Recent developments in the field of microwave planar sensors have led to a renewed interest in industrial, chemical, biological and medical applications that are capable of performing real-time and ...non-invasive measurement of material properties. Among the plausible advantages of microwave planar sensors is that they have a compact size, a low cost and the ease of fabrication and integration compared to prevailing sensors. However, some of their main drawbacks can be considered that restrict their usage and limit the range of applications such as their sensitivity and selectivity. The development of high-sensitivity microwave planar sensors is required for highly accurate complex permittivity measurements to monitor the small variations among different material samples. Therefore, the purpose of this paper is to review recent research on the development of microwave planar sensors and further challenges of their sensitivity and selectivity. Furthermore, the techniques of the complex permittivity extraction (real and imaginary parts) are discussed based on the different approaches of mathematical models. The outcomes of this review may facilitate improvements of and an alternative solution for the enhancement of microwave planar sensors' normalized sensitivity for material characterization, especially in biochemical and beverage industry applications.
This study proposes a single-port dual-band independent microwave sensor for detecting solid materials. The sensor structure consists of a pair U-shaped resonators connected by a power divider and a ...microstrip feed line with an impedance of 50 Ohms with two different sensing hotspots. The <inline-formula> <tex-math notation="LaTeX">1^{\text {st}} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">2^{\text {nd}} </tex-math></inline-formula> resonators operate at a frequency of 1.200 GHz and 2.100 GHz, respectively. The type of material under test (MUT) is a standard material with a size of 10 mm <inline-formula> <tex-math notation="LaTeX">\times10 </tex-math></inline-formula> mm (RO5880, RO4003C, and FR4). The proposed sensor had a very high accuracy compared with both of using permitivitty from datasheet and calibrated frequency from simulation for the <inline-formula> <tex-math notation="LaTeX">1^{\text {st}} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">2^{\text {nd}} </tex-math></inline-formula> resonator, respectively. Moreover, the pair of the U-shaped resonators had independent performances and they did not affect each other when the MUT was loaded. Furthermore, it can also operate with single-port measurement, which is a more efficient resource. Finally, the proposed microwave sensor can be a promising solution for detecting different permittivity of solid materials independently with high accuracy for applications such as the food industry, material quality control, and biomedical.
Vehicular communication networks is a powerful tool that enables numerous vehicular data services and applications. The rapid growth in vehicles has also resulted in the vehicular network becoming ...heterogeneous, dynamic, and large-scale, making it hard to meet the strict requirements, such as extremely latency, high mobility, top security, and enormous connections of the fifth-generation network. Previous studies have shown that with the increase in the application of Software-Defined Networking (SDN) on Vehicular Ad-hoc Network (VANET) in industries, researchers have exerted considerable efforts to improve vehicular communications. This study presents an exhaustive review of previous works by classifying them based on based on wireless communication, particularly VANET. First, a concise summary of the VANET structure and SDN controller with layers and details of their infrastructure is provided. Second, a description of SDN-VANET applications in different wireless communications, such as the Internet of Things (IoT) and VANET is provided with concentration on the examination and comparison of SDN-VANET works on several parameters. This paper also provides a detailed analysis of the open issues and research directions accomplished while integrating the VANET with SDN. It also highlights the current and emerging technologies with use cases in vehicular networks to address the several challenges in the VANET infrastructure. This survey acts as a catalyst in raising the emergent robustness routing protocol, latency, connectivity and security issues of future SDN-VANET architectures.
This study proposed the use of coplanar waveguide Ultrawide-band strawberry artistic shaped printed monopole (SAPM) antenna with a single-layer frequency selective surface (FSS) as the metallic plate ...to improve the gain of antenna application. The intersection of six cylinders is used to structure the strawberry artistic shaped radiating element, which leads to enhancing the antenna bandwidth. The proposed FSS reflectors used a <inline-formula> <tex-math notation="LaTeX">10\times10 </tex-math></inline-formula> array with the unit cell of 6mm <inline-formula> <tex-math notation="LaTeX">\times6 </tex-math></inline-formula>mm in introducing a center-operating frequency. This study used the FR4 substrate with coplanar waveguide (CPW) fed to print the proposed antenna, which provided a wide impedance bandwidth of 8.85 GHz (3.05-11.9GHz) that covers the licensed Ultrawide-band. The proposed FSS transmitted a stop-band transmission coefficient, which is below −10 dB with the linear reflection phase over the bandwidth in the range from 3.05 GHz to 11.9 GHz. The UWB SAPM antenna with FSS reflector showed an improvement from 1.65 dB to 7.87 dB in the lower band and 6.3 dB to 9.68 dB in the upper band with an enhancement of 6.22 dB. The gain value is enhanced by the gaping between the antenna and FSS, which has an approximately constant gain response through the band, the gain is sustained among 7.87 dB to 9.68 dB. The total dimension of the antenna is 61mm<inline-formula> <tex-math notation="LaTeX">\times 61 </tex-math></inline-formula>mm<inline-formula> <tex-math notation="LaTeX">\times 1.6 </tex-math></inline-formula> mm. The proposed antenna structure provides the directional and balanced far-field pattern, which is suitable for Ultrawide-band (UWB) applications and ground-penetrating radar (GPR) applications.
