A 3-D printed UWB microwave imaging antenna

Abstract

Microwave imaging utilizes low-power Near-field electromagnetic fields at microwave frequencies to detect the internal structure of an object [1-2]. Microwave-based malignant tissue detection methods have been intensively studied as a potential complementary screening method in recent years. These methods are based on differences in permittivity and permeability of the malignant and benign tissue within the microwave frequency ranges. The microwave scanning system is advantageous because of its high sensitivity to detect the tumorous areas, as well as it is cost-efficient, non-ionizing/ non-invasive, thus offering comfortable screening/testing for patients. Sending and receiving both low and high-frequency signals to the material is necessary to execute this task properly with possible multiple-frequency band interferential stimulations. Sufficient resolution through the thickness is crucial in biomedical applications to detect small objects of concern.

Parameters such as the frequency of microwave signals, the design, and the material of the antenna are the most important issues to consider in constructing an accurate and easy-to-use system for microwave-based biomedical sensing [2]. The proposed antenna yields advantages such as compactness in size, ease of fabrication, wider impedance bandwidth, simple design, and good performance. In the proposed work, the effect of the substrate material and design is analyzed.

Novel conductive material 3D-printed on a Polylactic acid (PLA) substrate were produced. The proposed microwave antenna was evaluated using Ansys HFSS. The parameters are designed to ensure optimum radiation efficiency. Within the scope of this study, a microwave imaging antenna prototype was developed and tested. The UWB characteristics were observed as S₁₁< -10dB for a frequency of 3 GHz to 15GHz. As well, the radiation patterns obtained were omnidirectional in H-plane and bidirectional in E-plane.