Design and analysis of a single-feed arrangement of stacked rectangular patches is proposed, which is capable of providing circular polarization along with broadband performance. An antenna is designed on a glass epoxy FR-4 substrate with overall thickness of the structure less than 8 mm or 0.11 0 . The patch area of the corner truncated driven patch is marginally smaller than that of a parasitic patch to achieve improved performance. Both driven and stacked patches have narrow slots of unequal size in a way that their centers lie one over the other. The locations of the feed point, the amount of corner truncation of the driven patch, and the size of slots on both the driven and the stacked patches are optimized. Axial ratio bandwidth better than 11% and impedance bandwidth better than 27% may be achieved with the proposed geometry. Measured gain and axial ratio variations of the proposed antenna with frequency are compared to simulated results for better understanding. The measured E-and H-plane radiation patterns in the entire impedance bandwidth are identical in shape, and the direction of maximum radiations is normal to the patch geometry. In the entire axial ratio bandwidth range of the proposed antenna, the E-plane left circularly polarized patterns are nearly 15 dB higher than the corresponding right circularly polarized patterns.Index Terms-Axial ratio bandwidth, broadband, circularly polarized, radiation patterns, stacked microstrip antenna.

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The radiation performance of a compact gap‐coupled assembly of patches forming the geometry of elliptical patch antenna is simulated and tested using glass epoxy FR4 substrate material. This assembly is achieved by cutting a conventional elliptical patch antenna geometry into three independent patches through two narrow slits parallel to minor axis of elliptical patch. The two outer patches are identical in shape and size, and the central patch is excited through inset probe feed. Two outer patches are gap coupled to the center patch. This arrangement of antenna elements resonate at three frequencies 3.41, 3.62, and 5.54 GHz, respectively. The first two frequencies are closely spaced and gives an improved bandwidth (>10%). The radiation patterns of antenna at all three frequencies are almost identical in shape and nature. Details of the antenna design approach and experimental results are presented and discussed systematically. Measurements are in excellent agreement with simulation results which make the proposed structure promising for Wi‐Max applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:340–344, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25693

The radiation performance of a right isosceles triangular microstrip antenna (RITMA) having a narrow L slot is analyzed in free space. The designed antenna on glass epoxy FR‐4 substrate efficiently resonates at three different frequencies that lie in three frequency bands allotted by IEEE 802.16 working group for Wi‐Max systems. Two of these frequencies present excellent matching with inset feed network applied during this course of work. The bandwidth and directivity of proposed RITMA structure with ‘L’ shaped slot has also improved considerably in comparison to that of a simple RITMA geometry, although gain and efficiency of antenna are marginally decreased. The E and H plane co‐polar and cross‐polar radiation patterns of this antenna are also drawn. The measured and simulated results of this antenna are compared with that of a simple RITMA having identical dimensions to obtain important conclusions. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 3006–3010, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24781