ANTENNAS AND PROPAGATION FOR BODY CENTRIC

COMMUNICATIONS

Hall P S 1 and Hao, Y 2

1

University of Birmingham, Edgbaston, Birmingham, UK, p.s.hall@bham.ac.uk

2

Queen Mary, University of London, Mile End Road, London, UK, y,hao@elec.qmul.ac.uk

and fire-fighters, as well as military personnel.

ABSTRACT

Use for medical sensing and support, with

Body centric wireless communication is now

either skin mounted sensors or implants, is also

accepted as an important part of 4th generation

attracting much attention.

(and beyond) mobile communications systems,

taking  the  form  of  human  to  human

A parallel research activity is that of wearable

networking incorporating wearable sensors and

computers, where the emphasis is on high

communications. There are also a number of

levels of computational power, coupled with

body centric communication systems for

sensors and interface equipment. Currently

specialized occupations, such as paramedics

these are bulky and have wired connections.

and  fire-fighters, military personnel and

The use of wireless connections in these

medical sensing and support.

systems is desirable although there is also a

trend to the development of wired garments,

To support these developments there is

and the fabric antennas noted below are part of

considerable ongoing research into antennas

this.

and

propagation

for

body

centric

communications systems, and this paper will

Body centric communications takes its place

summarise  some  of  it,  including  the

firmly within the sphere of personal area

characterisation of the channel on the body, the

networks and body area networks (PANs and

optimisation of antennas for these channels,

BANs). The content of a PAN or BAN

and communications to medical implants

contains  a  range  of  communications

where  advanced  antenna  design  and

requirements. These can be classified as

characterisation and modelling of the internal



body channel are important research needs. In

communications from off-body to an

all of these areas both measurement and

on-body device or system ­ off-body

simulation pose very different and challenging



communications  within  on-body

issues to be faced by the researcher.

networks and wearable systems ­ on-body



communications to medical implants

1

INTRODUCTION

and sensor networks ­ in-body

Body centric wireless communication is now

All of the antenna and propagation studies for

accepted as an important part of 4th generation

personal mobile communications come within

(and beyond) mobile communications systems

the fist class. What is now of great interest is

and  will  be  part  of  the  forthcoming

the second and third. Of course, in an

convergence and personalization across the

integrated system, all may communicate with

various domains, which include personal area

each other and the boundaries will become

networks, (PANs), and body area networks,

blurred. Thus, whilst this is not a perfect

(BANs), as noted in a forthcoming book, [1].

subdivision, it does serve to highlight some of

Advancements  in  the miniaturisation  of

the different challenges for antennas and

wearable hardware, embedded software, digital

propagation in the body centric system.

signal processing, and biomedical engineering

have  made  possible  human  to  human

2

ON BODY SYSTEMS

networking incorporating wearable sensors and

communications. This can be seen as a

2.1

Radiowave Propagation

continuation of a trend spearheaded by the

At low frequencies, electromagnetic energy

mobile phone, which, over the last few

has a significant penetration depth, and the

decades has become smaller and more

body can be used to support communications

convenient  for  personalized  operation.

channels, [2-4]. For example at 10MHz the

Alongside this trend, there have been a number

penetration depth is about 200mm for muscle

of body centric communication systems for

and over 1 m for fat. At 2.45GHz the depths

specialized occupations such as paramedics

are 25 and 120mm respectively. The range of