1. An electronic circuit board comprising:a substrate having a multilayer structure including at least one ground layer; and
an oscillation circuit provided on the substrate,
wherein the oscillation circuit includes an oscillator and a circuit including an amplifier electrically connected to each other, the oscillator and the amplifier each including an electrically conductive bump, and
a ground layer closest to the oscillation circuit in the multilayer structure includes a plurality of apertures formed therein that correspond to locations of the electrically conducive bumps in a plan view of the electronic circuit board,
wherein edges of the apertures entirely surround and are spaced apart from the electrically conductive bumps in the plan view of the electronic circuit board.