This article proposes the integration of microwave sensors (MSs) and antenna sensors (ASs) for contact and noncontact characterization of solid materials. Integration between MS and AS was determined ...based on the reflection coefficient (Formula Omitted), where Formula Omitted of Formula Omitted dB was proposed as MS and Formula Omitted of Formula Omitted dB was proposed as AS. The proposed sensor consists of a dual T-shaped resonator with single port operating at a resonant frequency of Formula Omitted GHz for MS and Formula Omitted GHz for AS using FR-4 substrate with Formula Omitted of 4.3, tanFormula Omitted of 0.0265, and thickness of 1.6 mm. Furthermore, the two resonant frequencies had independent characteristics with different sensing hot spots. MS is proposed for permittivity detection of the material under test (MUT) for contact detection while non-contact detection is proposed by utilizing AS. The procedure for contact detection was carried out by placing the MUT on the surface of the sensor, while noncontact detection was carried out by placing the MUT with an air gap between the MUT (Formula Omitted) and the AS was 0.5–1.5 mm. The measurement results showed that the average accuracy was 99.30% and 99.31% for the MS and AS for the permittivity range of 1–6.15, while the normalized sensitivities (NSs) of the proposed sensors were 1.15% and 0.16%, respectively. The results of this research are novel and can be recommended for several purposes related to biomedical and pharmaceutical industries requiring contact and noncontact detection of material characterization.
This article presents an integrated technique for reconfigurable substrate integrated waveguide (SIW) and reconfigurable patch antenna by using the varactor diodes. A reconfigurable SIW filter and ...reconfigurable patch antenna were integrated using the multilayer technique into a single structure in order to realize the integration technique. Design and validation of an equivalent circuit with the varactor diode is presented to study the tunable mechanism. A good performance between the simulated and measured results was achieved. This proposed structure of the reconfigurable integrated SIW filter and antenna is useful for wireless communication systems especially in telecommunication technology.
Fifth generation (5G) cellular networks promise to support multi-radio access technologies (multi-RATs) with low and high frequencies aiming at delivering good coverage, several gigabits data rate, ...and ultra-reliable services. In this context, user-association and resource allocation appear to be a huge challenge due to the variety of specifications and varied propagation environments. In this treatise, the focus is on the technical and administrative difficulties of the adoption of user association (UA) mechanism and spectrum sharing approach (SSA) in millimeter wave (mmWave) systems, for example, the technical design considerations and their underlying options, as well as their impact on users and network performance. In addition, details on the importance of the rules and regulations of SSA are presented. This study also identified a few possible design solutions and potential promising technologies in both UA and SSA. In the context of UA, several mechanisms are identified, such as backhaul-, caching-, and hybrid multi-criteria-aware UA to achieve seamless connectivity and to enhance the network utility. In the context of SSA, this study pinpoints varied subjects that need to be explored, such as joint efficient rules and regulations enactment, assessment of fairness and independence in multi-independent mobile network operators (multi-IMNOs) that support SSA, as well as the implementation of hybrid-SSA via Virtualized Cloud Radio Access Network. Finally, attention is drawn to several key conclusions to enable readers and interested researchers to learn about the most controversial points of mmWave 5G cellular networks.
A new broadband circular polarization (CP) monopole antenna with simple structure is proposed. The antenna consists of a P-shaped monopole and modified ground plane with rectangular stub, and results ...demonstrated that the 10 dB impedance bandwidth (ZBW) is 118.5% (1.6-6.25 GHz) and the 3 dB axial-ratio bandwidth (ARBW) is 104.4% (1.9-6.05 GHz). Procedures to improve the proposed antenna design and the CP mechanism analysis were performed. The performance of different parameters is presented. The advantages of the proposed antenna are broader ZBW and ARBW, simpler structure, and compact size.
This article proposes the design, fabrication and measurement of a triple-rings complementary split-ring resonator (CSRR) microwave sensor for semi-solid material detection. The triple-rings CSRR ...sensor was developed based on the CSRR configuration with curve-feed designed together, utilizing a high-frequency structure simulator (HFSS) microwave studio. The designed triple rings CSRR sensor resonates at 2.5 GHz, performs in transmission mode, and senses shift in frequency. Six cases of the sample under tests (SUTs) were simulated and measured. These SUTs are Air (without SUT), Java turmeric, Mango ginger, Black Turmeric, Turmeric, and Di-water, and detailed sensitivity analysis is conducted for the frequency resonant at 2.5 GHz. The semi-solid tested mechanism is undertaken using a polypropylene (PP) tube. The samples of dielectric material are filled into PP tube channels and loaded in the CSRR centre hole. The e-fields near the resonator will affect the interaction with the SUTs. The finalized CSRR triple-rings sensor was incorporated with defective ground structure (DGS) to deliver high-performance characteristics in microstrip circuits, leading to a high Q-factor magnitude. The suggested sensor has a Q-factor of 520 at 2.5 GHz with high sensitivity of about 4.806 and 4.773 for Di-water and Turmeric samples, respectively. The relationship between loss tangent, permittivity, and Q-factor at the resonant frequency has been compared and discussed. These given outcomes make the presented sensor ideal for detecting semi-solid materials.
The article presents a compact multifunctional power divider loaded with short‐ended stub for RF front end system at 2.5 GHz application. The proposed structure consists of PIN diodes and short‐ended ...stub at the output transmission line. Wilkinson power divider and SPDT switch at 2.5 GHz can be achieved by changing the bias voltage of the integrated PIN diodes. As the proposed design transitions from a power divider to an SPDT switch, a short stub is introduced at the output ports to prevent mismatches from occurring. The proposed SPDT switch design has been mathematically analyzed and presented in detail. Two frequency component functions are combined in a small package with three RF connectors. This proposed design is constructed and characterized for experimental‐demonstration purposes. The method proposed in this article is simpler compared to the previous work and easy to fabricate. This technique will reduce the overall size and manufacturing cost. It also can be applied to design the multifunctional power divider at any desired specifications and operating frequencies that compatible with RF/microwave applications, such as smart antennas and phase‐array antennas.
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