New Insight and Design Strategy to Optimize Cross-Polarized Radiations of Microstrip Patch Over Full Bandwidth by Probe Current Control
TL;DR: In this paper, a new design insight has been developed indicating possibilities of improved characteristics to be achieved in coax-fed microstrip antennas in terms of their polarization purity over the entire operating bandwidth.
Abstract: A new design insight has been developed indicating possibilities of improved characteristics to be achieved in coax-fed microstrip antennas in terms of their polarization purity over the entire operating bandwidth. The investigation involves multiple configurations and variations of rectangular and circular patches to ensure conclusive inference. Their impedance profile including the probe parameters has been identified as the controlling factor to the cross-polarized (XP) profile over the band. Subsequently, a well-defined co-relation between the input and XP radiations has been established which leads to a theoretical model. Based on this understanding, an engineered feed with controlled reactance has been conjectured and proposed to achieve improved XP profile with increased polarization purity. This new finding and conjecture have been experimentally verified using multiple sets of prototypes operating in C-band. It confirms the predicted improvement in polarization purity over the entire bandwidth with a maximum of about 7 dB at the band-edge without imposing any change or degradation in other characteristics.
Citations
More filters
[...]
TL;DR: In this paper, a bracketed stub-loaded single layer rectangular microstrip antenna structure was proposed to suppress cross-polar radiation of microstrip antennas due to its own dominant TM mode by achieving the uniformity of field distribution between lower and upper half-sections of a patch to suppress the effective orthogonal radiations from the patch corners.
Abstract: In this work, the modulation of the magnetic field locus beneath a microstrip antenna due to placement of feeding probe has been exploited to evolve a simplified single element single layer structure for improved impedance matching and radiation performance. Unlike the earlier investigations, the present study tackles the issue of cross-polar radiation of microstrip antenna due to its own dominant TM
10
mode by achieving the uniformity of field distribution between lower- and upper-half-sections of a patch to suppress the effective orthogonal radiations (cross-polar radiations) from the patch corners, without bothering the orthogonal and higher order resonances. Unlike the earlier approaches available in the literature, no slot or short has been made on the patch surface and in the ground plane to suppress cross-polar radiation, which makes the present structure extremely simple. The proposed bracketed stub-loaded single layer rectangular microstrip antenna structure exhibits high gain of 8 dBi with 27 dB of co-cross polar isolation in H plane. The two-element array constituted with same structure has also been examined and 10 dBi gain with >27 dB of co-cross polar isolation is obtained. The obtained results are theoretically justified with simulation and measurement.
4 citations
[...]
TL;DR: In this paper, a low-profile fractal antenna and its array for DSRC-band applications have been proposed, where a single element is a newly designed RF which is right-handed circularly polarized (RHCP) and derived from the Koch-snowflake 1st-iteration.
Abstract: In this paper, a low-profile fractal antenna and its array for DSRC-band applications have been proposed. The proposed single element is a newly designed fractal antenna which is right-handed circularly polarized (RHCP) and derived from the Koch-snowflake 1st-iteration. Moreover, a diagonal slot defect in the ground plane has been implemented for resonating the structure at the desired frequency and, to get a low cross-polarization over the operating frequency. The compact feed-network of the array is designed using a Wilkinson power-divider. A single element and a 4 × 1 antenna array are designed, prototyped, and verified. The antenna array is designed by a single-layer microstrip structure with a compact size of 151.70 × 43.50 mm2. According to the experimental results, the single element and the antenna array have S11 of −15.27 dB and −13.95 dB, and RHCP gain of 6.14 dBic and 11.98 dBic, respectively. Moreover, the computed radiation efficiencies of single element and array are 78.17% and 71.50%, respectively, while CP bandwidths of single element and array are 49.00 MHz and 58.00 MHz, respectively. The performance of the proposed RHCP antenna is suitable for the DSRC-band application.
2 citations
Cites methods from "New Insight and Design Strategy to ..."
[...]
[...]
TL;DR: In this paper, the significance of point-symmetric (PS) and non-point-smooth (NPS) geometries has been analyzed on the basis of Field Asymmetry Ratio (FAR), a new parameter defined to quantify the level of electric field asymmetry leading to XP radiation in any regular shaped microstrip patch antennas.
Abstract: This paper proposes a new quantitative parameter on identifying the primary factor for appropriate geometry selection of microstrip patch antennas dedicated to low cross-polarization (XP) applications. The significance of point-symmetric (PS) and non-point-symmetric (NPS) geometries has been analyzed on the basis of ‘Field Asymmetry Ratio’ (FAR), a new parameter, defined to quantify the level of electric field asymmetry leading to XP radiation in any regular shaped microstrip patch antennas. Based on this analysis, a conclusive inference has been established on the importance of point-symmetric patch geometry selections to achieve lower XP radiation. The 6-element circular cluster of shorting pins (CCSP) has been adopted as the XP suppression tool for S-band applications to validate the proposition. An XP suppression of approximately 9 dB at the boresight and 5 dB at ± 30°around the boresight in H-plane has been achieved for the square-shaped patch geometry.
