3D antenna for UHF RFID tags with near omni-direction

An improved design of 3D antenna for passive UHF RFID tags is presented. Tags using the proposed near omni directional antennas are situated in three orthogonal planes. Due to the combined magnitude of the electric field components for two orthogonal polarizations of the designed 3D antenna, the passive tag is invariant to its orientation. The shorted load is introduced to fix the situation of the two arms of the antenna. Through the adjustment of the height of the bifurcation point from the end of the two arms, the fine match of given ASIC and the designed antenna is acquired. The new type is similar to the carrier tape and can be made easily.