Metamaterial based sensor integrating transmission line for detection of branded and unbranded diesel fuel

Highlights

• Transmission line integrated metamaterials based liquid sensor.

• To determination authentic and inauthentic diesel samples in the microwave frequency region.

• An approximately 60 MHz frequency difference in the characteristic resonance.

• This transmission line based sensor can be used for the precise detection of the different liquids.

Abstract

In this paper, a high sensitive metamaterial – based liquid sensor employing microstrip transmission line have been designed and investigated for detection of authentic and inauthentic diesel samples both numerically and experimentally. The proposed structure employs sensor layer along the radiating edge of patch antenna which is printed on FR4 substrate. Sensitivity of the proposed sensor compared with similar metamaterial or antenna-based sensors which uses resonance frequency shifts. Obtained results showed that the proposed structure provides more than two times greater than similar sensor studies.

In addition to higher sensitivity, proposed structure showed good agreement between simulated and tested data.

Introduction

Nowadays, sensor applications always attract attention scientists and engineers, sensor studies have been rapidly growing of interesting applications and advanced technologies such as smart devises, robotics and industrial applications [1], [2]. Along this line, different techniques and approaches to fabricate viable sensor can be found in literature because of their simple geometry, small size ease of fabrication and low cost [3], [4]. These sensors are realized by artificial engineering electromagnetic structures having unique electromagnetic properties, which are not available, compared to other types of materials in nature these kinds of special materials called metamaterials (MTM) [5], [6], [7]. MTM sensor studies can be divided into two categories which are non-resonant and resonant methods [8]. Microstrip structures, especially split ring resonator (SRR) based MTM sensors have been widely used for complex permittivity-based sensor studies due to their ease of application property [9], [10], [11], [12]. Also, transmission line integrated sensors have been investigated for different and multipurpose sensor applications [13], [14], [15], [16], [17]. Like the MTM sensors which are developed for dielectrics, liquids and biomolecules, they can be used for physical parameters as temperature, pressure, purity, and cancer cell detection [18], [19], [20]. In order to explain the purpose and focus of this study brief literature can be explained as below. MTM sensors which employs resonance frequency shift according to the parameter that is going be sensed [21], [22]. Since fuel adulteration is global problem especially in Asian countries this study focused on the adulteration of diesel fuel [23]. There are different methods and different studies conducted to sense resonance frequency shift as fiber grating sensors, density measurement methods and filter paper method and gas chromatography [24], [25], [26]. These methods have positive and negative sides for example they need laboratory equipment and need time for show correct results which can be evaluated as negative sides. Positive sides of these methods, they show the correct results with right equipment. In this study as alternative to these methods, a transmission line integrated metamaterial sensor has been designed produced and tested to sense the branded and unbranded diesel. Transmission lines have effectively been used in micro-fluid, strain and rotation sensing in Refs. [27], [28]. Chang ming Chen, Jun Xu and Yao Yao[29] designed and fabricated half-mode substrate integrated waveguide (HMSIW) loaded with a complementary split ring resonator (CSRR) as a humidity sensor with high sensitivity in 2018, Tumkaya et al. [30] also presented the distinguish authentic and in authentic fuel samples by using metamaterials based sensor waveguide with a reservoir for the liquids, after one year Tamer with his group [31] investigated the determination authentic and in authentic gasoline samples by using the transmission line based metamaterials sensor, both mentioned pervious work are similar but they used different method. Tumkaya et al. have conducted another study for fuel sensor by using three rhombus slots in [32].

In this work, MTM based liquid sensor integrated transmission line are investigated both numerically and experimentally to determination the authentic and inauthentic diesel at microwave frequency range. CST Microwave Studio, which can be classified as a full-wave electromagnetic (EM) solver using finite integration technique, have been used to design and simulation studies. The electrical properties (relative dielectric constant and lost tangent) of the authentic and inauthentic diesel samples are examined in a frequency range between 8 GHz and 12 GHz. Also, compatible results observed between 1 GHz and 20 GHz to verify wideband usability. The dimensions of the proposed structure are determined by using the parametric studies in the simulation program. The mechanism of the sensing studies, electric field and surface current distribution have been presented in the next chapter. The sensor structure has been fabricated by using LPKF E33 PCB machine in the same condition as simulated. The selected samples have been placed in the sensor layer after production. Agilent PLN-A Vector Network Analyser (VNA) was used to measure the transmission coefficient of the proposed structure. Both experimental and simulation study results are complying with each other and the proposed structure have effectively been used for the separation of branded and unbranded diesel. In addition to the diesel separation, the proposed structure can be used for similar liquids for adulteration since it has two times greater sensitivity with similar metamaterial sensor studies when it is compared with [30], [31], [32] by its unique design and sensing method.