A Low-Profile Wideband Connected Dipole Array with Compact Balun and Power Divider

Microstrip patch antennas are typically used in low- profile array designs. Nevertheless, the bandwidth is usually less than 10% unless special loading and/or feed coupling techniques are used. In this paper, we propose a low-profile (0.09 λ
_low
), wideband connected dipole array, operating at a center frequency of 200 MHz. The array consists of 10 × 20 electrically short (0.08 λ
_low
) dipole elements, forming a 2.3 m × 2.3 m aperture. The dipole elements are fed in pair using a combination of a tapered microstrip balun and a power divider. Within a small area, the 50 Ω unbalanced coaxial input is matched to two 200 Ω broadside coupled strip lines. The design reduces the profile and avoids the use of narrow 200 Ω microstrip lines. Simulation results show that the antenna array has a 32% bandwidth. As a comparison, a center-fed patch array with the same profile using air substrate would only have a bandwidth of less than 20%.