4: Measurements
Understanding the role and implications of impedance in RF transmission lines and antennas is vital to successful system performance. The previous section looked at the basics of VSWR. This section looks at two approaches to measuring impedance and VSWR. Q: What do engineers and users need to know? A: For some applications, such as connecting […]
VSWR and impedance, Part 3: Implications
Understanding the role and implications of impedance in RF transmission lines and antennas is vital to successful system performance. The previous sections looked at the basics of impedance and VSWR. This section looks at the implications of VSWR measurements. Q: Why should I care about reflected waves due to impedance mismatch and resultant non-unity VSWR? […]
VSWR and impedance, Part 2: Reflected power
Understanding the role and implications of impedance in RF transmission lines and antennas is vital to successful system performance. Part 1 of this article looked at the basics of impedance matching and power transfer. This part looks at the closely related topic of nominal impedance and VSWR. Q: Why all this worry? Aren’t RF systems […]
The basics of VSWR and impedance, Part 1
Understanding the role and implications of impedance in RF transmission lines and antennas is vital to successful system performance. In any design requiring transfer of an RF signal and its energy from one functional block or component in a system to a subsequent one in the signal chain, there’s almost always the issue of impedance […]
Understanding the lock-in amplifier, Part 2: The homodyne solution
The lock-in amplifier allows tiny signals from sensors to be captured with precision despite unavoidable noise limitations and other test and measurement challenges of the signal chain. Part 1 of this article looked at the challenges of capturing low-level signals such as from a photodetector despite unavoidable signal-path noise, drift, offsets, and other imperfections. This […]
Understanding the lock-in amplifier, Part 1: The sensing challenge
The lock-in amplifier allows tiny signals from sensors to be captured with precision despite unavoidable noise limitations and other signal-chain test and measurement challenges. There are some basic test and measurement instruments common to scientific labs and engineering benches of all types, whether electronic, biomedical, chemical, optical, or mechanical. Among these are the digital voltmeter, […]
Stress & Strain, Part 2: Implications for electronics
The mechanical strain induced on electronic components due to mechanical and thermal stress is an important aspect of their performance consistency and limitations; stress is also used to enable some materials to provide critical electronic functions. Part 1 of this FAQ looked at the basic principles and tests for material strain when stress is applied. […]
Stress & Strain, Part 1: Fundamental principles
The mechanical strain induced on electronic components due to mechanical and thermal stress is an important aspect of their performance consistency and limitations; stress is also used to enable some materials provide critical electronic functions. Although electronic systems and circuits invoke intangibles such as voltages, currents, power, EM fields, and Maxwell’s equations — to cite […]
