| 摘要 |
A multilayer dielectric substrate 2 in which a cavity 33 is formed on a substrate and semiconductor devices 3 are mounted in the cavity 33 includes openings 50 formed in surface-layer grounding conductors 18 arranged on the substrate in the cavity 33, impedance transformers 60 electrically coupled with the cavity 33 via the openings 50 and having a length of about 1/4 of an in-substrate effective wavelength of a signal wave, short-circuited-end dielectric transmission lines 80 having a length of about 1/4 of the in-substrate effective wavelength of the signal wave, coupling openings 65 formed in inner-layer grounding conductors in connecting sections of the impedance transformers 60 and the dielectric transmission lines 80, and resistors 70 formed in the coupling openings 65. The multilayer dielectric substrate 2 improves efficiency of absorption of radio waves to surely control cavity resonance and cause a semiconductor device and a transmission line to stably operate. |
