Planar Microwave Sensors for Accurate Measurement of Material Characterization: A Review

Microwave sensor is used in various industrial applications and requires highly accurate measurements for material properties. Conventionally, cavity waveguide perturbation, free-space transmission, open-ended coaxial probe, and planar transmission line technique have been used for characterizing materials. However, these planar transmission lines are often large and expensive to build, further restricting their use in many important applications. Thus, this technique is cost effective, easy to manufacture and due to its compact size, it has the potential to produce sensitivity and a high Q-factor for various materials. This paper reviews the common characteristics of planar transmission line and discusses numerous studies about several designs of the microstrip resonator to improve the sensor performance in terms of the sensitivity and accuracy. This technique enables its use for several industrial applications such as agriculture and quality control. It is believed that previous studies would lead to a promising solution of characterizing materials with high sensitivity, particularly in determining a high Q-factor resonator sensor

Embroidered Rectangular Split-Ring Resonators for the Characterization of Dielectric Materials

In this paper, we report an embroidered rectangular split-ring resonator (SRR) operating at S band for material characterization based on the differences in dielectric parameters. We designed, fabricated and characterized SRR sensors on a conventional fabric that can be conformally attached over the surface of samples under investigation. The structures are made of conductive threads and can be embroidered on any dielectric fabric at low cost using conventional embroidery methods. We have demonstrated material characterization capability of the sensors using a specific design with a length of 60 mm and a width of 30 mm. We wrapped the sensors on low-density polyethylene (LDPE) bottles filled with deionized (DI) water and common solvents (ethanol, methanol, isopropanol and acetone) in our experiments. We measured the nominal resonant frequency of a specific sensor wrapped around an empty bottle as 2.07 GHz. The shifts in resonant frequencies when the bottle was filled with the solvents follow the dielectric constants of the solvents

Microwave Planar Sensor for Determination of the Permittivity of Dielectric Material

This paper proposed a single port rectangular microwave resonator sensor. This sensor operates at the resonance frequency of 4GHz. The sensor consists of micro-strip transmission line and applied the enhancement method. The enhancement method is able to improve the return loss of the sensor, respectively. Plus, the proposed sensor is designed and fabricated on Roger 5880 substrate. Based on the results, the percentage of error for the proposed rectangular sensor is 0.2% to 8%. The Q-factor of the sensor is 174

High Quality Factor Using Nested Complementary Split Ring Resonator For Dielectric Properties Of Solids Sample

A Nested complementary split ring resonator (CSRR) was proposed based on planar structure. The main objective of this work is to get a higher quality factor (Q-factor) with minimal error detection of complex permittivity. The sensor operated at the 3.37GHz resonant frequency and simulated by ANSYS HFSS software. Subsequently, the designed sensor has been fabricated and tested with the presence of several material under test (MUTs) placed over the sensor. The result achieved high unloaded Q-factor, 464. There has been proof of good agreement concerning the results between theoretical, simulation, and measured parameters of error detection, which is below 13.2% real part permittivity and 2.3% the loss tangent. The proposed sensor is practically useful for the food industry, bio-sensing, and pharmacy industry applications

