Efficient Single- and Dual-Band Rectifiers With Wide Range of Load Variations

With the development of low-power devices, wireless power transfer and wireless energy harvesting techniques become increasingly important. As the critical component, the rectifier is required to maintain good performance under different scenarios. Most existing works focus on the improvement in bandwidth and input power range with a constant load value. However, the impedance of the driven devices cannot be predicted in practical applications, resulting in performance deterioration. Thus, an adaptive signal diversion approach is proposed to diver the injected signal to the parallel high and low load branches with distinct reactance compensation networks. This topology can be applied to both single- and dual-band rectifiers with simplicity and scalability in design. For validation, two rectifiers are designed, fabricated, and measured. The rectifier operating at 2.4 GHz achieves a load range of 0.16 k<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> to 6 k<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> (load variation ratio of 37.5). The dual-band rectifier working at 2.49 GHz and 5.14 GHz achieves load ranges from 0.21 to 5.4 k<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> (load variation ratio of 25.7) and from 0.07 to 4.2 k<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> (load variation ratio of 60), respectively. It can be found that the proposed rectifiers exhibit the largest load variation ratio with the minimum number of diodes and load compared with the state-of-the-art works.