Abhishek Joshi

Probe feed effect in polygonal patch antennas

The objective of this paper is to present an analysis to the feeding mechanism for a polygonal patch antenna fed by a vertical probe. The full wave electromagnetic simulations are performed to characterize polygonal patch antennas by changing feed points to observe changes in scattering, gain and impedance characteristics. The probe feed effect in polygonal patch antennas is demonstrated using a simulation software CST Microwave Studio® (CST MWS). A planar pentagonal and hexagonal patch antenna is designed and explored for probe feed effects. The gain characteristics of pentagonal patch is observed better when compared to hexagonal patch over a band of 11.4 to 20 GHz.

Gain improvement in polygonal patch antennas

The effect of polygonal slot in vertex-fed polygonal patch antennas is studied and analyzed. A polygonal shaped slot is obtained by creating a polygonal slot at the center of polygon. Here, the pentagonal and hexagonal shaped slot is created at the center of a pentagon and a hexagon. Pentagonal and hexagonal shaped slotted patch designs are simulated for different radius of slot (R2) formed when vertices of polygonal slot moves from center towards the vertices of polygon to understand the effect of polygonal slot. The characterization of antenna designs to observe the effect of slot in patch design on scattering, impedance and gain characteristics of antennas is performed through simulation on CST MWS®. It is observed that wideband characteristics between 12 to 28 GHz of pentagonal and hexagonal patch antennas are retained with pentagonal and hexagonal shaped slot geometries till radius is equal to 15 mm and 16 mm respectively. For lower values of R2, multiband behavior is observed for polygonal shaped slotted patch antenna designs. Analyzing gain results of all slotted patch geometries reflects that the performance of the hexagonal patch antenna is better in terms of gain compared to others within the operating band.

Edge perturbation effect in polygonal patch antennas

The effect of edge perturbation in vertex-fed polygonal patch antennas is studied and analyzed. A polygram shape is obtained by perturbing the edge of polygon. Here, edges of a pentagon and a hexagon are perturbed to obtain a pentagram and hexagram respectively. Pentagram and hexagram patch designs are simulated for different angles (θ) formed when midpoint (vm) of edge of polygon moves towards the center of polygon between adjacent vertices to understand the effect of edge perturbation. The characterization of antenna designs to observe the effect of change in patch design on scattering, impedance and gain characteristics of antennas is performed through simulation on CST MWS®. It is observed that wideband characteristics between 12 to 20 GHz of pentagonal and hexagonal patch antennas are retained with pentagram and hexagram geometries till angle θ is greater than 165.63° and 163.15° respectively. For lower values of θ, multiband behavior is observed for polygram patch antenna designs. Analyzing results of all patch geometries reflects that the performance of the pentagonal patch antenna is better in terms of gain compared to others within the operating band.

Probe-fed regular hexagonal narrow-slot antenna with reduced ground plane for WLAN applications

The effect of hexagonal slot in probe-fed hexagonal shaped patch antenna with reduced ground plane is proposed, analyzed and studied. In this paper, experimental and simulation results for a probe-fed proposed antenna required for impedance characterization are presented and compared. The hexagonal slot in hexagonal antenna improves the gain of the antenna compared to antenna without slot. With a thickness of 0.027 times the free space wavelength (λ0), the hexagonal shaped patch antenna with hexagonal slot and reduced ground plane can achieve a bandwidth of around 400 MHz in C-band centered at 5.5 GHz. The fabricated hexagonal shaped patch antenna with hexagonal slot can be utilized for requirements of WLAN applications.

Performance comparison of probe-fed polygonal patch antennas for L-band applications

An analysis to investigate the performance of various polygonal shaped patch antennas is presented here in this paper. The comparative analysis is based on the simulation results generated by full wave simulation software CST MWS®. Basic polygonal patch antennas with patch geometries such as triangle, rectangle, pentagon and hexagon are simulated and compared with the circular radiator as well to understand the behavior and performance of low profile antennas fed with a probe. The coordinates of feed point lie at the midpoint of the circumradius in all patch geometries and are varied angularly for half a sector of each polygon to optimize performance within L-band. Simulated analysis and comparison of the polygonal patch antennas demonstrate that decreasing the number of edges spreads the operating band. The triangular and hexagonal patch antenna yields impedance bandwidth of 0.79% and 2.8% centered at 1.5 GHz respectively. The polygonal shaped patch antennas are designed for requirements for L-band applications.

Energy Efficient Clustering Based Network Protocol Stack for 3D Airborne Monitoring System

Wireless Sensor Network consists of large number of nodes densely deployed in ad hoc manner. Usually, most of the application areas of WSNs require two-dimensional (2D) topology. Various emerging application areas such as airborne networks and underwater wireless sensor networks are usually deployed using three-dimensional (3D) network topology. In this paper, a static 3D cluster-based network topology has been proposed for airborne networks. A network protocol stack consisting of various protocols such as TDMA MAC and dynamic routing along with services such as time synchronization, Cluster Head rotation, and power level management has been proposed for this airborne network. The proposed protocol stack has been implemented on the hardware platform consisting of number of TelosB nodes. This 3D airborne network architecture can be used to measure Air Quality Index (AQI) in an area. Various parameters of network such as energy consumption, Cluster Head rotation, time synchronization, and Packet Delivery Ratio (PDR) have been analyzed. Detailed description of the implementation of the protocol stack along with results of implementation has been provided in this paper.

Vertex-fed hexagram patch wideband antenna

Design and analysis of a vertex-feed arrangement of hexagram patch is proposed. The hexagram patch is designed over a glass epoxy FR-4 substrate with an overall thickness of 1.57 mm. The hexagram is a polygon with six vertices and one of the vertices is directly fed with microwave energy using an SMA connector. The performance characteristics of hexagram patch antenna with a square ground plane is examined and observations are reported in the paper. A simulation software CST Microwave Studio® (CST MWS) is used to design and analyze the hexagram patch antenna. From simulation results, it is observed that hexagram patch antenna possess wideband characteristics between 7.21-11.18 GHz.