AWR eBooks

RF Electronics Chapter 1: Introduction Page 1 2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0. Chapter 1 Introduction RF Electronics Design The Radio Frequency (RF) spectrum range is normally considered to include frequencies from 30 MHz to 300 GHz. That frequency range is further divided into Very High Frequency (VHF), Ultra High Frequency (UHF), Super High Frequency (SHF) and Extremely High Frequency (EHF) as shown in figure 1.1. The Tremendously High Frequency (THF) or Terahertz frequency band requires design techniques that are not covered by this book. Figure 1.1 RF Spectrum Bands. RF electronic designs require different techniques than electronic designs at lower frequency since: 1 The resistors, capacitors and inductors used do not necessarily behave like ideal components. In particular, leads on resistors and capacitors have an inductance associated with them, which can easily dominate. 2 The wavelength of the signals is comparable to the size of components used. This presents some challenges and some opportunities. 3 The track lengths may be a significant fraction of a wavelength, allowing Microstrip-lines or Striplines, to be used as elements for filters, couplers, impedance matching circuits etc. 4 The tracks on the circuit boards should be seen as transmission lines with a characteristic impedance, chosen such that the transmission line and the devices connected to it, satisfy the circuit specifications at all the required frequencies. Conventional printed circuit boards are lossy at high frequencies. Circuit boards for RF and Microwave frequencies normally use low loss materials and have carefully controlled thicknesses, to provide constant impedances for transmission lines. 5 For EHF designs, the wavelength is comparable to the package size of IC's used to realise the circuit, so that filters, couplers, impedance matching circuits and antennas, can be realises in silicon as part of the IC. RF Electronics: Design and Simulation 1 www.cadence.com/go/awr

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