Compact broadband dual‐polarized omnidirectional array with rotational subarray

Abstract

SummaryA broadband ±45° dual‐polarized omnidirectional array with small size is presented. A crossed‐arranged dipole element is proposed to generate a wide unidirectional radiation beam. A crossed‐arranged parasitic strip is used to dramatically widen the impedance bandwidth of the dipole element. Based on the dipole element, a rotational two‐unit subarray, which comprises a small number of dipole elements and occupies a small space, is originally proposed to generate excellent omnidirectional radiation performance. Then a four‐unit array with a simple feed network is designed based on the rotational subarray. The array obtains a wide bandwidth of 59.4% (1.55–2.86 GHz) for reflection coefficient <−10 dB and an isolation beyond 21 dB between the two polarizations. Meanwhile, a very low gain variation of below 3 dB, as well as a stable and high realized gain of 5.1 ± 0.5 dBi are achieved over the operating band.