Users Manual

Smart Module Series
SC200R Series Hardware Design
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6.3.2. Recommended Circuit for Active Antenna
The active antenna is powered by a 56 nH inductor through the antenna's signal path. The common
power supply voltage ranges from 3.3 V to 5.0 V. Despite its low power consumption, the active antenna
still requires stable and clean power supplies. Therefore, it is recommended to use high-performance
LDO as the power supply. A reference design for GNSS active antenna is shown below.
Figure 32: Reference Circuit Design for GNSS Active Antenna
6.4. Reference Design for RF Layout
For user’s PCB, the characteristic impedance of all RF traces should be controlled to 50 Ω. The
impedance of the RF traces is usually determined by the trace width (W), the materials’ dielectric constant,
the height from the reference ground to the signal layer (H), and the spacing between RF traces and
grounds (S). Microstrip or coplanar waveguide is typically used in RF layout to control characteristic
impedance. The following are reference designs of microstrip or coplanar waveguide with different PCB
structures.
Figure 33: Microstrip Design on a 2-layer PCB