— Multiple Input Multiple Output (MIMO) antenna is expected to form a major technique of 5G communication to get a high channel capacity. However the antenna performance is degraded significantly because of mutual coupling between close elements in portable equipments. In this paper, a novel EBG structure for 28/38GHz dual-band MIMO antenna with its equivalent is proposed. Having round shape and double side design, the proposed double-side EBG (DS-EBG) structure is able to improve significantly both mutual coupling and gain without any decoupling structure between antenna elements. Thus the MIMO antenna gets compact size of 15.3x8.5x0.79mm with no distance between antenna elements from edge to edge. The antenna radiation efficiency is also refined at both bands. This improvement has not attained from any previous EBG structure studies. At 28GHz, the radiation efficiency is increased from 83.2% to 87.6% while it is raised from 83.1% to 91.1% at 38GHz. Besides, the antenna achieves wide bandwidth of 7.1% and 13.16% at 28GHz and 38GHz, respectively that is suitable for 5G terminals. All dimensions of EBG cell as well as antenna are optimized by using Computer Simulation Technology (CST) software.

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Improving Characteristics of 28/38GHz MIMO Antenna for 5G Applications by Using Double-Side EBG Structure

Wi-Fi (Wireless Fidelity) is one of the most popular wireless communication standards in the market. This technology is widely used both in offices, shopping centers, campuses and other public places. To optimize the Wi-Fi communication system antenna optimization is needed. The role of the antenna is to transmit voice communication and data communication. However, due to the influence of several factors, the signals received by users often experience instability. The design of the trident microstrip antenna aims to find the microstrip antenna formula needed by Wi-Fi technology. So, the research will design a trident microstrip antenna for Wi-Fi that works at 2.40 GHz and 5.80 GHz frequencies. The software needed to design this antenna is computer simulation technology (CST). From the simulation results for the 2.4 GHz trident microstrip antenna has a return loss value of -18,514 dB, a VSWR value of 1.26 dB and a Gain value of 4.71 dB. As for the simulation results of the 5.8 GHz microstrip antenna has a return loss value of -40,437 dB, a VSWR value of 1.02 dB and a Gain value of 4.19 dB. As for the measurement results of the 2.4 GHz trident microstrip antenna has a return loss value of -24,767 dB, a VSWR value of 1,122 dB and a Gain value of 3.24 dB. As for the measurement results of the 5.8 GHz microstrip antenna has a return loss value of -37,554 dB, a VSWR value of 1,027 dB and a Gain value of 3.57 dB. Where the overall results of simulations and measurements can be said 5.8 GHz microstrip antenna has good performance results for the parameters needed.

Design of 2.4 GHz and 5.8 GHz Microstrip Antenna on Wi-Fi Network

This study investigates the optimized Sierpinski carpet fractal patch antenna and also explores the possibility of the integration of the proposed design with monolithic microwave integrated circuits. The optimization process has been performed using an ant lion optimization algorithm to achieve the required operating frequency and impedance matching. Further, due to surface waves excitation in the high index substrates used for the antenna design, the performance of the antenna degrades. Therefore, a process of micro-machining has been adopted to overcome this limitation. The micro-machining process creates an air cavity underneath the patch which further creates the low index environment in the patch antenna causing drastic improvement in the performance parameters along with the compatibility with monolithic microwave integrated circuits. The design shows multiple resonance frequencies in X-band and Ku-band. The proposed micro-machined design shows the resonance at 7.9 GHz, 9.6 GHz, 13.6 GHz, and 19 GHz with a maximum gain of 6 dBi.

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Design and Optimization of Micro-Machined Sierpinski Carpet Fractal Antenna Using Ant Lion Optimization

In this research article, a compact wideband stack patch antenna array integrated with compact stack electromagnetic band gap (EBG) structure for multiple input multiple output (MIMO) application is proposed. The wide resonance bandwidth is achieved at 2.45 GHz band by stack arrangement of compact meander line slot driven and parasitic patch elements. The isolation bandwidth is matched with resonance bandwidth with the design of a compact stack L slot EBG structure. The polarization diversity and three-layer EBG structure ensure an enhancement in isolation level. To validate the performance of the proposed stack antenna array, a prototype was fabricated and tested for different MIMO parameters. The measured result confirms the effectiveness of the proposed antenna array in a diverse MIMO environment.

