Line-loss and size-reduction techniques for millimeter-wave rf front-end boards by using a polyimide/alumina-ceramic multilayer configuration

This paper proposes a concept for constructing low-loss and small-size millimeter-wave RF front-end boards by using a polyimide/alumina-ceramic multilayer configuration. This configuration enables us to design wide line-width low-loss microstrip lines. In addition, the board size can be reduced by compactly arranging all RF and DC lines in the intermediate layers of the polyimide/alumina-ceramic substrate. A prototype board designed for the quasi-millimeter-wave region was successfully demonstrated with good performance.