Ceramic provides a better dielectric conductivity. Therefore ceramic is the optimum substrate for all applications that operate in high frequency regions, such as Radar technology.
Ceramic as a substrate has an excellent thermal conductivity – better than FR4. As a result, the temperature stability of your product is considerably increased.
Ceramic is generally more suitable for rough ambient conditions, such as Oil or extreme climatic conditions. Furthermore, in a hybrid circuit with integrated resistors in thick layer circuits less mechanical connections are necessary than in the case of a PCB circuit. This mechanical strength provides an increased reliability even at high vibrations.
Organic PCBs contain resins that can outgas. In certain circumstances this may lead to corrosion and subsequently to failure of the module. Concerning ceramic outgassing is excluded due to the material properties.
On ceramic the components can be placed in a very high density and still ensure a high reliability. Thus a hybrid circuit can be carried out significantly smaller than on a PCB board.