## 1 Introduction  
Microwave power transmission (MPT) transmits power through free-space without the use of wires or cables, which is attractive for applications in oil-less helicopters, 24 h high-altitude platforms and solar power satellites. Recently, MPT technology has also been used to supply power for wireless sensors, radio frequency identification, and portable electrical devices. The power amplifiers for MPT often work in the nonlinear area, but the wireless communication transmitter generally works in the linear area to obtain a lower bit error rate (BER). Thus, a dual-band antenna that can be applied simultaneously for wireless energy harvesting and communication with compact size is highly desirable.  
The emerging substrate integrated waveguide (SIW) technique has gained renewed attention for the integration of planar and non-planar circuits into a simple and low-cost PCB or LTCC fabrication process [1,2]. Then, the traditional waveguide, which is costly with a bulky non-planar hollow rectangular structure and high power capacity, can be synthesized into a planar substrate with metalized slots or even arrays of metallic via posts. The SIW has provided very attractive applications in designing low-cost, low-profile, and highly efficient waveguide microwave printed circuitry, active devices, and antennas. Benefitting from superior characteristics, which include significant surface wave suppression, reduced coupling, better matching, and wider scanning, SIW cavity-backed patch antennas have been extensively studied and employed [3, 4, 5, 6, 7, 8, 9]. In [3, 4, 5], various cavity-backed antennas with different cavity shapes and patch structures were discussed. In [6], SIW cavity-backed dual-band circularly polarized (CP) antennas with planar configurations were investigated. A dual-mode SIW cavity-backed triangular ring slot antenna was proposed and developed for dual-band application in [8]. To increase the bandwidth, an SIW-fed cavity-backed rectangular patch antenna was proposed in [9], and it was designed to operate in its TE210 mode. However, with the demand for compact wireless terminals, designing a planar antenna that occupies minimal circuit board area is still a challenge. The use of metamaterials has been proven to be an efficient approach for reducing the antenna size while maintaining satisfactory antenna performance. In [10], a miniaturized magnetic dipole antenna is proposed, which is based on the mechanism of the conventional SRR. The fractal geometries are also conducive to the miniaturization of antenna designs and realization of antenna ultra-wideband or multiband characteristics [11,12].  
Alternately, dual-band and dual-polarized antennas have attracted much attention with the increasing demand for polarization diversity in dual-band wireless communication [13,14]. However, dual-polarized microstrip antennas are generally associated with narrow frequency bandwidth and poor isolation performance [13]. To explore a greater operational frequency range, a dual-band and dual-polarized SIW fed slot antenna was investigated in [14], which is constructed with the usage of a frequency selective surface right above it.  
This paper presents a novel compact dual-band and dual-polarized CSRR-fed SIW cavity-backed fractal patch antenna, which aims to work simultaneously for wireless energy harvesting and communication. The proposed antenna utilizes an SIW cavity. To reduce the dimension, a [PERSON] fractal patch has been employed. For further performance enhancement, a CSRR-fed network has been utilized to substantially lower the resonant frequency. The proposed antenna has been analyzed, fabricated and tested.