User Manual

Table Of Contents

Model SM240 Data Sheet · Document Number 430154-01A · Page 7 of 12

1.3 Mechanical Drawings

Figure 1.1 shows the PCB layout of the F antenna, and the keep out area for the F-

antenna.

Recommended Antenna:

Figure 1.1

The antenna pattern should be present on the top and bottom layer of the PCB. The

antenna patters should be connected by sufficient vias to maintain an impedance of 50

ohms. There should be no plane or trace on the inner layers between the antenna

patterns. In the antenna area, there should be no parts in the area between the edge of

the ground plane and the edge of the PCB on either side of the PCB.

A sample layer stack up which will yield the correct impedance is shown in Table 1.5.

The antenna is connected directly to the module by a 50 ohm trace (18.5mil width using

stack shown in Table 1.5), and connected by vias to the antenna on the opposite side at

the point in Figure 1.1 labeled “To Balun”. Example Gerber files are available.

In order to verify the completed design, connect a whip antenna with a known gain,

such as a Pulse P/N W1027, to a spectrum analyzer. Verify that the circuit radiates only

at the intended frequencies, and that spurious frequencies are below regulatory agency

limits. Regulatory certification will require testing at a licensed facility.

Production line testing should also include verification, with a spectrum analyzer, that

the unit is transmitting only in the intended frequency band.