A Low‐Profile and Compact Omnidirectional Antenna for Indoor Base Station Using Property‐Matched Dielectric Materials

A novel omnidirectional antenna that has both extra‐low‐profile and electrically small size is proposed for indoor base station applications. The antenna consists of a rectangular monopole radiator, a metal top cap with two slots, two shorting pins, and two types of materials that include the dielectric material with relatively high permittivity and the magneto dielectric. The reduced size and increased bandwidth are simultaneously achieved by loading the materials in their property‐matched regions. The antenna achieves extremely small dimensions of 0.12 λ 0 × 0.096 λ 0 × 0.028 λ 0 , where λ 0 is the free‐space wavelength at the lowest operation frequency. A measured impedance bandwidth for |S 11 | < −6 dB ranging from 824 to 894 MHz is realized, which covers the GSM850 band. The peak realized gain is up to 1.2 dBi within the operating frequency.