Vertically Polarized Loop-Fed Slot Antenna With Top-Loading Metasurface for Omnidirectional LTE Base Station Application

A novel wideband vertically polarized omnidirectional antenna is proposed in this letter. Two crossed bowtie slots are fed by a loop, which is arranged on the ground vertically. The loop works in the one wavelength mode together with its image with respect to the ground, and accordingly the quasi-omnidirectional radiation can be achieved. The bowtie slots are introduced to expand the working bandwidth. Afterwards, a top-loading patch is utilized to improve the impedance matching. Furthermore, the complete patch is replaced by the metasurface to suppress the lateral current so that the stable omnidirectional radiation can be maintained in the operating band. A prototype is fabricated and measured, and the –10 dB impedance bandwidth covers the long-term evolution band of 1.7–2.7 GHz. The proposed antenna is well tailored for Indoor ceiling base station applications.