Integration Instructions

Document Information Page 15 of 31
FSS JODY-W263 Integration Instructions Rev 02.docx
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Item
Requirements
Remarks
Isolation
(in-band)
S21 > 30 dB recommended
The antenna-to-antenna isolation is
the S21 parameter between the two
antennas in the band of operation.
Lower isolation might be acceptable
depending on use-case scenario
and performance requirements.
Isolation
(out-of-band)
S21 > 35 dB recommended
S21 > 30 dB acceptable
Out-of-band isolation is evaluated
in the band of the aggressor to
ensure that the transmitting signal
from the other radio is sufficiently
attenuated by the receiving antenna
to avoid saturation and
intermodulation effect at the
receiver’s port.
Table 8: Summary of Wi-Fi/Bluetooth coexistence requirements
⚠ In dual antenna configuration, a good isolation is critical to achieve optimal throughput
performance in Wi-Fi/Bluetooth coexistence mode while operating in the same 2.4 GHz band. In
both the cases, while selecting external or internal antennas, observe the following
recommendations:
• Select antennas that provide an optimal return loss (or VSWR) over all operating
frequencies.
• Select antennas that provide optimal efficiency figure over all operating frequencies.
• Select antennas that provide appropriate gain not to exceed the regulatory limits
specified in some countries like the FCC in the United States.
A method to design for antenna micro-strip evaluation is to place an U.FL connector close to the
embedded PCB or chip Antenna. The UFL connector needs only to be mounted on units used for
verification.
5.2.2.1 RF Connector Design
If an external antenna is required, the designer should consider using a proper RF connector. It
is the responsibility of the designer to verify the compatibility between plugs and receptacles
used in the design.
Table 9 suggests some RF connector plugs that can be used by the designers to connect RF
coaxial cables based on the declaration of the respective manufacturers. The Hirose U.FL-R-SMT
RF receptacles (or similar parts) require a suitable mated RF plug from the same connector
series. Due to wide usage of this connector, several manufacturers offer compatible equivalents.