2.45-GHz Wireless Power Transmitter with Dual-Polarization-Switching Cantenna for LED Accessories

We have developed a wireless power transfer scheme with a dual-polarization-switching cantenna that varies the supply power of two adjacent LED accessories with ultra-small rectennas and changes the light intensity of the LEDs. Such operation is enabLED through the use of a dual-polarization-switching cantenna composed of two antennas embedded in the can so that radiated waves are orthogonally polarized. Each antenna enables high-power emission compared with a dipole antenna, and the difference between the gains of the antennas becomes small. In this way, switching between the antennas makes it possible to vary the supply power to the LED accessories. We fabricated a 2.45-GHz cantenna composed of two monopole antennas 8.5 cm in length and a can with a diameter of 12 cm and height of 20.5 cm. The antenna gains of the horizontal and vertical antennas were 12.2 dBi and 0.4 dBi, respectively. The difference of the two gains was suppressed within 12 dB. We also fabricated a wireless power transfer system that consists of a transmitter and LED false nails with an ultra-small rectenna. Experimental results show that our system can vary the luminous intensity of the LEDs in false nails in time to the music of a CD.