Bandwidth Extension of Dual-Polarized 1-D TCDA Antenna Using VMS

Abstract

In this paper, a wideband, low-profile, 1-D tightly coupled dipole array (1-D TCDA) antenna with vertical metal strips (VMSs) is proposed. The 1-D TCDA has a limited scanangle due to variations in vertical wave numbers according to the scanangle. Floquet theory and the electric field profile can be used to analyze the theory of a TCDA, obtaining scan-independent characteristic. Removing some metal strips from the side walls also improved the radiation efficiency. The overlapped impedance bandwidth (IBW) for dual polarization was 0.8–2.5 GHz (3.1:1) for VSWR < 3, and the maximum scanangle was ±50°. The radiation efficiency was over 70% within the IBW and maximum scanangle. The measurement results show that the gain was 7.0–12.4 dB for vertical polarization and 7.3–15.4 dB for horizontal polarization within the IBW and maximum scanangle. Furthermore, the height of the antenna was <inline-formula> <tex-math notation= LaTeX >$0.13\\lambda _{\\mathrm {low}}$ </tex-math></inline-formula> at the lowest operating frequency, and the overall dimension of the full array structure was <inline-formula> <tex-math notation= LaTeX >$1.69\\lambda _{\\mathrm {low}}\\times 0.59\\lambda _{\\mathrm {low}}\\times 0.13\\lambda _{\\mathrm {low}}$ </tex-math></inline-formula>.