Baseball-shaped circular microstrip antennas for miniaturization

This paper presents the design of linear and circular polarization baseball-shaped circular microstrip antenna (BCMA) with 3-dimensional structure using perturbation effect to reduce its size, which runs at 1.575 GHz frequency bandwidth. As a result, the size of linear polarized antenna could be reduced up to 23.7% in patch diameter and 41.8% in its area. Linear polarized antenna has -26.04 dB of return loss, 69 MHz(4.38%) of -10 dB bandwidth, 4.51 dBd of gain, and its -3 dB beamwidth are 99deg in E-plane, 83deg in H-plane. Circular polarized antenna has -17.43 dB of return loss, 113.7 MHz (7.2%) of -10 dB bandwidth, 2 dBd of gain, 2 dB of axial ratio and its -3 dB beamwidth are 87deg, 86deg x-axis polarized, 80deg, 84deg y-axis polarized. It has 82 mm of diameter, which is 28.5% reduced compared to the linear polarized CMPA. Therefore, in this paper we verified that baseball-shaped 3-dimensional structure of circular microstrip patch antenna applied with perturbation effect is appropriate for miniaturization