2 citations
DOI•
[...]
TL;DR: In this paper , two or more floating metal cylinders are added to the probe-fed air-filled patch antennas to suppress the X-pol level of a typical XSP antenna.
Abstract: In this paper, H-plane cross-polarization (X-pol) radiation of probe-fed air filled patch antennas is substantially suppressed by introducing two or more floating metal cylinders underneath the patch, respectively. The X-pol is cancelled by the radiation of induced currents on metal cylinders. The working principle of the new X-pol suppressed patch (XSP) antenna is revealed by an approximate model. X-pol level of a typical XSP antenna can be suppressed to lower than -49 dB and -37 dB theoretically and experimentally for |θ| ≤ 60°. Two 1×8-element arrays constructed by XSP antennas and conventional patch antennas are prototyped and measured at scanning beam angles of θ = 0°, -40°, and -65°. The measured co-polarization gain of XSP antenna array is 0.7 and 0.9 dB larger than that of conventional patch array at θ = -40° and -65°, respectively. Besides, beam scanning angle with -30 dB X-pol level of XSP antenna array can be as wide as |θ|≤40° while that of conventional patch array is about |θ|≤12°. A wide band dual polarized XSP antenna is also presented. The measured maximum H-plane X-pol level can be lower than -29 dB within 8.7% fractional bandwidth.
2 citations
[...]
TL;DR: In this article, the fringing characteristics as well as modal fields of a suspended substrate circular patch are restricted to achieve wide circularly polarized (CP) bandwidth in a simple probe-fed microstrip antenna.
Abstract: Achieving wide circularly polarized (CP) bandwidth in a simple probe-fed microstrip antenna is essential for many practical applications. Existing knowledge guides exploring a thick substrate-based patch design. However, it suffers from two major inherent issues: squinting of beam and high cross-polarized (XP) radiation. No solution is available so far. This letter successfully addresses both issues by imposing restriction on the fringing characteristics as well as modal fields of a suspended substrate circular patch. Engineered ground plane bearing different strategic defects has been explored leading to about 50% correction in beam squinting with reference to antenna boresight and 2–8 dB reduction in a peak XP level. Realistic design, physical insight, and the experimental validation ensure its huge potential for practical applications.
1 citations
Cites background from "New Insight and Design Strategy to ..."
[...]
References
More filters
[...]
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.
239 citations
[...]
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.
88 citations
[...]
TL;DR: In this paper, a broadband probe-fed patch antenna with a W-shaped ground plane is presented, which is obtained by bending the conventional planar ground plane into an inverted V-shape, seen in the resonant direction of the patch antenna and then adding proper flanges at the two straight edges of the ground plane.
Abstract: A new design of a broadband probe-fed patch antenna with a W-shaped ground plane is presented. The W-shaped ground plane is obtained by bending the conventional planar ground plane into an inverted V-shape, seen in the resonant direction of the patch antenna and then adding proper flanges at the two straight edges of the bent ground plane. The proposed design is applicable to the patch antenna with a planar radiating patch with a thin air substrate. With the use of the proposed W-shaped ground plane, the required probe-pin length in the substrate remains small, although the effective substrate thickness is significantly increased, resulting in a much wider operating bandwidth. Also, by choosing proper dimensions of the W-shaped ground plane, the antenna gain for frequencies over the obtained wide bandwidth is enhanced, compared to the conventional patch antenna with a planar ground plane. In addition, the cross polarization is also reduced for the proposed design and the cross-polarization level (XPL) in the H-plane pattern can even be better than that of a conventional probe-fed patch antenna with a thin air substrate.
70 citations
"New Insight and Design Strategy to ..." refers background in this paper
[...]
[...]
TL;DR: In this article, the L-probe proximity-fed short-circuited quarter-wavelength patch antennas were used to obtain an impedance bandwidth of 39% and a gain of >7.0 dBi.
Abstract: Experimental results for L-probe proximity-fed short-circuited quarter-wavelength patch antennas are presented. Using a foam layer of thickness /spl sim/0.1/spl lambda//sub 0/, as a supported substrate, an impedance bandwidth of 39% and a gain of >7.0 dBi have been obtained. The far field patterns are stable across the passband.
67 citations
"New Insight and Design Strategy to ..." refers methods in this paper
[...]
[...]
TL;DR: In this paper, the crosspolarisation characteristics of coaxially fed microstrip patch antennas were studied using the cavity model, and numerical results showing the variation of cross-polarization level for different feed positions, substrate thicknesses, substrate permittivities and resonance frequencies were given when the antenna is excited in the TM 11 mode.
Abstract: The crosspolarisation characteristics of coaxially fed microstrip patch antennas are studied using the cavity model. Numerical results showing the variation of crosspolarisation level for different feed positions, substrate thicknesses, substrate permittivities and resonance frequencies are given when the antenna is excited in the TM 11 mode
66 citations
Related Papers (5)
[...]