Users Manual

GSM/GPRS Module Series
M66 Hardware Design
M66_Hardware_Design Confidential / Released 64 / 82
Figure 39: Reference Design for GSM Antenna
M66 provides an RF antenna pad for antenna connection. The RF trace in host PCB connected to the
module RF antenna pad should be coplanar waveguide line or microstrip line, whose characteristic
impedance should be close to 50Ω. M66 comes with grounding pads which are next to the antenna pad in
order to give a better grounding. Besides, a π type match circuit is suggested to be used to adjust the RF
performance.
To minimize the loss on the RF trace and RF cable, take design into account carefully. The following table
shows the requirement on GSM antenna.
Table 25: Antenna Cable Requirements
Type Requirements
GSM850/EGSM900 Cable insertion loss <1dB
DCS1800/PCS1900 Cable insertion loss <1.5dB
Table 26: Antenna Requirements
Type Requirements
Frequency Range Depending by frequency band (s) provided by the network operator
VSWR ≤ 2
Gain (dBi) 1
Max Input Power (W) 50
Input Impedance (Ω) 50
Polarization Type Vertical
4.1.2. RF Output Power
Table 27: The Module Conducted RF Output Power
Frequency Max. Min.
GSM850 33dBm±2dB 5dBm±5dB