A Novel Flexible Microstrip Patch Antenna with Different Conductive Materials For Telemedicine and Mobile Biomedical Imaging Systems

Telemedicine and mobile healthcare communication devices require compact antennas with superior performance and reduced size and weight. The design and development of such antennas for broadband applications are challenging for many researchers. In this study, a wearable rectangular microstrip antenna was designed and implemented to detect many tumors. The patch and ground part of the antenna, which can be used as both a transmitter and a receiver in microwave imaging systems, are made of copper tape, graphene, conductive paint, and the substrate is made of felt (Ɛr = 1.3). Antenna parameters were optimized using the CST Microwave Studio program. The conventional microstrip antennas have a narrow band and low gain. The antenna in this study is designed and implemented differently from the conventional microstrip antennas and can be easily used in applications requiring ultra-wideband. In addition, the radiation characteristic of the designed antenna is quite good, and the electric field change around it is at a level that will not cause any health problems. The variation of the conductivity values ​​of the organs in the human body is high in the 1 GHz-10 GHz frequency band. The antenna, which is designed based on the fact that the conductivity values ​​of healthy tissues and tumor/cancer tissues are different, can be used in microwave imaging systems to detect tumors in organs such as the lung, brain, liver, and kidney. Also, the designed antenna is in a wearable form, allowing continuous monitoring of patients with high cancer risk. In this article, a microstrip patch antenna with a flexible substrate with copper tape, conductive paint, and graphene-based conductor that can be used for imaging and telemedicine applications is proposed, and its performance is experimentally analyzed. A standard and low-cost 3D printer are used to produce the graphene-based conductive part. In addition, copper tape and conductive paint materials were used to produce the patch part with an easier and cheaper method without a special device. The performance, return loss, and gain of the produced antennas were analyzed both in simulation and experimentally.

Flexible ECG circuit fabrication and application using vinyl cutting technique

The aim of this study is to prove the capability of vinyl cutting technique to cut the conductive traces of electronic circuit layout which used a copper tape (Copper tape 1181 from 3M) on flexible substrate to replace the method of using nano-scale particle material. A wireless electrocardiography (ECG) circuit was integrated and fabricated on flexible substrate, namely a polyethylene terephthalate (PET) substrate by using vinyl cutting method to produce the conductive line traces. After that, the fabricated circuit is used for acquiring ECG signals from a patient simulator and human subjects to measure the performance differences and compatibility as a wearable device. In the data processing stage, ECG data were denoised using sym20 from Wavelet Transform tool provided by MATLAB. Then, Signal-to-noise-ratio (SNR) was calculated and used as the signal quality indicator. At the end of the study, flexible circuit performance was compared to MIT-BIH Arrhythmia database and it shows that there is no significance difference between both. In conclusion, vinyl cutting method shows a promising fabrication output on PET substrate as the performance of both flexible ECG circuit is comparable with rigid ECG circuit by a previous study.

Electrokinetically Assisted Paper-Based DNA Concentration for Enhanced qPCR Sensing

Paper-based microfluidics have gained widespread attention for use as low-cost microfluidic diagnostic devices in low-resource settings. However, variability in fluid transport due to evaporation and lack of reproducibility with processing real-world samples limits their commercial potential and widespread adoption. We have developed a novel fabrication method to address these challenges. This approach, known as “Microfluidic Pressure in Paper” (μPiP), combines thin laminating polydimethylsiloxane (PDMS) membranes and precision laser-cut paper microfluidic structures to produce devices that are low-cost, scalable, and exhibit controllable and reproducible fluid flow dynamics similar to conventional microfluidic devices. We present a new μPiP DNA sample preparation and processing device that reduces the number of sample preparation steps and improves sensitivity of the quantitative polymerase chain reaction (qPCR) by electrophoretically separating and concentrating nucleic acids (NAs) continuously on paper. Our device was assembled using two different microfluidic paper channels: one with a larger pore (25 microns) size for bulk fluid transport and another with a smaller pore size (11 microns) for electrophoretic sample concentration. These two paper types were aligned and laminated within PDMS sheets, and integrated with adhesive copper tape electrodes. A solution containing a custom DNA sequence was introduced into the large pore size paper channel using a low-cost pressure system and a DC voltage was applied to the copper tape to electrophoretically deflect the solution containing NAs into the paper channel with the smaller pore size. Samples were collected from both DNA enriched and depleted channels and analyzed using qPCR. Our results demonstrate the ability to use these paper devices to process and concentrate nucleic acids. Our concentration device has the potential to reduce the number of sample preparation steps and to improve qPCR sensitivity, which has immediate applications in disease diagnostics, microbial contamination, and public health monitoring.

Design of Slotted Hexagonal Wearable Textile Antenna Using Flexible Substrate

In this chapter, a dual wideband textile antenna is proposed for WLAN and WiMax application. For antenna to be wearable, jeans material is used as a substrate to make ground plane, and copper tape is used to make patch of the anticipated antenna. The proposed antenna shows dual band performance with bandwidth of 82.48% covering 1.456 GHz to 3.5 GHz and 13.39% covering 4.32 GHz to 4.94 GHz. The simulated results like reflection coefficient, directivity, and radiation characteristics have been studied and analyzed.