Systematic Design of Dual-band MIMO Antenna using Characteristic Mode Analysis

Author(s):  
Harsh Verdhan Singh ◽  
Shrivishal Tripathi ◽  
Ramesh Vaddi
2019 ◽  
Vol 70 (3) ◽  
pp. 187-197
Author(s):  
Ehab K. I. Hamad ◽  
Ahmed Abdelaziz

Abstract Metamaterials (MTMs) have received considerable attention due to their novel electromagnetic properties. Their applications include enhancing gain and bandwidth in microstrip antennas. In this article, a dual band microstrip antenna design based on characteristic mode analysis (CMA) using MTM superstrate is proposed for 5G wireless communication. The CMA is used for the modelling, analysis and optimization of the proposed antenna to examine the underlying modal behaviour of the MTM unit cell and to guide mode excitation. The antenna structure consists of a microstrip feed line connected to a rectangular patch. Then triangular split ring resonator unit cell is inserted on the ground of a traditional patch antenna that resonates at 15 GHz to produce additional resonance at 10 GHz. A planar array of 2 × 3 triangle MTM unit cells is used as superstrate to improve the gain and bandwidth at both resonances simultaneously. The optimal distance between MTM superstrate and the antenna patch is determined using the Fabry-Perot cavity theory to maximize power directivity and efficiency of the proposed antenna. The CST microwave studio software is used to model and optimize the proposed antenna. A prototype of the designed antenna that was fabricated showed good agreement between measurement and simulation results.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Arnon Sakonkanapong ◽  
Chuwong Phongcharoenpanich

This research proposes an integrated high-frequency (HF) and ultrahigh-frequency (UHF) passive radio frequency identification (RFID) tag antenna for near-field (13.56 MHz) and far-field (920–925 MHz) communication. This tag antenna is advantageous for the applications with lossy material in the near-field communication and mitigates polarization loss in the far-field communications. The HF-RFID tag antenna is of square spiral structure, and the circularly polarized UHF-RFID structure consists of a square loop radiator with cascading loop feeding and shorted stub. The structure of HF-RFID tag antenna situated inside the circularly polarized UHF-RFID tag can avoid the significant effect of the near-field magnetic coupling from the square loop. The UHF-RFID tag antenna is realized by using characteristic mode analysis for wideband circular polarization. The HF-RFID structure is conjugate-matched with NXP NT3H2111 chip, and the UHF-RFID structure is conjugate-matched with NXP G2X chip. Simulations were carried out, and an antenna prototype was fabricated. The experimental results reveal that the radiation pattern of UHF-RFID tag antenna is bidirectional with a gain of 0.31 dBic. The impedance bandwidth covers the frequency range of 903–944 MHz, and the axial ratio in boresight direction at 922.5 MHz is 1.67 dB, with the axial ratio bandwidth over 863–938 MHz. The maximum near-field and far-field reading ranges are 4.9 cm and 8.7 m. The proposed integrated dual-band passive tag antenna is operationally ideal for HF-RFID and UHF-RFID applications.


Electronics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 68 ◽  
Author(s):  
Adamu Halilu Jabire ◽  
Hong-Xing Zheng ◽  
Anas Abdu ◽  
Zhiwei Song

This paper presents a full wave simulation and characteristic mode-based design of a multiple-input-multiple-output (MIMO) antenna at 5.8 GHz for wireless local area network applications. The driven analysis comprises two antennas that are placed orthogonal to each other. A metamaterial unit structure in the form of a rectangular loop resonator is placed around the antenna element to reduce the electromagnetic interference and to increase the isolation between the two monopoles. A characteristic mode technique is employed to find out the dominant mode of the proposed antenna without a feeding port. It was revealed that mode 1 was the dominant mode among the three modes used. The MIMO antenna is constructed and measured using a vector network analyzer. A good isolation of less than 25 dB was attained with a wide impedance bandwidth of 65.5%.


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