VHF / UHF Filters and Multicouplers: Application of Air Resonators

Chapter 13

Various Questions and Exploratory Ways

Each profession, each activity, each branch of physics, has its specific problems, its techniques and ideas. Depending on the field of application, innovations come more or less quickly, discoveries are more or less easy, but each engineer has to take care, when daily obligations allow them the time, to improve their knowledge and technologies, to contribute to the progress made. In spite of this being a particular domain where the essential already seems to be known, the small world of high-frequency passive devices also possess its margin of progression, related particularly to the ever new demands of radiocommunications. We will find in what follows a certain number of ideas not implemented yet, but that merely await the opportunity to be so, as well as certain questions with or without answers, but that constantly inspire existential thinking among technicians.

13.1. The coupler without intrinsic loss

A myth, or an eternal hope, the coupler without internal loss has become a recurrent theme for free discussion that sometimes takes place during breaks in the most diverse mediums of HF applications. We can ask ourselves if there is a precise justification for the fact we are condemned to having to sacrifice half of the power of two signals, from the time we have decided to combine them in the same propagation channel. In fact, there are many devices where we can group two carriers without having to pay the price these fatidic ...