Improvement of Port-to-Port Isolation Characteristics of a Linearly Dual-Polarized Dual-Band and Wideband Multi-Ring Microstrip Antenna Fed by Two L-Probes with a Via

Sakuyoshi SAITO

IEICE TRANSACTIONS on Communications   Vol.E105-B    No.6    pp.715-721
Publication Date: 2022/06/01
Publicized: 2021/12/17
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2021ISP0004
Type of Manuscript: Special Section PAPER (Special Section on Recent Progress in Antennas and Propagation in Conjunction with Main Topics of ISAP2020)
Category: Antennas
multi-ring microstrip antenna,  planar antenna,  wideband,  multiband,  L-probe,  isolation,  

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This paper presents improvement of port-to-port isolation characteristics of a linearly dual-polarized dual-band and wideband multi-ring microstrip antenna (MR-MSA) fed by two L-probes. The linearly dual-polarized dual-band and wideband MR-MSA consists of two circular ring patches and two L-probes arranged in a multi-layered dielectric substrate. By using a thick substrate for the L-probe and arranging two ring patches as radiation elements, the proposed antenna operates wideband and dual-band characteristics. Furthermore, by arranging two L-probes at the orthogonal positions, the proposed antenna can radiate dual linear polarizations. In this paper, for improving port-to-port isolation characteristics of the linearly dual-polarized dual-band and wideband MR-MSA fed by two L-probes, a via connected to the ground plane at the center of the radiation elements is arranged. The fractional bandwidths below -10dB reflection obtained by the simulation of the MR-MSA with the via were 17.0% and 14.4%. Furthermore, the simulated isolation characteristics were more than 21.0dB and 17.0dB in the two bands. Improvement of the isolation characteristics between two ports as well as the dual-band and wideband performance of the proposed MR-MSA with the via were confirmed by the simulation and the measurement.