A circuit board comprises a signal routing layer, a first dielectric layer, a second dielectric layer, a third dielectric layer, a first ground layer, a second ground layer, and a third ground layer. The signal routing layer includes chip traces, connector traces, and signal traces connected to components. The first dielectric layer, the first ground layer, the second dielectric layer, the second ground layer, the third dielectric layer, and the third ground layer, in that order, are located at gradually increasing distances from the signal routing layer. The first ground layer corresponds to the chip traces, the second ground layer corresponds to the signal traces, and the third ground layer corresponds to the connector traces.