PCB circuit board, signal detection device and PCB circuit board preparation method

The invention relates to a PCB circuit board, a signal detection device and a PCB circuit board preparation method. The PCB circuit board comprises at least three core boards, at least one buried groove, at least one insulating blind hole and dielectric layers, wherein the at least three core boards, the at least one buried groove and the at least one insulating blind hole are sequentially stacked in the thickness direction, and the dielectric layers are located between the adjacent core boards in the thickness direction. Wherein the at least one buried groove is located in the core plate between the adjacent dielectric layers in the thickness direction, and the at least one buried groove is used for containing a target oil body; the at least one insulating blind hole penetrates through the at least one core plate and the at least one dielectric layer in the thickness direction and is communicated with the at least one buried groove, so that a target oil body can be stored in the PCB, the overall assembly are