Near-field Antenna Research Articles

Partial Near-Field Antenna Characterization

Partial Near-Field Antenna Characterization

Warping-Driven Greedy Method for Data Reduction in Planar Near-Field Antenna Measurements

Warping-Driven Greedy Method for Data Reduction in Planar Near-Field Antenna Measurements

Beam Defocus in Near-Field Wideband Cylindrical Antenna Array Systems: Analysis and Mitigation

Beam Defocus in Near-Field Wideband Cylindrical Antenna Array Systems: Analysis and Mitigation

Electrically Small, Near-Field Resonant Parasitic Monopole Antenna With Large Gain-Bandwidth Product and Harmonic Modes Migration

Electrically Small, Near-Field Resonant Parasitic Monopole Antenna With Large Gain-Bandwidth Product and Harmonic Modes Migration

Multi-Frequency Spherical Near-Field Antenna Measurements Using Compressive Sensing

Multi-Frequency Spherical Near-Field Antenna Measurements Using Compressive Sensing

Phaseless Probe-Corrected Spherical Near-Field Antenna Measurements Using Two Scan Spheres

Phaseless Probe-Corrected Spherical Near-Field Antenna Measurements Using Two Scan Spheres

Monostatic Free-Space Method for Relative Permittivity Determination Using Horn Antenna Near-Field Measurements

Monostatic Free-Space Method for Relative Permittivity Determination Using Horn Antenna Near-Field Measurements

Significantly improved near-field communication antennas based on novel Ho 3+ and Co 2+ ions co-doped Ni–Zn ferrites

Significantly improved near-field communication antennas based on novel Ho ³⁺ and Co ²⁺ ions co-doped Ni–Zn ferrites

Single-Feed Near-field Excited Quad-Beam Metasurface Antenna

Single-Feed Near-field Excited Quad-Beam Metasurface Antenna

Electromagnetics-Aware Path for UAV-Based Near-Field Antenna Measurements Implemented With a High Dynamic Range SDR

Electromagnetics-Aware Path for UAV-Based Near-Field Antenna Measurements Implemented With a High Dynamic Range SDR

Planar Near-Field Antenna Measurements with a Uniform Step Larger than Half-Wavelength

Planar Near-Field Antenna Measurements with a Uniform Step Larger than Half-Wavelength

A Deep Learning Convolutional Neural Network for Antenna Near-Field Prediction and Surrogate Modeling

A Deep Learning Convolutional Neural Network for Antenna Near-Field Prediction and Surrogate Modeling

Design of VHF Horizontal Polarization Omnidirectional Antenna

Horizontally-polarized antennas are usually used in the system of polarization diversity to improve the performance of communication chain and its reliability. Furthermore, the bandwidth of the antenna openly governs the rates of data communication. In order to meet the engineering requirements of high rates for data transmission and multi-band communication, the antenna bandwidth of the communication system needs to be further increased. In this paper we present the scheme of an omnidirectional loop antenna for horizontally-polarized systems. The research status of the horizontally-polarized omnidirectional antenna, and the working principle and radiation characteristics of the small loop antenna are elaborated in detail. The field expression of the loop antenna is deduced from the wave equation, and the characteristics of the far-field and the near-field of the loop antenna are analyzed. On the basis of theoretical analysis, a practical loop antenna is researched and developed for the demands of wireless communication engineering applications. Moreover, we present the related loop antenna technology and how to implement it. The radiation pattern of the antenna is obtained through computer simulations. Our empirical results show that the small loop antenna based on capacitive loading can realize the radiation characteristics of the horizontal polarization omnidirectional pattern. The small loop antenna has the advantages of small size and easy portability, and the small loop antenna operating in the resonant state has a high Q value, which gives it better frequency selectivity. The design and research of this paper have important reference significance for the engineering design and application of the VHF band horizontally-polarized omnidirectional antenna.

