Wideband Multiport Antennas

In this paper, a wideband four port 2–6 GHz antenna is proposed. One-, two-, and four-port antennas are implemented and characterized between 2 and 6 GHz. The isolation between the ports is improved by connecting and optimizing the ground plane sections. The results show that the antennas’ reflection coefficients are better than 10 dB in the frequency band. The measured isolation between the ports is greater than 15 dB (between 2.3 and 6 GHz) and 10 dB in the whole band for two- and four-port antennas, respectively, however, it is more than 20 dB around 2.4 and 5–6 GHz for both antennas. The calculated correlation coefficient between ports is below −30 dB (>2.14 GHz) and −15 dB for the two- and four-port antennas, respectively. The measured gain and efficiency scale are 3.1–6.75 dBi and 62–98%, respectively. To the best of our knowledge, an antenna both being wideband from 2 to 6 GHz and having independent four ports is only addressed in this work. The four-port antenna can be used for MIMO systems or smartphones operating on many wireless systems simultaneously such as 3G/4G/5G Sub-6 GHz and WLAN including the next generation WiFi7 with full-duplex operation.

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Compact UWB–MIMO antenna with quad-band-notched characteristic

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078716001239 ◽

2016 ◽

Vol 9 (5) ◽

pp. 1147-1153 ◽

Cited By ~ 3

Author(s):

Ling Wu ◽

Yingqing Xia

Keyword(s):

Correlation Coefficient ◽

Radiation Pattern ◽

Mimo System ◽

Ground Plane ◽

Multiple Input Multiple Output ◽

Mimo Antenna ◽

X Band ◽

Multiple Input ◽

Input Multiple Output ◽

Better Than

With quad-band-notched characteristic, a compact ultrawideband (UWB) multiple-input-multiple-output (MIMO) antenna is introduced in the paper. The UWB–MIMO system has two similar monopole elements and occupies 30 × 45 mm2. By inserting two L-shaped slots, CSRR and C-shaped stubs, four notched bands are achieved (3.25–3.9, 5.11–5.35, 5.5–6.06, and 7.18–7.88 GHz) to filter WiMAX, lower WLAN, upper WLAN, and X-band. Meanwhile, the isolation is obviously enhanced with three metal strips on the ground plane. Results indicate that the antenna covers UWB frequency band of 3.1 – 10.6 GHz except four rejected bands, isolation of better than −18 dB, envelope correlation coefficient of <0.02, and good radiation pattern, thus making it useful for UWB systems.

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Miniaturized MIMO Antenna with Low Inter-radiator Transmittance and Band Rejection Features

Journal of Electromagnetic Engineering and Science ◽

10.26866/jees.2021.4.r.38 ◽

2021 ◽

Vol 21 (4) ◽

pp. 307-315

Author(s):

Muhammad Irshad Khan ◽

Muhammad Irfan Khattak ◽

Mauth Al-Hasan

Keyword(s):

Correlation Coefficient ◽

Radiation Pattern ◽

Mimo System ◽

Ground Plane ◽

Diversity Gain ◽

Reflection Coefficients ◽

Mimo Antenna ◽

Transmission Coefficients ◽

Multiple Input ◽

Envelope Correlation

In this article, compact a multiple-input and multiple-output (MIMO) system with flag-shaped radiators and a mountain-shaped ground plane is presented. Isolation is enhanced with the help of a decoupling stub placed between radiators, where two bands are stopped with the help of slits etched into the radiators. The overall size of the proposed antenna is 15 mm ×25 mm ×1.6 mm. The reflection coefficients are less than -10 dB between 3–10.9 GHz, except the bands WiMAX (3.2–3.7 GHz) and WLAN (5–6 GHz); similarly, measured and simulated transmission coefficients are less than -20 dB across the entire band of UWB. The envelope correlation coefficient (ECC) is less than 0.02 and the diversity gain is greater than 9.9 dB. The gain, ECC, radiation pattern, multiplexing efficiency, diversity gain and various other parameters are discussed and evaluated in detail.

