Textile UWB Antenna with Metamaterial for Healthcare Monitoring

A new metamaterial-based UWB band-notched textile antenna for body area network (BAN) with an operational frequency range of 3 GHz to 11 GHz is created in this paper. The ultra-ide band (UWB) frequency band is covered by the antenna (3.1 GHz to 10.6 GHz). The antennas are smaller because of the usage of denim (jeans) material, which has a permittivity of 1.67. To increase the impedance transmission capacity, the ground plane is reduced to a partly rectangular conductive substance. The hexagonal cut on the bottom side is utilised to boost bandwidth by enhancing the electric field dispersion at the edges. The fabrication is built of a 1 mm thick denim (jeans) substrate, and the feed is a traditional microstrip feed. The return loss and gain characteristics of the proposed antenna are investigated. The performance of a specified antenna is investigated step by step with variable feed length, feed breadth, and substrate properties.

NodeMCU controlled tortoise-shaped bandwidth reconfigurable antenna for 4G and 5G applications

A NodeMCU controlled tortoise-shaped bandwidth reconfigurable antenna for 4G and 5G applications depending upon the condition of the PIN diode switch is presented in this paper. By using FR-4 substrate and limited ground plane antenna is designed with a dimensions of 33 × 22 × 1 mm3. The fabricated antenna is working for Wi-Fi, INSAT C-band, & direct broadcast service in the Ku band with a frequency range of 2.13–2.98 GHz, 6.86–8.42 GHz, and 12.03–13.13 GHz, respectively. PIN diode used to adjust the operational frequency ranges, which will be operated by the NodeMCU module. When the PIN diode is in the OFF state, the design antenna resonates at 2.24, 7.81, and 13.70 GHz, and when the PIN diode is in the ON state, it resonates at 2.45, 7.21, and 12.46 GHz. The designed antenna has a gain of 2.2 to 3.25 dB. In the ON state, the proposed bandwidth reconfigurable antenna has a radiation efficiency of more than 92 percent at all operational frequencies. The measured and simulated (CST Microwave Studio) findings are very similar. The CDAC Cmote unit examines the proposed reconfigurable antenna in a practical situation, and sensor data is successfully sent to the cloud. The data is analyzed using the machine learning technique.

Broadband metasurfaces loaded with non-Foster elements

Metasurfaces have been widely used to design low-profile antennas, thin absorbers, lenses etc. The operational frequency band of a metasurface is rather narrow due to its resonant nature. Loading metasurface unit cells with non-Foster elements allows for remarkable bandwidth extension. In this paper, design of a broadband metasurface to operate as an artificial magnetic conductor is considered. The main issues which influence the bandwidth extension such as implementation of the non-Foster load, minimization of conversion error of a negative impedance converter, and circuit stabilization are addressed.

A Mode Decoupling Method for Circular Patch Antennas

In this contribution, we investigate the effect of mode decoupling for dual-feed circular patch antennas. We consider an antenna comprising a circular disc patch placed inside an annular-ring patch. Both patches are resonant radiators, which can be fed by two different vertical posts. Due to the field interaction of the patches, the feeds experience parasitic cross-talk limiting the receive diversity performance of the system. Here, we demonstrate the possibility to suppress the cross-talk at the operational frequency by including a capacitive decoupling element into the circular patch. The physical mechanism of the method consists in the excitation of two different eigenmodes (TM01 and TM11) in a certain combination canceling the mutual coupling. The presented decoupling method can be used for patches operating either at the same frequency or at two different frequencies. In the proposed dual-feed antenna it is possible to achieve an isolation level of better than -45 dB. In contrast to the method of decoupling and matching network used for the same type of antennas, one does not need couplers to feed the patches, which reduces losses.

Experimental Testing of Passive Linear TMD for Postural Tremor Attenuation

Research interest to provide a mechanical solution for involuntary tremors is increasing due to the severe side effects caused by the medications used to lessen its symptoms. This paper deals with the design of a cantilever-type tuned mass damper (TMD) used to prove the effectiveness of passive controllers in reducing the involuntary tremor’s vibrational signals transmitted by the muscles to the hand segment. TMD is tested on an experimental arm, reflecting the flexion-extension motion of the wrist, excited by a mechanical shaker with the measured tremor signal of a patient with essential tremor. The designed TMD provides a new operational frequency for each position of the screw fixed to its beam. Modal damping ratios are also calculated using different methods for each position. The effectiveness of the TMD is quantified by measurements using a vibrometer and inertial measurement unit. Three TMDs, representing 15.7% total mass ratio, cause a reduction of 29% for the acceleration, 69% for the velocity, 79% for the displacement, 67% for the angular velocity, and 82% for the angular displacement signals. These encouraging results will allow the improvement of the design of the passive controller in the form of a wearable bracelet suitable for daily life.

Valveless microliter combustion for densely packed arrays of powerful soft actuators

Existing tactile stimulation technologies powered by small actuators offer low-resolution stimuli compared to the enormous mechanoreceptor density of human skin. Arrays of soft pneumatic actuators initially show promise as small-resolution (1- to 3-mm diameter), highly conformable tactile display strategies yet ultimately fail because of their need for valves bulkier than the actuators themselves. In this paper, we demonstrate an array of individually addressable, soft fluidic actuators that operate without electromechanical valves. We achieve this by using microscale combustion and localized thermal flame quenching. Precisely, liquid metal electrodes produce sparks to ignite fuel lean methane–oxygen mixtures in a 5-mm diameter, 2-mm tall silicone cylinder. The exothermic reaction quickly pressurizes the cylinder, displacing a silicone membrane up to 6 mm in under 1 ms. This device has an estimated free-inflation instantaneous stroke power of 3 W. The maximum reported operational frequency of these cylinders is 1.2 kHz with average displacements of ∼100 µm. We demonstrate that, at these small scales, the wall-quenching flame behavior also allows operation of a 3 × 3 array of 3-mm diameter cylinders with 4-mm pitch. Though we primarily present our device as a tactile display technology, it is a platform microactuator technology with application beyond this one.

