# An Optimization Design of Bi-log Hybrid Antenna with Taguchi's Method for EMI Measurements
## 1 Introduction
For cost-effective antenna design, the challenge of optimization design needs to be overcome by achieving uniform radiation characteristics, stable AF, and polarization rejection in a wide frequency range. The successful optimal design with [PERSON]'s method [16] could be a potential approach for these achieving goals. The [PERSON] method has been adopted for effective optimization design in recent decades in industrial, scientific, and medical areas. Many scholars have conducted research with this method to optimize parameters of interest, such as for industrial manufacturing [17; 18], neural networks [19; 20; 21], and medical applications [22; 23; 24], and it also can be employed in other areas [25; 26; 27]. Notably, the [PERSON] method has consistently exhibited remarkable optimization capabilities. Transitioning from a traditional to an iterative process within [PERSON]'s method [16; 28] can establish it as a robust global optimization technique. Although [PERSON]'s method has found widespread adoption in a variety of presented kinds of literature as above, it provides limited applications, particularly in the field of electromagnetism [29; 30]. The [PERSON] method has found application in the design of UWB antennas [28], slot antennas [31], dual-band/polarization patch antennas [32], antenna arrays [33; 34; 35], and even bandpass filters [36]. However, within the realm of broadband EMI measurement antenna design, the utilization of [PERSON]'s method for antenna optimization has remained somewhat scarce. Despite the broad acceptance and implementation of [PERSON]'s method across diverse types of literature, its application in electromagnetic contexts has been somewhat constrained. This is especially notable in the realm of broadband EMI measurement antenna design, where the adoption of [PERSON]'s method for antenna optimization has been comparatively limited. However, in the realm of broadband EMI measurement antenna design, there have been relatively few instances where antennas have been crafted and fine-tuned through the application of [PERSON]'s methodology. This study proposes a significantly smaller and lighter broadband Bi-log hybrid antenna using a simple, fast, and accurate [PERSON]'s method to analyze the impedance match and miniaturization. Our optimization design process follows [PERSON]'s methodology, employing distinctive orthogonal arrays (OAs) to extract antenna parameters efficiently. Itgathers comprehensive data from a limited set of experimental parameters. This approach encompasses the optimization of both element length and relative spacing to achieve selected proportionality factors, while also mitigating variations in radiated performance due to dimensional discrepancies. The proposed antenna uses Numerical Electromagnetics Code (NEC2) and Computer Simulation Technology (CST) Microwave for simulation and design, respectively. The antenna performance fully satisfies the antenna qualification conditions proposed by the ANSI C63.4 standard [37]. The measured results correspond well with the simulated data. This antenna not only confirms the validity and precision of the optimal design methodology but also contributes to its high sensitivity in EMI testing applications, ensuring accurate measurement results.