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

TABLE II

INITIAL PREDICTIONS BY THE EVS, EVALUATION OF SHARED BANDWIDTH STABILITY, ANALYSIS OF PATTERN RECONFIGURABILITY, AND RESULTING

FINAL RANKING OF THE DIFFERENT POSITIONS

Fig. 11.  Measured azimuthal radiation patterns showing the effects of

scattering objects at position 4 with vertical polarization. (a) and (b) Represent

the reconfigured frequency configurations

and

(dashed circumferential

line represents plot maximum of all other radiation measurements).

free-space operation. While the EVS predicted the best perfor-

mance of the antenna at position 3, the coverage in the back

plane of the screen at position 1 was determined to outweigh the

prediction of the EVS alone. For both position 1 and position 3,

the reconfigured frequency operated within desirable limits. Po-

sition 2 was unchanged from its original ranking, which shows

good behavior in the reconfigured frequency but demonstrates

no significant pattern reconfigurability other than a slight broad-

Fig. 10.  Measured azimuthal radiation patterns for reconfigured frequency

and

with vertical polarization. (a), (b), and (c)

configurations

ening of the beam. Position 4 also remains unchanged from

Measurements taken on the dielectric work surface with no scattering

its original ranking with unacceptable pattern reconfigurability

objects at positions 1, 2, and 3, respectively. (d) Measurement on the

dielectric work surface with the addition of scattering objects for position 4

(similar to position 2) and the effects of local scattering objects

(dashed circumferential line represents plot maximum of all other radiation

that can severely deteriorate the performance of the antenna in

measurements).

all modes.

is ultimately undesirable. This is seen in Fig. 11, which illus-

VIII. CONCLUSION

trates the effects of the scattering objects on the reconfigurable

Using the EVS, a conformal antenna integration scheme has

frequency configurations at position 4.

been outlined and performed for a novel microstrip antenna

capable of reconfiguring its radiation pattern and frequency

response. Experimental results of the antenna integrated into

VII. ELECTROMAGNETIC VISIBILITY STUDY REVISITED

different positions on the generic laptop computer chassis,

For this study, the reconfigured radiation is considered to

along with a set of changing electromagnetic environments, are

be the most advantageous objective, and was therefore given a

encouraging and indicate the feasibility of the process. Although

higher priority in the final ranking process than the reconfig-

it may be impractical to directly evaluate the performance of

ured frequency. Results are summarized in Table II. Based on

the antenna on the laptop, the process (at worst) is able to

this criterion, position 1 is chosen to have the highest degree

determine the upper and lower echelons of antenna performance

of integrated performance, or "highest visibility," on the laptop

in relation to position with very little computational expense.

computer. This differs slightly from the initial ranking of posi-

For this study in particular, the EVS was able to predict the best

tion 3 as most visible with radiation characteristics that mimic

performance of the antenna at a given position, and its initial