Designing of Microwave Metamaterial Biosensor for Water Pollution Monitoring

This paper focuses on developing a microwave metamaterial-based Microstrip Ring Resonator for water quality monitoring. Water pollution is increasing at an alarming rate, worsening pollution and destroying natural habitats. This paper aims to design a metamaterial-based resonator, analyse its performance with various biosamples, and then fabricate the designed product to validate the sensing performance. For this purpose, Computer Simulation Technology (CST) is used to design and simulate the proposed biosensor, with Rogers-RO3003 as the substrate material. In addition, for the proof of concept, different types of liquid materials under test were used in simulation and measurement. The procedures begin with the design and simulation of the MRR using CST, followed by the fabrication stage when the simulation produced the desired results, and finally, laboratory measurements for data collection. The sensing area of the microstrip ring resonator was observed through electric field distribution, where a gap was introduced in the ring structure. The results show that proposed structure of the resonator was able to distinguish different types of liquid that were placed in the sensing gap, by shifting the resonance frequency based on their dielectric constant. In summary, a new metamaterial-based microstrip ring resonator is produced to monitor liquid quality. The concept behind the paper was proven through simulations and experiments where it is suitable to be used as a sensing algorithm. In future work, this product could be used to monitor residue in our clean water, such as river, to minimise the polluted drinking water risk.

Ink-jet printed ring resonator with integrated Microfluidic components

Purpose The main purpose of this study is to test the performance of the ink-jet printed microwave resonant circuits on Low temperature co-fired ceramics (LTCC) substrates combined with microfluidic channels for sensor applications. Normally, conductive patterns are deposited on an LTCC substrate by means of the screen-printing technique, but in this paper applicability of ink-jet printing in connection with LTCC materials is demonstrated. Design/methodology/approach A simple microfluidic LTCC sensor based on the microstrip ring resonator was designed. It was assumed the micro-channel, located under the ring, was filled with a mixture of DI water and ethanol, and the operating frequency of the resonator was tuned to 2.4 GHz. The substrate was fabricated by standard LTCC process, and the pattern of the microstrip ring resonator was deposited over the substrate by means of an ink-jet printer. Performance of the sensor was assessed with the use of various volumetric concentrations of DI water and ethanol. Actual changes in concentration were detected by means of microwave measurements. Findings It can be concluded that ink-jet printing is a feasible technique for fast fabrication of micro-strip circuits on LTCC substrates, including microfluidic components. Further research needs to be conducted to improve the reliability, accuracy and performance of this technique. Originality/value The literature shows the use of ink-jet printing for producing various conductive patterns in different applications. However, the idea to replace the screen-printing with the ink-jet printing on LTCC substrates in connection with microwave-microfluidic applications is not widely studied. Some questions concerning accuracy and reliability of this technique are still open.

Enhancement Coupling Method of Microstrip Ring Resonator (MRR) Design for Different Material Sensor Characterization

This work is to design a microstrip ring resonator (MRR) sensor that has the capability to measure the Q-factor and dielectric constant of the selective material. The first step is to design a basic microstrip ring resonator, called Design A. Then the enhancement coupling method of microstrip ring resonator, called Design B is done to improve the performance of the return loss and to ensure the wanted resonant frequency. The performance of this enhancement coupling method of microstrip ring resonator shows of the resonant frequency at 2.096 GHz with the return loss of – 22.063 dB and bandwidth of 10 MHz in between of 2.090 GHz and 2.100 GHz. Using this return loss and the resonant frequency, the Q-factor can be calculated. Then, this microstrip ring resonator with the selective material under test (MUT) or namely as the sample are simulated and compared with the air (εr = 1) as the reference sample. The MUT that apply in this work are Roger 5880 (εr = 2.2), Roger 4350 (εr = 3.48) and FR-4 (εr = 4.4) while the measured dielectric constant that captured are 0.958, 2.163, 3.437, 4.360, respectively.