Ultrawideband In-Ground Multiport Antenna for Small Cell Applications

In this paper, a four-port ultrawideband antenna design is proposed. The antenna is suitable for installation in pavements. The main application of this antenna is in the reuse of the existing manholes for radio equipment and antenna installation. Equally important is its application in dense network deployment as a result of its capability to alleviate intercell interference. The antenna can support up to 4×4 multiple-input and multiple-output (MIMO) systems. The isolation between different ports exceed 28 dB over the commercial long term evolution bands 3 and 7. The multiport matching bandwidth of the antenna (>-0.3 dB) extends over 1700-3000 MHz range. The antenna is mechanically robust and can withstand a weight of 40 ton. MIMO performance of this antenna is verified by virtue of field measurements. A comparative study between the proposed antenna and a classic half-wavelength dipole antenna is presented highlighting the advantages of the proposed antenna. Finally, its compliance with the exposure limits for nonionizing radiation is also demonstrated.