Wideband Isotropic Antenna With Miniaturized Ground for Enhanced 3 dB Coverage Ratio

In this letter, a wideband three-dimensional (3-D) isotropic antenna is proposed with improved 3 dB coverage ratio. Based on the investigation about the effect of the metallic ground size on isotropic radiation, a compact sequential-phase feeding network made of lumped components with miniaturized ground is elaborately designed for wide operating bandwidth and enhanced 3 dB coverage ratio in 3-D space. In the measurement, the antenna prototype is with the size of 70 x 70 x 0.5 mm(3) (0.23 x 0.23 x 0.0017 lambda(3)(0)). The measured result shows that the proposed antenna provides the 6 dB gain variation fractional bandwidth of 4% and the 3 dB coverage ratio of more than 80%, leading to promising usage for wideband isotropic radiation applications.

Automated summary

This paper proposes a wideband three-dimensional isotropic antenna with improved 3 dB coverage ratio. By investigating the impact of metallic ground size on isotropic radiation, a compact sequential-phase feeding network made of lumped components with miniaturized ground is elaborately designed to achieve wide operating bandwidth and enhanced 3 dB coverage ratio in 3-D space. The measurement results demonstrate that the proposed antenna provides a 6 dB gain variation fractional bandwidth of 4% and a 3 dB coverage ratio of more than 80%, indicating promising potential for wideband isotropic radiation applications.