| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that conventional circuit board a high-frequency wave of 10 GHz or higher cannot be transmitted due to deterioration of transmission characteristics of a high-frequency signal, by abruptly changing an impedance at a connecting pad by generating a stray capacitance between the pad and a round layer of the board. SOLUTION: The circuit board 1 for the high-frequency wave comprises the connecting pad 3 electrically connected to a high-frequency semiconductor element 2 on the lower surface of an insulating board 1a, having a relative permittivity (ε) to input/output a high-frequency signal having a frequency F (GHz) to/from an external electric circuit 4. In this board 1, an area S (mm2) of the pad 3 satisfies the equation 2<=S×1,000<=404.4-4.2F-16.7ε. Thus, a high stray capacitance which would adversely influences the input/output the high-frequency signal are not generated between the pad and the ground layer of the board 1, and signals of 10 to 80 GHz can be transmitted with proper transmission characteristics. |
