Heptaband swastik arm antenna for MIMO applications

Abstract

In this study, a two‐element multiple‐input–multiple‐output (MIMO) antenna with heptaband characteristics is proposed. The total size of the proposed antenna is 82 × 40 × 0.8 mm3. The geometry of the radiating element is derived from a hybrid Quadric–Koch island fractal for size miniaturisation. The antenna operates at the bands of 0.95–1.02 GHz (GSM 900), 1.73–1.79 GHz (GSM 1800), 2.68–2.85 GHz (LTE‐A), 3.66–3.7 GHz [ultra‐wideband (UWB)], 4.20–4.40 GHz (UWB), 5.50–5.65 GHz [worldwide interoperability for microwave access/high‐performance radio local area network] and 5.93–6.13 GHz (UWB). The spacing between the two radiating elements is maintained at 5 mm. The proposed heptaband swastik arm MIMO antenna exhibits an S11 ≤ −6 dB and S21 ≤ −17 dB over the entire bands of operation. It provides high isolation without requiring any additional structures. The antenna also offers stable radiation characteristics with circular polarisation at the operating bands of 3.66–3.7 GHz and 5.93–6.13 GHz and linear polarisation at 0.95–1.02 GHz, 1.73–1.79 GHz, 2.68–2.85 GHz, 4.20–4.40 GHz and 5.50–5.65 GHz bands. The diversity performance of the antenna is studied in terms of the envelope correlation coefficient which is <0.05, and capacity loss which is <0.5 bits/s/Hz at all the operating frequencies, making it suitable for use in fifth generation communication systems incorporating the existing bands.

Novel sunflower MIMO fractal antenna with low mutual coupling and dual wide operating bands

“…The specifications of the MIMO sunflower fractal antenna are better than those of the previous MIMO fractal antennas investigated in [3, 8, 9, 17, 18, 19, 26, 27] due to the following reasons. None of the previous MIMO fractal antennas with the same size (40 × 50 × 0.8 mm 3 ) can support 3G, LTE (4G), WLAN (IEEE 802.11n and IEEE 802.11ac), WiMAX (IEEE 802.16), and 5G (5–6 GHz) communication networks.The mutual coupling between the antennas reduced 20 dB by inserting a strip line into the outer edges of the ground plate.None of the previous MIMO antennas with the same size (40 × 50 × 0.8 mm 3 ) have the same mutual coupling (from −45 to −25 dB), CCL (0.15–0.4 b/s/Hz), efficiency (65–85%), and gain (1–6 dBi).The MIMO sunflower fractal antenna exhibits a novel design with a low profile etched on a low-cost and commercial FR-4 substrate.…”

“…El), impedance bandwidth, efficiency, gain, mutual coupling ( S ij ), and size. Previous MIMO antennas were either too large such that they cannot be used in modern portable communication devices [2, 6, 7, 8, 13, 14, 16, 17, 19, 20, 21, 29, 30], or small but cannot support the requirements of modern communication networks, such as 3G, WLAN, LTE, and WiMAX [3, 10, 12, 15, 18, 22, 23, 25, 27, 28].…”

“…A mutual coupling of <−20 dB is preferred [19]. The antennas listed in Table 1 exhibit mutual coupling greater than −20 dB, except for those investigated in [4, 8, 1718, 19, 23, 28]. However, the antennas reported in [8, 17, 19] had a large size, whereas those studied in [4, 18, 23, 28] do not support all the required spectra.…”

MIMO antenna with built‐in circular shaped isolator for sub‐6 GHz 5G applications

“…Mutual coupling between various antenna elements degrades the performance of MIMO systems. Techniques like space decoupling [2] and using other decoupling structures [3] were being reported in the literature for achieving isolation between elements in MIMO systems. In [4] a MIMO antenna design with a built‐in decoupling mechanism was introduced with an edge to edge separation of 0.2 mm between the two monopoles for achieving isolation.…”

A Penta-Band Reject Inside Cut Koch Fractal Hexagonal Monopole Uwb Mimo Antenna for Portable Devices

“…These limitations can be overcome by using Multiple Input Multiple Output (MIMO) technology [1]. The advantages of using MIMO is the increased channel capacity and the overall transmission range for the same power requirements as it uses multiple antennas in the transmitter and receiver sides [2].…”