CHAPTER EIGHT
CAD for Low-Cost and High-Volume Production
There have been extraordinary recent advances in computer-aided design (CAD) of RF/microwave circuits, particularly in full-wave electromagnetic (EM) simulations. They have been implemented both in commercial and specific in-house software and are being applied to microwave filters simulation, modeling, design, and validation [1,2]. The developments in this area are certainly stimulated by ever-increasing computer power.
Another driving force for the developments is the requirement of CAD for low-cost and high-volume production [3,4]. In general, besides the investment for tooling, the cost of filter production is mainly affected by materials and labor. Microstrip filters using conventional printed circuit boards are of low cost. Using better materials such as superconductors can give better performance of filters, but is normally more expensive. This may then be evaluated by a cost-effective factor in terms of the performance. Labor costs include those for design, fabrication, testing, and tuning. Here the weights for design and tuning can be reduced greatly by using CAD. For instance, in addition to controlling fabrication processes, to tune or not not-to-tune is also more of a question of design accuracy; tuning can be very expensive and time-consuming for mass production. CAD can provide more accurate design with less design iterations, leading to first-pass or tuneless filters. This not only reduces the labor intensiveness ...
