MAX-7 / NEO-7 / LEA-7 - Hardware Integration Manual
GPS.G7-HW-11006-1
Design
Page 34 of 55
3.4.5
Design with GLONASS / GPS passive antenna
In general, GPS patch antennas only receive GPS signals well. A typical return plot (S11 measurement) shows
that the GLONASS signal is highly attenuated. (
u-blox 7 modules supporting GLONASS have a GPS & GLONASS SAW filter (see Figure 30) that lets both GPS
and GLONASS signals pass. For best performance with passive antenna designs, use an external LNA. (See
section 3.4.1.2).
Figure 31: 25*25*4 mm GPS patch antenna on 70*70 mm GND plane
To receive GPS and GLONASS, a special antenna patch (which can receive both GPS and GLONASS) is needed.
The return plot (S11 measurement) in Figure 32 below shows the two areas of lower attenuation.
Figure 32: 25*25*4 mm GPS / GLONASS patch antenna on 70*70 mm GND plane
