Simulation software can be costly, especially when considering a full-featured suite of programs with S-parameter-based circuit simulators, layout editors, and three-dimensional (3D) electromagnetic (EM) simulators. But in the early days of high-frequency computer modeling, many engineers relied on free tools for analysis and design, including the collection of utilities compiled by the then Hewlett-Packard Co. (now Agilent Technologies) known as ApCAD. The ApCAD programs included such programs as cascaded noise-figure calculators for receiver front ends and simple impedance-matching tools for transistors.

In the spirit of no-cost simulations, Analog Devices has offered tools in the past for such tasks as analyzing phase-locked-loop (PLL) performance and examining direct-digital-synthesizer (DDS) characteristics. The company's latest free simulation offering is the short-range-device (SRD) Design Studio, which is based on their lines of SRD transmitters and transceivers. As someone who has spent many years in designing and developing integrated circuits, Christian Kermarrec, the firm's Vice-President for RF and Wireless Systems, notes "Designers using SRD Design Studio can quickly and efficiently conduct real-time simulations, test various configurations, and troubleshoot potential problems when implementing short-range wireless links in their design."

This level of software support certainly makes it easier to experiment without reaching for the full-scale simulation tools. And making it easier to use a given transmitter or transceiver ultimately speeds the time to market for the final product, even if it was accomplished with a free program.

By Jack Browne, MWRF Technical Director