Characteristic mode analysis of near-field mutual coupling between wire and loop antennas

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.

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Characteristic mode analysis applied to reduce the mutual coupling of a four‐element patch MIMO antenna using a defected ground structure

IET Microwaves Antennas & Propagation ◽

10.1049/iet-map.2019.0570 ◽

2019 ◽

Vol 14 (2) ◽

pp. 215-226 ◽

Cited By ~ 2

Author(s):

Erik Fritz‐Andrade ◽

Angel Perez‐Miguel ◽

Ricardo Gomez‐Villanueva ◽

Hildeberto Jardon‐Aguilar

Keyword(s):

Mutual Coupling ◽

Mode Analysis ◽

Defected Ground Structure ◽

Ground Structure ◽

Characteristic Mode ◽

Mimo Antenna

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On the Bandwidth of Loop Antennas using Characteristic Mode Analysis

2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting ◽

10.1109/apusncursinrsm.2019.8889289 ◽

2019 ◽

Author(s):

Daniel Santillan-Haro ◽

Ferdaous Abderrazak ◽

Eva Antonino-Daviu ◽

Miguel Ferrando-Bataller

Keyword(s):

Mode Analysis ◽

Characteristic Mode ◽

Loop Antennas

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Metamaterial Based Design of Compact UWB/MIMO Monopoles Antenna with Characteristic Mode Analysis

Applied Sciences ◽

10.3390/app11041542 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1542

Author(s):

Adamu Halilu Jabire ◽

Adnan Ghaffar ◽

Xue Jun Li ◽

Anas Abdu ◽

Sani Saminu ◽

...

Keyword(s):

Mutual Coupling ◽

Ground Plane ◽

Multiple Input Multiple Output ◽

Surface Current ◽

Dominant Mode ◽

Mode Analysis ◽

Physical Parameters ◽

Antenna Aperture ◽

Characteristic Mode ◽

Mutual Coupling Reduction

In this article, a novel metamaterial inspired UWB/multiple-input-multiple-output (MIMO) antenna is presented. The proposed antenna consists of a circular metallic part which formed the patch and a partial ground plane. Metamaterial structure is loaded at the top side of the patches for bandwidth improvement and mutual coupling reduction. The proposed antenna provides UWB mode of operation from 2.6–12 GHz. The characteristic mode theory is applied to examine each physical mode of the antenna aperture and access its many physical parameters without exciting the antenna. Mode 2 was the dominant mode among the three modes used. Considering the almost inevitable presence of mutual coupling effects within compact multiport antennas, we developed an additional decoupling technique in the form of perturbed stubs, which leads to a mutual coupling reduction of less than 20 dB. Finally, different performance parameters of the system, such as envelope correlation coefficient (ECC), channel capacity loss (CCL), diversity gain, total active reflection coefficient (TARC), mean effective gain (MEG), surface current, and radiation pattern, are presented. A prototype antenna is fabricated and measured for validation.

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