Santanu Dwari

Analysis of Linear Tapered Waveguide by Two Approaches

This paper presents the analysis of linear tapered waveguide. Voltage-standing-wave-ratio (VSWR) is obtained from transmission matrix of the taper waveguide. Taper section is divided into number of section having uniform length. Transmission matrix of taper waveguide is found by multiplication of transmission matrix of each section. Transmission matrix of each section is obtained as the product of three matrices. One is of the initial length of transmission line,second one is due to discontinuity and third one is of the final length of transmission line. Transmission matrix of discontinuity is obtained by two methods. One is by equivalent circuit of step discontinuity and another is by moment method. The results are seen to be in good agreement with (1,2) and (3).

ANTENNA WITH HEXA-BAND CAPABILITIES FOR MULTIPLE WIRELESS APPLICATIONS

In this paper, a novel multiband microstrip patch antenna with small frequency ratio is designed and analysed. One can design a multiband antenna at any desired frequencies through these proposed methods. The proposed antenna shows six operating frequencies with very small frequency ratio between two consecutive resonant frequencies 1.1248, 1.1123, 1.0792, 1.1469 and 1.3254 and can be used for various wireless applications, i.e., 2.5 GHz for UMTS and Wi-Fi, 2.812 GHz for CCTV with wireless video links, 3.128 GHz and 3.376 GHz for WiMAX, 3.872 GHz for C-band applications and 5.132 GHz for Lower WLAN. Design procedure and formation of all six bands are presented and discussed. Analysis is done by Ansoft HFSS v. 15 which is based on Finite Element Method (FEM), and simulated results are verified with experimental results of fabricated prototypes which are found in close agreement.

Analysis and Optimization of Conformal Patch Excited Wideband DRA of Several Shapes

Abstract In this paper various shapes of DR antennas excited by common feed have been proposed and successfully implemented for wideband applications. Proposed structures are Hemispherical, Arrow-shaped and Triangular DRA, while common excited feed is inverted trapezoidal conformal patch. These shapes of DR offer significant optimization in several parameters such as impedance bandwidth, peak gain and bandwidth per unit volume of the antenna. By using inverted trapezoidal patch feed mechanism an impedance bandwidth (VSWR<2) of about 63 % for hemispherical shape, 66 % for arrow shape, and 72 % for triangular shape DRA has been achieved with maximum bandwidth per unit volume. Proposed wideband DRAs i. e. triangular, hemispherical, and arrow shapes of DR antennas cover almost complete C-band (4 GHz–8 GHz) frequency spectrum of microwave. The average peak gain within the operating band for hemispherical, arrow, and triangular shape DRA are about 5, 5.4, and 5.5 dB respectively. A comparative analysis of proposed structures for various antenna parameters has been analyzed by HFSS (High-Frequency Structure Simulator) and validated by experimental results.

Investigation of Compact Dielectric Monopole Antenna Integrated with 3D Printed Horn for UWB Applications

Abstract A novel broadband portable Dielectric Resonator Antenna (DRA) with integrated unshorted horn and broadside radiation pattern is implemented for ultra-wideband (UWB) and Electromagnetic sensor applications. A rectangular DRA composed of TMM 10i (Dielectric constant 9.8 and loss tangent 0.002) material is mounted over four supporting pillars to separate the DRA from the ground plane. A conical shaped horn with the copper foil conductor is used as a reflector to increase the gain and realize stable radiation pattern over the wide frequency range. The horn and supporting pillars are fabricated by a 3-D printer using light weight thermoplastic composite polymer Poly-Lactic Acid (PLA). The proposed antenna contributes measured VSWR (2:1) impedance bandwidth of 106 % ranging from 6.8 GHz to 22.2 GHz for a Quasi-TM111 mode with a low cross-pol level which ensures its linear polarization. The measured peak gain of the DRA is 7.8 dBi at 14 GHz, while estimated average efficiency is more than 88 %. The measured average group delay of the proposed antenna is ~ 1.5 ns within operation band. The proposed antenna is suitable for UWB operation and other broadband applications having omnidirectional coverage and stable radiation pattern ranging from C-band to K-band.

Gain and Bandwidth Enhancement of Tetracuspid-shaped DRA Mounted with Conical Horn

Abstract A novel Tetracuspid-shaped dielectric resonator antenna (DRA) mounted with conical horn is presented and investigated for broadband applications. The dielectric used for investigation is a ceramic composite material having a dielectric constant ( εr

Compact 4-Port MIMO/Diversity Antenna with Low Correlation for UWB Application

\varepsilon_r

Compact 4-Port UWB-MIMO Slot Antenna with Dual Polarization and Low Correlation for Spatial Diversity Application

) of 12.9. Tetracuspid-shaped resonator geometry achieves a broadband impedance bandwidth of 70.9 % for |S11|<‒10 dB, ranging from 2 GHz to 4.2 GHz. Tetracuspid-shaped reduces the DRA volume by 78 % (without horn) as compared to conventional cylindrical DRA; with reduced volume of 14.4 cm3 which diminishes the cost and weight. Gain of proposed antenna is further enhanced up to 9.5 dBi in operating band by mounting a conical horn. Achieved average peak gain is ~7 dBi. Proposed antenna covers bands of different wireless communication systems like Wi-Max and WLAN (2.4 GHz, 2.5 GHz, 3.3 GHz and 3.5 GHz). The simulated results are validated by experimentally measured outcomes and these are well in agreement.

Narrow-Band Bandpass Filter for Wireless Communication System

Abstract A compact four port multiple-input-multiple-output (MIMO) antenna with polarization diversity for ultrawideband (UWB) application is proposed. The antenna contains four monopoles where each monopole has three concentric rings. Orthogonal arrangement of monopoles of the antenna provides good isolation and polarization diversity. The antenna has compact size of 36×36×1.6 mm3. It operates in the frequency band of 3.2 to 11 GHz where isolation is better than 15 dB. The envelop correlation coefficient (ECC) and diversity gain from S-parameter have been calculated to evaluate MIMO performance of the antenna. In addition to ensure distortion less transmission in UWB group delay is also calculated.

Design Investigation of a Laminated Waveguide Fed Multi-Band DRA for Military Applications

Abstract A compact 4-port ultra-wide band (UWB) multiple-input-multiple-output (MIMO) slot antenna with dual polarization is presented. The key features of antenna are: has directive radiation in two planes and low correlation without use of additional decoupling structure. The antenna contains four microstrip feedlines having circular patches backed by stepped circular slots. Orthogonal arrangement of each slot antenna increases compactness with polarization diversity and good isolation. The antenna has compact size of 36×36×0.8 mm3. It operates in the frequency band of 3.1 to 11.9 GHz and isolation is better than 15 dB. The superior diversity performance is ensured by calculating envelope correlation coefficient (ECC) and diversity gain. In addition to guarantee distortion less transmission in UWB group delay is also measured.

Size reduction and harmonic suppression of microstrip branch-line coupler using defected ground structure

Abstract This paper presents the design of a compact narrow-band bandpass filter using the cylindrical dielectric resonator (CDR) coupled with a microstrip line. The TE11δ mode of the dielectric resonator is used to obtain the narrow passband performance while, spurious mode suppression can be improved by etching the slot on the ground plane of the filter due to mode separation with the desired mode. Presented narrow bandpass filter performances are: center frequency 6.15 GHz, fractional bandwidth 0.7 %, and insertion loss (IL) 0.16 dB. To validate the above concept a second order narrow-band bandpass filter is designed, fabricated and measured. There is good agreement between simulated and measured results.