Isolation Enhancement Using a Novel Array-Antenna Decoupling Surface for Microstrip Antennas

Abstract

A novel array-antenna decoupling surface (ADS) for mutual coupling reduction in microstrip patch antenna is proposed in this paper. The proposed ADS is composed of a group of primary reflector patches and a pair of rectangular and T-shaped secondary reflector patches. Through generating the reflected waves with equal magnitude but out of phase of the coupling waves, the isolation of the antenna elements could be significantly improved by the novel proposed ADS. Then, for verification, a two-element microstrip antenna array covered by the proposed ADS with an edge-to-edge separation of 0.11λ 0 (λ 0 is the wavelength of the operating frequency in free space) was designed and fabricated. As expected, the experimental results have demonstrated that an additional 40.4 dB isolation enhancement at the resonant frequency was achieved by the proposed ADS. Moreover, a much wider bandwidth of the isolation was also obtained than that of return loss of 10 dB. In addition, a gain improvement of 0.95 dB was achieved at 2.45 GHz by utilizing the novel ADS. Thus, the decoupling structure can be applied to multiple-input multiple-output (MIMO) systems for its simple structure and high isolation providing.

A novel defect ground structure for decoupling closely spaced E-plane microstrip antenna array

“…In recently published literature, several approaches were proposed to reduce the mutual coupling between two antenna elements. In [1–3], by placing a decoupling surface above the antenna array, the reflected wave is used to cancel the coupling between the antenna elements, thereby achieving the purpose of improving the isolation. However, the decoupling surface typically has a distance of 0.5 λ 0 from the antenna array, increasing the profile of the antenna.…”

Isolation enhancement in Chinese character antenna array using simple defect ground structure

“…It is proposed in References 11 and 12 that a layer of array‐antenna decoupling surface (ADS) is placed above the antenna array to achieve the decoupling purpose by means of generating the reflected waves, which is equal magnitude and out of phase of the coupling waves. However, since the ADS is placed directly over the antenna array, not only obscures the appearance of the CCAA, but also increases the profile height of the array antenna.…”