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Miniaturized band-notched UWB MIMO antenna with high isolation

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2016年第4期58卷 878-881页

作者： Kang, Le Li, Hui Wang, Xin-Huai Shi, Xiao-Wei Xidian Univ Sci & Technol Antenna & Microwave Lab Xian 710071 Shaanxi Peoples R China

A compact multiple-input multiple-output (MIMO) antenna is presented for band-notched ultra-wideband (UWB) applications. Miniaturization of the proposed antenna is realized by employing the asymmetric coplanar strip (ACS)-fed structures. To obtain the band-notched function, open stubs are introduced on the radiators. In addition, an H-shaped slot is etched on the ground to reduce the mutual coupling between the antenna elements. The designed antenna with an overall size of 28 x 22 x 0.8 mm(3) was fabricated and tested. Measured results show the antenna operates over a frequency band of 2.9-11.8 GHz with reflection coefficient less than -10 dB, except at the rejection band of 4.9-6 GHz. Within the operating band, measured port isolation is better than 20 dB. Radiation characteristics and diversity performance of the antenna are also investigated through measurement. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:878-881, 2016

关键词： band-notched isolation enhancement multiple-input-multiple-output ultra-wideband antenna

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An Eight-Port Circularly Polarized Wideband MIMO Antenna Based on a Metamaterial-Inspired Element for 5G mmWave Applications

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IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2023年第7期22卷 1572-1576页

作者： Khan, Asif He, Yejun Chen, Zhi Ning Shenzhen Univ Coll Elect & Informat Engn State Key Lab Radio Frequency Heterogeneous Integr Shenzhen 518060 Peoples R China Natl Univ Singapore Dept Elect & Comp Engn Singapore 119077 Singapore

This letter presents a low-profile, single-layer wideband metamaterial-inspired circularly polarized (CP) multiple-input-multiple-output (MIMO) antenna array. An 8 x 8 antenna array is manufactured on the Rogers RT/Duroid 5880 substrate with a partial ground plane. The dimensions of the proposed MIMO antenna array are 0.285 lambda x 0.11 lambda x 0.001 lambda at 28 GHz, where. is the free-space wavelength. The isolation, gain, and higher axial bandwidth ratio are significantly improved by the introduction of a metamaterial-inspired element. As a result, the proposed circularly polarized MIMO antenna has an impedance bandwidth of 18 GHz, a mutual coupling of no more than -20 dB, an axial ratio bandwidth (ARBW) of 13 GHz, and a peak gain of 20.5 dBi. Significantly, the designated mm Wave band (25-29.5 GHz) for 5G communication is covered by the operating bandwidth of the antenna. MIMO parameters are also discussed in terms of cross-correlation, diversity gain, and mean effective gain to further investigate the performance of the MIMO antenna. Therefore, the suggested antenna array is a good candidate for 5G new radio (NR) smart devices and sensors.

关键词： Circular polarization cross-correlation isolation metamaterial multiple-input-multiple-output

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Constant Weight Polar Coded Orthogonal Space-Time Block Codes for Dimmable Indoor MIMO-VLC Systems

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IEEE COMMUNICATIONS LETTERS 2022年第10期26卷 2395-2399页

作者： Babalola, O. P. Balyan, V Cape Peninsula Univ Technol Dept Elect Elect & Comp Engn ZA-7535 Bellville South Africa

The concatenation of constant weight polar code (CWPC) with orthogonal space-time block code (OSTBC), known as CWPC-OSTBC scheme is proposed for the indoor multiple-input multiple output visible light communication (MIMO-VLC) systems in this letter. The CWPC helps to mitigate against flickering, provides desired dimming targets, and coding gain while the OSTBC achieves MIMO diversity gain. Flicker mitigation and dimming control are obtained based on the modified Knuth balancing method with enhanced prefix coding. This method does not utilise lookup table and thus, it is practicable in the real-time. Numerical results are presented to discuss the channel capacity and bit-error-rate (BER) performance of the proposed CWPC-OSTBC scheme considering different parameters. The results show that increasing the transmission antennas of the OSTBC system provides diversity gains. More so, the CWPC-OSTBC scheme yields an improved coding gain compared to polar code without balancing and other state-of-the-art methods.

