Defected ground structure (DGS)-integrated rectangular microstrip patch has been experimentally investigated with an aim to improve polarisation purity in radiated fields. Width to length ratio (aspect ratio) of a patch attributes different characteristic features. Therefore present experimental studies have been executed for four different aspect ratio values like 1.6, 1.3, 1.0 and 0.8. Folded defects have been employed in H-plane. Possibility of achieving high polarisation purity (over 25 dB isolation between co- to cross-polarised fields) with improved impedance bandwidth has been demonstrated. The variation in XP fields as a function of the patch aspect ratio has been investigated and a strong physical insight into the modal fields with and without DGS has been developed. © The Institution of Engineering and Technology 2014.

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

IET Microwaves, Antennas and Propagation

Truncated-corner probe-fed (TCPF) patches are popular for their simple design that provides circularly polarized (CP) radiation with a very low axial ratio (AR). For a thin substrate (∼ 0.026λ), this antenna provides approximately 0.3% CP bandwidth (BW) (AR 3 dB along with S11 -10 dB). However, as the substrate thickness is increased for enhancing the matching BW, an offset among the frequencies featured with minimum AR and optimum S11 is observed. This degrades the effective BW, with an overlapping of both S11 &amp;lt;-10 dB and AR &amp;lt; 3 dB. © 1990-2011 IEEE.

IEEE Antennas and Propagation Magazine

Application-Friendly Improved Designs of Single-Fed Circularly Polarized Microstrip Antenna [Antenna Applications Corner]

This paper presents a symmetric patterned defect introduced on the ground plane of a 2× 2 array of rectangular microstrip patches. A C-band design has been examined by removing nearly 50% metal from ground cladding which promises about 10 dB improvement in co-to-cross-polarized (XP) isolation over ±50° angular range around the boresight compared to a conventional geometry. A single unit has also been repeated in S-band for experimental studies indicating close corroboration with the simulated predictions. © 2018 IEEE.

2018 IEEE Indian Conference on Antennas and Propagation, InCAP 2018

Specially Designed Microstrip Array with Patterned Ground Plane for Improved Characteristics

This communication proposes a new idea of compensating spurious radiations usually occurring from the sharp transitions at patch to feed and feed to impedance transformer junctions which result in added cross-polarized (XP) fields in planar microstrip-fed patches. A strategic design and deployment of defected ground structure (DGS) have been explored successfully as a potential means to resolve such long-standing radiation issues. The quantum of radiations from the feed has been theoretically estimated. These along with the main source of XP fields (higher order mode) have been addressed by introducing a composite type of DGS. The experimental validation executed at the C-band establishes this simple low-cost solution with a promise of 10 to 14 dB improvement in the H-plane XP fields. It is also ensured that the proposed technique is equally useful in realizing dual-fed dual-polarized configurations without affecting the primary radiation and antenna performance. © 1963-2012 IEEE.

IEEE Transactions on Antennas and Propagation

Simultaneous Compensation of Microstrip Feed and Patch by Defected Ground Structure for Reduced Cross-Polarized Radiation

Defected ground structure (DGS) integrated microstrip array has been explored and demonstrated here for the first time with the primary aim of achieving improved polarization purity. A shaped DGS with variable configuration has been conceived and designed for rectangular arrays. This unleashes new potential of DGS design by reducing the etched out area by 50%. A 2 × 2 DGS integrated array has been designed and experimentally demonstrated in X-band showing 12 dB improvement in the isolation between the copol and cross-pol radiations. © 2002-2011 IEEE.

IEEE Antennas and Wireless Propagation Letters

Defected ground structure integrated microstrip array antenna for improved radiation properties

A symmetric as well as nonproximal defected ground structure has been conceived for a square microstrip patch to achieve high co- to cross-polarized (XP) isolation over the principal radiation planes. This design does not follow the thumb rule of earlier works where the defect was deployed either underneath or in close proximity to the patch boundary. The proposed configuration, therefore, appears to be ideal for some specific applications, such as dual-polarized or circularly polarized patches with improved polarization purity. A representative design in C-band has been discussed, leading to the proof of concept. Experimental verification confirms up to 8-10 dB improvement in XP level, particularly in the H-plane. © 2002-2011 IEEE.

Microstrip Patch with Nonproximal Symmetric Defected Ground Structure (DGS) for Improved Cross-Polarization Properties over Principal Radiation Planes

The input impedance of a rectangular microstrip patch with a variable air gap has been studied theoretically and experimentally. Unlike earlier investigations, the influence of the air gap along with the varying patch width in changing the patch impedance is thoroughly examined. An efficient computer aided design formulation is developed and used for this study, and the computed results are experimentally verified. Superiority of the present theory compared to some earlier models is also indicated. © The Institution of Engineering and Technology 2009.

Input impedance of probe-fed rectangular microstrip antennas with variable air gap and varying aspect ratio

Application of defected ground structure (DGS) to suppress cross-polarized (XP) radiation from a microstrip patch antenna has been reinvestigated using a new DGS geometry for much improved characteristics. Arc-shaped defect has been used in pair, symmetrically located under a circular patch. A number of optimization parameters have been examined using simulated results, leading to a design indicating improved XP behavior. A set of identical prototypes, with and without DGS, have been experimentally studied. The presence of the DGS shows as much as 30 dB isolation of the XP level from its peak radiation, and that compared to an identical patch without DGS indicates an improvement by as much as 12 dB. The relative suppression in XP values are found to be around 7-12 dB over ±75° elevation around the boresight of the patch. © 2010 IEEE.

Improved cross-polarization characteristics of circular microstrip antenna employing arc-shaped defected ground structure (DGS)

Use of a simple ring-shaped defected ground structure is experimentally demonstrated to suppress considerable mutual coupling between two cylindrical dielectric resonators. About 5dB suppression has been obtained near the operating frequency around 3.3GHz. The radiation characteristics with and without defect in the ground plane are also reported. © 2008 The Institution of Engineering and Technology.

Fulltext

Electronics Letters

Defected ground structure to reduce mutual coupling between cylindrical dielectric resonator antennas

A defected ground structure (DGS) is proposed to reduce the cross-polarized (XP) radiation of a microstrip patch antenna. The proposed DGS pattern is simple and easy to etch on a commercial microstrip substrate. This will only reduce the XP radiation field without affecting the dominant mode input impedance and co-polarized radiation patterns of a conventional antenna. The new concept has been examined and verified experimentally for a particular DGS pattern employing a circular patch as the radiator. Both simulation and experimental results are presented. © 2005 IEEE.

Journal	IET Microwaves, Antennas and Propagation
Publisher	Institution of Engineering and Technology
ISSN	1751-8725
Open Access	No