Compact stack EBG structure for enhanced isolation between stack patch antenna array elements for MIMO application

A new and very simple way of implementing defected ground structure (DGS) in a microstrip patch antenna is presented. The dimension of DGS is exactly same as the dimension of radiating element. There are two different DGSs implemented in this paper. The DGSs are complement of each other with respect to their structures. The antennas with these complementary DGSs show four different frequencies of operation (10 GHz, 12 GHz, 16 GHz and 16.6 GHz) with enhanced bandwidth maximum of 22% with respect to the antenna without DGS. The proposed antenna can be implemented for X-band and Ku-band application.

Design of dual band patch antenna with bandwidth enhancement using complementary defected ground structure

Defected Ground Structure (DGS) is a newly introduced revolutionary technique in the field of microstrip antenna to enhance the performance of antenna parameters as bandwidth. In this paper, a design of compact MIMO antenna using DGS is proposed. The antenna operates at 3.5 GHz for WiMax/LTE tablet applications. Compare to theoretical microstrip antenna design, the suggested MIMO antenna using a simple DGS shape has achieved not only an enlarged bandwidth but also more compact size. In addition, the mutual coupling between two antenna elements with close distance is low (less than −20dB) thanks to proper position in antenna ground as well as the fed method using.

Compact MIMO antenna with low mutual coupling using defected ground structure

A dual-band Multiple Input Multiple Output (MIMO) antenna system with enhanced isolation for LTE and WLAN applications is proposed. Using a double-rectangular Defected Ground Structure (DGS), the MIMO antenna gets two resonant frequencies of 2.6 GHz and 5.7 GHz with bandwidth of 5.7% and 4.3% respectively. To reduce much more mutual coupling between dual-band MIMO antenna ports, a novel double-side Electromagnetic Band Gap (EBG) structure with equivalent circuit model is proposed. Size of t gain of the antenna is getting better, especially at the low band. he EBG unit cell is 8.6x8.6 mm2 that is built on FR4 substrate with height of 1.6 mm, so it is achieved more compact size than conventional EBG structures. With 1x7 EBG structures, the mutual coupling gets -40dB in the low frequency band and -30 dB in the high one with narrow distance of 0.11 from feeding point to feeding point. Furthermore, radiation efficiency as well as gain of the antenna is getting better, especially at the low band.

Design and Implementation of Dual-Band MIMO Antenna with Low Mutual Coupling Using EBG for Handheld Applications

A double-side EBG structure with equivalent circuit model is proposed in this paper. Making H shape on surface and H with bridge shape on ground, the novel EBG that is built on FR4 substrate with height of 1.6mm, gets compact size of 8.6x8.6 mm 2 at 2.6 GHz resonant frequency. Using 1x7 EBG structures for dual-band MIMO system, several performance parameters of antenna are improved. Firstly, the mutual coupling between antenna elements gets -40dB in the lower band and -30dB in the higher one with narrow distance of 0.11l from feeding point to feeding point. Then, at 2.6GHz, the antenna gain is increased significant by 160% as well as radiation efficiency of antenna is better. This improvement is unable to get in previous EBG studies

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Double-Side Electromagnetic Band Gap Structure for Improving Dual-Band MIMO Antenna Performance

Recent advances in deep learning facilitate the development of end-to-end Vietnamese text-to-speech (TTS) systems with high intelligibility and naturalness in the presence of a clean training corpus. Given a rich source of audio recording data on the Internet, TTS has excellent potential for growth if it can take advantage of this data source. However, the quality of these data is often not sufficient for training TTS systems, e.g., noisy audio. In this paper, we propose an approach that preprocesses noisy found data on the Internet and trains a high-quality TTS model on the processed data. The VLSP-provided training data was thoroughly preprocessed using 1) voice activity detection, 2) automatic speech recognition-based prosodic punctuation insertion, and 3) Spleeter, source separation tool, for separating voice from background music. Moreover, we utilize a state-of-the-art TTS system that takes advantage of the Conditional Variational Autoencoder with the Adversarial Learning model. Our experiment showed that the proposed TTS system trained on the preprocessed data achieved a good result on the provided noisy dataset.

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Nguyen Van Hoc

Papers

Compact MIMO antenna with low mutual coupling using defected ground structure

Design and Implementation of Dual-Band MIMO Antenna with Low Mutual Coupling Using EBG for Handheld Applications

Double-Side Electromagnetic Band Gap Structure for Improving Dual-Band MIMO Antenna Performance

TTS - VLSP 2021: Development of Smartcall Vietnamese Text-to-Speech