An Optimization Design of Bi-log Hybrid Antenna with Taguchi’s Method for EMI Measurements

Abstract

This paper presents a comprehensive design approach for a biconical log-periodic dipole array (Bi-log) hybrid antenna optimized specifically for electromagnetic interference (EMI) measurements. The antenna’s elements, scaling function, feed structure, balanced-to-unbalanced (Balun) geometry, and key parameter selection are carefully considered to achieve enhanced broadband testing capabilities. The proposed compact Bi-log hybrid antenna is optimized using Taguchi’s method within the frequency range of 30 MHz to 6 GHz. The optimization focuses on the discontinuity of the antenna factor (AF), incorporating miniaturized elements. The dimensions of the proposed antenna are minimized, with a length of 95 cm, width of 148.5 cm, height of 60 cm, and weight of 2.5 kg. Simulation results and experimental validations demonstrate its efficacy through comparison. Optimization results indicate that the voltage standing wave ratio VSWR < 2 (with 5 dB attenuator) and symmetry < ±0.5 dB also meet the regulatory standards according to ANSI C 63.4. This makes the proposed antenna suitable for use in various types of semi-anechoic chambers.