A novel feed network based on the microstrip/slotline transition is proposed in this paper. This feed network not only has ultra-wide impedance bandwidth but also can improve space utilization and make the design of antenna array easier. Then an ultra-wideband (UWB) antenna array with four elements fed by the network is designed. The antenna array is simulated, manufactured and measured. The results show that: the impedance bandwidth with return loss under -10 dB is 88.76%, from 2.35 GHz to 6.1 GHz. Within the impedance bandwidth, the radiation performance is satisfactory, and the gain of the array is 2.1-7.1 dB, higher than that of the element. The cross-polarization level of the array is lower than -20 dB, just as the element. A reasonable agreement of results is achieved between simulation and measurement.
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