Lectura Tesi Doctoral Lu Wang
Tesis Jorge Mario Garzón Rey 28.03.2019 Tesis  - 

Difusió de les dades de la Lectura de la Tesi Doctoral de : Lu Wang
Directors: Carles Ferrer Ramis i Marta Prim Sabrià
Data i hora lectura: 12/04/2019 a les 11:00h
Lloc lectura: Sala de Graus de l’Escola d’Enginyeria – Edifici Q
Programa de Doctorat: Enginyeria Electrònica i de Telecomunicació
Departament on està inscrita la tesi: Departament de Microelectrònica i
Sistemes Electrònics

In recent years, using indwelling wireless sensor nodes to collect and transmit essential bioclimatic data  from  the  reticuloruminalchamber  is  gaining  a  global  recognition  in  cattle  management. Benefits  of  these  devices,  usually  referred  to  as  ruminal  (sensing)  boluses,  include  real-time supervisions  of  rumen  stability,  loss  prevention,  and  improved  animal  welfare.  As  the  principal export party of global dairy products, Europe has been pioneering in the research and development of ruminal boluses, mostly working at the license-free industrial, scientific, and medical radio band of 433.05 MHz—434.79 MHz. Meanwhile, the increasing need to apply adequate ruminal boluses to monitor the health status of small ruminants, such as sheep and goats, is bringing new challenges to  researchers.  In  consideration  of  the  much  smaller  body  size  compared  to  cows,  a  notable downsizing  of  device  form-factor  is  indispensable.  However,  this  would  affect  not  only  the radiation  efficiency  but  also  the  shelf  life  of  the  small  ruminal  boluses,  since  both  the  radio component and the power unit would benefit from abundant space. For devices used in wireless body area networks, power consumption is closely related to system configurations in view of the wireless  channel:  not  only  the  radiation  elements,  but  also  the  characteristics  of  the  radio transmission channel. Unfortunately, very few research efforts have been dedicated to the wireless channel of ruminal boluses for small ruminants. 
This doctoral thesis focused on the search of a radio solution for ruminal boluses targeted on small ruminants, which could balance the restrictions in device dimension and performance. This radio solution  consists  of  the  implementation  of  a  small  antenna  that  could  fit  for  a  compact  ruminal bolus  working  at  433  MHz,  and  the  characterization  of  the  in-to-out  body  radio  transmission channel between a small ruminal bolus and an on-bodyreceiver. A small spiral antenna was devised for  integration  into  a  ruminal  bolus  for  small  ruminants,  taking  into  consideration  of  the  other encapsulated  components  and  mediums,  as  well  as  the  in-body  environment  where  the  ruminal bolus  resides.  To  investigate  the  radio  link  between  the  spiral  antenna  and  a  reference  receiver, theoretical path loss models were developed, by means of both laboratory measurement in a tissue-simulating liquid and numerical analysis with 3-dimensional computational electromagnetics tools. Link viability was verified on a system level through link budget analysis, utilizing the theoretical path loss models. Beyond the theoretical channel studies, the actual radio transmission channel also exhibits time-varying features, some ofwhich are aligned with biological behaviors of the ruminant animals. On-site studies were therefore carried out with a rumen-cannulated animal in a barn. Series of in vivo measurement campaigns were arranged to investigate the radio channel’s characteristics in  the  authentic  scenarios.  A  diurnal  path  loss  pattern  was  developed  through  continuous observations based on a prototype of the small bolus and an on-body receiver. Variances of path loss in the radio channel across the day were demonstrated and associated with ruminal digestive statuses. A power-reduction plan was then proposed combining the diurnal path loss pattern to the existing power profile of the small ruminal bolus.
Investigador de contacte: Lu Wang  
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Departament de Microelectrònica i Sistemes Electrònics
Carrer de les Sitges
Escola d'Enginyeria (Edifici Q)
Universitat Autònoma de Barcelona
08193 - Bellaterra - Cerdanyola del Vallès (Barcelona)



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