Abstract: We present a novel wideband ring antenna for polarization/pattern diversity. The proposed antenna consists of eight printed dipole elements in the form of a circular array. The arms of adjacent elements overlap for capacitive loading. Unlike traditional circular arrays, a method of exciting elements in the form of every two intervals is first introduced. We prove that this method can maintain the wideband characteristics of the antenna. Four independent feeding ports in a ring antenna aperture are designed for the polarization/pattern diversity with suitable feeding networks. As an example, a wideband dual-polarized antenna was designed based on the proposed ring antenna. To achieve two orthogonal linear polarizations with maximum radiation in the Z direction, two adjacent elements are extracted periodically to feed through one port. The differential feeding network and integrated Baluns have been designed to realize broadside radiation patterns, considering impedance and phase matching. Because the proposed antenna is hollow, it is a good candidate for a multiband sharing aperture antenna element. Results show that the proposed antenna has an overlapped bandwidth of 50.5% (1.04–1.82 GHz) with voltage standing wave ratio (VSWR)<2 for the two polarizations, and port isolation less than 23 dB. The measured realized gain ranges from 6.1 to 8.1 dBi, with stable broadside radiation patterns over the operating frequency band.

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