Sreedevi K. Menon

Analysis of Dual Beam Pentagonal Patch Antenna

In this paper, we present a high gain, dual beam pentagonal patch antenna. The pentagonal geometry is inspired from a rectangle patch antenna and a triangle patch antenna. The architecture of the antenna resembles an irregular pentagon comprised a triangle placed on top of a rectangle. FEM is used for the analysis of the antenna design. The pentagonal antenna gave good reflection and radiation characteristics with a 2:1 VSWR bandwidth of 8.1 % at resonant frequency. As we combined the geometry of a rectangle and a triangle for the pentagonal design, the single pentagon patch antenna radiated two directional beams with a peak gain of 6.1 dBi at resonant frequency. Even though the pentagon patch had slightly less gain than the rectangular patch, it had an additional advantage since it radiated in two directions. The proposed pentagonal antenna architecture can be used in applications where there is a need to produce a dual beam without the need of any additional circuits for switching.

Wideband rectangular dielectric resonator antenna for W-LAN applications

A wideband rectangular dielectric resonator antenna suitable for W-LAN applications is reported. The antenna is excited by a top-loaded 50 /spl Omega/ microstrip line at a frequency of 5.45 GHz. The proposed configuration exhibits a bandwidth of 21.6%, and nearly omnidirectional radiation pattern, indicating the suitability for W-LAN applications.

ON THE MINIATURIZATION OF LOG PERIODIC KOCH DIPOLE ANTENNA USING SPLIT RING RESONATORS

In this paper, a printed split ring resonator (SRR) loaded log-periodic Koch dipole antenna (SLPKDA) is proposed. Koch-shaped dipoles when being loaded with split ring resonator (SRR) yielded a compact antenna, still preserving the radiation properties of log-periodic dipole antenna (LPDA). Measurement results show that the proposed antenna has a wide bandwidth, good impedance match and gain of 4 dBi over the band of frequencies from 0.9 GHz to 2.5 GHz. Both vertical and horizontal dimension reductions are achieved by loading Koch dipoles with SRR.

Analysis of hexagonal Split Ring Resonator

Split Ring Resonator (SRR) is found to be an effective filter at microwave frequencies. Different geometries of SRR can be designed to provide filter characteristics in frequency spectrum. In this paper a novel hexagonal SRR which provides band pass characteristics is presented. Different geometric parameters that influence the filter characteristics are analyzed in detail to derive at the optimum design at 2.45 GHz. The electrical property of the proposed filter is investigated in ANSYS High Frequency Structure Simulator (HFSS).

A coplanar pentagonal antenna for wireless applications

Investigation of a coplanar pentagonal antenna is presented in this paper. The antenna offers a bandwidth of 9.48 % at 2.53 GHz with a gain of 4.39 dBi. The antenna has an omnidirectional radiation pattern. The advantage of coplanar antenna is that active circuitry can be mounted easily making it applicable for Monolithic Microwave Integrated Circuit applications (MMIC). The results are compared with a Bow-Tie antenna with the same substrate at same frequency.

Design and development of on-chip coplanar strip open loop resonator filter

In this paper, a compact on chip band stop filter (BSF) using open loop resonator (OLR) integrated on silicon substrate is proposed. The BSF can be fabricated using the CMOS process without any additional steps thus making the filter cost effective in fabrication. The effect of additional layers in the filter characteristics is also presented. The proposed filter has a bandwidth of 4.3 GHz and has a stopband attenuation of -30 dB. The filter is 8.6×4×0.525 mm3 in size and can be fabricated using simple CMOS process flow.

A novel EBG structured ground plane for microstrip antennas

A simple electromagnetic band gap (EBG) structure consisting of cross-shapes etched in the ground plane of microstrip transmission line is presented. Microstrip antenna characteristics on employing this EBG structure as ground plane are also studied.

Direction of arrival estimation in smart antenna for marine communication

A communication link between fishing vessels or with the sea shore using Wi-Fi is explored in this paper. For effective communication a high gain antenna is mounted at the sea shore which acts as base station (BS). Although narrow band directional antenna used in the Base Station (BS) ensures the connectivity for a long distance, the coverage will be poor without any steering mechanism, as the antenna beam is fixed in a particular direction. The proposed smart antenna with adaptive beamforming and multiple access technique can ensure the coverage without losing connectivity at long distance. The main objective is to find the Direction of Arrival (DoA) of the received signal from the fishing vessel moving at a constant velocity for adaptive steering of the antenna beam. The DoA parameter gives the phase and amplitude of the signal transmitted from the fishing vessel. The same phase and amplitude help to calculate the beam forming vectors in the smart antenna and it adaptively steers the beam towards fishing vessel. This paper describes how DoA estimation can apply to a beam forming Wi-Fi antenna array which is used for marine communication, and give a mathematical model of DoA estimation.

Microstrip patch based high isolation planar crossover for beamforming applications

In this paper, a microstrip patch is extended to form planar crossover by suitably choosing the feed locations for orthogonal polarizations. The overlap is modified as a hexagonal patch which offers an isolation of −35 dB at 2.4 GHz. Crossover is a part of butler matrix, which is finds applications in beamforming networks. The proposed crossover is compared for reflection and transmission characteristics and compactness with rectangular and circular crossover at same frequency.

Planar Crossover Using Microstrip Patch Antenna for Beamforming Networks

In this paper, a simple planar design for a symmetric four-port crossover is presented. The proposed crossover is derived from a microstrip patch antenna with a set of two orthogonal feeds. Electrical length of the microstrip patch antenna is increased by incorporating slots achieving a frequency shift to the lower side. The slot in the patch antenna is derived from fractal geometry, which allows three stages of iteration. Isolation better than −15 dB and transmission ~0 dB is observed in the frequency range of interest. The proposed crossover is a potential candidate for Butler matrix in beamforming applications.