Locosys MC-1010 Hardware Design Manual page 4

Design patch antenna with GPS module.
(1). Generally speaking, a 50 Patch antenna will work good with GPS module just connect the
RF_IN with a 50 impedance trace.
(2). Pleases keep the patch antenna far away noise source such as switch power supplier and
high speed digital logics.
(3). The 50 trace should keep as short as possible to reduce the chance to receive the noise
from air and PCB. A simple direct line is recommended.
(4). If need, a matching circuit could be place between patch antenna and GPS module as
following. The match circuit should be discussed with module and patch antenna maker by
case.
Select an external antennal architecture with GPS module.
For an external antenna, it needs a DC power to have it work properly.
A typical method is to feed a DC into the RF trace and the external antenna can extract the DC
from RF trace. Thus we can use the RF trace to transport both RF signal and DC volt.
We use a RF chock coil to couple the DC to RF trace to perform the mentioned method.
The power supply needs to be externally provided and is connected directly to the external
antenna via chock coil or 27nH inductor as following figure.
Gain (antenna):
Gain (embedded LNA):
Total Gain:
3
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Xizhi Dist., New Taipei City 221, Taiwan
www.locosystech.com
> -2dBi
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