Design of a Three-Dimensional Uniform UHF Near-Field RFID Reader Antenna

Design of a Three-Dimensional Uniform UHF Near-Field RFID Reader Antenna

A Near-Field Focused Array Antenna Empowered by Deep Learning for UHF-RFID Smart Gates

A Near-Field Focused Array Antenna Empowered by Deep Learning for UHF-RFID Smart Gates

Towards fully green printed device with environmental perspectives

Printed electronics (PE) is growing rapidly through innovation in several pathways: ink formulation, substrate improvement, printing and drying process optimization. All these developments are combining to enable the production of a new generation of PE devices that reduce e-waste. However, the main question of the recyclability of these devices is critical. This article is focused on (1) the industrial fabrication of recyclable substrates prepared by roll-to-roll printing using flexographic printing units to cover paper with shellac solution and (2) the environmental impact assessment of new development of PE. To investigate the performance of the produced substrate, a battery-less near-field communication antenna was printed with a flatbed screen printing using silver ink. The print quality, electrical resistance and the basic functional characterization of these paper-based antennas were investigated and reported. To validate the functionality of printed devices, a mm2 electronic chip was integrated onto the printed device. In order to predict the future perspectives and development of the PE, environmental challenges of the ink and substrates, during the production and end-of-life phases, are explored and discussed.

Phaseless Spherical Near-Field Antenna Measurements With Reduced Samplings

Phaseless Spherical Near-Field Antenna Measurements With Reduced Samplings

Enhanced Measurement Sensitivity Using Near-Field Antenna With MMIC Low-Noise Amplifier for Deep Tissue Microwave Thermometry

Enhanced Measurement Sensitivity Using Near-Field Antenna With MMIC Low-Noise Amplifier for Deep Tissue Microwave Thermometry

Metallo-Dielectric Millimeter-Wave Huygens’ Quarter-Wave and Half-Wave Plates

A novel metallo-dielectric Huygens’ unit cell is proposed that can be designed to operate either as a quarter-wave plate (QWP) or as a half-wave plate (HWP). The unit cell is based on a single-layer perforated dielectric, with straight (non-metallized) and 45° (metallized) elliptical holes. The novelty of the unit cell is its suitability for millimeter-wave implementation in printed-circuit board (PCB) fabrication due to the absence of metallic patterns of small line widths and gaps. As an example of their applicability, the wave plates are demonstrated in the near-field of 60-GHz band diffusion-bonded slot array antennas. The unit cell operating as a QWP is demonstrated in full-wave simulations and experimentally for linear-to-circular polarization conversion, whereby the combination of a linearly-polarized (LP) antenna and the QWP produces a circularly-polarized (CP) wave. Measurement results of the antenna and the QWP show ≤ -10-dB reflection from 59 to 63 GHz (6.6%), ≤ 3-dB axial ratio from 59.5 to 61.5 GHz (3.3%), and an overall efficiency ≥ 77% from 59.5 to 61.5 GHz. The unit cell operating as a HWP is demonstrated in full-wave simulations for polarization rotation of the LP antenna, and for changing the sense of rotation of a right-hand CP antenna into left-hand circular polarization.

A Quad-Band Near-Field Antenna Array for a Multistatic Microwave Imaging Chamber

A new quad-band tapered patch transmit-receive antenna array designed for a multistatic microwave imaging cavity system is presented. The reverberating cube-shaped chamber is filled with a matching fluid emulsion and encompasses 64 antenna elements mounted on its sidewalls (16 per panel). Four resonant frequencies that lie in the range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.5 - 3$</tex-math></inline-formula> GHz are achieved. The design procedure is provided based on system constraints and performance requirements that need to be taken into account: (1) the near-field nature of the electromagnetic wave in the presence of a shielded chamber and (2) the propagation of waves into the immersion fluid within the imaging domain. The antenna array design was numerically verified, and its prototype was fabricated. Results show good agreement between measurements and simulations, achieving antenna system performance requirements.