A Novel Calculation Method to Design Parasitic Decoupling Technique for Two Antennas

Abstract

In this paper, a systematic and calculation-based parasitic decoupling technique (PDT) is proposed to mitigate the mutual coupling between two closely coupled antennas. The adopted parasitic decoupling structure consists of two transmission lines connected to the feed lines of antennas and a parasitic element connected with a transmission line and terminated by a reactive load. Rigorous decoupling theory and systematic design procedures are presented. The lengths of transmission lines and value of reactive load can be precisely calculated to increase antenna isolation. The superiority of the proposed PDT is verified by four decoupling examples. The simulated and measured results show that high isolations over 24 dB, efficiencies above 70%, and envelop correlation coefficients below 0.05 are achieved simultaneously. The results indicate the proposed PDT a promising decoupling method for MIMO systems. INDEX TERMS Decoupling technique, high isolation, MIMO antenna, parasitic element, pattern diversity.

Decoupling of Isosceles Triangular Array by Loaded Parasitic Element in Combination With Decoupling and Matching Network

“…The method loaded with a single parasitic element [15] is very effective in dealing with equilateral triangular arrays, which can be extended to the isosceles triangular arrays where the mutual couplings between three elements are not much different (9 dB, 11.5 dB) [18]. When the vertex angle of the isosceles triangle has a more significant deviation from 60°, leading to a more considerable difference in mutual couplings, such as 5 dB in [19] and this paper, the method in [15] is not applicable. The method presented in this paper has no restrictions on the layout of the antenna, nor does it involve time-consuming EM optimizations.…”

“…The method presented in this paper has no restrictions on the layout of the antenna, nor does it involve time-consuming EM optimizations. In addition, parasitic elements are reduced to one in this article compared with [19], and the decoupling effect achieved is first-class.…”

“…The methods that can be applied to various antenna types without changing the original antenna structure are the reactive loaded parasitic element (LPE) [15]- [19] and decoupling networks [20]- [31]. How the trans-parameter of two radiators varies with the load connected to the parasitic scatter is analyzed and formulated [15].…”

“…One parasitic element can also decouple the isosceles triangular array by optimizations [18], but the isolation enhancement is limited, i.e., the farther the vertex angle differs from 60°, the worse the enhancement. Although the calculation-based parasitic element method [19] is not restricted by the array arrangement, avoiding time-consuming optimizations simultaneously, three parasitic elements are inserted to deal with the couplings resulting in a complexity of assembly.…”

Compact 8 × 8 MIMO Antenna Design for 5G Terminals

“…Traditional decoupling methods, such as neutralization line [3][4][5], parasitic element [6][7][8], EBG electromagnetic band gap [9][10][11], DGS defect ground structure [12][13][14][15] and decoupling network technology [16][17][18], all need to add additional decoupling structures in the middle of the antenna, which increases the complexity of the design. The occupied area of the antenna is large, and it cannot meet the compact requirements of the future 5G terminal antenna.…”