Editor-in-Chief : V.K. Rastogi
|AJP||ISSN : 0971 – 3093
Vol 18, No. 2, 2009
Vol. 18, No.2 (2009) 145-152
ANN as eigenfunction expansion for analysis of microstrip antenna in dominant mode
Sridhar Pattanaik and R K Mishra
A neural network is proposed as a trial solution of the Helmoltz’s equation. It includes construction of the boundary conditions and is then trained to satisfy the differential equation. The results obtained through this method follow closely to results from other standard methods, indicating that it can be a promising tool for tackling problems of higher dimensions. The possibility of extending the method for the analysis of arbitrary shaped Microstrip antennas is also examined. © Anita Publications. All rights reserved.
Index Terms: Cavity Model, Helmoltz Equation, Microstrip Antenna, Neural networks.
Vol. 18, No. 2 (2009) 153-160
Design and development of microstrip antennas for mobile applications
Jibendu Sekhar Roy
Electronics and Telecommunication Engineering Department
The design and development of new microstrip antennas for the application in mobile communication are reported here. The antennas are either dual-frequency antenna or broadband antenna. The antennas are designed for GPS, WLAN and UWB systems. The simulated results using IE3D software are verified with the measured results. © Anita Publications. All rights reserved.
Keywards: Microstrip antenna, GPS, Bluetooth, HIPERLAN, UWB.
Vol. 18, No. 2 (2009) 161-174
Characteristics of U-slots in the narrow wall of a standard X-band rectangular waveguide
A Mallikarjuna Prasad1 and G S N Raju2
1Department of Electronics and Communication Engineering, JNTU College of Engineering, Kakinada – 533 003, India
This paper presents analysis of inclined U- slot radiator in the narrow wall of standard X-band rectangular waveguide. The slot considered is accommodated only in the narrow wall without protruding into broad walls. The admittance characteristics of such a slot are not available in open literature. The analysis consists of the concept of self-reaction and discontinuity in modal current. These two parameters are evaluated separately for longitudinal as well as inclined portions of the U-slot. The computed results on normalized admittance of the slot, coupling and VSWR as a function of frequency are presented by considering slot width and slot inclination as variables. The data presented in this paper are extremely useful for the design of linear and planar arrays of narrow wall slots.
© Anita Publications. All rights reserved.
Indexing Terms—Slot radiator, self reaction, discontinuity in modal current and admittance.
Vol. 18, No. 2 (2009) 175-186
Optimized design of monopulse arrays
U Jayalakshmi, P V Sridevi and G S N Raju
Conventionally, monopulse sum and difference patterns are obtained using two antennas : one being directional and another being omni-directional antenna. However, in the present work, these patterns are generated from a single array antenna which is basically directional in its radiation properties. The array antenna is designed to optimize the monopulse sum and difference patterns. A few standard amplitude distributions are considered and they are suitably tapered to produce useful sum patterns. The resultant patterns are converted into difference patterns with anti-phase excitation to one half of the array. The monopulse sum and difference patterns are numerically computed for few typical antennas. The data on radiation patterns are presented in sin q-domain. The results of the present work are useful in tracking radars. © Anita Publications. All rights reserved.
Index Terms—Array, monopulse patterns, tracking radar.
Vol. 18, No. 2 (2009) 187-192
Novel dual polarized high gain planar antenna for GSM base station applications
Samik Chakraborty1, Ayona Sarkar2 and Bhaskar Gupta2
1Marine Engineering and Research Institute, P-19 Taratala Road, Kolkata-700 088, India
Microstrip antennas have a number of useful properties like small size, conformability etc but one of the serious limitations of these antennas is their narrow bandwidth characteristic. This makes them unsuitable to operate over the entire GSM band for mobile telephony. Efforts to improve the bandwidth usually result in reduction of radiation efficiency and consequently antenna gain. By making the antenna nonplanar, band width may be increased but at the cost of distorted radiation patterns and loss of planarity. Moreover, its radiation pattern is normally linearly polarized instead of being dual polarized, suitable for wire less communication. A novel single feed dual polarized microstrip antenna is presented here, which is formed by a deformed square patch fed by another capacitively coupled smaller square patch with a single coaxial feed at its centre. Additional inductive loading is provided by using two shorting posts to ensure adequate bandwidth retaining the planar structure. The radiation patterns are also not compromised and the gain is found to improve. © Anita Publications. All rights reserved.
