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In this paper, a compact planar dual-band multiple-input and multiple-output (MIMO) antenna with high isolation is presented to satisfy the increasing requirements of wireless communication. The proposed antenna array consists of two identical radiating elements which are fed through micro-strip lines. A rectangular micro-strip stub with defected ground plane is employed to achieve a high isolation which is less than −15 dB between the two antenna elements. The size of the entire MIMO antenna is 32 × 32 × 1.59 mm3, which is printed on an FR4 substrate. The proposed MIMO antenna is optimized to operate in 2.36–2.59 GHz and 3.17–3.77 GHz bands, which can cover the fifth-generation (5G) n7 (2.5–2.57 GHz) and the fourth-generation (4G) Long Term Evolution (LTE) band 42 (3.4–3.6 GHz). The proposed MIMO antenna is feasible for the 5G and 4G applications.

A novel compact wideband and dual-band microstrip-fed antenna is proposed. By using symmetrical inverted-L-shaped strips, a forkshaped strip, a rectangular slot and a defected ground plane, the dual-band resonances of the antenna are generated. The measured impedance bandwidths are 1.12 GHz for the lower frequency band (1.87-2.99 GHz), and 780 MHz for the higher frequency band (5.10-5.88 GHz). The fabricated antenna can be used to cover the entire required bands for time-division-long-term evolution (1880-2655 MHz) and wireless local area network 802.11 a/b/g (2.4-2.4835, 5.15-5.875 GHz). The measured gain at 2.4 and 5.5 GHz is 2.1 and 6.1 dBi, respectively. The antenna shows a compact size of 25 × 30 × 0.8 mm. The details of the antenna design, the operation mechanism and the simulated and measured results are presented.

Abstract-In this paper, the design of a multiband antenna for WLAN and WiMAX applications is proposed. The proposed antenna comprises a circular radiating patch with a pair of rectangular slits and an inverted U-shaped slot. A hexagon-shaped slot is cut on the ground plane. By adjusting the inverted U-shaped slot, a pair of rectangular slits, and a hexagon-shaped slot, three distinct resonance frequencies centered at 2.4 GHz, 3.52 GHz, and 5.68 GHz can be generated. The measurements show that the proposed antenna can cover three frequency bands with sufficient bandwidth. The proposed antenna exhibits an omnidirectional radiation pattern and acceptable gain. The overall dimension of the proposed antenna is 25 × 39 × 1.59 mm 3 .

This paper presents a dual-band four-element multiple-input-multiple-output (MIMO) array for the fifth generation (5G) mobile communication. The proposed antenna is composed of an open-loop ring resonator feeding element and a T-shaped radiating element. The utilization of the open-loop ring resonator not only reduces the size of the antenna element, but also provides positive cross-coupling. The dimension of a single antenna element is 14.9 mm × 7 mm (0.27λ × 0.13λ, where λ is the wavelength of 5.5 GHz). The MIMO antenna exhibits a dual-band feature from 3.3 to 3.84 GHz and 4.61 to 5.91 GHz, which can cover 5G New Radio N78 (3.3–3.8 GHz), 5G China Band N79 (4.8–5 GHz), and IEEE 802.11 ac (5.15–5.35 GHz, 5.725–5.85 GHz). The measured total efficiency and isolation are better than 70% and 15 dB, respectively. The calculated envelope correlation coefficient (ECC) is less than 0.02. The measured results are in good agreement with the simulated results.