Compact Dual-Band Rectenna Based on Dual-Mode Metal-Rimmed Antenna

This paper proposes the design of a dual-band integrated rectenna. The rectenna has compact size of 0.4 x 0.3 x 0.25 cm3and operates at 925 MHz and 2450 MHz bands. In general, the rectenna consists of two main parts, the metal-rimmed dual-band antenna used for harvesting the radio frequency (RF) signals from the environment and the rectifier circuit to convert these receiving powers to the direct current (DC). Because of the dual resonant structure of the antenna, the rectifier circuit can be optimized in terms of size and the frequency bandwidth, while the conversion efficiencies are always obtained 60% at the RF input power -2.5 dBm and -1 dBm for the lower band and the higher band, respectively. Measured results show that the metal-rimmed antenna exhibits -10 dB reflection coefficient in both desired frequency bands. Moreover, the antenna achieves 47% and 89% of total efficiency respectively at 925 MHz and 2450 MHz, which confirms that the proposed rectenna is well applicable in most of the miniaturized wireless sensor networks and IoT systems.