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Parallel Soft Spherical Detection for Coded MIMO Systems

Advances in Wireless Technologies and Telecommunication - Fourth-Generation Wireless Networks ◽

10.4018/978-1-61520-674-2.ch028 ◽

2010 ◽

pp. 644-665

Author(s):

Hosein Nikopour ◽

Amin Mobasher ◽

Amir K. Khandani ◽

Aladdin Saleh

Keyword(s):

Mimo Systems ◽

Mimo System ◽

Wireless Systems ◽

Next Generation ◽

A Posteriori Probability ◽

Outer Code ◽

Average Complexity ◽

Problems And Solutions ◽

Input Multiple Output ◽

Priori Information

This Chapter briefly evaluates different multiple-input multiple-output (MIMO) detection techniques in the literature as the candidates for the next generation wireless systems. The authors evaluate the associated problems and solutions with these methods. The focus of the chapter is on two categories of MIMO decoding: i) hard detection and ii) soft detection. These techniques significantly increase the capacity of wireless communications systems. Theoretically, a-posteriori probability (APP) MIMO decoder with soft information can achieve the capacity of a MIMO system. A sub-optimum APP detector is proposed for iterative joint detection/decoding in a MIMO wireless communication system employing an outer code. The proposed detector searches inside a given sphere in a parallel manner to simultaneously find a list of m-best points based on an additive metric. The metric is formed by combining the channel output and the a-priori information. The parallel structure of the proposed method is suitable for hardware parallelization. The radius of the sphere and the value of m are selected according to the channel condition to reduce the complexity. Numerical results are provided showing a significant reduction in the average complexity (for a similar performance and peak complexity) as compared to the best earlier known method. This positions the proposed algorithm as a candidate for the next generation wireless systems. The proposed scheme is applied for the decoding of the rate 2, 4 × 2 MIMO code employed in the IEEE 802.16e standard.

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Full-Duplex Non-Orthogonal Multiple Access for Next Generation Wireless Systems

IEEE Communications Magazine ◽

10.1109/mcom.2019.1800578 ◽

2019 ◽

Vol 57 (5) ◽

pp. 110-116 ◽

Cited By ~ 16

Author(s):

Mohammadali Mohammadi ◽

Xiaoyan Shi ◽

Batu K. Chalise ◽

Zhiguo Ding ◽

Himal A. Suraweera ◽

...

Keyword(s):

Multiple Access ◽

Wireless Systems ◽

Full Duplex ◽

Next Generation

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Smart antennas for next generation wireless systems

2nd European Conference on Antennas and Propagation (EuCAP 2007) ◽

10.1049/ic.2007.1540 ◽

2007 ◽

Author(s):

A. Alexiou

Keyword(s):

Smart Antennas ◽

Wireless Systems ◽

Next Generation

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Zero-Forcing Max-Power Beamforming for Hybrid mmWave Full-Duplex MIMO Systems

2020 4th International Conference on Advanced Systems and Emergent Technologies (IC_ASET) ◽

10.1109/ic_aset49463.2020.9318295 ◽

2020 ◽

Author(s):

Elyes Balti ◽

Neji Mensi

Keyword(s):

Mimo Systems ◽

Full Duplex ◽

Zero Forcing

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A tuneable rat-race coupler for full duplex communications

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078721000787 ◽

2021 ◽

pp. 1-7

Author(s):

G. T. Watkins

Keyword(s):

Interference Cancellation ◽

Phase Shifter ◽

Dipole Antenna ◽

Full Duplex ◽

Frequency Channel ◽

Ism Band ◽

Single Antenna ◽

Variable Attenuator ◽

Degree Of Isolation ◽

Better Than

Abstract Full duplex (FD) could potentially double wireless communications capacity by allowing simultaneous transmission and reception on the same frequency channel. A single antenna architecture is proposed here based on a modified rat-race coupler to couple the transmit and receive paths to the antenna while providing a degree of isolation. To allow the self-interference cancellation (SiC) to be maximized, the rat-race coupler was made tuneable. This compensated for both the limited isolation of the rat race and self-interference caused by antenna mismatch. Tuneable operation was achieved by removing the fourth port of the rat race and inserting a variable attenuator and variable phase shifter into the loop. In simulation with a 50 Ω load on the antenna port, better than −65 dB narrowband SiC was achieved over the whole 2.45 GHz industrial, scientific and medical (ISM) band. Inserting the S-parameters of a commercially available sleeve dipole antenna into the simulation, better than −57 dB narrowband SiC could be tuned over the whole band. Practically, better than −58 dB narrowband tuneable SiC was achieved with a practical antenna. When excited with a 20 MHz Wi-Fi signal, −42 dB average SiC could be achieved with the antenna.

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