A rectenna (rectifying antenna) is a special type of receiving antenna that is used for converting electromagnetic energy into direct current (DC) electricity. A lectenna is based on the same principle using a light emitting diode (LED) to visualize the effectively harvested electromagnetic energy. It essentially consists of two electronic components (see Fig. 1): (i) a Schottky diode which is used as the rectifier and (ii) a LED to visualize the effect of the energy harvest. The lectenna is constructed by connecting (ideally, by soldering) the LED to the Schottky diode (see Fig. 2). Since an antenna is required to capture the electromagnetic energy, a simple solution is to use the wire of the Schottky diode. As an example, the length of the wire to capture WiFi signals at 2450 MHz is about 60 mm. However, an elaborated antenna may also be designed for more efficient energy harvesting. For the example considered herein, when the lectenna is placed at an appropriate distance from the location of the WiFi antenna of a mobile phone, the LED should light up (see Fig. 3).

Fig. 1: The two electronic components of a lectenna: (i) a Schottky diode and (ii) a light emitting diode (LED).

Fig. 2: The LED soldered (optional) to the Schottky diode. As an example, the metallic wire of the Schottky diode of this lectenna serves as an antenna to harvest WiFi signals at 2.45 GHz.

Fig. 3: Using the lectenna considered in Fig.2, the LED lights up when the lectenna is placed close to the location of the WiFi antenna of an Iphone 11.

The IEEE Antennas and Propagation Society (AP-S) Mauritius Chapter in close collaboration with the Radio Society (Mauritius) is launching the IEEE AP-S STEM Hands-on Antennas and Radio Visualization for Engineering, Science and Technology (HARVEST) National Challenge in Mauritius. It targets college as well as undergraduate university students.

The challenge is as follows:

What is the maximum number of LEDs that you can light up simultaneously for at least 1 second using lectennas and a mobile phone?

To enter the challenge, send an email with the names and emails of the members of your team by 31^st January 2026 to: secretariat@radiosociety.org.

The challenge will be open from 1^st February to 31^st March 2026. A photo and a video of the experimental setup that clearly shows the number of LEDs being lit for at least 1 second, should be submitted by 31^st March 2026. After selection of the top ten submissions, an on-site demonstration will be organized after March 2026. The first, second and third place winners will receive a certificate, a shield and cash prizes of: Rs 15 000, Rs 10 000 and Rs 5 000, respectively.

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