Index Terms—Antenna, mobile, radiation, microstrip, dielectric
Vol. 18, No. 2 (2009) 193-198
New single layer wideband rectangular patch antenna
L Lolit Kumar Singh1, Bhaskar Gupta2, K Yoshitomi3 and K Yasumoto4
1&2Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata-700 032, India
A simple single layer wideband rectangular patch antenna with double U- shaped slot is presented. The antenna gives impedance bandwidth (–10 dB return loss) of 45% (3.125 GHz) with average gain of about 6.45 dBi over the entire band of operation and peak gain of 9.25 dBi. Air substrate of thickness 4.5 mm is used. The antenna is on single layer having single feed and simple structure; it also has a small size and small height. The proposed antenna has many advantages in terms of simplicity, gain, bandwidth and height as compared with other reference antennas. Both simulated and experimental results are presented. The radiation patterns are stable across the bandwidth.
© Anita Publications. All rights reserved.
Total Refs : 3
Vol. 18, No. 2 (2009) 199-206
Design of broadband antenna matching networks
Binboga Siddik Yarman
The purpose of this paper is to provide the necessary background to design broadband antenna matching networks employing real the frequency techniques at radio frequencies. The importance of the topic stems from the recent advances taking place in the conceptual design and manufacturing technologies of the next generation wireless and mobile communication systems which will operate over ultra-wide frequency bands. In fact, for all communication systems, construction of wide-band power transfer networks is inevitable. Therefore, in this manuscript, modern methods, so called real frequency techniques to design broadband antenna matching network are covered, a design roadmap is given with relevant recommendations. Practical examples are presented to design antenna matching networks and microwave amplifiers for various applications. © Anita Publications. All rights reserved.
Key Words-Antenna matching networks, Power transfer networks, Switches for antenna arrays, Microwave amplifiers.
Total Refs : 7
Vol. 18, No. 2 (2009) 207-210
Aanlysis of eigenvalue distribution of smart-antenna arrays in
wireless communication systems
Nilesh Mishra, Manish Kumar and Lalan Jha
The demand for ubiquitous, heterogeneous, and sophisticated wireless systems has led to the need for a better understanding of fundamental issues in space-time communication theory, and their implications for the design of reliable, high-bandwidth and high-speed wireless communications. The authors discuss the issue of eigenvalue distribution for antenna arrays. The present paper provides an approach that should be useful in simulations, analysis, and design of smart-antenna wireless systems. The results show that this parameter of the spatial channel has an important role to play in analyzing the performance of antenna arrays in wireless systems.© Anita Publications. All rights reserved.
Vol. 18, No. 2 (2009) 211-222
A study on the excitation and the input impedance of an antenna
Department of Computer Science and Communication Engineering, Kyushu University
Several source models which can be used in the numerical solution of the electric field integral equation (EFIE) using thin wire theory are studied. These source models include the conventional delta gap source, a magnetic ribbon source, an infinitesimal dipole source, and the magnetic frill source. The magnetic ribbon source model is derived by the equivalent magnetic current corresponding to the gap field. In the thin wire theory it was found that the magnetic ribbon source and an infinitesimal dipole source provide more stable input impedance than the delta gap source or the magnetic frill source. © Anita Publications. All rights reserved.
Total Refs : 9
Vol. 18, No. 2 (2009) 223-230
C – and X – band multifrequency antenna for radar applications
SL Mallikarjun, PM Hadalgi, RG Madhuri and SA Malipatil
A novel design of corporate feed four element modified rectangular microstrip array antenna (FMRMAA) etched on a low cost single substrate operating at multifrequency in C – and X – band is presented. By increasing the number of array elements from four to eight, the antenna performance is improved. The eight element modified rectangular microstrip array antenna (EMRMAA) also resonates for multifreqencies with improvement in gain. The experimental results of the antennas are presented and discussed. © Anita Publications. All rights reserved.
Vol. 18, No. 2 (2009) 231-242
Loss calculation of copper microstrip lines on Si3N4 and SiO2 dielectrics by spectral domain approach for application in VLSI
MG Tiary1, AK Aditya1 and Bhaskar Gupta2
1Asansol Engineering College, Asansol – 713304, West Bengal, India
The VLSI interconnection structure which is nothing but a microstrip line is formulated by using boundary value problem in terms of hybrid mode representation. The resulting equations are transferred to spectral domain by using Spectral Domain Galerkin’s technique to find its dispersion characteristics and hence conductor loss and dielectric loss. The VLSI interconnections are considered to be made of low resistivity metallic Cu deposited on a composite substrate formed by SiO2 and a thin layer of Si3N4 on top of it to ensure proper adhesion of Cu. Numerical results for conductor and dielectric losses obtained upto 20 GHz are presented in this paper. Their validity is established by cross checking with available experimental results and computed results for another similar structure as available in open literature and also with data generated by standard commercial software ‘ IE3D’ marketed by Zeland Technology Inc., USA. © Anita Publications. All rights reserved.
Index Terms—Electromigration, Galerkin’s method, hybrid mode, interconnection.
Total Refs : 15