Projects:2017s2-275 Creating Microwave Antennas with 3D Printing

Supervisor

Dr. Withawat Withayachumnankul, Prof. Christophe Fumeaux

Project Team

Chengjun Zheng, Runni Yu

Introduction

Motivation

With the development of communication technology, information exchanging has become an important issue of the research in the contemporary society. As a part of information exchanging, antennas are indispensable elements of any wireless communication system. It is prevalent for antennas as they are such useful in mobile phones, tablets and many advanced technologies. It is significant that antennas make our life easier, it could reduce the number of wires and cables. Moreover, without increasing the complexity of the system, smart antenna can expand the capacity, decrease the error rate and make coverage area larger. However, there are many research challenges remain, either to make them smaller, flexible, adjustable, or multi-functional. Meanwhile, 3D printing is an emerging technology, it provides a light, cheap way to build up things. For this project, it is interesting to combine the 3D printing technology with the microwave antenna to create a Dielectric Resonator Antenna with superior performance.

Aim

• Design and fabricate a new microwave antenna with 3D printing technology
• Designed antenna should work at 5 GHz
• The bandwidth of antenna should be between 10% and 50%

Dielectric Resonator Antenna(DRA)

The dielectric resonator antenna is a kind of radio antenna, which is mainly used for microwave frequency and higher frequency. It is composed of various shapes of ceramic material. The dielectric resonator is installed on the metal surface which is the ground plane. One advantage of dielectric resonator antennas is their lack of metal parts, which become dissipative at high frequencies. Therefore, these antennas have lower loss and higher efficiency than metal antennas at high microwave and millimetre wave frequencies.The Dielectric Resonators has been widely used in the design of miniature microwave filters and oscillators. In addition to its small size characteristics, DRA also has wider bandwidth and zero conductor loss. These characteristics make them particularly suitable for working at high frequencies, so as to meet the requirements of modern communication systems. The characteristics of DRA depend on its near-field distribution, such as its working mode.

Material for Dielectric Resonator

The most popular materials used in 3D printer are Acrylonitrile Butadiene Styrene (ABS) and Polylactic Acid (PLA). Moreover, all thermoplastic materials perform well in mass fabrication. However, they are not optimized for high frequency applications, and their dielectric properties are usually poor. The dielectric properties of standard plastics are usually given at 50 Hz, which does not give any performance proof at frequencies of 1 GHz or higher. Therefore, those standard thermoplastic materials cannot be used for the fabrication of DRA. In this project, the material for the dielectric resonator uses the premix PREPERM L1000HF which has permittivity 10. For PREPERM, the dielectric measurement data can even reach 250GHz. The experimental results show that the dielectric constant of PREPURM is stable and does not depend on the frequency level. Furthermore, the chemical structure of the material has an effect on the dielectric properties. Polar materials such as polyamide and polyester show higher dielectric loss than their non-polar counterparts. In addition, additives and water sensitivity can significantly change dielectric properties in different materials. The required permittivity of Dielectric Resonator is 8, but the permittivity 10 will be used for fabrication due to the fact that the 3D printed model will contain the air bubbles which will reduce the material permittivity to about 8.