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This paper presents a method to wirelessly power sensors using magnetoelectric (ME) structures as receivers. ME receivers consist of composites of magnetostrictive (MS) and piezoelectric material. Using ME receivers, as opposed to inductively coupled coils, is useful when a combination of small size and low frequency are desirable. Most ME receivers require a large DC magnetic field bias for high-performance operation. We present magnetization grading approach with multiple layers of MS material that results in high-performance structures with no DC magnetic field bias required. Our device produces 600 microwatts when excited by a 100 microtesla AC magnetic field at 192.3 kHz. The device is 12.4 mm X 5 mm X 1 mm. The corresponding normalized power density is 10.71 mWcm−3Oe−2, which is the highest reported to our knowledge. 

Abstract Wireless power transfer (WPT) has received increasing attention primarily as a means of recharging batteries in the last few decades. More recently, magnetoelectric (ME) structures have been investigated as alternative receiving antennas in WPT systems. ME structures can be particularly useful for small scale devices since their optimal size is much smaller than traditional receiving coils for a given operating frequency. WPT systems using ME laminate receivers have been shown to be helpful in wirelessly powering various sensors and biomedical implants. In recent years, a large number of studies have been conducted to improve the performance of ME composites, in which various configurations have been proposed, along with the use of different magnetostrictive and piezoelectric materials. In addition, many efforts have been devoted to miniaturizing ME devices. An essential obstacle to overcome is to eliminate the need for a DC bias field that is commonly required for the operation of ME structures. In this review paper, we will discuss the basic principle of ME effects in composites, materials currently in use, various ME receiver structures, performance measures, limitations, challenges, and future perspectives for the field of WPT. Furthermore, we propose a power figure of merit which we use to compare recent ME WPT research papers.