Compact Design of Dual-Band Circular Polarized Microstrip Antenna with Single Feed

A novel and compact dual band dual sense circularly polarized microstrip patch antenna with single coaxial feed has been reported in the present work. The key idea of generating dual band circular polarisation (CP) is the integration of a square patch with corner truncation and a smaller concentric circular patch with double slits. The first resonance is provided by the larger patch whose corner truncation generates two orthogonal modes. The inner patch controls the higher-order resonance with the CP contributed by two narrow slits. The higher order resonating frequency can be monitored by controlling the dimensions of the circle and the slits. The antenna provides the CP in two orthogonal planes with two different sense of polarisation. The lower order CP is of left-handed orientation, whereas the higher order shows right-handed polarization. The cross-polarization level is also found to be very low.Comment: 9 page

Enabling Technologies For 6g Future Wireless Communications: Opportunities And Challenges

5G wireless communications technology is being launched, with many smart applications being integrated. However, 5G specifications merge the requirements of new emerging technologies forcefully. These include data rate, capacity, latency, reliability, resources sharing, and energy/bit. To meet these challenging demands, research is focusing on 6G wireless communications enabling different technologies and emerging new applications. In this report, the latest research work on 6G technologies and applications is summarized, and the associated research challenges are discussed.Comment: 9 pages, 4 figure

Robust Algorithms for Localizing Moving Nodes in Wireless Sensor Networks

The vivid success of the emerging wireless sensor technology (WSN) gave rise to the notion of localization in the communications field. Indeed, the interest in localization grew further with the proliferation of the wireless sensor network applications including medicine, military as well as transport. By utilizing a subset of sensor terminals, gathered data in a WSN can be both identified and correlated which helps in managing the nodes distributed throughout the network. In most scenarios presented in the literature, the nodes to be localized are often considered static. However, as we are heading towards the 5th generation mobile communication, the aspect of mobility should be regarded. Thus, the novelty of this research relies in its ability to merge the robotics as well as WSN fields creating a state of art for the localization of moving nodes. The challenging aspect relies in the capability of merging these two platforms in a way where the limitations of each is minimized as much as possible. A hybrid technique which combines both the Particle Filter (PF) method and the Time Difference of Arrival Technique (TDOA) is presented. Simulation results indicate that the proposed approach outperforms other techniques in terms of accuracy and robustness.Comment: 16 pages, 8 figure

Near-Field Radiation Exposure Control in Slot-Loaded Microstrip Antenna: A Characteristic Mode Approach

Microstip antenna topology is commonly loaded with a narrow slot to manipulate the resonance frequency or impedance bandwidth. However, the tuning of the resonance frequency or impedance bandwidth results in the variation of the current and field distributions. In this regard, this work adopts the concept of characteristic modes to gain an initial understanding of the perturbation mechanism of the rectangular patch when loaded with a slot. The performance of microstrip antennas with finite ground plane is then studied using full-wave simulation. It has been found that the distribution of the induced current density is highly dependent on the orientation of the slot The incorporation of a narrow slot suppresses the nearby orthogonal eigen mode and, as a consequence, the radiation behavior is affected. Specifically, in the presence of biological tissues in the near-field region, both antenna input impedance properties and the realized gain are dependent on the slot orientation. Different examples are included for understanding the impact of slot loading on the energy absorption by biological tissues, by calculating the the specific absorption rate (SAR). The proposed analysis facilitates the design of miniaturized antenna geometries for biomedical applications via systematic loading of narrow slots.Comment: 21 Page

Modeling of Vertical Dipole Above Lossy Dielectric Half-Space: Characteristic Mode Theory

This work introduces a theoretical extension of the characteristic mode formulation for analysing the vertical electric dipole lying above a lossy dielectric half-space. As the conventional characteristic formulation fails to maintain the orthogonality of the characteristic field modes over the infinite sphere, an alternate modal formulation is proposed here to maintain the orthogonality for both the current and field modes. The modal results are found to match closely with its method of moment counterparts. Later, the modes of an isolated dipole with no ground plane have been used to predict the role of the lossy ground plane through a theory of the linear combination of the eigenvectors. The proposed formulations have been studied with different heights from the ground plane and are compared with the direct modal solutions to validate its accuracy. It helps to provide a thorough understanding of how the isolated modes interact among each other to constitute the perturbed modes in the presence of the lossy half-space. It can find application to include the lossy earth effect in the study of the lightning fields and the path loss modelling of the antennas over the lossy ground.Comment: 23 pages, 5 Figure