Negative Cable Effect Shield Omnidirectional Antenna Based on Radiation Pattern Synthesis

An omnidirectional antenna design approach is proposed based on the radiation pattern synthesized method to shield the negative effects caused by feeding cables. Based on the combined effect of the inconsistent binary dipole unit patterns, the proposed antenna can realize the omnidirectional beam without the negative occlusion and reflection effects from the parallel feeding cable. Hence, it can support multiple antennas stacked in the array axis direction and fed by multiple cables, which is a cost-effective topology for multiple antenna applications with an omnidirectional beam coverage range. To verify the feasibility of the proposed design approach, an antenna prototype is fabricated and measured. The operating bandwidth of the antenna is from 0.95 GHz to 1.37 GHz with a voltage standing wave ratio (VSWR) of less than 2. Omnidirectional radiation patterns with the maximum gain and out-of-roundness of 5.6 dBi and 2.0 dB are realized in the horizontal plane. At the same time, several different scenarios of parallel cables located around the antenna are analyzed to observe the performance variation in both simulation and measurement. The results prove that the extra cable does not affect the radiation performance of the proposed antenna.