Foreword: Special Issue on Microwave Circuits

The articles chosen for this Special Issue on Microwave Circuits reflect both the consolidation of previous knowledge, in the form of pragmatic designs and design metb ods, and new trends in the field. The new trends include the increasing use of transistors in microwave circuits, and the coalescence of the formerly dichotomous "microwave" and "logic\´ disciplines. The latter trend is accelerated by the need of logic circuit designers to incorporate microwave technology into their ever-faster systems.