Bessel Beam Microwave Platform for Livestock and Carcase Surface Fat Depth Imaging

Summary

The project planned to run from October 2018 until November 2019 but the project was terminated by Meat & Livestock Australia due to research priorities.

This document provides a summary of work undertaken for MLA during by Lincoln Agritech between the dates 1 October 2018 – 26 November 2018. Note that there was a two-week shutdown from 29 October 2018, after which work resumed until the termination date.

 This project was undertaking the underpinning research and development of a prototype for the first application of an "on-the-hoof" body condition sensor. It planned to be a valuable stock management tool for production, livestock health, and nutrition, which would be developed in collaboration with our industry partners. Bessel beams which are a relatively new discovery, is a narrow, non-divergent beam of microwave radio waves, and are well-suited to sensing because of the consistent narrow beam. Further, the signals scattered from objects or layers provide information about their size and the material from which they are made. The research planned to extend knowledge of how Bessel beams behave, as well as how they can be used to provide high resolution data.

 For live animal surface fat depth assessment, and fat coverage in carcases, the project was to develop a sensor which would collect several tens of fat depth measurements from the flank of the passing animal, and exploit the following properties of Bessel beams: low power (safe), narrow (~30mm) central non-diffracting (somewhat parallel) beam, range of ~1 metre, scattering properties that are amenable to distinguishing fat layers.

The largest scattered signal will be from the skin surface and the next from the fat-to-muscle layer. The phase lags between transmission and these two dominant reflections will represent transmitter to skin and transmitter to muscle distances respectively. Spurious signals, such as from the outer wool profile of wet sheep or from multiple skin-muscle reflections, are expected to be easily distinguished; wool reflections will occur before the stronger skin reflection and secondary or multi¬path reflections will be strongly attenuated.

Lincoln Agritech had already completed the developed and proof of concept via simulation, design, and preliminary testing, the theoretical and practical basis for generating a range of Bessel beam geometries using a sparse circular patch array antenna.