Abstract
The circular polarized antenna composed of an unbalanced fed ultra low profile inverted L antenna and a parasitic inverted L element is proposed for the reader antenna of the portable terminal of UHF band RFID. When the size of rectangular conducting plane is 228.5 mm by 275.5 mm, and the antenna height is 14 mm, the return loss less than -10 dB is obtained at the frequencies from 902 MHz to 930 MHz. The axial ratio less than 3 dB is satisfied from 915 MHz to 922 MHz. In the numerical analysis, the electromagnetic simulator "WIPL-D" based on method of moment is used.
