Users Manual

GSM/GPRS Module Series
M66 Hardware Design
M66_Hardware_Design Confidential / Released 63 / 82
4 Antenna Interface
M66 has two antenna interfaces, GSM antenna and BT antenna. The Pin 26 is the Bluetooth antenna pad.
The Pin 35 is the GSM antenna pad. The RF interface of the two antenna pad has an impedance of 50Ω.
4.1. GSM Antenna Interface
There is a GSM antenna pad named RF_ANT for M66.
Table 24: Pin Definition of the RF_ANT
4.1.1. Reference Design
The external antenna must be matched properly to achieve best performance, so the matching circuit is
necessary, the reference design for RF is shown as below.
Pin Name Pin No. Description
GND 34 Ground
RF_ANT 35 GSM antenna pad
GND 36 Ground
GND 37 Ground