Experimental study of rectenna coupling at low power level

Abstract

The experimental results presented in this paper focus on the performance of a rectenna array by studying the effect of mutual coupling between two rectennas. The measurements in several planes of the space are investigated and used to help us to define the minimum distance for future rectenna arrays that can be used at a low power density level. The single element chosen for the array is composed of a rectifier circuit and a CSPA (Circular Slot Patch Antenna). This study shows that at a distance greater than 6 cm (>λ/2) between two rectennas in reception, we observe that the DC received voltage is constant in the Y plane. While, in the X plane, the DC received voltage remains constant whatever the distance is. We deduce that these rectennas are uncoupled in this case. We can consider each rectenna like an independent system.

Impact of the coupling effect and the configuration on a compact rectenna array

“…From this observation, a more compact rectenna array is build. This rectenna array is composed of 5 rectennas spaced of 9 mm, and has the same area size as a rectenna design in a previous work [3] for a comparative study (see figure 6). This previous rectenna was build for the same operating point and measured in a similar approach.…”

“…The rectifier presented in a previous work [3] is simple, compact and efficient for low power input. A matching circuit is essential in providing the maximum power transfer from the antenna to the rectifier circuit.…”

“…First, we inquire the effect of mutual coupling on two different DC-combining configurations, series and parallel for a finite number of elements. Then, a comparative study is conducted between a rectenna array and a single rectenna using a conventional patch antenna [3], with the same physical surface area. Last, an application of the rectenna array is tested, where a battery-less temperature sensor is powered over a distance of one meter.…”