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Journal ArticleDOI

Microstrip Patch With Grounded Spikes: A New Technique to Discriminate Orthogonal Mode for Reducing Cross-Polarized Radiations

01 Mar 2022-IEEE Transactions on Antennas and Propagation (IEEE Transactions on Antennas and Propagation)-Vol. 70, Iss: 3, pp 2295-2300
TL;DR: In this article , the surface current distribution in a rectangular microstrip patch is modified to reduce the H-plane cross-polarized (XP) radiations along with minimizing the backside radiation to some extent.
Abstract: This work explores an idea of modifying surface current distribution in a rectangular microstrip patch which contributes to reducing its H-plane cross-polarized (XP) radiations along with minimizing the backside radiation to some extent. A pair of grounded spikes has been strategically used and the physics behind its operation in weakening the XP generating TM02 mode has been thoroughly discussed. The vertical height of the spike is typically $\lambda $ /4 and a further investigation demonstrates shortening of its effective height by folding the same by 90°. A set of prototypes has been experimentally studied to ensure the predicted characteristics viz. the 12 dB consistent suppression of XP level over the whole range of elevation in H-plane and an average of 5–7 dB suppression in backside radiation. These achievements are also associated with more than 1 dB improvement in peak gain. The design is straightforward, low cost, and commercially viable. The nonplanar feature restricts its use only to those applications where antenna front is open or can accommodate the vertically extended or 90° bent spikes.
Citations
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OtherDOI
22 Nov 2022
TL;DR: In this article , a few defected ground structure-based approaches were discussed for cross-polarized (XP) sources in the microstrip antenna. But the main focus was on the feed, bandwidth, and radiation properties without any attention to the issue of crosspolarization.
Abstract: The microstrip antenna was conceptually realized in 1953 and tested as a practical radiator in the early 1970s. Till the early 1980s, the main focus was studying the feed, bandwidth, and radiation properties without any attention to the issue of cross-polarized (XP) fields. An investigation with lateral strip fed rectangular microstrip array first accounted for the orthogonal modes and considered them as XP source. Conventionally, the XP values are discussed across the principal radiation planes and predominantly in the H-plane. This is based on a notion that orthogonally polarized XP fields would be more aligned to the orthogonal plane or H-plane. This chapter discusses a few defected ground structure-based approaches. An isolated patch behaves as a partially open cavity with perfect electric walls at the top and at the bottom and magnetic walls surrounding the edges.
Journal ArticleDOI
TL;DR: In this article , the authors proposed an asymmetric defected ground structure (DGS) under the patch, which perturbs the TM http://www.w3.org/1998/Math/MathML" XMLns:xlink="http:// www.mw3-org/1999/xlink">02 mode.
Abstract: For cross-polarization (XP) reduction of microstrip antenna, it is proposed to use asymmetric defected ground structure (DGS) under the patch, which perturbs the TM 02 mode. Unlike conventional DGS, the proposed DGS reduces the XP without increasing the back radiation. A method of higher order modes and surrounding electric fields is used to explain the DGS. The feasibility and superiority of the proposed scheme are further verified by constructing H-plane linear 4-element arrays. The XP reduction and decoupling are achieved simultaneously, as supported by simulation and measurement.
Proceedings ArticleDOI
12 Dec 2022
TL;DR: In this paper , two coax-fed stub loaded microstrip antennas have been designed and studied in order to develop a planar improved polarization purity and low backside radiation patch compared to a non-planar configuration.
Abstract: Two coax-fed stub loaded microstrip antennas have been designed and studied here. The idea has been evolved in need of developing a planar improved polarization purity and low backside radiation patch compared to a non-planar configuration published in a recent article by the same author. The proposed structures show 10dB enhanced co-to-cross isolation. One of them shows low backside radiation. An X-band prototype has been fabricated and examined using an in-house measurement facility. 15dB isolation has been achieved in the H-plane following 25dB in the E-plane. Also, a trace of suppressing backside radiation has been identified.
OtherDOI
22 Nov 2022
TL;DR: In this paper , the authors discussed the resonant modes of interest in two most commonly used microstrip geometries which follow the principle of weakening the unwanted modes by DGS-based engineering.
Abstract: Different aspects of Defected Ground Structure (DGS) are mostly associated with microwave printed circuits and components. This chapter addresses its other application to microstrip antennas. It begins with a quick recap of the resonant modes of our interest in two most commonly used microstrip geometries which follow the principle of weakening the unwanted modes by DGS-based engineering. These include: rectangular patch and circular patch. The cross-polarized fields are not the desired output from a linearly polarized antenna. This limits its applications and hence the antenna researchers have been trying to explore several techniques to improve the polarization purity by controlling or suppressing this unwanted XP radiation. The arc- and the folded-DGS are quite successful in improving the cross-polarized isolation of the circular/elliptical and rectangular microstrips, respectively. One of the trends is to use different variations in DGS shapes with a view to reduce the size and increase in XP suppression.
Journal ArticleDOI
TL;DR: In this article , the authors proposed a way of mitigating near field issues based on theoretical analysis and proposed a simple strategic approach to reform the same for a rectangular patch, which achieved an overall XP discrimination by nearly 27dB from the perspective of 3D radiation scenario.
Abstract: This work addresses a concern of aperture coupled microstrip patch which is commonly overlooked. Such feeding configuration is typically believed to be immune to high cross-polar (XP) radiations, which indeed is a paradox. It actually offers considerably low XP only across H-plane, but concerning high XP over its diagonal or skewed planes (azimuth ≈ 45∘-70∘). An aperture feed, therefore, hardly reveals any advantageous feature in terms of the overall XP discrimination. Such a major shortcoming of aperture-fed microstrip, to the best of our knowledge, has been addressed and successfully resolved in this article for the first time. It explores a way of mitigating near field issues based on theoretical analysis and has proposed a simple strategic approach to reform the same for a rectangular patch. A representative design, theoretical justification, and experimental studies with an S-band prototype have been presented. XP suppression by 11dB has been experimentally achieved in the diagonal (D-) plane with no considerable changes in its H-or E-plane. That eventually attains an overall XP discrimination by nearly 27dB from the perspective of 3D radiation scenario. The proposed technique hardly affects the co-polar radiations or gain of its traditional design. Moreover, this is satisfactorily functioning for a 2 × 2 sub-array with a remarkable co-to-cross isolation by about 34dB over the entire radiation planes.
References
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Journal ArticleDOI
TL;DR: In this paper, the performance of printed antenna elements on substrates which may be electrically thick, as would be the case for printed antennas at millimeter wave frequencies, is investigated, and an optimization procedure for maximizing or minimizing power launched into surface waves from a multielement printed antenna array is presented.
Abstract: Calculated data are presented on the performance of printed antenna elements on substrates which may be electrically thick, as would be the case for printed antennas at millimeter wave frequencies. Printed dipoles and microstrip patch antennas on polytetrafluoroethylene (PTFE), quartz, and gallium arsenide substrates are considered. Data are given for resonant length, resonant resistance, bandwidth, loss due to surface waves, loss due to dielectric heating, and mutual coupling. Also presented is an optimization procedure for maximizing or minimizing power launched into surface waves from a multielement printed antenna array. The data are calculated by a moment method solution.

