Nathan Sokal and the Class-E Amplifier [From the Guest Editor's Desk]

The articles in this special issue expand on a session at the 2017 IEEE Microwave Theory and Techniques Society International Microwave Symposium, focuses on Nathan Sokal and the class-E amplifier. It serves both as a memorial to Nat Sokal and an overview of class-E technology. I began interacting and collaborating with Nat in 1973 on RF applications.