An in-band full-duplex scheme is proposed for simultaneous power transfer and data delivery in far-field wireless sensor systems. To realize two independent links for power and data delivery, a high isolation level between the local transmitter and receiver of the in-band full-duplex system is critical. An RF front-end architecture, here standing for a dual-polarized antenna array with its feeding network, is presented and detailed in this paper. By using the proposed architecture, self-interference can be well canceled within a wide frequency band, leading to a high inter-port isolation level. To demonstrate the performance of such a front-end structure, an on-board prototype has been developed and examined experimentally. Measured results show that the impedance bandwidth of the developed antenna is from 4.5 to 5.8 GHz. The achieved inter-port isolation is higher than 65 dB from 4.4 to over 6.0 GHz, and over 71 dB from 5.36 to 5.82 GHz, indicating a very high self-interference suppression level. Furthermore, RF power and video transferring experiments are carried out, and good consistency with calculated results is observed.