Indoor object localization and positioning is part of the space-awareness concept which has seen a rising popularity in recent Internet of Things (IoT) research and applications. This article ...presents a novel method to improve the localization performance of ultra-wide band (UWB) real-time locating systems (RTLS) by improving the transmitting and receiving reader and tag antennas. Patch directional UWB antennas with relatively higher gain compared to the generally used standard omnidirectional monopole UWB antennas have been exploited to achieve a larger localization range. Furthermore, the patch antennas were designed to have wideband circular polarization to achieve two objectives: a received power independent of the orientation of the tagged objects that need to be detected, and the filtering of unwanted multipath signals. A measurement campaign was conducted using a commercially available RTLS with conventional antennas and then with the newly designed antennas. A comparison between the localization results of the two antenna types demonstrates an improved range with almost 100 m difference, received power independent of tag orientation, and increased multipath mitigation with the directional circularly polarized antennas.
A compact single-fed omnidirectional circularly polarized (OCP) antenna is presented. The circular polarization is obtained by combining an Alford Loop (AL) and a Wire-Patch (WP) radiating ...structures, which are used to generate two orthogonal E-field components. The antenna exhibits a clear right-handed circular polarization (RHCP) with a dipole-like omnidirectional radiation pattern. A prototype has been realized using two FR-4 printed circuit boards (PCBs) and experimentally tested. The measured overlapped −10 dB impedance matching and 3 dB axial ratio bandwidth is 120 MHz wide (4.9%) from 2.40 to 2.52 GHz. The measured RCHP maximum realized gain and total efficiency are 1.91 dBic and 87%, respectively. Its compact size <inline-formula> <tex-math notation="LaTeX">(0.25\lambda \times 0.25\lambda \times 0.08\lambda) </tex-math></inline-formula>, and its low-cost, robust, and easy-to-realize structure make this antenna suitable for IoT applications.
In this paper, an electronically pattern reconfigurable antenna for Internet of Things (IoT) applications is presented. The antenna consists of 4 wire-patches sharing the same ground plane. This ...radiating element can switch between four end-fire radiation states in less than 5 us and achieves a 290 MHz frequency bandwidth from 2.25 to 2.54 GHz. The results show that this antenna can realize a peak gain of 3.9 dBi at 2.44 GHz and a front-to-back ratio greater than 6.5 dB. A single low-power, low-insertion loss SP4T switch enables the radiation pattern steering. This approach avoids the use of multiple electronic components in the reconfiguration mechanism, thus accommodating the IoT microcontroller's limited resource constraints. The antenna structure is compact and printed on two cost-effective FR-4 printed circuit boards (PCBs). Thanks to its high performance, small size, low cost, and low-power characteristics, the proposed structure is suitable for IoT applications.
In this paper, a two efficient Planar Inverted-F Antenna (PIFA) system for dual-band functionality on fourth-generation (4G) band (2.5-2.7 GHz) and future fifth-generation (5G) band (3.4-3.8 GHz) is ...presented. During the optimization process, in order to obtain an efficient system, particular attention has been paid to the antenna system efficiency as well as the isolation between the antennas. Thus, the influence of the antenna slot design used to achieve a dual-band behavior on the antenna efficiency has been particularly studied. Moreover, the antenna positions on the Printed Circuit Board (PCB) have been chosen thanks to the use of characteristic mode analysis to obtain high isolation levels in both bands. The final system is optimized for Multiple Input Multiple Output Half Duplex (MIMO HD) 4G communications and Tx/Rx Full-Duplex (FD) 5G communications. A prototype with 140 mm × 70 mm ground plane was simulated, fabricated and measured. A high isolation level between the two ports of the PIFA elements, better than 35 dB in 5G band and 20 dB in 4G band in simulation and measurement that were done in free space, is obtained. Additionally, the most important diversity metrics are computed to evaluate the potential of this two-antenna system for diversity applications.
In this paper, a directional pattern-reconfigurable slot antenna at 2.4 GHz is presented. The antenna can provide three evenly-separated directional patterns and one omnidirectional pattern. The ...proposed solution is fully suitable for the integration in Internet of things (IoT) network base stations to increase the communication range and reduce packet collisions. The performance of the proposed antenna is numerically and experimentally assessed.
In this article, a slot-based electronically steerable parasitic array radiator (ESPAR) antenna suitable for Internet-of-Things (IoT) applications is proposed. The antenna can provide 12 directive ...and two slightly different omnidirectional radiation states. The 12 directive patterns allow the antenna to focus the radiated energy toward six different directions uniformly distributed in the azimuth plane and with two different beamwidths. The reconfiguration of the radiation pattern is based on the use of low-capacitance low-power consuming diodes that can be digitally controlled. This article details the design of the antenna structure and the practical implementation of the reconfiguration mechanism, discussing the effects of real electronic components on the antenna performance. The antenna effectiveness is numerically and experimentally assessed.
The Internet of things is increasingly focused on UAV-based long-range applications. This necessitates versatile, low-cost antenna designs for both ground stations and drones. This study proposes the ...design of a pattern reconfigurable parasitic element antenna system operating in the LoRa 868 MHz band and its on-field characterization. The electronic steerable parasitic array radiator (ESPAR) antenna consists of a single-fed shorted patch surrounded by four rectangular parasitic elements. The antenna system can develop four directive beams, each activated by one of four PIN diodes, and an omnidirectional pattern obtained when all diodes are turned off. The antenna has been characterized both in an anechoic controlled environment and in a practical on-field drone-to-ground packet transmission scenario. Results based on received signal strength indicator (RSSI) show that the pattern reconfigurability becomes increasingly relevant with the end-point distance and that pointing the beam at the end point always allows the highest RSSI level to be received.
A 4 × 4 MIMO multiband antenna system for mobile handsets is proposed in this paper. The placement of the elements on the terminal chassis as well as the single structure has been optimized in order ...to reduce the Envelope Correlation Coefficient (ECC). Simulated and measured results, including also the integration with a a real 7-inch commercial tablet, aimed at validating the proposed solution are presented.
Several solutions are presented to reduce the mutual coupling between two planar inverted-F antennas (PIFAs) working in close radiocommunication standards and positioned on a finite-sized ground ...plane modeling the printed circuit board (PCB) of a typical mobile phone. First, the two PIFAs are designed on separate PCBs to, respectively, operate in the DCS1800 and UMTS bands. In a second step, they are associated on the top edge of the same PCB. Realistic arrangements are then theoretically and experimentally studied. Finally, several solutions are investigated to maximize the isolation. They consist in inserting a suspended line between the PIFAs' feedings and/or shorting points. All along this paper, several prototypes are fabricated and their performances measured to validate the obtained IE3D moment method-based simulation results
This letter proposes an approach for the realization of three-dimensional flexible antennas based on the use of liquid metal and additive printing technologies. As a representative example, a ...miniaturized inverted-F antenna (IFA) operating at 885 MHz and suitable for wearable applications is designed, realized, and measured. The antenna sensitivity to the bending is strongly reduced, thanks to the proposed structure. The performance of the antenna in several bent configurations and in presence of the human body has been evaluated.
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