Caracterización de materiales para sensores de radiofrecuencia

El conocimiento de la permitividad dieléctrica es imprescindible para cualquier ámbito en electromagnetismo, microelectrónica, RF (Radiofrecuencia), óptica, y en general en los problemas de transmisión de información desde un punto de vista electromagnético. Cuando se emplean dieléctricos comerciales para una aplicación particular, estos vienen caracterizados por el fabricante, que emplea una técnica determinada de medida de la permitividad. Sin embargo, cuando se desea conocer la permitividad de dieléctricos que no son comerciales, se hace conveniente emplear técnicas de caracterización específicas para poder estimar su valor con precisión. La aplicación concreta donde surge este TFG (Trabajo Fin de Grado), que es donde es necesario aplicar las técnicas de medida, es en el diseño de sensores de RF basados en estructuras metamateriales, en ámbitos como el industrial o el biomédico, con aplicaciones tales como la detección de sustancias o biomoléculas. El objetivo fundamental de este trabajo es investigar y corroborar técnicas experimentales precisas de caracterización de la permitividad de dieléctricos, en el rango de microondas, con el fin de aplicarlas a substratos (p. ej., cuarzo, vidrio, silicio puro, etc.) que presentan ciertas ventajas si se utilizan como substrato para los sensores mencionados. Se trata de materiales paramagnéticos de bajas pérdidas cuya permitividad dieléctrica relativa, εr, se desconoce a priori y se desea averiguar. Por ejemplo, un caso interesante en el vidrio es que puede usarse como substrato en la detección de proteínas, con ciertas técnicas como la espectrometría de masas y la resonancia de plasmones superficiales. Se ha llevado a cabo una metodología exhaustiva para la selección de la técnica adecuada, en tres niveles distintos (de la teoría a la práctica). En el primer nivel, teórico, se ha descrito y discutido una serie de alternativas que se emplean en la actualidad. En el segundo nivel, de simulación electromagnética, se han comparado las prestaciones de distintas técnicas seleccionadas, basadas en tecnologías planas, y se han descartado las que no interesaban. Y en el tercer nivel, de medida experimental con el VNA (Analizador Vectorial de Redes), finalmente se han comprobado los resultados previos y se han seleccionado las técnicas óptimas. Tanto en simulación como en medida en el laboratorio, primeramente se ha determinado la εr de varios materiales de RF estandarizados y disponibles en el laboratorio a partir de los parámetros de scattering, [S]. A continuación, la εr obtenida se ha contrastado con la proporcionada por el fabricante, para cada uno de las variantes utilizadas. Se ha demostrado la fiabilidad de dos técnicas concretas: el resonador en “T” y el resonador en anillo. Como complemento a lo anterior, se han realizado pruebas del resonador en anillo en los substratos que nos interesan, que en este caso han sido el vidrio borosilicato y el cuarzo, ya que disponemos de sus muestras. La dificultad añadida por la capa de Kapton®, que debe adherirse a los substratos para poder metalizarlos, hace que se deban investigar soluciones ad hoc para obtener una caracterización más precisa.Ingeniería en Tecnologías de Telecomunicació

Passive Planar Microwave Devices

The aim of this book is to highlight some recent advances in microwave planar devices. The development of planar technologies still generates great interest because of their many applications in fields as diverse as wireless communications, medical instrumentation, remote sensing, etc. In this book, particular interest has been focused on an electronically controllable phase shifter, wireless sensing, a multiband textile antenna, a MIMO antenna in microstrip technology, a miniaturized spoof plasmonic antipodal Vivaldi antenna, a dual-band balanced bandpass filter, glide-symmetric structures, a transparent multiband antenna for vehicle communications, a multilayer bandpass filter with high selectivity, microwave planar cutoff probes, and a wideband transition from microstrip to ridge empty substrate integrated waveguide

Review of recent microwave planar resonator-based sensors: Techniques of complex permittivity extraction, applications, open challenges and future research directions

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

Development and Application of a Design Flow for Photonic Integrated Circuits

Silicon photonics allows for the fabrication of many optical elements on a single photonic integrated circuit (PIC). By taking advantage of the established foundry technology used in the CMOS and silicon’s high refractive index, high feature density manufacturing can be achieved in mass quantities. In CMOS fabrication, from conception of an electronic circuit to testing, the process of designing an electronic circuit is dictated by a design flow which has been developed over the course of decades. This flow includes circuit level design and simulation, layout of the circuit, layout and verification of the chip, fabrication, packaging, and testing. Given the identical fabrication technologies used in photonic and electronic circuit manufacturing, electronic design paradigms have been applied to photonic design. Current photonic design puts emphasis on physical layout with minimal simulation. Some post-layout verification exists but is unable to capture complex behavior such as optical and thermal cross-talk between photonic circuits. In addition, there is no design verification besides the traditional design rule check (DRC). To further develop the PIC design process, the need to fully characterize the current state of the photonic design flow is evident. In this work, a design flow is developed for photonic circuits fabricated through the American Institute for Manufacturing Integrated Photonics, or AIM Photonics. More specifically, this design flow has been developed for their Multi-Project Wafer (MPW) Process Design Kits (PDKs). A photonic circuit containing a ring resonator with a heater was designed and simulated using ANSYS Lumerical and laid out in Klayout, an open source layout software for photonic circuits, using the AIM Photonics PDK version 4.5a. This circuit was then characterized in an optics laboratory to compare its physical and simulated performance. Finally, through this comparison, we identified gaps in the current photonic layout and simulation tools as compared to electronic design automation (EDA)

Tunable Terahertz Metamaterials with Germanium Telluride Components

Terahertz (THz) technology is an emerging field with many exciting applications. THz waves can be used to locate explosives and illicit drugs in security applications, or DNA and other molecule resonances in medical applications. THz frequencies represent the next level of modern, high-speed computing, but they also can be used for covert battlefield communications links. Metamaterials are an integral part of THz technology because they can be used to create exotic material properties—permittivities and permeabilities—in a part of the frequency spectrum that is otherwise rather empty and passive. This work aims to acquire a fuller understanding of THz metamaterials in terms of background and theory, and then use this understanding to create a few novel, actively tunable structures using the phase-change material germanium telluride