Wideband Ceiling-Mount Omnidirectional Antenna for Indoor Distributed Antenna Systems

A wideband omnidirectional antenna is presented in this letter. The proposed antenna consists of three radiators over a ground plane, a monopole composed of three patches fed by a coaxial line, a coupling patch with three shorting legs above the monopole to extend the lowest frequencies of operation, and a top-loading disk located on the top of the coupling patch for further decreasing the lowest frequencies of operation. An enhanced impedance bandwidth of 9.23:1 ranging from 650 MHz to 6 GHz with 13.9 dB (for SWR ≤ 1.5) is achieved. The antenna meets network operator's requirements for cellular bands and has good radiation efficiency in the WiFi bands. The proposed antenna can be widely used in indoor distributed antenna systems, such as 3G, 4G LTE, and WiFi (2.4 and 5.8 GHz) bands. The antenna is simulated by ANSYS HFSS and measured in a microwave anechoic chamber. The simulated and measured results show good agreement.