Design of Hemispherical Patch Antenna With Conformally Spaced Log-Periodic Elements for Multi-Directional and Multi-Band Operation

In this paper, the design of an Ultra Wide Band (UWB) hemispherical antenna with Log-Periodic Elements (LPEs) capable of operating at multiple resonating frequencies lying in L, S, C, X, and Ku frequency bands is presented.The design consists of a complex structure of silver hemisphere with LPE mounted on an FR-4 substrate fed by a 50 Ω microstrip line.The dependency of the inclination of log-periodic elements mounted on the hemisphere is analyzed with parametric study.The proposed miniaturized antenna uses LPEs to obtain an impedance bandwidth of above 100% and a multidirectional radiation pattern.The measured results show that a wide operating band of 12.63 GHz (1.68 GHz-14.31GHz) (8.52 : 1) has been achieved with a multi-directional radiation pattern with a peak realized gain of 8.12 dBi.