1. Technology

1.1 Substrates

The performance obtained with circuits is highly dependent on the quality of the dielectric (or even semiconductor) substrates used in their manufacture. The material chosen will be decisive in achieving low losses and high stability of the propagation constant, which are essential conditions for ensuring the proper functioning of a microwave circuit, even under severe operating conditions (temperature, humidity, vibrations).

Various materials have been developed, with relative permittivities ranging from 2 to 12 for the most common ones.