Design and Implementation of a Non-Uniform Conical Log-Spiral Antenna Using Additive Manufacturing

• Grant number: 25/02139-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2025
• End date: June 30, 2026
• Field of knowledge: Engineering - Electrical Engineering - Telecommunications
• Principal Investigator: Rafael Abrantes Penchel
• Grantee: Fernando Masato Tanaka
• Host Institution: Faculdade de Engenharia. Universidade Estadual Paulista (UNESP). Campus São João da Boa Vista. São João da Boa Vista , SP, Brazil

Abstract

This project aims to develop, optimize, and characterize a conical logarithmic spiral antenna based on a generalized helical model. Unlike conventional approaches, the antenna geometry will be described by a set of parametric equations that allow gradual variations in the coil diameter, spacing between turns, and conductor cross-section. This innovative approach seeks to improve antenna efficiency, optimize broadband response, and facilitate fabrication.The first stage of the project involves the numerical modeling of the antenna using Ansys HFSS (High Frequency Structure Simulator). The generalized model will enable a detailed analysis of the influence of geometric parameters on directivity, reflection coefficient, and radiation patterns. Optimization will be performed for operation in the X-band (8-12 GHz).Fabrication will be carried out using additive manufacturing (Fused Filament Fabrication - FFF) with high-strength polymers such as PETG and Nylon. The conductor will be printed with a variable cross-section, following the parametric modeling, and subsequently coated with a conductive paint based on aluminum and copper. This innovative technique aims to enable the production of complex geometries with precision and low cost.Experimental characterization will be conducted in an anechoic chamber using a Vector Network Analyzer (VNA) N9918B FieldFox (up to 26 GHz) to measure S-parameters, along with tests for gain, directivity, and radiation patterns.