In-body path loss model for homogeneous human muscle, brain, fat and skin

In this paper, we study the wave propagation within various lossy homogeneous human tissues such as the muscle tissue, brain, skin, and the fat layer at 2.4 GHz using insulated dipole antennas. Path loss (PL) in these tissues is determined by means of measurements and simulations, based on which suitable path loss models are proposed. By understanding the path loss within the human body one can establish optimal communication between the antennas embedded within it. We further investigate the influence of the insulation thickness of the insulated dipoles on the antenna resonance frequency

Specific absorption rate and path loss in specific body location in heterogeneous human model

A multi-implant scenario is considered using insulated dipole antennas for specific locations such as the liver, heart, spleen and the kidneys where implants communicate with a pacemaker acting as a central hub. Wireless communication within human body experiences loss in the form of attenuation and absorption, and to identify these losses, the path loss is studied in this paper for an adult and child heterogeneous human model. Link performance is calculated to investigate the applicability of in-body communication. The specific absorption rate for all these locations is also studied to verify compliance with international safety guidelines

In-body path loss model for homogeneous human tissues

A wireless body area network (WBAN) consists of a wireless network with devices placed close to, attached on, or implanted into the human body. Wireless communication within human body experiences loss in the form of attenuation and absorption. A path loss (PL) model is thus necessary to identify these losses in homogeneous medium which is proposed in this paper. The model is based on 3-D electromagnetic simulations and is validated with measurements. Simulations are further extended for different relative permittivity epsilon(r) and conductivity sigma combinations spanning a range of human tissues at 2.45 GHz, and the influence of the dielectric properties on PL is investigated and modeled. This model is valid for insulated dipole antennas separated by a distance up to 8 cm. Furthermore, PL in homogeneous medium is also compared with the path loss in heterogeneous tissues. The path loss model for homogeneous medium is the first in-body model as a function of epsilon(r), sigma, and separation between antennas and can be used to design an in-body communication system

Compliance boundaries for LTE base station antennas at 2600 MHz

Compliance boundaries and allowed output powers based on on the whole body averaged specific absorption rate (SAR) and the 10 g averaged SAR in both the limbs and the head and trunk and the root mean squared electrical field, are determined for three orientations regarding three base station antennas (BSAs) emitting at 2600 MHz. The ICNIRP basic restrictions and reference levels for both the general public and occupational exposure, are used to determine these compliance boundaries. FDTD simulations are carried out using the virtual family male and CAD models of the three antennas. The results for the different basic restrictions and reference levels are compared and we observed that the reference levels are not conservative when the antenna is only partially radiating. The simulation results show that the basic restriction on the 10g averaged SAR in the head and trunk of the body determines the compliance boundaries at lower antenna powers. Combined compliance distances, which ensure compliance with all reference levels and basic restrictions, have been determined for every frequency. The errors on the estimated allowed power are used for an uncertainty analysis for the compliance distances

Extraction of antenna gain from path loss model for in-body communication

Proposed for the first time is an in-body path loss model for homogeneous human muscle and head tissue that is independent of the antennas for in-body communication at 2.45 GHz. The path loss model obtained can be used to design in-body communication systems at 2.45 GHz

Maternal and neonatal outcome in primigravida with mobile head at ≥39 weeks of gestation

Background: Primigravida with mobile head at ≥39 weeks of gestation are prone to the probability of caesarean section. With this study we aimed to identify the maternal and neonatal outcome of primigravida with mobile head at ≥39 weeks of gestation under the watchful expectancy and good conduct of labour.Methods: A cross sectional study was conducted among primigravida with mobile head at ≥39 weeks admitted for delivery in the department of obstetrics and gynaecology, govt. medical college, Kottayam, Kerala, from February 2021 to September 2021. A sample size of 247 was identified considering 28% proportion of presentation with deflexed head, 95% confidence interval and 2% margin of error. A detailed history, physical examination and ultrasonography was performed.Results: Of the 250 participants, the mean age of the study subjects was 24.97±3.93 and mean body mass index (BMI) was 23.72±4.78 kg/m2. The most common cause for mobile head was a deflexed head (35.2%). A lower segment caesarean section (LSCS) was conducted in 28.8% participants while vacuum assistance ad forceps assistance was required for 9.6% and 4.4% participants respectively. The most common indication for LSCSC being moderate to thick meconium-stained amniotic fluid (MSAF) 23% followed by 1st degree CPD failed trial in 17% cases. A significant association with maternal morbidity was observed in undiagnosed placenta previa (p=0.039) and vacuum-assisted deliveries (p=0.001). We observed that 3.6% of babies have meconium aspiration syndrome, and 8% of new born were admitted in intensive care for foetal distress.Conclusions: Primigravida with mobile head at term during labour requires intense monitoring. Although the duration of labour appeared to be prolonged in a small proportion of patients with watchful expectancy and good conduct of labour and timely intervention, vaginal delivery is possible with minimal maternal and neonatal morbidity.