Title: Electromechanical design and testing of smart antennas based on the use of artificial muscles

Introduction

Wireless communications systems are continuing to grow at an exponential rate, driven by public demand for information, business services, social networking and community activities, and enabled by the continual development of new techniques and decreasing hardware costs. The quality and accessibility of such communications systems are now pivotal to economic and social well-being.  Efficient usage of the spectrum is becoming increasingly important as greater interference between users is increasingly limits communication quality. Smart antennas allow users to share the spectrum better and to optimize capacity efficiency. They can suppress interference at the expense of extra complexity at the terminals, and no other technology can offer usage of the shared spectrum as efficiently. Consequently the research field is of international significance and new knowledge and technology has large potential for impact, both scientifically and economically. 

The key challenge addressed in this project is to develop a deformable electromechanical system suitable for antenna movement. For complex deformations (surfaces, etc.), the strategy is to use distributed actuators and position sensors embedded to make a deformable mechanical support. In a final rendition of such a system, therefore, structure, actuation, and sensing will be completely integrated in one thin and simple layer.

Technology

Technologies relevant for the proposed project are briefly summarized in the following paragraph.

Electro-Active Polymers (EAPs)

Promising recent developments in materials science and processing have enabled the efforts on the design and development of novel “artificial muscles”, using EAPs. These polymeric actuators are capable of sizable active strains (deformation of 10-200%) in response to electrical stimulus. They have interesting properties such as down-scalability, low cost, and be used both as actuators and sensors. There are two main categories: ionic and electronic EAPs. The ionic EAPs are activated by an electrically induced transport of ions or molecules and can therefore operate only within a surrounding electrolyte medium. The repeatability is generally poor. They are low voltage, viz., less than 10V. The electronic EAPs, on the other hand, are activated by an external electric field and Coulomb forces. They require typically a high voltage (up to 100V/mm) but are very simple and reliable. The main focus of this research study will be on dielectric elastomers, an electronic EAP that we was assessed to be the most suitable for antenna applications owing to its robustness. 

Shape Memory Alloys (SMAs)

These are metallic materials capable of recovering their original shape from an induced deformed configuration when the temperature is increased. This property relies on a crystalline phase transition (from “martensite” to “austenite”). The advantages are: reliability, simplicity, high force-to-mass ratio and the possibility to manufacture them in many shapes. Current drawbacks are low energy efficiency, small relative deformation (3-8%), and the difficulty in controlling them smoothly as dependent on environmental parameters.

Objectives

Focus of this project (involving different students in Menon’s laboratory) is to develop and test new electromechanical system capable to move miniaturized antennas. Dielectric elastomers and SMAs will be used as smart materials for actuation. Prototypes will be designed using CAD software (e.g. Solidworks), manufactured through rapid prototyping manufacturing systems (e.g. InVision 3D Printer), and tested using instruments available in the school of engineering at SFU. A controller will be developed in LABView. Tests will be performed in the SFU anechoic chamber. 

The coop student involved in this project will assist in some of the following tasks:

1. Improve reliability and system design of existing prototypes
2. Possibly conceive a new design with potentially better performance than existing systems
3. Assist the manufacturing phase 
4. Control the smart antenna
5. Design customized electronics
6. Test the developed systems and characterize their behavior

The student will work with the assistance of graduate students and Post doctorate fellows.

Required skills: 

Prerequisite: at least 100 credit hours.

NB: There is a strong possibility to be involved on the publication of a scientific article.