Wireless Communications

Antennas and Propagation for On-, Off- and In-Body Communications based on UWB (Ultra WideBand) Technology

Research grant by DFG (German Research Foundation) research area UKoLoS

Timeframe: 01.10.2010 - 30.09.2012

DFG MA 4981/2-1:

Introduction:

Nowadays, portable multimedia applications as well as medical systems use wireless links in order to communicate data through or along the human body. Using the example of medical applications this includes not only body worn devices, but also implants to monitor the state of health of handicapped persons in their home environment (ambient assisted living). In the context of our aging society an increasingly important aspect for the care of elderly people is the transmission of crucial vital signs, e.g. blood heat, metabolism, circulation, heart beat rate and breathing from their home environment to medical care centers. Due to this fact, the reliability of such body centric systems is essential.

 

 


Key problem in terms of body centric antenna design:

The ongoing miniaturization of such systems makes the users body to become an important part affecting the systems performance. The body-system interaction depends on the short distance between the antenna and the human body. Concomitant with this fact an overlap of the antenna characteristic HTX/HRX and the channel characteristic HCh takes place, so standardized antenna design methods are limited in their applicability.

ban_1

The objective of this research project is the derivation of a standardized methodology to characterize body centric antennas as well as the associated channels. A basic problem-solving approach has been developed by our group in the DFG priority program SSP 1202 UKoLoS  which includes an approach to separate the antenna and channel characteristics. Essential elements of this theory are far field models of basic body centric propagation scenarios which are based on the dominant related electromagnetic effects.

De-embedding approach for wireless body area networks:

The underlying theory is structured in two sections. The first part focuses on an in-body link i.e. the main propagation path of the electromagnetic wave leads through the tissue of the human body. Typical applications are medical implants like wireless endoscopy or RF breast cancer detection systems. The second part characterizes an on-body link. This means that the propagation path is defined along the body surface and the antenna is located in close proximity of the human body.

ban_2
 

In the last century fundamental studies have been done to describe the radio wave propagation effects over the earth. Due to the similarity of the underlying problem to body worn antennas a transfer of this theory to the scientific field of on-body antennas is obvious. In Terms of in-body antennas a model of attenuated spherical waves provides a simple but elemental approach.


ban_3

Hereon, body centric antenna parameters will be evaluated and the derived far field models will be gradually extended. Principal aim of the project is a description of realistic scenarios by a selective combination of the basic models. First results indicate a great potential of the developed theory to be transferred to complex propagation scenarios.

                                  

ani_ban_family

 

In summary, the research project will provide a basis for the analysis of body centric communication systems to provide an initial point for a structured and optimized antenna design. By the derived theory a methodology for a systematic optimization of future wireless body area networks is intended.


Publications:

  1. Grimm, M. and Manteuffel, D. , "Electromagnetic Wave Propagation on Human Trunk Models Excited by Half-Wavelength Dipoles", In Antennas and Propagation Conference (LAPC), 2010 Loughborough., nov., 2010. , pp. 493 -496. DOI
  2. Manteuffel, D., Hoeher, P. and Mehdorn, M. , "Evaluation of RF Localization for Deep Brain Implants", In Antennas and Propagation (EUCAP), Proceedings of the 5th European Conference on., april, 2011. , pp. 2372 -2376. DOI
  3. Grimm, M. and Manteuffel, D. , "Characterization of Electromagnetic Propagation Effects in the Human Head and its Application to Deep Brain Implants", In Antennas and Propagation in Wireless Communications (APWC), 2011 IEEE-APS Topical Conference on., sept., 2011. , pp. 674 -677. DOI
  4. Manteuffel, D. and Grimm, M. , "Localization of a Functional Capsule for Wireless Neuro-Endoscopy", In Biomedical Wireless Technologies, Networks, and Sensing Systems (BioWireleSS), 2012 IEEE Topical Conference on., jan., 2012. , pp. 61 -64. DOI
  5. Grimm, M. and Manteuffel, D. , "Evaluation of the Norton Equations for the Development of Body-Centric Propagation Models", In Antennas and Propagation (EUCAP), 2012 6th European Conference on., march, 2012. , pp. 311 -315. DOI
  6. D. Manteuffel, M. Grimm , "On- and In-Body Path Loss Models Based on Antenna De-Embedding", In International Conference on Electromagnetics in Advanced Applications - Antennas and Propagation in Wireless Communications 2012 (ICEAA-IEEE APWC 2012). Cape Town, South Africa, September, 2012.
  7. Grimm, M. and Manteuffel, D. , "Discussion of Body Worn Dipole Antennas Based on an Improved De-embedding Approach", In Antennas and Propagation (EUCAP), 2013 7th European Conference on., April 2013.
  8. Grimm, M. and Manteuffel, D., "Norton Surface Waves in the Scope of Body Area Networks," Antennas and Propagation, IEEE Transactions on , vol.PP, no.99, pp.1, Feb. 2014. (accepted for publication) DOI 
    [Abstract]
     
    This paper presents an evaluation on how Norton surface waves can be used to analytically model the on-body propagation in wireless body area networks. Based on a brief review of the Norton surface wave theory the general problem as defined for terrestrial propagation by Sommerfeld is unified taking into account the further extensions by Norton and Bannister which motivates its evaluation for on-body propagations. A discussion of Sommerfeld's numerical distance reveals useful properties to evaluate the capability of a certain configuration to excite Norton surface waves in specific on-body scenarios. Based thereon antenna design guidelines for on-body propagation links can be derived. All investigations are carried out for human muscle, skin and fat tissues in the frequency range from 0.4 GHz to 60 GHz. A comparison of the simplified model consisting of a planar homogeneous ground to a realistic inhomogeneous human body model shows good results for the attenuation of the electric field strength along the on-body path.
    [BibTeX]
     
    @null{6746004,
    
    
    author={Grimm, M. and Manteuffel, D.},
    
      journal={Antennas and Propagation, IEEE Transactions on}, 
    
     title={Norton Surface Waves in the Scope of Body Area Networks}, 
    
      year={2014},
    
      month={},
    
      volume={PP},
    
      number={99},
    
      pages={1-1},
    
      keywords={Dipole antennas;Electric fields;Muscles;Skin;Surface waves;EM theory;Norton surface wave;Wireless Body Area Networks},
      doi={10.1109/TAP.2014.2307347},
    
      ISSN={0018-926X},}
  9. Manteuffel, D. and Grimm, M. , "Towards Analytic Path Loss Models in On-Body Wireless Communications", Antenna Technology (iWAT), 2014 International Workshop on , Feb. 2014. (accepted for publication)
  10. Grimm, M. and Manteuffel, D. , "Far Field Modeling of Body Worn Antennas by the Superposition of Equivalent Electric Sources", In Antennas and Propagation (EUCAP), 2014 8th European Conference on., April 2014.