User's Manual

AN-D-212 SC14CVMDECT_SFxx_DB External Antenna Design and Leveraging Modular Approval
© 2013 Dialog Semiconductor B.V. Company Confidential 7 June 28, 2013 v0.2
(i.e. with 100pF 0402 component placed across the
length extension gap) is depicted in the Figure 5. One
important note with respect to KDECT operation:
though the printed antenna design can be made to
operate at 1.8GHz, the embedded antenna that is part
of the SC14CVMDECT_SFxx module would remain
centered at 1.9GHz since here are no external tuning
components to alter the resonant frequency of the
SC14CVMDECT_SFxx embedded antenna. This
implies that when operating at the KDECT frequencies,
FAD can’t be supported and only the printed antenna
design should be selected for operation. This would
limit the applicability to PP mode operation.
3.1.3 Boundary Conditions
In order to be allowed to leverage the CVMDECT Mod-
ular Approval for the SC14CVMDECT_SFxx_DB
design, the PCB should meet the following specifica-
tions:
• PCB material: FR4
• PCB layer stackup:
• L1 copper thickness: 18um
• L1-L2 prepreg thickness: 360um (2x “Prepreg
7628”)
• L2 copper thickness: 35um
• L2-L3 core thickness: 710um
• L3 copper thickness: 35um
• L3-L4 prepreg thickness 360um (2x “Prepreg
7628”)
• L4 copper thickness: 18um
In addition, it is imperative that the physical design of
the printed antenna is accurately copied. Also the con-
tours of the ground plane surrounding the printed
antenna must be accurately copied. The printed
antenna location should be the same (i.e. in a corner
with the same orientation/spacing with respect to the
SF module).
When deviating in any way from these specifications,
the Modular Approval will be invalidated and recertifi-
cation on end-product/system level will be required.
3.2 TUNING COMPONENTS
The printed antenna design tuning has been validated
and found to not require any RF tuning components.
However, it should be noted that the printed antenna
design’s impedance is a short at DC. So a coupling
capacitor is required to connect the SC14CVM-
DECT_SFxx module to the printed antenna design.
In addition, it may be advisable to make provisions for
an optional ?-matching network in case any product
non-idealities (e.g. enclosure, nearby components,
etc.) may influence the printed antenna’s performance.
3.3 OTHER ANTENNAS
If an antenna is connected to CVMDECT that has a
dissimilar radation pattern than that of the SC14CVM-
DECT_SFxx_DB design and/or if the antenna has a
higher gain than that of the SC14CVMDECT_SFxx_DB
design, then FCC-04-165 dictates that the Modular
Approval is invalidated and that recertification is
required on end-product/system level.
If the antenna connected to CVMDECT is user acces-
sible, then the antenna connector shall be proprietary
(per FCC DA-00-1407)