Stably Polarized Wideband Circular Microstrip Antenna Excited in TM<sub>12</sub> Mode

This work presents a bandwidth enhanced high gain rectangular patch antenna operating under two similar spectrally close modes created from a TM 50 -like mode in the vicinity of another higher order mode of the patch. The patch is embedded with two wide slots and meandered linkages are used to maintain current continuity. The whole structure is studied using the theory of characteristic modes and the excitation of these higher order modes is controlled to enhance the bandwidth. One of the two similar modes is very weakly excited and does not affect the antenna's performance. The beam tilting at lower frequencies are compensated by properly choosing the capacitors as phase shifter elements on the meander linkages. The antenna size is miniaturized by properly choosing the dimensions of the meander linkages and the resonant length is reduced by λ/2 as compared to that of a conventional TM 50 mode supporting patch. The patch size becomes 3.35 Â 4.03λ/2 instead of 5 Â 5λ/2 (λ is the substrate wavelength). The coaxial probe fed structure exhibits a good performance of impedance bandwidth of 10.5% around the center frequency of 5.7 GHz with a gain variation 10-12 dBi, which appear to be better than other antennas of similar size. K E Y W O R D Sbeam tilting, enhanced bandwidth, high gain, higher order mode, meander lines, rectangular micro strip patch, theory of characteristic modes, wide slot.

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“…In reference 20, though the bandwidth is quite high and the size is small but the gain is significantly lower as compared to this work.…”

Section: Resultsmentioning

confidence: 99%