Getting Started with EZ-BT WICED Modules
Document Number: 002-23400 Rev. **
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8
Module Placement and Enclosure Considerations
EZ-BT WICED Modules are designed to be soldered to a host PCB to provide seamless Bluetooth connectivity. To
maximize the RF performance of the final product, care needs to be taken on the placement of the module and antenna.
This section describes in detail the recommended placement of the module on a host board to ensure optimal RF
performance. This section also details the effect of metallic or nonmetallic enclosure and metal obstructions near the
module.
8.1
Antenna Ground Clearance
A monopole antenna requires that no ground plane is present below the antenna. The ground plane below it will not
allow the field to propagate. This is defined as the Ground Clearance requirement. However, after some distance, a
ground must be present for a monopole antenna. Defining this region is a very significant step for any antenna design.
The Ground Clearance region defines the bandwidth and efficiency of the antenna.
Each specific EZ-BT WICED Module marketing part number specifies the Ground Clearance used for the design of the
module, and offers recommended additional ground keep-out area to maximize the RF performance. The following
examples reference the
module specifically. For details on other modules, see the specific module
datasheet.
The following example references a PCB trace antenna implementation (shown in the green hatched area), but the
same rules and properties apply for chip antennas used on other Cypress EZ-BT Modules. The specific PCB trace
antenna shown in
requires a Ground Clearance area of 4.62 mm × 14.52 mm. To maximize the RF
performance, an additional 4 mm of ground clearance is recommended. This is denoted in the blue hatched area. This
additional ground clearance is not required but may improve the RF performance if implemented.
Figure 30. Antenna Clearance
In
, the PCB trace antenna is placed at the edge of the module. The green area in
does not have
any ground on any layer. The module placement in a host board needs to ensure that no traces or ground layers of the
host board comes within this region. Any ground plane below a monopole antenna degrades the radiation and adversely
affects the RF efficiency.