the duplexer may result in
degradation of insertion loss at
the high end of the Tx band, or
other performance issues.
RF Ground
Many of the same considerations,
which apply to the thermal
ground plane, also apply to the
RF ground plane. A large surface
ground area, as shown in Figure
14, provides data sheet perform-
ance for the duplexer. In addition,
a series of 56 (or more) plated
and plugged via holes to a lower
ground plane (0.25 to 0.30 mm in
diameter) should be provided
under the perimeter of the
duplexer, as shown in Figure 15.
The rectangular opening in the
center of the duplexer ground
plane (Figure 15) is strongly
suggested. The 5 mm x 5 mm
miniature FBAR duplexer has
two via hole openings on the
underside. They are DC insulated
from any ground plane with a
patch of solder mask, but RF
coupling to the ground may affect
duplexer performance. Agilent
Technologies recommends that
the user remove the ground in
the 1.0 x 1.4 mm rectangle
shown. Note that the mounting
includes a solder mask frame,
4.6 mm x 4.6 mm (shown in
green). This solder mask assists
with the alignment of the du-
plexer during soldering.
Details of the input/output pads
are shown in Figure 16.
0.5mm typ
Hole spacing
-0.5
0.5
Duplexer (source of heat)
0.55
Rx
-0.55
Tx
2.3 (solder mask)
0.25mm filled plated-thru
hole, 56 places, on a
See detail
0.5mm X 0.5mm grid
0.7
having 44 empty places.
0.25
0.0 Ref
-0.7
-1.6
Ant
-2.3 (solder mask)
-2.3 (solder mask)
2.3 (solder mask)
0.55
0.0 Ref
Etched rectangle in the center of
the pattern, 1.0mm X 1.4mm.
Reference lines cross in the
center of the duplexer.
Green = solder mask
Brown = exposed dielectric
Gold = exposed conductor
-0.55
1.6
Figure 14. Thermal and Electrical Ground Plane.
.
Figure 15. Thermal and Electrical Ground Plane Details.
0.7
0.4
Input/output pad
0.35
0.4
0.35
Exposed dielectric (brown)
Solder mask (green)
Exposed ground plane
( ld)
Figure 16. Detail of Input/output Pads.
All
dimensions
are in mm
6
-1.6
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
