Very Compact Fully Lumped Decoupling Network for a Coupled Two-Element Array

Wu, Cheng-Hsun; Chiu, Chih-Yi; Ma, Tzyh‐Ghuang

doi:10.1109/lawp.2015.2435793

Cited by 111 publications

(61 citation statements)

References 11 publications

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“…2 ( |S23| and |S14| ) remain very low and almost unchanged. In comparison with most previously reported isolation elements and strategies, which are effective in only one specific direction , use high-Q decoupling networks [34][35][36][37][38], or introduce modified ground planes [39], our decoupling approach is suitable over a wide frequency range for both polarizations and for large arrays with arbitrary lattice configurations. Furthermore, when compared to a recently reported dual-polarized array decoupling technology that depends on a ~1.3 λ0 inter-element separation [41], our approach with its much smaller Accepted for publication in IEEE Transactions on Antennas and Propagation inter-element distance, ~0.6 λ0, is more suitable for high-density arrays.…”

Section: Mutual Coupling Reduction Mechanismsmentioning

confidence: 99%

“…This specificity limits their applications to only single-polarized arrays; it is ineffective for dual-/multi-polarized arrays . The decoupling networks suffer from quite narrow bandwidths and, hence, cannot be applied to wideband arrays [34][35][36][37][38]. The ground plane related strategies can only be utilized when the ground planes are limited in size and, hence, they cannot be applied to large arrays [39].…”

mentioning

confidence: 99%

“…A second class of mutual coupling suppressors relies on the construction of decoupling networks behind the radiators. There are two versions of these networks, i.e., distributed [34][35][36][37] and lumped [38] ones. A third set of mutual coupling reducers involves simply rearranging the radiator positions within the array without resorting to any auxiliary structure.…”

mentioning

confidence: 99%

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Mutual Coupling Reduction Using Meta-Structures for Wideband, Dual-Polarized, and High-Density Patch Arrays

Tang

Chen

Wang

et al. 2017

IEEE Trans. Antennas Propagat.

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-A mutual coupling reduction strategy that employs meta-structures is introduced for wideband, dual-polarized, high-density, planar, patch antenna arrays. The meta-structures consist of two types of resonators: grounded capacitively loaded loops (GCLLs) and π-shaped elements. By incorporating the meta-structures into the array configuration, the isolation levels between adjacent radiating elements in both the E-and H-plane orientations are improved by as much as 7.15 dB. The surface current distribution behaviors of the array with only the GCLLs and with only the π-shaped elements are investigated thoroughly to explain the mutual coupling reduction mechanisms. A proof-of-concept array was constructed and tests were performed that validate the reported design principles and simulation results. M. (5G) communication systems [1,2]. It has several unique advantages that arise from its ability to facilitate the presence of additional signal channels instead of requiring the use of extra frequency spectrum or power. Benefits include being able to increase the data capacity and to make the system more adaptable. Index TermsMIMO approaches are based on antenna arrays. With the ever increasing demand for more capacity, it is anticipated that massive MIMO will be central to 5G systems; and it will be facilitated by compact dense arrays. However, strong inter-element coupling occurs when the element spacing is small; it dramatically increases the spatial correlations and seriously deteriorates the signal-to-interference-plus-noise -ratio (SINR) [3]. Consequently, mutual coupling effects between array elements have attracted intense attention.There exist a plethora of reported approaches that are capable of reducing the mutual coupling in the physical layer. However, because of known fundamental physical limitations [4], it cannot be eliminated completely. Nevertheless, mutual coupling reduction can significantly improve the performance of MIMO systems.In general, the existing, most widely used mutual coupling reduction strategies can be classified into the following three categories. One approach focuses on introducing a variety of compact isolation elements between the radiators. The choices have been rather diverse. They include parasitic elements, such as monopoles [5], scatterers [6], and radiation patches [7]. Also, they include electromagnetic band-gap (EBG) structures, such as mushroom-like EBG structures [8], F-shaped EBG structures [9], and uniplanar compact EBG structures [10,11]. Defected ground structures (DGSs), such as periodic rectangular slits [12], back-to-back U-shaped slots [13], T-shaped slots [14], and loop slots [15] have also been used. More recently, numerous metamaterial-inspired structures have been considered, such as folded single split ring resonators [16], grounded split-ring resonators (GSRRs) [17], multiple split-ring resonators (MSRRs) [18] While the above strategies have reduced mutual coupling, one witnesses certain drawbacks accompanying each of them. As a result, their widespre...

