With the increase of power and frequency of wireless power transmission systems, requirements for the control performance of power transmission and real-time high-frequency data interaction between the power transmitter and receiver continue to increase. This paper proposes an implementation method for low-cost and highly robust wireless power and signal transfer (SWPDT). Based on the traditional magnetically coupled wireless power transfer (WPT) system structure, the two metal-shielded pole plates on the outside of the magnetically coupled coil provide an independent capacitive channel for data transmission, and the magnetically coupled mutual inductance coil provides an independent inductive channel for power transmission, which achieves decouples energy transmission and signal transmission. The six-plate capacitive coupling is constructed under the coil parasitic capacitance. The mathematical and physical models of six-plate capacitive coupling are constructed, and the fourth-order resonant network is built to achieve full-duplex communication through four blocking networks and compensation structures. The overall cost and size of the WPT system are significantly reduced. The crosstalk of power transmission on signal transmission is reduced without changing the power transmission capability, and the power transmission frequency no longer restricts the transmission frequency. Finally, a 50 W power transmission prototype is constructed. The power transmission efficiency reaches 80% under the 17 cm coil distance condition. The full-duplex parallel transmission of power and signals is achieved within a serial communication bit rate range from 240 to 800 kbit/s. The BERs can be maintained at a low level, and the effects of the pole plate offset on the signal and power transmission are verified. The transverse drift ratio reaches 87.5.0%. In the case of the pole plate offset with an 87.72% lateral drift ratio, the signal transmission efficiency of the system is only 22.66%. Under the magnetic shielding function of the metal pole plate, the signal transmission is robust under extreme working conditions, improving the reliability of the power transmission process. The shielding pole plate reduces the power transmission efficiency but has a significant shielding effect on electromagnetic leakage. Compared with the existing wireless energy and data synchronous transmission technology in transmission efficiency, transmission distance, signal rate, and BER, the correctness and feasibility of the proposed method are verified.