Reference Design - Quectel EC21 Series Hardware Design

LTE-FDD B7 (10 MHz)
LTE-FDD B8 (10 MHz)
LTE-FDD B20 (10 MHz)
LTE-FDD B28 (10 MHz)

4.1.5. Reference Design

A reference design of ANT_MAIN and ANT_DIV antenna pads is shown as below. A π-type matching
circuit should be reserved for better RF performance. The capacitors are not mounted by default.
NOTE
1. Keep a proper distance between the main antenna and the Rx-diversity antenna to improve the
receiving sensitivity.
2. ANT_DIV function is enabled by default.
diversity. See document [3] for details.
3. Place the π-type
possible.
EC21_Series_Hardware_Design
-97.0 dBm
-98.5 dBm
-97.5 dBm
-98.0 dBm
Figure 33: Reference Circuit of RF Antenna Interface
matching components
-96.0 dBm -99.5 dBm
-97.0 dBm -101.0 dBm
-99.0 dBm -100.5 dBm
-98.7 dBm -101.0 dBm
AT+QCFG="divctl",0
(R1 & C1 & C2, R2 & C3 &
LTE Standard Module Series
-94.3 dBm
-93.3 dBm
-93.3 dBm
-94.8 dBm
can be used to disable receive
C4) as close to the antenna as
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