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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 52, NO. 12, DECEMBER 2004

Directional Reconfigurable Antennas on Laptop

Computers: Simulation, Measurement and

Evaluation of Candidate

Integration Positions

Greg H. Huff, Student Member, IEEE, Judy Feng, Shenghui Zhang, Student Member, IEEE, Garvin Cung, and

Jennifer T. Bernhard, Senior Member, IEEE

integration into computer cards [1], [2], which has been inves-

Abstract--This study reports on the integration of a novel

reconfigurable microstrip antenna capable of reconfiguring both

tigated and implemented in commercial products, including

its radiation pattern and frequency response onto a generic

the implementation of complete RF systems to support the

laptop computer structure. The purpose of such an exercise is

antenna. The next approach is the vertically oriented antenna

to provide the relevant information necessary to integrate high

surface (VOAS) [3], in which a surface is hinged from the top

performance antennas onto structures that can be used in ad hoc

of the screen and swings to keep vertically oriented and more

communication scenarios as well as other demanding applications.

visible to incoming data. Moving closer to direct integration of

To pre-evaluate candidate antenna locations on the laptop chassis,

an electromagnetic visibility study (EVS) is performed. Once

an antenna, the placement of a novel dual frequency antenna

integrated into candidate positions that have been analyzed by

onto a laptop chassis has also been experimentally investigated

the EVS, the operation of the antenna on the host structure

in [4] as well as an iterative/parametric method of moments

is measured and assessed with consideration to several realistic

investigation of position in [5], which simulates pseudo-integra-

electromagnetic environments. The resulting performance and

tion in different positions. However, aside from the microstrip

packaging issues are discussed. A formalized procedure for the

patch antenna discussed in [5], all of these integration schemes

integration of the antenna onto any host chassis using the EVS

as a tool is also included.

are nonconformal. This condition not only gives rise to elec-

tromagnetic constraints, but also serious practical issues as

Index Terms--Antenna integration, antenna packaging, recon-

well (including wear and breakage). To avoid some of these

figurable antenna.

issues, an inverted-F antenna has been conformally mounted

on a laptop computer prototype in [6] using a primarily ex-

I. INTRODUCTION

perimental methodology to achieve the integration position.

Although the outcome is effective and provides meaningful

UTURE generations of portable communication devices

measured results, [6] does not present a conformal integration

will require high quality wireless links capable of high data

process that can determine the best location for the antenna.

rate delivery, as well as the ability to maintain these links in

Certainly, a full modal current evaluation of a host chassis

harsh conditions or when communicating with multiple targets.

and antenna could be considered, each in a unique operating

To accomplish this, the use of innovative reconfigurable antenna

scenario. To avoid these potential pitfalls, the present work

designs should be considered to sustain the highest quality path

develops a process that can expediently predict the conditions

for data. When the candidate antenna utilizes both reconfig-

for which an antenna capable of altering its radiation and/or

urable radiation characteristics as well as frequency agility, the

frequency characteristics can maintain a maximum degree of

performance issues surrounding the integration, packaging and

reconfigurability once integrated onto a host device.

electromagnetic environment of the antenna become increas-

To investigate the integration of the reconfigurable antenna

ingly important factors.

onto a laptop computer, the following topics are addressed. First,

Previous integration and packaging schemes have placed

the operation of the reconfigurable antenna is discussed. Next,

radiating elements onto a number of different surfaces and

the electromagnetic visibility study (EVS) is performed on the

locations on the laptop chassis. The first of these is antenna

host chassis, and the pertinent information describing the can-

didate positions for integration is calculated. With this informa-

Manuscript received April 3, 2003; revised January 28, 2004. This work was

tion, the experimental portion of this study is conducted. The

supported in part by the National Science Foundation under Grant ECS-9983460

reconfigurable antenna is conformally mounted onto a physical

and in part by NASA under Research Grant NAG3-2555.

G. H. Huff, S. Zhang, C. Cung, and J. T. Bernhard are with the Electro-

model of a laptop computer, and the VSWR, input impedance,

magnetics Laboratory, Department of Electrical and Computer Engineering,

and radiation characteristics are measured for all positions under

University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA (e-mail:

consideration. While in these positions, the effects of realistic

jbernhar@uiuc.edu).

electromagnetic environments are also observed. Finally, with

J. Feng was with the Electromagnetics Laboratory, Department of Electrical

and Computer Engineering, University of Illinois at Urbana-Champaign, Ur-

the information obtained from both the EVS and measurements,

bana, IL 61801 USA. She is now with BAE Systems, Information and Electronic

the candidate positions are evaluated on the merits of reconfig-

Warfare Systems, Merrimack, NH 03054 USA.

urability and performance.

Digital Object Identifier 10.1109/TAP.2004.836425