NB-IoT Module Series
BC66 Hardware Design
BC66_Hardware_Design 33 / 50
4
Antenna Interface
The pin 35 is the RF antenna pad. The antenna port
has an impedance of 50Ω.
4.1. Antenna Interface
Table 13: Pin Definition of NB-IoT Antenna Interface
4.1.1. Reference Design
The external NB-IoT antenna must be matched properly to achieve the best performance, so a matching
circuit is necessary. A reference design for RF interface is shown as below.
Module
RF_ANT
R1 0R
C1
NM
C2
NM
Figure 21: Reference Design for NB-IoT Antenna Interface
BC66 provides an RF antenna pad for external NB-IoT antenna connection. The RF trace in host PCB
connected to the module
’s RF antenna pad should be coplanar waveguide line or microstrip line, whose
characteristic impedance should be close to 50Ω. BC66 comes with ground pads which are next to the
antenna pad in order to give a better grounding. Additionally
, a π type matching circuit is recommended to
be used to adjust the RF performance. Please
place the π-type matching components (R1/C1/C2) as
close to the antenna as possible, and mount them according to actual needs. The capacitors (C1/C2) are
not mounted and a 0Ω resistor is mounted on R1 by default.
Pin Name
Pin No.
Description
RF_ANT
35
RF antenna interface
GND
34, 36, 37
Ground