Investigation of microwave sensor and integrate with polydimethylsiloxane for medical imaging application

The small-sized wideband antenna is one of the antennas used in the medical field to detect body tissue. The antenna's direct contact with the human body causes reflected signal due to the high body coupling, and the narrower bandwidth tends to reduce the data transfer rate in transmission. Therefore, this paper aims to design a wideband antenna with wearable properties operated in the frequency range of 3 GHz to 6 GHz. The antenna is designed with a rectangular-shaped patch with notches and the t-slot shaped partial slot ground. The connected speech test (CST) studio suite software is used to design and optimize the miniature antenna, which measures 24 mm (W) x 38 mm (L) x 0.168 mm (H). The antenna is then embedded with polydimethylsilixane (PDMS) at the top half of the antenna with the dimension 24 mm (W) x 19 mm (L) x 1 mm (H) and also fully occupied. The antenna is configured with the bending capabilities to adapt the human body surface at an angle of 30º. The antenna is having the benefits of small size, cost-effective, and easy to fabricate. The antenna design can effectively detect unusual body tissue, and it safe to be used

Accurate characterizations of material using microwave T-resonator for solid sensing applications

The topic of microwave sensors in enclosures is one of the most active areas in material characterization research today due to its wide applications in various industries. Surprisingly, a microwave sensor technology has been comprehensively investigated and there is an industry demand for an accurate instrument of material characterization such as food industry, quality control, chemical composition analysis and bio-sensing. These accurate instruments have the ability to understand the properties of materials composition based on chemical, physical, magnetic, and electric characteristics. Therefore, a design of the T-resonator has been introduced and investigated for an accurate measurement of material properties characterizations. This sensor is designed and fabricated on a 0.787 mm-thickness Roger 5880 substrate for the first resonant frequency to resonate at 2.4 GHz under unloaded conditions. Various standard dielectric of the sample under test (SUT) are tested to validate the sensitivity which making it a promising low-cost, compact in size, ease of fabrication and small SUT preparation for applications requiring novel sensing techniques in quality and control industries

Determination of solid material permittivity using T-ring resonator for food industry

In this paper, we present a simple design of a T-ring resonator sensor for characterizing solid detection.  The sensor is based on a planar microwave ring resonator and operating at 4.2 GHz frequency with a high-quality factor and sensitivity. An optimization of the T-ring geometry and materials were made to achieve high sensitivity for microwave material characterizations. This technique can determine the properties of solid materials from range of 2 GHz to 12 GHz frequencies. Techniques of current microwave resonator are usually measuring the properties of material at frequencies with a wide range; however, their accuracy is limited. Contrary to techniques that have a narrowband which is normally measuring the properties of materials to a high-accuracy with limitation to only a single frequency. This sensor has a capability of measuring the properties of materials at frequencies of wide range to a high-accuracy. A good agreement is achieved between the simulated results of the tested materials and the values of the manufacturer’s Data sheets. An empirical equation has been developed accordingly for the simulated results of the tested materials. Various standard materials have been tested for validation and verification of the sensor sensitivity. The proposed concept enables the detection and characterization of materials and it has miniaturized the size with low cost, reusable, reliable, and ease of design fabrication with using a small size of tested sample. It is inspiring a broader of interest in developing microwave planar sensors and improving their applications in food industry, quality control and biomedical materials

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

A Novel Symmetrical Split Ring Resonator Based On Microstrip For Microwave Sensors

