Dual band rectenna with one rectifier

In this paper, we propose a dual band rectenna for wireless energy harvesting. Nowadays, most of the mainstream wireless access points are designed for dual band usage which frequency is located at 2.4GHz and 5GHz. As a result, the proposed design is focused on these two frequency bands. In the proposed dual band rectenna, we utilize only one single feed point to achieve the dual band, where 2.4G band is generated by microstrip antenna and 5G band is generated by the slot antenna. After optimization, the return loss of this dual band rectenna can achieve -33dB at 2.45GHz and -25dB at 5.48GHz. Moreover, the radiation pattern gain can reach 7.7 dBi and 8.8 dBi at 2.45GHz and 5.48GHz, respectively. In addition, we also can get 80% radiation efficiency at 5.48GHz, and even 90% radiation efficiency at 2.45GHz. Besides, we use the dual band matching network to achieve the dual band antenna and impedance matching of rectifier circuit, and also use simulation software to optimize the AC-to-DC transform efficiency of the rectifier circuit. As a result, the measured transform efficiency can reach 56.3% and 37.8% at 2.46GHz and 5.44GHz, respectively. Finally, we use an ultra-low power boost charger, Texas Instruments bq25505, to stabilize the DC voltage at 5V to facilitate charging of the end device. To our knowledge, this is the first rectenna use only one single feed point and one rectifier to achieve the 2.4G and 5G dual band characteristic. Also, it is a simple geometric structure that is easy to be implemented.