Patent ID: 6856131

Claim:
A magnetic sensor comprising a multilayer circuit board with a triplate stripline, comprising: said multilayer circuit board having a first surface conductor layer, a second surface conductor layer, and an inner conductor layer; said first surface conductor layer and said second surface conductor layer having respective one-turn looped ground patterns, and respective ground lead patterns connected respectively to said one-turn looped ground patterns; said one-turn looped ground patterns having respective gaps; said inner conductor layer having a substantially C-shaped signal line sandwiched between said one-turn looped ground patterns and serving as a central conductor of the stripline, and a signal lead line sandwiched between said ground lead patterns and serving as the central conductor of the stripline; said substantially C-shaped signal line extending across said gaps; said substantially C-shaped signal line being connected through a via to said one-turn looped ground patterns; the arrangement being such that if said one-turn looped ground patterns have an inductance L and a capacitor composed between both electrodes provided by ends of said one-turn looped ground patterns which face each other across said gap, one of said ends including said via as an electrode, has a capacitance C, then the product L×C of said inductance L and the capacitance C is 2.5×10 −20 or less and the maximum outer circumference length of said one-turn looped ground patterns is 50 [mm] or less.