1. Technology

1.1 Substrates

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

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