Microstrip patches and dielectric resonators (DRs) are two low-profile variants of modern microwave and wireless antennas. However, the DR antenna (DRA) is relatively new and still passing through the stages of development. Both variants are quite similar in terms of performance and characteristics. This article focuses on a meaningful comparative study where we have considered all commonly used feed mechanisms such as coaxial probe, microstrip line, and rectangular aperture for both antennas operating near the same frequency. Circular geometry, i.e., cylindrical DRA (CDRA) and circular microstrip patch antenna (CMPA), have been chosen, and a systematic investigation based on thorough experiments has been executed. Multiple sets of prototypes have been fabricated and measured at 4 GHz. All available data have been furnished and compared, indicating relative advantages and disadvantages. This comparative study should provide qualitative and quantitative instructions to a designer for choosing the right element and corresponding feed based on design requirement and feasibility. © 2016 IEEE.

DEBATOSH GUHA

Radio Physics and Electronics

C KUMAR

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Microstrip Patch versus Dielectric Resonator Antenna Bearing All Commonly Used Feeds: An experimental study to choose the right element.

IEEE Antennas and Propagation Magazine

A technique of dielectric perturbation in a dielectric resonator antenna (DRA) has been explored with specific application to filter out higher resonating modes causing unwanted radiations. This is especially conceived and conjectured for microstrip-fed cylindrical DRA (CDRA). Creating a protruded cavity in it filled with dielectric material of varying \varepsilon-{r} is the primary mechanism. Effect of such perturbation has been experimentally demonstrated establishing air ( \varepsilon-{r}=1) as the simplest and most promising one for a specific application in weakening \text {HEM}-{21\delta} mode in it, recently identified as the source of cross-polar radiations. Physical insight into this new technique is also clarified. As much as 10 dB reduction in the principal plane cross-polarized values without affecting the primary radiations has been documented. © 2002-2011 IEEE.

IEEE Antennas and Wireless Propagation Letters

New Technique of Dielectric Perturbation in Dielectric Resonator Antenna to Control the Higher Mode Leading to Reduced Cross-Polar Radiations

Controlling higher order modes up to third harmonic of the fundamental operating frequency in a microstrip line-fed patch antenna has been successfully demonstrated. Harmonic rejection in the antenna has been achieved at its feed level using highly compact design of defected ground structure (DGS). Rejection characteristics have been improved adding an open stub to the feed line. All possible higher order modes occurring in between the fundamental and the 3rd harmonic have been identified. Relative suppression of radiated fields with and without DGS-control has been quantitatively measured and effective control of harmonics has been experimentally ensured. The area occupied by the proposed DGS has been compared with earlier designs and over 40-90% reduction in size has been documented. © 2013 IEEE.

IEEE Transactions on Antennas and Propagation

Control of higher harmonics and their radiations in microstrip antennas using compact defected ground structures

A resonant mode (HEM 12δ), other than those (HEM 11δ and TM 01δ) conventionally excited and used in a cylindrical dielectric resonator antenna (CDRA) has been examined with a view for using it as another radiating mode with broadside radiation patterns. Excitation of the mode, being the most challenging aspect, has been discussed and resolved by employing an innovative technique. The proposed concept has been successfully verified and experimentally demonstrated for the first time. More than 8-dBi peak gain with excellent broadside radiation has been obtained from a prototype shaped from a commercially available low-loss dielectric material with relative permittivity 10. © 2006 IEEE.

Higher order mode excitation for high-gain broadside radiation from cylindrical dielectric resonator antennas

Experiments with probe-fed circular patches using conventional and defected ground planes flashed some interesting features relating to cross-polarized (XP) electric fields and associated radiations before the present authors. Those led to a series of new investigations for understanding the nature of XP fields and to deal with them using defected ground structure (DGS) for improved XP performance. In the first phase of investigation, the XP radiations of a probe-fed circular patch with conventional ground plane have been critically studied as a function of the radial probe location. Remarkably significant effect is experimentally demonstrated. New information about orthogonal resonant fields and its importance in designing an antenna is provided. In the second phase of investigation, limitations of dot-shaped DGS in reducing XP level are experimentally studied. As its improved variants, two new DGS geometries such as annular ring and circular arcs have been explored. The arc-DGS appears to be highly efficient in terms of suppressing XP fields. Suppression by 10-12 dB has been experimentally demonstrated. Each design has been experimented in both C- and X-bands to earn confidence on the measured data. © 2006 IEEE.

Nature of cross-polarized radiations from probe-fed circular microstrip antennas and their suppression using different geometries of defected ground structure (DGS)

Microstrip and Printed Antennas: New Trends, Techniques and Applications

Preface

An improved analytical model is presented for calculating the resonant frequency of circular microstrip antennas with and without air gaps. Unlike the previous models, the present one is widely applicable to all patch diameters - from very large to very small compared to the height of the dielectric medium below the patch and also to the substrates covering the entire range of dielectric constants. The computed results for different antenna dimensions and modes of resonance are compared with the experimental values.

Journal	Data powered by TypesetIEEE Antennas and Propagation Magazine
Publisher	Data powered by TypesetIEEE Computer Society
ISSN	1045-9243
Open Access	No