User's Guide
Table Of Contents
- 1. WFM200 Pinout
- 2. Device Configuration
- 3. Features Description
- 4. Power Supplies
- 5. Application Schematic Recommendations
- 6. Typical Application Schematics
- 7. Layout Recommendations
- 7.1 Generic RF Layout Considerations
- 7.2 GND and RF Pads Including the Diversity Port and External Antennas
- 7.3 Module Antenna
- 7.3.1 Small Board Size Recommendations for Good RF Performance
- 7.3.2 Extended X Dimension Recommendation for Good RF Performance
- 7.3.3 Y Dimension (65 to 80 mm) Recommendation for Good RF Performance
- 7.3.4 Y Dimension (80 mm or Larger) Recommendation for Good RF Performance
- 7.3.5 WFM200 Portion One Corner Bias with 3 mm Metal Keep-Outs
- 7.3.6 Recommended Antenna Loop Trace Capacitor Values
- 7.4 WFM200 Reference Evaluation Board
- 8. Recommendations for Certification
- 9. Package Outline
- 10. Integral Antenna Loop and Keep-Out Required Dimensions
- 11. Recommended PCB Land Pattern
7.3.6 Recommended Antenna Loop Trace Capacitor Values
This sections provides guidelines for antenna matching component values for various board sizes. System integrators should verify the
antenna impedance in their full application with all housings and connections attached and mounted. The antenna matching component
values can be adjusted to achieve Max VSWR of 2:1 in the actual application. As the board size is reduced, the antenna gain also
reduces, and it becomes more important to adjust these component values to meet 2:1 max VSWR.
Table 7.1. Recommended BOM vs. PCB Size
Carrier PCB Dimensions Size of WFM200 Section
C_ANT
[pF]
C_SER
Antenna Re-
alized Gain
Typ. [dBi]
Notes
X [mm] Y [mm] X [mm] Y [mm]
17.5 55 17.5 55 0.9 0 Ω +2.5
Small PCB size as shown in
Figure 7.4 on page 18
14.5 55 14.5 55 0.9 0 Ω +2.4
20.5 55 20.5 55 0.8 0 Ω +2.2
17.5 45 17.5 45 0.7 0 Ω +2.2
27 45 27 45 0.7 0 Ω +2.0
17.5 65 17.5 65 0.8 0 Ω +2.0
14 42 14 42 0.8 4.3 nH +1.0
100 55 28 55 0.8 0 Ω +2.8
Extended X-dimension PCB
size as shown in Figure 7.5 on
page 19
100 45 17.5 45 0.6 0 Ω +1.2
100 65 17.5 65 0.9 0 Ω +3.3
85 55 17.5 55 0.8 0 Ω +2.8
100 65 21.5 55 0.7 1.8 pF +4.0
Maximum gain is +4.7 dBi.
Configured as shown in Figure
7.5 on page 19
75 75 17.5 45 0.6 0 Ω +2.1
Extended PCB size as shown in
Figure 7.6 on page 20
35 100 17.5 45 0.8 0 Ω +2.4
Extended PCB size as shown in
Figure 7.7 on page 21
75 100 17.5 45 0.8 0 Ω +3.7
100 100 17.5 45 0.8 0 Ω +2.2
200 100 17.5 45 0.8 0 Ω +3.7
75 80 17.5 45 0.8 0 Ω +3.6
75 120 17.5 45 0.8 0 Ω +3.7
75 150 17.5 45 0.8 0 Ω +2.0
75 200 17.5 45 0.8 0 Ω +2.5
200 200 17.5 45 0.8 0 Ω +2.8
110 140 15 30 0.6 1.0 pF +0.3
Ext. PCB size, in corner, as
shown in Figure 7.8 on page 22
Note:
1. C_SER can be a series tuning capacitor [pF] / inductor [nH] option mounted between the 2G4ANT_IN and RF_1 ports for carrier
boards with small GND metallization size. C_ANT is the antenna loop trace capacitor.
2. Using FR-4 Carrier PCB with a relative permittivity of ɛ
r
= 4.4 ± 10%
3. The recommended component values provided in this table might need to be optimized on a custom design within its final enclo-
sure by measuring S11 at pin 2G4ANT_IN to ensure VSWR antenna requirements are met.
UG395: WFM200 Hardware Design User's Guide
Layout Recommendations
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