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IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 46, NO. 1, FEBRUARY 2004
Fig. 7. SARs and radiation efficiencies as a function of chassis length with hand2 at (a) 900 and (b) 1800 MHz. Distance from head to phone
7 mm.
1 W.
Fig. 8. (a) Antenna configurations for the 900-MHz model with different feed and short-circuit positions. Details of the antenna element are given in Fig. 1(a).
(b) Simulated (MoM) impedance bandwidths
6 dB in free space as a function of chassis length.
and 5(a) for Loc1), are quite similar with both antenna orien-
tations. The reason for this is apparent; owing to the shape of
with Loc1 and Loc2 is similar, the SAR features are not. Com-
the antenna element, there occur only relatively small changes
paring Fig. 10(a) with Fig. 10(b), it is observed that the SARs
in the current distribution of the antenna-chassis combination
are clearly lower with Loc2 than with Loc1. From the distri-
when turning the antenna element.
bution profiles [Fig. 11(a) and (b)], it is seen that this is due
Fig. 9 shows that at 1800 MHz, larger bandwidth is obtained
to much lower SAR maximum near the antenna element with
when the short circuit of the patch is located on the top of the
Loc2. The reason for this can be assumed to be the location of
chassis (Loc1 and Loc2) than in the opposite case where the ra-
the loop formed by the feed and short circuit. For Loc1, this loop
diating edge is located on the top (Loc3 and Loc4), which is ex-
can excite currents flowing along the right edge of the chassis,