Chatting with colleagues recently recalled some classic board designs in microstrip and stripline and how far the design process has come in a few decades. Computer-aided engineering (CAE) software came on a floppy disk less than 30 years ago, during a time when most engineers were still relying on fundamental mathematics to calculate the line width of a 50-Ohm transmission line. The substrates have gotten much better in the process, with a wider array of material types and dielectric constants now at a designer's disposal.
Perhaps because of today's tools, circuit designers have become more imaginative and creative, based on some of the integrated microwave assemblies (IMAs) developed by companies seeking to combine multiple component functions within a single housing (see Microwaves & RF, December 2010, p. 99). Having the design tools and the high-performance laminates, designers can explore nontraditional ways to design and integrate components, often with significant reductions in size and weight over earlier efforts. With faster computers, more powerful software, and ever-improving microwave materials, it is easy to say that, for microwave circuit designers, the best is yet to come.