3D Frequency Selective Surface Displacement Sensor using Complementary Dielectrics

A novel displacement sensor using a frequency selective surface (FSS) with a removable substrate complement is proposed. The new concept sensor is based on modifying the effective permittivity of the FSS when the substrate complement is gradually withdrawn. The change in the effective permittivity produces a change in capacitance, and thus in the resonant frequency. The FSS consists of an array of square loops elements in a square lattice. A 3D convoluted version of the FSS sensor improves the angle of incident behavior and increases the displacement range. The dielectric layers of the 3D FSS sensor were 3D printed while the metal layers were painted using silver conductive paint. The transmission response, S 21 , has been employed as the validation parameter. The proposed sensor operates in a frequency range between 2.0 GHz and 2.8 GHz and has achieved a 0.052 GHz/mm sensitivity and 12 mm dynamic range and has a dimension of 207mm by 207mm. The sensor is passive, compact, inexpensive, and easy to operate. The envisaged application is the wireless detection of structural movement, which can be critical in civil structures such as bridges or buildings or earthquake monitoring

3D Printed Fingernail Antennas for 5G Applications

3D printing of antennas on removable fingernail for on-body communications at microwave and millimetre waves is proposed. Aerosol Jet technology, a fine-feature material deposition solution, has been used to directly print microstrip patch antennas on an acrylonitrile butadiene styrene (ABS) removable finger nail substrate. Two antennas have been printed and assessed, one operating at 15 GHz and the other at 28 GHz. Nanoparticle conductive silver ink has been employed to create the microstrip patch antennas and corresponding transmission line using an Optomec machine. The inks are then cured using a PulseForge machine. A further copper layer is added to the millimeter wave antenna via an electroplating process. The antennas have been simulated and measured off-the-finger and on-the-finger. Simulated and measured reflection coefficients (S 11 ) and radiation patterns are found to be in good agreement. The proposed on-body antennas can find application in the Internet of Things (IoT) where large amount of sensing data can be shared at the microwave and millimetre wave spectrum of future 5G communications. The removable finger nails could include other electronic devices such as on-body sensors, computational, storage and communication systems

3D Printing of Millimetre Wave and Low-Terahertz Frequency Selective Surfaces Using Aerosol Jet Technology

An investigation of the use of Aerosol jet 3D Printing of frequency selective surface for millimetre and low-THz applications is presented in this article. This 3D printing technique allows the fabrication of intricate details of the designs with high resolution. Band-stop and band-pass FSS are designed and tested. The band stop FSS consisted of a Square loop array that operated in the 26-28 GHz sub-millimetre band. This design is printed on glass substrate and can be used for deployment in windows. The bandpass FSS arrays consisted of simple slot elements arranged in a square lattice and operated at 125 GHz and 280 GHz. The slot arrays were printed on Kapton. Surface profiles demonstrated the uniformity and precision of this printing technique. Simulated and measured results compared well and offered good performances at both the millimetre wave and low-THz bands. The designs find applications in 5G and imminent 6G communications. This printing technique also provides environmentally friendly, rapid, and sustainable alternative for development of highly customised FSS which can be deployed to improve communications in buildings and in future Terahertz application

Decision-Making of Transnational Supply Chain Considering Tariff and Third-Party Logistics Service

Countries’ economic policies, such as tariff barriers, have a profound impact on the global economy and international trade. The imposition of tariffs seriously disturbs the global trade and supply chain operations. This paper studies a supply chain composed of an overseas manufacturer, a domestic supplier and a third-party integrated international logistics service provider. A three-level decentralized leader-follower decision-making model and its variant--leader-follower alliance decision-making models are established, and the influences of revenue sharing and cost sharing on the three-level decentralized decision-making are analyzed. The results show that it is difficult for the supply chain to achieve coordination when the transportation and insurance costs are considered in the tariff cost. The increase of tariff rates will reduce the profits of all parties and the overall profit of the supply chain, and weaken the dominant position of the supplier in the supply chain. Revenue sharing can improve the supply chain performance; the performance of the whole supply chain cannot be improved or may even deteriorate by sharing the transportation cost alone. The study can provide practitioners with implications for how to carry effective cooperation and coordination in the supply chain and how to effectively reduce the influence of tariffs in the global trade system

A wearable open-ring dielectric resonator antenna with frequency reconfiguration

A wearable open-ring dielectric resonator antenna (DRA) with frequency reconfiguration is proposed in this paper. The travelling wave mode inside DRA is utilized to achieve wideband characteristic. By varying the insertion depth of the feeding probe, three different operating frequencies can be realized located at 21.2 GHz, 26.3 GHz and 32.7 GHz, respectively. The three operating bands achieve relative bandwidths of 15.6% (19.5 GHz - 22.8 GHz), 12.9% (24.6 GHz - 28 GHz) and 12.2% (30.7 GHz - 34.7 GHz), covering several frequency ranges from K band to Ka band. The simple structure and compact size of the proposed antenna present great potential in the millimeter-wave (mmWave) body area network (BAN) applications

A Diamond Ring Antenna

A wearable antenna with diamond-ring shape is proposed in this paper. It employs differential feeding method to achieve a compact structure, whereas realizing dual-mode dual-band and high-gain performance at the same time. By exciting two different modes of the DR, dual millimeter-wave (mmW) operating bands located at 27.0 GHz and 32.5 GHz are realized. A unique higher-order mode is excited inside the diamond-shaped dielectric resonator (DR) which produces a peak realized gain of 8.4 dBi. The proposed antenna enjoys the benefits of compact structure, simple design and dual-band high-gain performances, which make it suitable for mmW Internet of Things (IoT) applications

Disposable 3D printed Liquid sensor

A device for detecting liquid chemicals of various permittivity using a 3D Printed frequency selective surface (FSS) is proposed. The sensor is an array of square loops on a square unit cell with trenches dug in the dielectric material around the loops. The trenches allow deposition of the liquid chemicals to be detected. The variation in the dielectric characteristics of the liquids in the trenches produces a change in the resonance frequency of the FSS. Transmission coefficient is measured to evaluate the resonance frequency due to each liquid chemical. Butan-1-ol, Propan-2-ol, Ethanol and Methanol were added to demonstrate the sensing technique. Good agreement was found to exist between simulated and measured results. The envisioned detector could be used in a laboratory or in chemical industry where liquids can fall into the trenches for detection purpose. 3D printing allows for the rapid fabrication of the structure which can be disposable

Decision-Making of Transnational Supply Chain Considering Tariff and Third-Party Logistics Service

Countries’ economic policies, such as tariff barriers, have a profound impact on the global economy and international trade. The imposition of tariffs seriously disturbs the global trade and supply chain operations. This paper studies a supply chain composed of an overseas manufacturer, a domestic supplier and a third-party integrated international logistics service provider. A three-level decentralized leader-follower decision-making model and its variant--leader-follower alliance decision-making models are established, and the influences of revenue sharing and cost sharing on the three-level decentralized decision-making are analyzed. The results show that it is difficult for the supply chain to achieve coordination when the transportation and insurance costs are considered in the tariff cost. The increase of tariff rates will reduce the profits of all parties and the overall profit of the supply chain, and weaken the dominant position of the supplier in the supply chain. Revenue sharing can improve the supply chain performance; the performance of the whole supply chain cannot be improved or may even deteriorate by sharing the transportation cost alone. The study can provide practitioners with implications for how to carry effective cooperation and coordination in the supply chain and how to effectively reduce the influence of tariffs in the global trade system