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

(a)

(b)

Fig. 6. Measured VSWR of antenna in free space and integrated on laptop for

.

and (b)

the reconfigured radiation configurations (a)

Fig. 5. (a) Measurement setup including scattering objects (not to scale, actual

positions differ slightly). (b) and (c) Measured free space radiation patterns

of the antenna in the plane of interest for the principle polarization of the

reconfigured radiation and reconfigured frequency configurations, respectively.

a comprehensive comparison of integration position, measure-

ments in the azimuthal plane of laptop have been provided in

the following sections. Elevation measurements of the laptop

were also performed, but only in the environments without

scattering objects and are not shown here since the EVS was

performed using incoming waves at azimuth relative to the

laptop computer. Elevation measurements do indicate the same

general kinds of chassis effects illustrated in the azimuthal

measurements.

Fig. 7. Measured azimuthal radiation patterns for reconfigured radiation

configurations

and

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

Measurements taken on the dielectric work surface with no scattering objects

A. Performance of Reconfigured Radiation Configurations

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

surface with the addition of scattering objects for position 4.

1) Shared Bandwidth: For the reconfigured radiation con-

figurations the effects of placement on the antenna's perfor-

loss of 12 MHz in shared bandwidth, indicating that the antenna

mance in terms of the shared bandwidth are addressed first.

may not be able to support the currents needed for the desired

Fig. 6 shows the VSWR of reconfigured radiation configura-

reconfigurability in those positions. The 2:1 VSWR bandwidths

and

(horizontally polarized with respect to the

tions,

for these configurations demonstrate that the antenna is affected

laptop). For the free space and integrated antenna positions 1,

as the integration position changes, and appears to be affected

2, 3, and 4, the shared 2:1 VSWR bandwidths between the

more in positions with low electromagnetic visibility.

(base) and

(reconfigured radiation) configurations are: 50,

2) Radiation Characteristics: The effects of integration po-

50, 54, 50, and 38 MHz, respectively. Although the bandwidths

sition on radiation characteristics are examined next for the

of the antenna are somewhat shifted, positions 1 and 3 show

reconfigured radiation modes. Fig. 7 contains the azimuthal

no appreciable loss in shared bandwidth. In position 2 there is a

radiation patterns for the antenna with reconfigured radiation

shared bandwidth increase of 4 MHz, and in position 4 there is a