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Section: Mutual Coupling Reduction Mechanismsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Mutual Coupling Reduction Using Meta-Structures for Wideband, Dual-Polarized, and High-Density Patch Arrays

Tang

Chen

Wang

et al. 2017

IEEE Trans. Antennas Propagat.

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“…they are included in Y 11 and Y 21 . Previous works such as [9], [22], [26] improve the input matching and antenna decoupling simultaneously, but they tend to result in a narrowband solution. Fig.…”

Section: A Proposed Decoupling Methodsmentioning

confidence: 99%

Impact of Using Resistive Elements for Wideband Isolation Improvement

Venkatasubramanian

Lehtovuori

et al. 2017

IEEE Trans. Antennas Propagat.

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Abstract-Improving the isolation between antenna elements in compact arrays has been a major focus of recent research. In this paper, we present ideas to improve the wideband isolation between closely spaced antennas. We do this by connecting lumped lossy (resistive) elements between the antenna feeds. A simple analytical expression is provided to compute the impact of resistive elements on efficiency to analyse the power lost in the resistive element. Three configurations of decoupling circuits are designed and fabricated for two closely spaced monopoles operating at 2.4 GHz. The decoupling circuit contains transmission lines of different lengths at the antenna inputs such that the mutual admittance between the antenna elements is 1) resistive, 2) resistive and inductive, or 3) resistive and capacitive. Lumped elements are then connected between the transmission lines followed by matching circuit. The paper shows that with configurations 2) and 3) we can improve the wideband isolation compared to 1), as well as compared to using only lossless elements. The wideband isolation was improved by 17.6 dB across a 200 MHz band at 2.4 GHz, with a final isolation level of 20 dB over that band. Better than 30 dB isolation was achieved across a narrower band of 55 MHz. The proposed technique provides wideband isolation improvement for multiple-input multipleoutput (MIMO) as well as narrowband performance with large isolation suitable for in-band full-duplex (FDX) applications. The impact on efficiency is investigated to verify that the advantages from the improved wideband isolation outweighs the possible reduction in overall efficiency.

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“…It is a great challenge to achieve good isolation, while the antenna element spacing is less than half-wavelength in a compact volume [1]. To solve this problem, several decoupling methods, such as defected ground structures [2], electromagnetic band gap [3], coupled resonator decoupling network [4][5][6][7], and lumped network [8], are used to improve isolation between closely packed antennas.…”

Section: Introductionmentioning

confidence: 99%

Two-Element Compact Antennas Decoupled With a Simple Neutralization Line

Ou¹,

Cai²,

Qian³

2017

PIER Letters

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Abstract-A simple and novel WLAN antenna and a kind of neutralization line, which introduces a certain amount of signal to cancel out the unwanted mutual coupling between two antennas, are designed in this paper. The WLAN antenna working at 2.45 GHz and 5.8 GHz frequency bands is designed, fabricated and measured. The simulated and measured results show that the isolation between the two decoupled antennas can be improved to above 20 dB in both frequencies after decoupling. The lumped match network occupies less space for antennas and gains a good matching performance in the operating frequencies.

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Very Compact Fully Lumped Decoupling Network for a Coupled Two-Element Array

Cited by 111 publications

References 11 publications

Mutual Coupling Reduction Using Meta-Structures for Wideband, Dual-Polarized, and High-Density Patch Arrays

Mutual Coupling Reduction Using Meta-Structures for Wideband, Dual-Polarized, and High-Density Patch Arrays

Impact of Using Resistive Elements for Wideband Isolation Improvement

Two-Element Compact Antennas Decoupled With a Simple Neutralization Line

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