Communication module
A communication module includes a filter element, a package substrate on which the filter element is mounted, and a module substrate on which the package substrate is mounted. Each of the package substrate and the module substrate is formed of a laminate of a plurality of metal layers and a plurality of insulation layers. An outermost insulation layer forming a mounting surface of the package substrate that is a surface on which the filter element is mounted has a thickness smaller than a thickness of at least one of the other insulation layers included in the package substrate. An outer insulation layer forming a mounting surface of the module substrate that is a surface on which the package substrate is mounted has a thickness smaller than a thickness of at least one of the other insulation layers included in the module substrate.
1. A communication module comprising:
a filter element;
a package substrate on which the filter element is mounted; and
a module substrate on which the package substrate is mounted,
wherein each of the package substrate and the module substrate is formed of a laminate of a plurality of metal layers and a plurality of insulation layers,
wherein an outer insulation layer forming a mounting surface of the package substrate that is a surface on which the filter element is mounted has a thickness smaller than a thickness of at least one of the other insulation layers included in the package substrate,
wherein an outer insulation layer forming a mounting surface of the module substrate that is a surface on which the package substrate is mounted has a thickness smaller than a thickness of at least one of the other insulation layers included in the module substrate, and
wherein said outer insulation layer of the package substrate is thinner than said outer insulation layer of the module substrate.
2. The communication module according to claim 1 , wherein a ground pattern is provided on a back face of the package substrate, the back face being opposite to the mounting surface of the outer insulation layer of the package substrate.
3. The communication module according to claim 1 , wherein a ground pattern is provided on a back face of the module substrate, the back face being opposite to the mounting surface of the outer insulation layer of the module substrate.
4. The communication module according to claim 2 , wherein a ground pattern is provided on a back face of the module substrate, the back face being opposite to the mounting surface of the outer insulation layer of the module substrate.
5. The communication module according to claim 1 , wherein the outer insulation layer of the package substrate has a relative dielectric constant smaller than, or identical to, a relative dielectric constant of another insulation layer included in the package substrate.
6. The communication module according to claim 1 , wherein the outer insulation layer of the module substrate has a relative dielectric constant smaller than, or identical to, a relative dielectric constant of another insulation layer included in the module substrate.