A 2.45-GHz dual-diode RF-to-dc rectifier for rectenna applications

This paper reports a novel dual-diode microwave rectifier with a microstrip access at 2.45 GHz. This circuit has been developed using a global analysis technique which associates electromagnetic and circuit approaches. Due to the differential topology of the rectifier, the input low-pass filter is not necessary. This makes the structure more compact. Two rectifiers with different Schottky diodes (HSMS 2860 and 2820) has been etched on Arlon 25N substrate and measured. Both rectifiers achieve an RF-to-dc conversion efficiency of 60% at 10 mW input power. A dc power more than 30 mW can be obtained with both rectifiers when the power density is 1 mW/cm². The proposed circuits can be interconnected to form rectenna arrays. The parallel-connected array has been investigated. It was shown that by properly choosing the optimal load of the array, higher output dc power can be reached.