High-frequency circuit device and detection system

A high-frequency circuit device comprising:

• a chip which includes a high-frequency element, a high-frequency circuit, a signal conductor, and a chip ground;
• and
• a package substrate which includes a base having an upper surface and a back surface on an opposite side of the upper surface, and on which the chip is disposed,
• the high-frequency circuit device further comprising:
• a shunt path which is constituted by a package signal conductor which is disposed on the upper surface of the package substrate and is electrically connected to the signal conductor, a package first ground which is electrically connected to the chip ground, and a shunt element which is electrically connected to the package signal conductor and the package first ground;
• and
• a package second ground which is disposed at least inside the base of the package substrate or on the back surface of the package substrate, wherein
• a part of the base, a part of the shunt path, and the package second ground constitute a capacitive structure.