In this paper, novel symmetrical split ring resonator (SSRR) is proposed as a suitable component for performance enhancement of microwave sensors. SSRR has been employed for enhancing the insertion loss of the microwave sensors. Using the same device area, we can achieve a high Q-factor of 141.54 from the periphery enhancement using Quasi-linear coupling SSRR, whereas loose coupling SSRR can achieve a Q-factor of 33.98 only. Using Quasi-linear coupling SSRR, the Q-factor is enhanced 4.16 times the loose coupling SSRR using the same device area. After the optimization was made, the SSRR sensor with loose coupling scheme has achieved a very high Qfactor value around 407.34 while quasi-linear scheme has achieved high Q-factor value of 278.78 at the same operating frequency with smaller insertion loss. Spurious passbands at 1st, 2nd, 3rd, and 4th harmonics have been completely suppressed well above -20 dB rejection level without visible changes in the passband filter characteristics. The most significant of using SSRR is to be used for various industrial applications such as food industry, quality control, bio-sensing medicine and pharmacy. The simulation result that Quasi-linear coupling SSRR is a viable candidate for the performance enhancement of microwave sensors has been verified

A Novel Symmetrical Split Ring Resonator Based On Microstrip For Microwave Sensors

In this paper, novel symmetrical split ring resonator (SSRR) is proposed as a suitable component for performance enhancement of microwave sensors. SSRR has been employed for enhancing the insertion loss of the microwave sensors. Using the same device area, we can achieve a high Q-factor of 141.54 from the periphery enhancement using Quasi-linear coupling SSRR, whereas loose coupling SSRR can achieve a Q-factor of 33.98 only. Using Quasi-linear coupling SSRR, the Q-factor is enhanced 4.16 times the loose coupling SSRR using the same device area. After the optimization was made, the SSRR sensor with loose coupling scheme has achieved a very high Q-factor value around 407.34 while quasi-linear scheme has achieved high Q-factor value of 278.78 at the same operating frequency with smaller insertion loss. Spurious passbands at 1st, 2nd, 3rd, and 4th harmonics have been completely suppressed well above -20 dB rejection level without visible changes in the passband filter characteristics. The most significant of using SSRR is to be used for various industrial applications such as food industry, quality control, bio-sensing medicine and pharmacy. The simulation result that Quasi-linear coupling SSRR is a viable candidate for the performance enhancement of microwave sensors has been verified

The CSIW Resonator Sensor for Microfluidic Characterization Using Defected Ground Structure

This paper presents a miniaturized circular substrate integrated waveguide (CSIW) resonator sensor with the integration of defected ground structure (DGS) to characterize the dielectric properties of the aqueous solvent. The sensor is developed based on the resonant perturbation method for high sensitivity and accurate measurement. The proposed structure is employed using a substrate integrated waveguide topology at 4.4 GHz with microliter ( ) volume of sample at a time. The integration of DGS structure significantly reduces the overall size of the sensor with more than 50% geometrical reduction. The changes in resonant frequency shows an identical performance based on the relative permittivity of the sample. Implications of the results and future research directions are also presented. Finally, a comparison between the proposed sensors are performed in order to identify the best sensing approach for an advancement of material characterization industry

A Review of Characterization Techniques for Material's Properties Measurement using Microwave Resonant Sensor

This paper presents a compilation of important review in the development of microwave resonant sensor technology used in previous years. The major research work for each year is reviewed. Most of the resonators are designed for material characterization in specific application areas such as food quality control, medical, bio-sensing and subsurface detection.  In the last few years, several resonant sensors based on the planar and non-planar structure are compared and examined in order to propose a new topology of microwave sensors designed. The weaknesses of conventional sensors such as bulky size, high cost manufacturing and consume high volumes of detectable sample have been reviewed. Most significantly, this new proposed structure must gain high quality factor to gain improvement in an accuracy of the sensing capability and can overcome previous design weaknesses. This device will discriminate the composition and properties of samples based on scattering parameters in certain operating frequency. The proposed system outlined in this paper, featuring new innovation in resonator structure as well as providing advanced capability design of future research works. The contribution of this study is useful for various types of applications where the characterizing of materials is very important, while improving its performance especially in terms of accuracy and sensitivity. The previous studies will be reviewed and critically compared in order to gain a better understanding in microwave resonant sensors and new ideas for further research improvement in application, which require characterizing of materials