Quite Universal Circuit Simulator (QUCS) is a great little Spice-like open-source tool that runs quickly, has a wide range of components, rather intuitie interface (but a so-so manual), and will execute S-parameter analysis. Available at qucs.sourceforge.net/.
Drones are, in essence, flying autonomous vehicles. Pros and cons surrounding drones today might well foreshadow the debate over the development of self-driving cars. In the context of a strongly regulated aviation industry, "self-flying" drones pose a fresh challenge. How safe is it to fly drones in different environments? Should drones be required for visual line of sight – as are piloted airplanes? Join EE Times' Junko Yoshida as she moderates a panel of drone experts.