Low-EMI electronic apparatus, low-EMI circuit board, and method of manufacturing the low-EMI circuit board.

An electronic apparatus comprising:

• a circuit board suppressing spurious radiation having a first ground layer, a second ground layer, a power layer, a first dielectric material layer, a second dielectric material layer and a resistor layer;
• an electronic part arranged on said circuit board and electrically connected to at least said first ground layer or said second ground layer or said power layer;
• and
• a housing for said circuit board on which said electronic part is arranged,
• wherein said power layer is arranged between said first ground layer and said second ground layer, said first dielectric material layer joins said first ground layer and said power layer, said second dielectric material layer joins said second ground layer and said power layer, and said resistor layer joins said first ground layer and said second ground layer.

A structure comprising a first conductor layer, a second conductor layer, a third conductor layer, a first dielectric material layer, a second dielectric material layer and a resistor layer, wherein:

• said second conductor layer is sandwiched by said first dielectric material layer and said second dielectric material layer, and said resistor layer is arranged between said first conductor layer and said third conductor layer;
• a capacitor C is formed by a series connection, through said second conductor layer, of a capacitor C1 formed by arranging said first dielectric material layer between said first conductor layer and said second conductor layer and a capacitor C2 formed by arranging said second dielectric material layer between said second conductor layer and said third conductor layer, and a resistor R is formed by arranging said resistor layer around said second conductor layer sandwiched by said first dielectric material layer and said second dielectric material layer to form a parallel circuit;
• and
• said resistor layer is arranged in an end periphery of a parallel plate line formed by said first conductor layer and said third conductor layer among three parallel plate lines formed by said first conductor layer and said second conductor layer, by said second conductor layer and said third conductor layer and by said first conductor layer and said third conductor layer to form the resistor R which is equal to a matching termination resistor R0.

A structure comprising a first ground layer, a second ground layer, a power layer, a first dielectric material layer, a second dielectric material layer and a resistor layer, characterized in that:

• said power layer is arranged between said first ground layer and said second ground layer;
• a capacitor C formed by a series connection, through said power layer, of capacitors C1 and C2 formed by sandwiching said first dielectric material layer and said second dielectric material layer between said first ground layer and said power layer and between said second ground layer and said power layer, respectively, and a resistor R formed by sandwiching said resistor layer between said first ground layer and said second ground layer and arranging said resistor layer around said first dielectric material layer, said second dielectric material layer and said power layer form a parallel circuit;
• and
• said resistor layer is arranged in an end periphery of a parallel plate line formed by said first ground layer and said second ground layer among three parallel plate lines formed by said first ground layer and said second ground layer, by said second ground layer and said power layer and by said first ground layer and said power layer to form the resistor R which is equal to a matching termination resistor R0.

An electronic apparatus comprising:

• a circuit board suppressing spurious radiation having a ground layer and a power layer, said circuit board including a dielectric material layer and a resistor layer arranged between said power layer and said ground layer;
• an electronic part arranged on said circuit board and electrically connected to at least said ground layer and said power layer;
• and
• a housing for said circuit board on which said electric part is arranged,
• wherein said resistor layer is contacted to said power layer or said ground layer and wherein a shape of said resistor layer is substantially the same as a shape of said power layer or said ground layer which is contacted to said resistor layer.

An electronic apparatus comprising:

• a circuit board suppressing spurious radiation having a ground layer and a power layer, said circuit board including a dielectric material layer and a resistor layer arranged between said power layer and said ground layer;
• an electronic part arranged on said circuit board and electrically connected to at least said ground layer or said power layer;
• and
• a housing for said circuit board on which said electronic part is arranged,
• wherein said first dielectric material layer and said second dielectric material layer are arranged between said power layer and said ground layer, and wherein said resistor is sandwiched by said first dielectric material layer and said second dielectric material layer such that said resistor layer is not electrically connected to said power layer and said ground layer.

An electronic apparatus comprising:

• a circuit board suppressing spurious radiation having a ground layer, a power layer, and a dielectric material layer and a resistor layer arranged between said one first conductor layer and said second conductor layer;
• an electronic part arranged on said circuit board and electrically connected to at least said ground layer or said power layer;
• and
• a housing for said circuit board on which said electronic part is arranged,
• wherein said resistor layer is contacted to said ground layer or said power layer, and a shape of said resistor layer is arranged to be the same as a shape of a peripheral portion of said ground layer or said power layer which is contacted to said resistor layer.

A method of manufacturing a circuit board comprising the steps of:

• forming a first conductor layer on a first surface of a first dielectric pre-structure and a second conductor layer on a second surface of said first dielectric pre-structure;
• laminating said first dielectric pre-structure and a second dielectric pre-structure to form a laminated structure;
• forming a third conductor layer on one surface of said second dielectric pre-structure;
• and
• forming a resistor layer on a side surface of said laminated structure to connect said first conductor layer and said second conductor layer through said resistor layer electrically.