Manufacturing Methods Based on Planar Circuits

Abstract

Manufacture of hybrid 3D-planar circuits, especially those incorporating empty waveguides on substrates, can benefit from most standardized planar fabrication processes, although they are not exactly the same. For this reason, planar circuit manufacturing methods must be adapted to the requirements of these new circuits. Through numerous fabrications and successful designs, several enhancing strategies have been established to improve all the manufacturing phases to achieve better results. They all have been proved in the following substrate-integrated technologies for the manufacturing of microwave devices: ESIW, ESICL, continuous profile, and microstrip. Thanks to these improvements, good-quality prototypes such as transitions, filters, circulators, couplers, antennas, among others, have been fabricated. Throughout the next chapter, these strategies applied along the manufacturing process will be explained: from the first manufacturing phase to the final welding of the whole circuit and taking into account external elements such as wires that may be present in these structures. For this purpose, some devices that have been published will be used as examples.