470 citations

Journal ArticleDOI
TL;DR: In this article, a defected ground structure (DGS) pattern is proposed to reduce the cross-polarized (XP) radiation of a microstrip patch antenna, which is simple and easy to etch on a commercial microstrip substrate.
Abstract: 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.

275 citations

Journal ArticleDOI
TL;DR: In this paper, a compact microstrip antenna design is demonstrated by embedding meandering slots in the antenna's ground plane, which can lead to a large antenna size reduction for a fixed frequency operation.
Abstract: A novel compact microstrip antenna design is demonstrated By embedding meandering slots in the antenna's ground plane, it is observed that the resonant frequency of the microstrip antenna is significantly lowered, which can lead to a large antenna size reduction for a fixed frequency operation In addition, enhanced impedance bandwidth and antenna gain are also observed for the proposed antenna Details of the proposed design and experimental results of the constructed prototypes are presented and discussed © 2001 John Wiley & Sons, Inc Microwave Opt Technol Lett 29: 95–97, 2001

152 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the effect of defected ground structure (DGS) on cross-polarized (XP) electric fields and associated radiations and found that the arc-DGS appears to be highly efficient in terms of suppressing XP fields.
Abstract: 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.

114 citations

Journal ArticleDOI
01 Jun 1998
TL;DR: In this article, the effects of various physical and electrical parameters of circular microstrip patch antennas on their radiation characteristics are investigated, such as the ground plane size, substrate permittivity, ground plane and substrate thicknesses and ground plane shape.
Abstract: The effects of various physical and electrical parameters of circular microstrip patch antennas on their radiation characteristics are investigated. These parameters include the ground plane size, substrate permittivity, ground plane and substrate thicknesses and the ground plane shape. The investigation is carried out for the first four modes. A numerical method based on the moment methods is utilised which computes surface currents on the conductors and field distributions on the dielectric substrate. To avoid excessive computation, circular patch and ground planes are selected to allow the use of moment method for bodies of revolution. Initially, a circular patch with a finite ground plane is studied. The ground plane is then deformed, above and below the substrate, to increase the gain or shape the radiation patterns. It is shown that the ground plane effects are significant and a wide range of radiation pattern shapes can be generated.

106 citations