关键词： Decoding Encoding Polar codes Codes Light emitting diodes Symbols Reliability Constant weight polar code multiple-input-multiple-output orthogonal space-time block code visible light communication

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Frequency-Domain Iterative SDFE for MIMO-OFDM Systems

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WIRELESS PERSONAL COMMUNICATIONS 2016年第3期86卷 1121-1140页

作者： Chung, Chi-Yang Ueng, Fang-Biau Chang, Yu-Kuan Natl Chung Hsing Univ Dept Elect Engn Taichung 40227 Taiwan

This paper proposes a frequency-domain iterative soft decision feedback equalization (SDFE) scheme for multiple-input-multiple-output orthogonal frequency division multiplexing communication systems in multi-path fading channels. Error propagation can seriously affect the performance of the adaptive decision feedback equalization. We propose an iterative SDFE to not only combat error propagation but also be suitable for multilevel modulation systems. Under a Gaussian approximation of the a priori information and the SDFE output, the output of an equivalent AWGN channel and expressions for the a posteriori log likelihood ratio (LLR) and the extrinsic LLR are derived for multilevel modulation. In addition, we also investigate the iterative receivers by employing irregular low-density parity check codes (LDPC) and turbo codes. The performance of the LDPC-coded iterative receiver is better than that of the turbo-coded iterative receiver. Some simulation examples are given to show the effectiveness and comparisons of the proposed receiver.

关键词： multiple-input-multiple-output Soft decision feedback equalization Turbo equalization

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An ultrawideband antenna for portable MIMO terminals

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2016年第1期58卷 51-56页

作者： Wani, Zamir Vishwakarma, Dinesh Kumar Indian Inst Informat Technol Design & Mfg Jabalpur 482005 Madhya Pradesh India

A compact printed ultrawideband (UWB) antenna system used to combat multipath fading has been proposed and investigated. The antenna consisting of two shovel-shaped monopole antenna elements (AE) on a low loss substrate with dimensions 35 x 30 mm(2) can be used for multi-input-multi-output (MIMO)/diversity applications. Both the monopole antennas are fed with microstrip lines, matched to 50 lines at each port. To reduce the mutual coupling, two F-shaped ground stubs are added to the ground plane and rectangular slots have been made to ensure proper impedance matching. Measured and simulated results show that the antenna system covers most of UWB with isolation greater than 22 dB. A low value of measured envelops correlation coefficient less than 0.005 is achieved throughout the entire band of interest (3.1-10.6 GHz). The proposed antenna satisfies all the requirements of an MIMO antenna used for UWB, thus is a potential candidate for MIMO/diversity applications in UWB communication. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:51-56, 2016

关键词： diversity envelope correlation coefficient ground stub isolation multiple-input-multiple-output ultrawideband

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Design and Analysis of MIMO Antenna with High Isolation and Dual Notched Band Characteristics for Wireless Applications

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WIRELESS PERSONAL COMMUNICATIONS 2020年第3期112卷 1587-1599页

作者： Sharma, Manish Chitkara Univ Inst Engn & Technol Rajpura Punjab India

A very compact Superwideband multiple-input-multiple-output antenna with dual notched band characteristics is presented. Superwideband characteristics is obtained by means of radiating patch and high isolation between two input ports are obtained by using T-shaped stub in ground plane. Two rejection bands (wireless interoperability for microwave access (WiMAX)/C-band and wireless local area network) are obtained by etching two elliptical slots on radiating patch. Antenna offers large measured useable bandwidth of 2.60-20.04 GHz. Diversity performance is studied in terms of envelope correlation coefficient, diversity gain and total active reflection coefficient. Antenna also offers desirable radiation pattern, gain and radiation efficiency which makes proposed antenna quite suitable for different wireless applications.

关键词： Superwideband multiple-input-multiple-output ECC DG TARC

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A compact four elements UWB MIMO antenna with on-demand WLAN rejection

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2016年第2期58卷 270-276页

作者： Khan, Saeed M. Iftikhar, Adnan Asif, Sajid M. Capobianco, Antonio-Daniele Braaten, Benjamin D. Univ Padua Dipartimento Ingn Informaz I-35131 Padua Italy N Dakota State Univ Dept Elect & Comp Engn Fargo ND 58102 USA COMSATS Inst Informat Technol Dept Elect & Comp Engn Islamabad Pakistan

This article presents a four elements frequency reconfigurable ultrawideband (UWB) multiple-input-multiple-output (MIMO) design, capable of rejecting on-demand WLAN band ranging from 4.8 to 6.2 GHz. The proposed design consists of two U-shaped monopole UWB radiators and two circular slotted-monopole radiators. These monopole radiators are placed orthogonally with respect to each other to exploit polarization diversity, whereas the PIN diodes are used to connect the band-stop design with the ground plane to introduce the on-demand band rejection feature. An isolation of better than 17 dB between the four UWB-MIMO elements is achieved in the 2.7-12 GHz frequency range for the both PIN diodes biased and unbiased states. The simulations and measurements results showed good agreement over the band of interest. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:270-276, 2016

