An efficient rectenna based on a dual Schottky diodes converter has been designed at 2.45 GHz. The proposed rectifying circuit is well suitable for wireless sensor applications because no input lowpass filter and no via-hole connections are required, resulting in a more simple structure. A simulation mixing an electromagnetic and circuit analysis has been first used to optimise the rectifier. In addition, the performances of the rectenna has been correctly predicted and characterised using an FDTD formulation extended to lumped circuit elements. The realised rectenna exhibits 83% efficiency over a 1050 V resistive load at a power density of 0.31 mW/cm 2 .Introduction: The rectenna is an important component for converting RF or microwave power into DC power. These techniques are of great interest to supply actuators [1] or wireless sensors [2] through free space without wire connections or a battery. A rectenna usually contains a receiving antenna, a combination of one or several Schottky diodes in series [3] or shunt [4], in voltage doubler configurations [5] or in a modified bridge converter [6], an input lowpass filter (LPF), an output DC pass filter and a resistive load. The input (LPF) rejects harmonics created by the diodes and provides matching between the antenna and the rectifier. It can be directly included on the radiating element by using harmonic-rejecting antennas [7].We propose an efficient rectenna design based on a dual diodes converter. In this configuration, the LPF between the antenna and diodes can be eliminated, reducing the insertion losses of the rectifier. The structure has been optimised and characterised using advanced design system (ADS) commercial software and the 3D-FDTD algorithm extended to lumped element circuits. Finally, simulated results are compared with the measured ones and show good agreement.

International audienceThis paper describes a compact and efficient rectenna based on a dual-diode microstrip rectifier at 2.45 GHz. This circuit has been designed and optimized using a global analysis technique which associates electromagnetic and circuit approaches. Due to the differential topology of the rectifier, neither input low-pass filter nor via-hole connections are needed. This makes the structure more compact reducing losses. Measurements of a single rectenna element show 83% efficiency over an optimal load of 1050 V at a power density of 0.31 mW/cm2. To increase the received RF power and then increase dc power over the load, identical rectennas have been interconnected to form arrays. Two and four elements rectenna arrays, connected either in parallel or in series, have been developed. It was shown that by properly choosing the interconnection topology and the optimal output load, higher dc voltage or dc power have been obtained. The four-element series-connected array can provide experimentally up to 3.85 times output dc voltage compared to the single rectenna. The parallel-connected rectenna arrays generate approximately 2.15 and 3.75 times output dc power for two and four elements, respectively