A low-profile dual-band RFID antenna combined with silence element

A low-profile dual-band three-dimensional antenna covering bands of 915 MHz and 2.45 GHz is proposed for radio frequency identification (RFID) applications. The eighth-wavelength antenna utilizes the planar triangular patches and a disk to reduce the profile. Planar tuning patches are adopted to replace the conventional tuning poles for improving the impedance matching. Silence element, defined as a radiator with little influence on others, is composed of quarter-wavelength patch working at higher band in this study. The antenna with a merit of good production consistency exhibits an impedance bandwidth of 22% from 842 to 1049 MHz in the lower band, while the upper band covers 100 MHz (from 2.4 to 2.5 GHz). The measured peak gain is 3dBi and 5dBi at 915 MHz and 2.45 GHz, respectively.