AWR eBooks

X Preface The material presented in this book evolved from teaching analogue electronics courses at James Cook University (JCU) over many years. When I started teaching, electronics design, computer simulation tools were non-existent and most of the design optimisation was done by replacing components in hardware. It was a big step forward when EESOF became available in the mid 1980's. The computer simulation tools have progressed enormously since then. Early in my career, I was given the following advice for designing electronic circuits. "Get the circuit to work and then start taking components out. Put back the one that stops the circuit from working." This is a silly statement, since in a proper design removing any component will stop if from working, but it does illustrate the goal of any designer: Design a circuit that will work first time, according to specification. It must do so reliably and at as low a cost as possible. Since labour is expensive, the circuits also should not require any adjustments after manufacture in order that they meet the specifications. Using the computer simulation used in this book, we can now design our analogue electronic circuits such that they satisfy all these conditions. We can change active device parameters in the simulation, to ensure that variations in performance during manufacturing do not cause the circuit to fail to meet the specifications. We can check that the circuit will meet specifications under any permitted temperature, power supply and input signal variations. For RF circuits, we can, by simulation, change microwave PCB substrates for lower cost FR4 type substrates to verify if the circuit still performs correctly with the lower cost substrate. For consumer or space critical applications, the computer simulation tools used in this book will allow Low Temperature Cofired Ceramic (LTCC) or MMIC circuits to be designed. With those circuits, one cannot open them up to change components. They must be correct right from the start. During the last 20 years, much of the analogue electronics in radio and TV receivers has been replaced with digital electronics, causing a change in the operating frequency of analogue electronic designs. There has been a rapid growth in the number of radio transmitters and receivers used. Many developed countries now have more mobile phones than people. Most smart-phones and computers use WLAN/WiFi to access the internet. WLAN/WiFi, Bluetooth, Wireless Gigabit, WiMax, Zigbee, W-CDMA, LTE and 5G are all relatively new communication systems using microwave (above 1 GHz) frequency bands. At present, there is a rapid growth in automotive radars for collision prevention and autonomous vehicle operation. IoT and Electricity Demand Side Management will result in most consumer devices having WiFi or similar communication technology, to control their operation or advise the owner of a fridge that the milk bottle is empty. Because of increasing demand for radio spectrum, the operating frequencies are getting higher and the transmitters need to have a higher spectral cleanliness. This explosion in microwave system applications requires a matching RF and microwave electronic design capability from our engineers. More stringent filtering is required and less intermodulation distortion is permitted from amplifiers, to ensure systems do not interfere with each other. 20 years ago, most electronic designs using microwave frequencies were for military, instrumentation, or high-end communication applications, such as microwave radio links operated by Telcos. Now most microwave designs are for consumer applications. As a result, the emphasis on reducing the cost of both the circuit and the design has become more important. RF and microwave circuit simulation play a significant part in this cost reduction. RF Electronics: Design and Simulation X www.cadence.com/go/awr

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