Decoupling of Two Strongly Coupled Dual-Band Antennas With Reactively Loaded Dummy Element Array

Abstract

An efficient antenna mutual coupling reduction (decoupling) technique using reactively loaded dummy element array for two dual-band closely coupled MIMO antennas is proposed in this paper. This dummy element array comprises three dummy elements, including one low-frequency dummy element and two symmetrically placed high-frequency dummy elements. A pair of dual-band antennas working at 2.45 GHz (low band) and 5.8 GHz (high band) simultaneously is used to demonstrate the effectiveness of the proposed method and to illustrate the decoupling design process. The dual-band antennas with and without the designed dummy element array are both fabricated and measured. Measurement results show good impedance matching for both antenna ports at both operating bandwidths. More importantly, the isolations have been improved from 9 dB at low band and 7.7 dB at high band to more than 20 dB at low band and more than 25 dB at high band, respectively. The envelop correlation coefficient (ECC) as one key figure of merits for MIMO antennas is also improved significantly. The proposed method can find plenty of applications in dual-band wireless systems where multiple antennas are installed. INDEX TERMS Envelope correlation coefficient (ECC), isolation, multiple-input-multiple-output (MIMO), mutual coupling reduction, parasitic decoupling technique.

Intercoupling Suppression of Very Closely Spaced MIMO Antenna Based on Current Cancellation Method

“…Compared with References [3], [8], [15], [19], [23], [29] and [37], the edge-to-edge distance between the proposed MIMO antenna elements is smaller and the isolation is greater. However, the profile height of the antenna proposed in this paper is slightly higher than that of the antenna in references [3], [11], [15], [17] and [37]. Although relatively novel weak field coupling selfdecoupling method was adopted in [31], it is more difficult to implement than traditional methods, and there are no system design guidelines currently.…”

“…To be specific, an indirect coupling field is added between antennas, which meets the requirement of approximate equalization in amplitude and opposite in phase between the original direct coupling field and the added indirect coupling field. At present, there are two main ways to increase the indirect coupling field, namely the non-connected type [11]- [15] and connected type [16]- [18]. To verify the correctness of the principle of field decoupling, the surface current distribution of the MIMO antenna with and without a decoupling structure at the center frequency of 5.37 GHz is simulated.…”

“…For example, methods to improve isolation by reducing or counteracting the original coupling field or coupling current are reported. Common decoupling structures include defected ground structure (DGS) [6]- [8], electromagnetic band-gap (EBG) structure [9], [10], parasitic resonance structure [11]- [15], neutralization lines [16]- [18], decoupling networks [19]- [21] and polarization-conversion decoupling [22], [23].…”

MIMO Antennas: Design Approaches, Techniques and Applications

“…Improved isolation is achieved by using a composite GP with four metallic strips. In [ 58 ], to produce a tiny dual-band WLAN MIMO antenna, lower and higher band dummy elements are employed. The desired frequency bands are achieved by adjusting the width of two branches and the angle between the branches.…”

Metasurface‐enabled isolation between antenna arrays

“…In the past, researchers have proposed a number of methods to decouple array elements. For example, neutralization lines [9][10][11][12] and parasitic elements 13,14 are all artificially introduce a new coupling path to make the signals coupled through the new path equal in amplitude and opposite in phase to the signals coupled through other ways, so as to reduce the coupling between antenna elements. Metamaterials decoupling [15][16][17][18][19] use negative permittivity or negative permeability to cut off the propagation of coupled electromagnetic (EM) waves.…”