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N.P. Agrawall

Bio: N.P. Agrawall is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Dipole antenna & Radiation pattern. The author has an hindex of 1, co-authored 1 publications receiving 845 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a simple formula is proposed to predict the frequency corresponding to the lower edge of the bandwidth for each of these configurations, including square, rectangular, and hexagonal disc monopole antennas.
Abstract: The circular disc monopole (CDM) antenna has been reported to yield wide-impedance bandwidth. Experiments have been carried out on a CDM that has twice the diameter of the reported disc with similar results. New configurations are proposed such as elliptical (with different ellipticity ratios), square, rectangular, and hexagonal disc monopole antennas. A simple formula is proposed to predict the frequency corresponding to the lower edge of the bandwidth for each of these configurations. The elliptical disc monopole (EDM) with ellipticity ratio of 1.1 yields the maximum bandwidth from 1.21 GHz to more than 13 GHz for voltage standing wave ratio (VSWR)<2.

866 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a planar circular disc monopole has been demonstrated to provide an ultra wide 10 dB return loss bandwidth with satisfactory radiation properties, and the parameters which affect the performance of the antenna in terms of its frequency domain characteristics are investigated.
Abstract: This paper presents a study of a novel monopole antenna for ultrawide-band (UWB) applications. Printed on a dielectric substrate and fed by a 50 /spl Omega/ microstrip line, a planar circular disc monopole has been demonstrated to provide an ultra wide 10 dB return loss bandwidth with satisfactory radiation properties. The parameters which affect the performance of the antenna in terms of its frequency domain characteristics are investigated. A good agreement is achieved between the simulation and the experiment. In addition, the time domain performance of the proposed antenna is also evaluated in simulations.

948 citations

Journal ArticleDOI
TL;DR: In this paper, the authors summarize the work that has been developed by the authors for the last several years, in order to demonstrate that the Theory of Characteristic Modes can be used to perform a systematic design of different types of antennas.
Abstract: The objective of this paper is to summarize the work that has been developed by the authors for the last several years, in order to demonstrate that the Theory of Characteristic Modes can be used to perform a systematic design of different types of antennas. Characteristic modes are real current modes that can be computed numerically for conducting bodies of arbitrary shape. Since characteristic modes form a set of orthogonal functions, they can be used to expand the total current on the surface of the body. However, this paper shows that what makes characteristic modes really attractive for antenna design is the physical insight they bring into the radiating phenomena taking place in the antenna. The resonance frequency of modes, as well as their radiating behavior, can be determined from the information provided by the eigenvalues associated with the characteristic modes. Moreover, by studying the current distribution of modes, an optimum feeding arrangement can be found in order to obtain the desired radiating behavior.

565 citations

Journal ArticleDOI
TL;DR: The planar monopole antenna is shown to provide extremely wideband impedance characteristics and the radiation performance is also shown to be acceptable over a wide frequency range.
Abstract: The planar monopole antenna is shown to provide extremely wideband impedance characteristics. Recently, many techniques to tailor and optimize the impedance bandwidth of these antennas have been investigated. These include the use of bevels, slots and shorting posts. These antennas are becoming popular, and have been proposed for modern and future wideband wireless applications. The radiation performance is also shown to be acceptable over a wide frequency range.

382 citations

Journal ArticleDOI
TL;DR: The planar inverted cone antenna (PICA) as mentioned in this paper provides ultrawideband (UWB) performance with a radiation pattern similar to monopole disk antennas, but is smaller in size.
Abstract: A new antenna, the planar inverted cone antenna (PICA), provides ultrawideband (UWB) performance with a radiation pattern similar to monopole disk antennas , but is smaller in size. Extensive simulations and experiments demonstrate that the PICA antenna provides more than a 10:1 impedance bandwidth (for VSWR<2) and supports a monopole type omnidirectional pattern over 4:1 bandwidth. A second version of the PICA with two circular holes changes the current flow on the metal disk and extends the high end of the operating frequency range, improving the pattern bandwidth to 7:1.

319 citations

Journal ArticleDOI
TL;DR: In this paper, a printed circular disc monopole antenna for ultra-wideband applications is presented, and the parameters which affect the performance of the antenna are investigated. Good agreement is achieved between simulation and experiment.
Abstract: A novel and simple design of a printed circular disc monopole antenna for ultra-wideband applications is presented. The parameters which affect the performance of the antenna are investigated. Good agreement is achieved between simulation and experiment.

314 citations