This paper presents a wideband, long-range RFID tag antenna design with platform tolerant features using characteristic mode analysis (CMA). The proposed design consists of a two-layer structure, that are separated by an air gap. The upper layer consists of T-match and dual loop-based meandered antenna optimized for achieving long read range characteristics in free space/low permittivity dielectrics. The second layer consists of multi-resonant strips printed on a grounded substrate carefully designed using CMA for producing multi-resonant modes in the required UHF RFID band. The multi-resonant strips help in achieving wide bandwidth and isolation between different environment surfaces. This tag antenna provides a wide bandwidth ranging from 900 – 940 MHz that covers both the US UHF RFID band (902 – 928 MHz) and the upper European UHF RFID band (915 – 921 MHz). Moreover, this design achieved a read range of 14.7 m in free space, 14 m on a metal plate, and 13 m on wood, and glass. Furthermore, the proposed antenna was also tested in harsh metal environments such as car number plates and cargo metallic containers. Therefore, the proposed tag can be used for tagging metallic containers, wood containers, and other harsh platforms for cargo management, Asset tracking, supply chain visibility, and Internet of Things (IoT) Applications.

This paper aims to review some of the available tunable devices with emphasis on the techniques employed, fabrications, merits, and demerits of each technique. In the era of fluidic microstrip communication devices, versatility and stability have become key features of microfluidic devices. These fluidic devices allow advanced fabrication techniques such as 3D printing, spraying, or injecting the conductive fluid on the flexible/rigid substrate. Fluidic techniques are used either in the form of loading components, switching, or as the radiating/conducting path of a microwave component such as liquid metals. The major benefits and drawbacks of each technology are also emphasized. In this review, there is a brief discussion of the most widely used microfluidic materials, their novel fabrication/patterning methods.

In this paper, a novel embedded helix dielectric rod antenna is presented for high gain radiation with circular polarization (CP) and low side lobe levels for IoT Applications. Different from the conventional dielectric rod antennas, this proposed antenna is an integrated structure that combines the advantages of the helix and dielectric rod antennas. The presented antenna mainly consists of three parts: a tapered helix as primary feeding for CP, a dielectric rod with printed loops embedded for higher directivity, and a dielectric rod end for improving the gain further. After studying and analyzing the working principles of each part, an optimum design operating at 8–9.7 GHz is carried out as an example. A prototype is also fabricated and tested. The measured results show that the prototype can provide 18.41 dB maximum gain within the length of 7.7 λ. The side lobe level is below −20 dB, and the axial ratio is better than 1.14 dB in the whole frequency band. Compared with the traditional helix antenna and dielectric rod antenna with the same electric length, the presented antenna has a higher gain with a lower side lobe level and with good polarization purity.

This articlefocuses on the multi-input multi-output (MIMO)antenna with smaller dimensionsand improved isolation between the ports which results in goodperformanceand is suitable for modern wireless communication systems,especially USB dongle and 5G mobile applications.Two mainproblemswith the conventionalantennas are (i)Largeheight between the top to ground plate and (ii)Smaller isolation between the ports.These two problems are carefully addressedin the proposed design.The height in the proposed antenna is minimized up to 4mm between the topand to ground plate.Furtherachieved isolation is more than -18dB by introducing a novel type of periodic slots in the ground plate of the antenna. Theantenna structure consists of a ground plate and two top plates, each with defined dimensions. The parameters are optimized using software for the best performance of the antennato ensure efficient signal transmission and reception. The proposed antenna aims to explore the impact ofdimension parameters like impedance matching and fractional bandwidth and isolation between the ports. The antenna resonates for 4.5GHz to 5.75GHz frequency bandwidth. The return loss for impedance bandwidth is below -20dB. The antenna is simulated on software andfabricated on substrate FR4. The simulated and measured results are compared which indicates that this antenna with high isolation and good impedance bandwidth is a moresuitable candidate for 5G mobile applications.Compared to the conventional same-class antenna, the proposed antenna has good performance with minimized dimensions.