关键词： multiple-input-multiple-output ultrawideband envelope correlation co-efficient on-demand band rejection

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Analog I/Q FIR Filter in 55-nm SiGe BiCMOS for 16-QAM Optical Communications at 112 Gb/s

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IEEE JOURNAL OF SOLID-STATE CIRCUITS 2020年第7期55卷 1935-1945页

作者： Verplaetse, Michiel Lambrecht, Joris Vanhoecke, Michael Breyne, Laurens Ramon, Hannes Demeester, Piet Torfs, Guy Univ Ghent IMEC Dept Informat Technol IDLab B-9052 Zwijnaarde Belgium

We propose a novel implementation of a complex analog equalization filter for the compensation of frequency-dependent variations in coherent optical links. The analog compensation filter can be used in coherent-lite optical communication links where digital signal processing (DSP) is removed to limit the complexity and power consumption. In these links, the filter can compensate for electrical bandwidth limitations and distortion introduced by chromatic dispersion in the fiber. The complex filter is implemented by combining four distributed analog finite-impulse response (FIR) filters to obtain the necessary response. The filter delays are implemented using active delay cell structures to create a compact solution. The analog filter is implemented in a 55-nm BiCMOS technology and consumes 185-mW core power for five complex filter taps. Performance is evaluated using the S-parameter measurements, noise and linearity measurements, and real-time system experiments using 112-Gb/s 16-QAM-modulated signals.

关键词： Finite impulse response filters Optical fiber communication Equalizers Dispersion Optical polarization Optical transmitters Delays Analog equalization coherent data center dispersion electronic compensation of dispersion (EDC) multiple-input-multiple-output

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Matrix inversion-less direct decoding for efficient channel estimation in fifth-generation massive MIMO systems

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IET COMMUNICATIONS 2020年第5期14卷 865-871页

作者： Zafar, Mohammad Haseeb Khan, Imran Basheri, Mohammed King Abdulaziz Univ Dept Informat Technol Jeddah Saudi Arabia Univ Engn & Technol Dept Elect Engn Peshawar Pakistan

Massive multiple-input-multiple-output (MIMO) is a fifth-generation wireless technology that equips the cellular base stations (BSs) with a very large number of antenna and is a communication technique of serving several users. Aiming at the problem of the high computational complexity of linear channel estimation and linear decoding in massive MIMO systems, this study proposes two low-complexity decoding algorithms according to the characteristics of the system. The fast decoding algorithm is designed by using the asymptotic orthogonality of the channel in the system to avoid solving the inverse of the channel matrix. In combination with increasing the number of base BS antennas to optimise user channel characteristics, a simple operator decoding algorithm is designed to realise direct decoding without estimating the channel. Simulation results show that the proposed algorithms can effectively reduce the computational complexity while ensuring system performance.

关键词： MIMO communication channel estimation decoding computational complexity matrix inversion-less efficient channel estimation fifth-generation massive MIMO systems multiple-input-multiple-output fifth-generation wireless technology cellular base stations communication technique high computational complexity linear channel estimation low-complexity decoding algorithms fast decoding algorithm channel matrix base BS antennas user channel characteristics simple operator decoding algorithm direct decoding system performance

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A UWB MIMO slot antenna using defected ground structures for high isolation

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2020年第5期30卷 e22155-e22155页

作者： Wang, Enhao Wang, Weimin Tan, Xiaohua Wu, Yongle Gao, Jinchun Liu, Yuanan Beijing Univ Posts & Telecommun Sch Elect Engn Beijing Key Lab Work Safety Intelligent Monitorin Beijing 100876 Peoples R China

In this article, a multiple-input-multiple-output (MIMO) antenna with high isolation is proposed for ultrawideband (UWB) applications. The proposed MIMO antenna consists of two symmetric slot antenna elements with quasi F-shaped radiators and L-shaped open-slots to increase impedance bandwidth. To improve isolation at the lower band, a decoupling network, composed of a narrow slot and a fork-shaped slot, is introduced in the common ground. The measured results show that the proposed antenna provides high isolation of better than 20 dB over the operating band from 3 to 10.9 GHz. The performances of the UWB MIMO antenna in terms of radiation patterns, peak gain, envelope correlation coefficient, mean effective gain, and diversity gain are also studied.

关键词： diversity gain envelope correlation coefficient mean effective gain multiple-input-multiple-output ultrawideband antenna

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