User's Manual

SC14CVMDECT_SFxx_DB Reference Design
Antenna Productsheet
Date: August 15, 2013
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2.5 Printed Antenna Design operating at 1.8GHz (KDECT)
For KDECT operation, the frequency band is centered around 1.8GHz, whereas the
default printed antenna design configuration is designed to be centered around 1.9GHz.
The printed antenna design holds a provision for this shift in operating frequency. Please
refer to the figure in section 2.1.2. If a 100pF capacitor (0402 footprint) is placed across
the gap indicated by the green ellipse indicated in figure 2, then effectively the antenna
length is increased resulting in a resonant frequency of 1.8GHz (without the 100pF 0402
component, the antenna’s resonant frequency remains at 1.9GHz for other DECT
operation). No other tuning components are required.
The S11 plot (measured on the actual SC14CVMDECT_SFxx_DB Reference Design HW)
with the printed antenna design configured in KDECT mode (i.e. with 100pF 0402
component placed across the length extension gap) is depicted in the following picture:
2.6 Tuning Components
The antenna design characteristics have been validated without the use of any additional
tuning components.
2.7 DC Impedance
As may be clear from the picture in section 2.1.2, the antenna will exhibit a short (0 Ohm
impedance) at DC. Therefore, it is advisable to use a coupling capacitor (e.g. 100pF).
Detailed drawing information and/or gerber files can be obtained through your Dialog
Semiconductor BV support contact window.