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.

DEBATOSH GUHA

Radio Physics and Electronics

M I PASHA

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.

&nbsp;

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.

&nbsp;

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

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

IEEE Transactions on Antennas and Propagation

A new approach based on the incorporation of Zshaped defected ground structure (DGS) in microstrip antenna (MSA) for improving impedance matching and cross polarization (XP) performances is proposed in this paper. Through detail analysis of the surface current densities, and input impedance, the proposed DGS is integrated into a rectangular MSA (RMSA) to realize flat relative XP reduction of 22 dB in the H-plane around broadside angular range of ±60°. Further, an equivalent circuit model (ECM) for the proposed antenna is introduced by considering the mutual coupling in between the DGS and patch and the model is verified using circuit-system-EM cosimulation software, Advanced Design System (ADS). A prototype has been fabricated and tested for the validation of simulated results and it shows good agreement with each other. The antenna operates over 2.32-2.58 GHz with good far-field radiation characteristics and a peak gain of 2.8 dBi at the resonating frequency 2.4 GHz. Hence, the proposed design can be useful for the IEEE 802.11b applications. © 2019 RADIOENGINEERING.

Fulltext

Radioengineering

Defected ground structure toward cross polarization reduction of microstrip patch antenna with improved impedance matching

A shaped defected ground structure (DGS) that is asymmetric in a specific radiating plane of a microstrip element has been explored with a view to addressing the cross-polarization (XP) issues. The asymmetric configuration has been conceived from an insight of the inherent asymmetry of the modal fields underneath a probe-fed microstrip patch and has been experimentally demonstrated as the best possible design compared to its predecessors in terms of the reduction in XP fields, angular span of suppression around boresight, and the space occupied by the defects. Different orientations of the defects with reference to the patches of different aspect ratio values have been thoroughly examined. More than 28-dB isolation between co-pol and cross-pol has been achieved over 190° angular range, which is indeed 140° more if compared with a conventional ground plane. Its superior characteristics with respect to the earlier designs have also been documented. © 2016 IEEE.

Asymmetric Geometry of Defected Ground Structure for Rectangular Microstrip: A New Approach to Reduce its Cross-Polarized Fields

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.

IEEE Antennas and Wireless Propagation Letters

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

A new method of suppressing cross-polarized (XP) radiation using resonant-type defected ground structure (R-DGS) on microstrip antenna has been proposed in this communication. A linearly shaped full wavelength R-DGS has been proposed and experimentally verified for different microstrip geometries. The design is supported by thorough investigations on the physical interaction between R-DGS and XP generating fields. Unlike previously explored nonresonant-type defects, this new approach is independent of patch geometry. A consistent suppression of the H-plane XP fields well below $- 30\,\hbox{dB}$ for different patch geometries has been experimentally demonstrated. © 1963-2012 IEEE.

Reduction in cross-polarized radiation of microstrip patches using geometry-independent resonant-type defected ground structure (DGS)

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.

IET Microwaves, Antennas and Propagation

Defected ground structure (DGS)-integrated rectangular microstrip patch for improved polarisation purity with wide impedance bandwidth

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)

Journal	Data powered by TypesetIEEE Transactions on Antennas and Propagation
Publisher	Data powered by TypesetInstitute of Electrical and Electronics Engineers Inc.
ISSN	0018-926X
Open Access	No