Antenna Connection
The antenna should be connected to the RF pin. The RF pin is matched to 50 Ohm. If the
antenna connector is placed away from the module at the motherboard, the track between the
RF pin and the connector should be a 50 Ohm transmission line.
On a two layer board made of FR4 the width of a microstrip transmission line should be 1.8
times the thickness of the board, assuming a dielectric constant of 4.8. The line should be run
at the top of the board, and the bottom side should be a ground plane.
Example: For a 1.6 mm thick FR4 board, the width of the trace on the top side should be 1.8 x
1.6 mm = 2.88 mm.
The simplest antenna to use is the quarter wave whip antenna. A quarter wave whip antenna
above a ground plane yields 37 Ohm impedance and a matching circuit for 50 Ohm are
usually not required.
A PCB antenna can be made as a copper track where the ground plane is removed on the
back side. The rest of the PCB board should have a ground plane as large as possible,
preferably as large as the antenna itself, to make it act as a counterweight to the antenna. If
the track is shorter than a quarter of a wavelength, the antenna should be matched to 50
ohms.
Regulatory Compliance Information
The use of RF frequencies and maximum allowed RF power is limited by national regulations.
The RC17xxHP-RC232 has been designed to comply with the RED directive 2014/53/EU
when used in European license free bands.
According to RED directives, it is the responsibility of Radiocrafts’ customers (i.e. RC17xxHP-
RC232 end user) to check that the host product (i.e. final product) is compliant with RED
essential requirements. The use of a CE marked radio module can avoid re-certification of the
final product, provided that the end user respects the recommendations given by Radiocrafts.
A Declaration of Conformity is available from Radiocrafts on request.
The relevant regulations are subject to change. Radiocrafts AS do not take responsibility for
the validity and accuracy of the understanding of the regulations referred above. Radiocrafts
only guarantee that this product meets the specifications in this document. Radiocrafts is
exempt from any responsibilities related to regulatory compliance.
PCB Layout Recommendations
The recommended layout pads for the module are shown in the figure below. All dimensions
are in thousands of an inch (mil). The circle in upper left corner is an orientation mark only,
and should not be a part of the copper pattern.