Isolation Enhancement for $1\times3$ Closely Spaced E-Plane Patch Antenna Array Using Defect Ground Structure and Metal-Vias

Abstract

This paper introduces an effective solution for improving isolation in linear antenna array. The array is composed of three-element E-plane single feed patch antennas (the overall size is 0.59 λ 0 × 1.02 λ 0), which are closely placed with approximately 0.037 λ 0 , where λ 0 is the free-space wavelength at 4 GHz. The decoupling structure consists of T-shaped and rectangular ring shaped defect ground structure (DGS) with six metal-vias. The decoupling mechanism is illustrated by investigating the current vector on the ground plane. The current distribution indicates that the decoupling structure along the outer edge of the radiation patch sever as coupling current converter to produce reverse current opposite to the direction of the ground coupling current, which transmits along the outer edge of the radiation edge. The measured results show that the enhancement in the isolation at 4 GHz is 10.8 dB for |S21|, 17.5 dB for |S23| and 16.6 dB for |S31|. After applying the decoupling structure, the 10-dB impedance bandwidth (3.95-4.04 GHz) of antenna 1 remains unchanged. Meanwhile, the 10-dB impedance bandwidth of the antenna, which is located in the middle of the three-element antenna array, increases by 86 MHz (from 114 MHz to 200 MHz). When the decoupling structure is loaded, the maximum gain only decreases by 0.12 dB (from 3.94 to 3.82 dB). The decoupling structure has the advantages of simple structure, easy processing, and independent design of the array, so it can be applied to multielement patch array, such as massive multiple-input multiple-output (M-MIMO) system. INDEX TERMS Linear antenna array, defect ground structure (DGS), mutual coupling, isolation.

Highly reduced mutual coupling between wideband patch antenna array using multiresonance EBG structure and defective ground surface

“…In, slotted‐ring EBG structure was used to achieve a 30 dB isolation between closely‐spaced 2 patch antennas at 27.7 GHz, the isolation bandwidth was merely 0.7% (ie, 200 MHz). Also, 17.5 dB maximum isolation improvement between linear antenna array that comprises of three‐element was obtained in Reference ; the coupling reduction was achieved using T‐shaped and rectangular ring defective ground surface within the impedance bandwidth of 3.95‐4.04 GHz. Also, in Reference , 28.4 and 25.9 dB isolation improvement were achieved at the 3.7 GHz and 4.1 GHz dual band resonance of a MIMO patch antenna, using H‐shaped defective ground surface and modified antenna decoupling surface.…”

Multiple‐input‐multiple‐output antenna with pattern reconfiguration and correlation reduction for WLAN applications

“…By investigating the E‐ and H‐field distributions in a near field resonator placed above two patch antenna elements, a 20 dB isolation improvement was achieved, with maximum efficiency of 80% around 2.23 GHz in Reference 3. A 16.6 dB maximum mutual coupling reduction was achieved in a three‐element E‐plane array antennas using metal vias and defected ground surface, with maximum gain and efficiency of 4.5 dB and 78%, respectively, between 3.95 and 4.04 GHz 10 . Three inter‐digital lines are placed among three patch antennas to achieve 24.7 dB maximum isolation improvement at 5.8 GHz 11 .…”

“…A 16.6 dB maximum mutual coupling reduction was achieved in a three-element E-plane array antennas using metal vias and defected ground surface, with maximum gain and efficiency of 4.5 dB and 78%, respectively, between 3.95 and 4.04 GHz. 10 Three inter-digital lines are placed among three patch antennas to achieve 24.7 dB maximum isolation improvement at 5.8 GHz. 11 Also, the authors in Reference 12 presented a novel hybrid electromagnetic structure and defected ground surface, which were employed to achieve 22 dB isolation enhancement between two patch antennas at 4.9 GHz.…”

On Inadequacy of Sequential Design of Experiments for Performance-Driven Surrogate Modeling of Antenna Input Characteristics

“…functionalities, e.g., circular polarization [6], multi-band [7] or MIMO operation [8], pattern/polarization diversity [9], let alone meeting additional requirements such as reduction of the physical size of the radiator [10], [11], calls for unconventional layouts [12]- [19]. These include incorporation of stubs [12], [13], slots [14], [15], defected ground structures [16], [17] or complex (e.g., spline-parameterized) profiles [18], [19] the exact effects of which cannot be quantified using analytical or equivalent network representations. Thus, utilization of full-wave electromagnetic (EM) simulation tools is imperative at all design stages to ensure the reliability of antenna evaluation [20], [21].…”