| 摘要 |
PROBLEM TO BE SOLVED: To provide a small high frequency semiconductor device and a small portable communication equipment which enable to reduce signal loss in microstrip transmission line and leakage of high frequency signals at the same time. SOLUTION: This high frequency semiconductor device is provided with a multilayer dielectric substrate 5, a package 4 mounted on the surface 19a of the multilayer dielectric substrate 5 which outputs high frequency signals, and a microstrip transmission line for transmitting the high frequency signals outputted from the package 4. The microstrip transmission line is formed by signal lines 15 and 18 which are set on the surface 19a of the multilayer dielectric substrate 5 and a GND pattern 8 which is set on the lower surface 20b of the plane on which the signal lines 15 and 18 in the multilayer dielectric substrate 5 are formed. A GND pattern 16 of the inner layer of the substrate to shield the package 4 is set so that its distance from the package 4 is shorter than that between the GND pattern 8 and the signal lines 15 and 18. |
