Dual band dual polarized modified circular microstrip antenna

Abstract

A variation of circular microstrip antenna, 270° sectoral microstrip antenna on thinner substrate is discussed. It has an additional resonant mode whose resonance frequency lies below the fundamental mode resonance frequency of the equivalent circular microstrip antenna. Further, the variations of sectoral microstrip antenna, 300° and 330° sectoral microstrip antennas on thinner substrates are discussed. With variation in sectoral angle, the separations between various resonant modes of sectoral patch changes, which results in dual and triple frequency response with variable frequency ratios and dual polarizations. Further dual band rectangular slot cut variations of 270° and 300° Sectoral microstrip antennas on thinner substrate, are proposed. The rectangular slot tunes the resonance frequency of second order mode of the patch with respect to fundamental patch mode to yield dual frequency response. The rectangular slot yields dual frequencies with variable frequency ratios from 1.6 to 0.9. The proposed antennas were designed in 1000 MHz frequency band and there dual band designs yields bandwidth of 2% in respective frequency bands.