Understanding GNSS Antenna Selection: Passive vs Active

The antenna affects your positioning quality as much as the module. Match it correctly and your design just works.

Why the antenna decides everything

A GNSS module can only be as good as the signal it receives. The antenna sits at the very front of the RF chain, so an antenna mismatch shows up as weak signal, slow fixes and poor accuracy — regardless of how good the module itself is.

Passive antennas: simple, but demanding

A passive antenna is just a tuned patch or ceramic element with no amplifier. It is cheap and needs no power, but its output is weak and easily lost in the cable run to the module. Passive antennas work well only when the antenna sits very close to the module with a short, well-matched trace — typical of compact trackers.

Active antennas: gain, at a power cost

An active antenna adds an LNA (low-noise amplifier) to boost the signal before it travels. It lets you place the antenna farther from the module and tolerate longer cables — the standard choice for vehicle telematics and dashcams. The trade-off is a few milliamps of supply current and the need to feed power to the antenna (bias).

	Passive	Active
Cost	Lower	Higher
Power	None	~few mA bias
Cable tolerance	Short only	Longer runs
Best for	Compact trackers	Vehicle installs

Antenna supervision: the hidden safety net

Modules with a built-in antenna supervisor detect short-circuits and open circuits on the antenna port. In the field, this is invaluable: a damaged or unplugged antenna fails loudly in diagnostics instead of silently degrading performance. Our standard modules (TAU1113/TAU1114) include this supervision and support both antenna types, so the same part serves either design.

If you are unsure which antenna suits your enclosure, send us your mechanical layout — antenna choice is exactly the kind of early-stage question worth getting right.

AntennaRF DesignIntegration