A flexible nonsymmetrical metamaterial (FNM) tag with high gain, high efficiency and wide readable angle range is proposed here, whose working band is 900MHz-930MHz. We improved impedance match between tag's antenna and chip to reduce the mismatch loss and increase radiation efficient of the tag by loading border cross units with top or bottom defaulted (BCUT/BCUB) units above and below the central folded dipole. Furthermore, the proposed tag is in size of 95mm×57mm×0.23mm, and it can realize 5dBi realized gain and radiation efficient of 89.13%, and 54m reading distance when the reader's effective isotropic radiated power is 42dBm if it's on a plane; and when it is conformal to cylinders whose radius over 26mm, the tag also can work at 900-930MHz, perform over 80% efficient and realize over 35m reading distance in measurement.

This paper proposes array antennas based on half Tyler (HT) distribution that can realize omnidirectional null-free (ONF) beams. Array 1 employs the usual edge feeding approach, working at 3.5 GHz with a bandwidth of 0.25 GHz, whereas array 2 operates at 26 GHz with a bandwidth of 3 GHz. We evaluated the far-field performance of linear arrays consisting of 6, 8, 12, and 16 elements. The simulation and measurement results show that the proposed HT approach can achieve a near-ONF pattern and cover a broad area of ±42° on an eight-element linear array. The ONF beam reduces community power fluctuations and increases power by 20 dBm in surrounding areas of the base station (BS). The fluctuation treatment effect can be influenced by adjusting the weighting of sidelobe depression (dp): compared to the uniformly excited one, for example, the maximum ONF gain of an eight-element linear operating at 3.5 GHz is only reduced by 0.5 dB when dp = −30 and by 1–2 dB when dp = −60.