The Internet of Bodies: The Human Body as an Efficient and Secure Wireless Channel

<div>Taking a cue from the Internet of Things, the Internet of Bodies (IoB) can be defined as a network of smart objects placed in, on, and around the human body, allowing for intra- and inter-body communications. This position paper aims to provide a glimpse into the opportunities created by implantable, injectable, ingestible, and wearable IoB devices. The paper starts with a thorough discussion of application-specific design goals, technical challenges, and enabling of communication standards. We discuss the reason that the highly radiative nature of radio frequency (RF) systems results in inefficient systems due to over-extended coverage that causes interference and becomes susceptible to eavesdropping. Body channel communication (BCC) presents an attractive, alternative wireless technology by inherently coupling signals to the human body, resulting in highly secure and efficient communications. The conductive nature of body tissues yields a better channel quality, while the BCC's operational frequency range (1-100 kHz) eliminates the need for radio front-ends. State-of-the-art BCC transceivers can reach several tens of Mbps data rates at pJ/b energy efficiency levels that support IoB devices and applications. Furthermore, as the cyber and biological worlds meet, security risks and privacy concerns take center stage, leading to a discussion of the multi-faceted legal, societal, ethical, and political issues related to technology governance.</div>

The Internet of Bodies: The Human Body as an Efficient and Secure Wireless Channel

<div>Taking a cue from the Internet of Things, the Internet of Bodies (IoB) can be defined as a network of smart objects placed in, on, and around the human body, allowing for intra- and inter-body communications. This position paper aims to provide a glimpse into the opportunities created by implantable, injectable, ingestible, and wearable IoB devices. The paper starts with a thorough discussion of application-specific design goals, technical challenges, and enabling of communication standards. We discuss the reason that the highly radiative nature of radio frequency (RF) systems results in inefficient systems due to over-extended coverage that causes interference and becomes susceptible to eavesdropping. Body channel communication (BCC) presents an attractive, alternative wireless technology by inherently coupling signals to the human body, resulting in highly secure and efficient communications. The conductive nature of body tissues yields a better channel quality, while the BCC's operational frequency range (1-100 kHz) eliminates the need for radio front-ends. State-of-the-art BCC transceivers can reach several tens of Mbps data rates at pJ/b energy efficiency levels that support IoB devices and applications. Furthermore, as the cyber and biological worlds meet, security risks and privacy concerns take center stage, leading to a discussion of the multi-faceted legal, societal, ethical, and political issues related to technology governance.</div>

Plasma and magnetic field conditions during radar blackouts at Mars.

&lt;p&gt;Large scale solar wind disturbances such as Interplanetary Coronal Mass Ejections (ICMEs) have a major impact on planetary systems.&amp;#160; At Mars, for example, Solar Energetic Particles released during the process that creates the ICME cause large scale radar blackouts as a result of enhanced ionisation at lower altitudes than normal.&amp;#160; The increased absorption of the radar signals can last for up to 10 &amp;#8211; 12 days, depending on the operational frequency of the radar.&amp;#160; These events occur at all latitudes and local times but there does appear to be a peak in occurrence at a solar zenith angle of about 160o, i.e. deep in the tail of the Martian plasma system. Using data from MAVEN, Mars Express and Mars Reconnaissance Orbiter we investigate the background plasma&amp;#160; and magnetic field conditions, which occur at the same time as these events to investigate how the SEP impact on the nightside atmosphere.&amp;#160; This will provide crucial evidence for plasma transport in the Martian system, in particular during the passage of ICMEs.&lt;/p&gt;

Meander And Koch Hybrid Fractal Curve Based Dual Hexagonal Radiating Patch Antenna For Quad Band Wireless Applications

A unique dual hexagonal-shaped radiating patch design with hybrid fractal curves (Meander and Koch) is presented for quad-band wireless applications. Initially, the antenna from 0th to 2nd iteration of hybrid fractal curves with PGP (Partial Ground Plane) is designed and investigated. Further, to get better results of the designed antenna in respect of Bandwidth (BW) and coefficient of reflection these hybrid curves are superimposed on the limited ground plane of 1st and 2nd iteration of the antenna, and the generated antennas are designated as Antenna – 1 and Antenna – 2. A comparison between both the antennas has been made and it is observed that antenna -2 shows better results in respect of improved BW and coefficient of reflection. The proposed antenna exhibits four resonant frequency bands 1.6, 4.8, 6.9, and 8.8GHz with improved corresponding impedance BW of 2.09, 1.36, 0.86, and 1.51GHz. The designed antenna is simulated and made on FR4 glass epoxy substrate with an overall size of 20×40×1.6 mm3. The fabricated proposed antenna is tested experimentally for the authentication of simulated results with experimental results and these are compatible with each other. The other performance indicators like radiation pattern, peak realized gain, and radiation efficiency are also determined for the proposed Hybrid Fractal Antenna (HFA) and all are found satisfactory. Due to the improved operational parameters, the designed HFA can be considered as a suitable applicant for distinct wireless applications in anticipated operational frequency ranges.