Cypress EZ-BT WICED CYBT-343026-01, Getting Started

Page: 50 / 120

Getting Started with EZ-BT WICED Modules
www.cypress.com
Document Number: 002-23400 Rev. ** 50
8.2 Module Placement in a Host System
The EZ-BT Module is soldered to a host board and a clearance must be provided for the antenna where no routing or
ground is allowed on any layer. Placing the module at the edge of the host board is recommended because it provides
the best RF performance and simplifies the requirement of not routing signal or ground traces under the antenna
Ground Clearance region.
Figure 31 shows four placement options on a host board, with option 1 being the most
efficient.
Figure 31. Module Placement in a Host Board
Figure 31 shows an example of four positions of the module in a host board,
‘1’, ‘2’, ‘3’, and ‘4’. The white area shown
around the module is the additional clearance area. For the antenna in question, it is recommended to provide a
clearance area of 4 mm in each direction. For details on the recommended clearance area for your EZ-BT Module, see
the specific module datasheet.
As can be seen in Figure 31 , when placing the module at the edge (placement options
‘1’ or ‘3’) of the host board, the
additional clearance area is only required facing inwards towards the center of the main board. In all cases, there must
be no possibility of signal or ground traces to be beneath the antenna Ground Clearance region. Conversely, if the
module is placed in the middle (placement option
‘2’) of the host board, the clearance area must be provided in order
to achieve an optimal RF performance.
Placement option
‘1’ or ‘3’ are the best options shown in
Figure 31 , because it removes the need to reroute signal or
ground traces away from the Ground Clearance region of the module (because no GPIO are located at the top left or
right corner of the module). Furthermore, it minimizes additional clearance area if optimal RF performance is required,
because the antenna faces outward with the antenna exposed to open space.
In placement option
‘4’, although the module is placed at the edge of the host board, the antenna is not exposed to the
maximum amount of free space.
Placement option
‘2’ not only wastes PCB real estate, but also provides diminished RF performance compared to
position
‘1’ and ‘3’.
Shield
4 mm 4 mm
4 mm
Clearance Region
outside of module
4 mm
4 mm
4 mm
Ground Clearance
Region
4 mm