The Global Positioning System (GPS) is a worldwide radio-navigation system. It is formed from a constellation of 24 satellites equipped with several atomic clocks that are precisely synchronized to Universal Time Coordinated (UTC) provided by the U.S. Naval Observatory (USNO). All GPS trackers use an antenna to receive these signals. What the GPS combination antenna do is combine GSM (3G / UMTS) frequencies with GPS / GNSS in the same package, maintaining one connector per frequency.
Clearly, the GPS combination antenna is superior. But the GPS combination antenna can be included in your car in many different formats. Should you purchase a GPS dielectric antenna or GPS passive antenna for your system?
Passive Vs. active GPS antennas
GPS combination antennas can be either GPS passive antennas or GPS amplified antennas. GPS Passive antennas just receive the GPS signal and relay it to the GPS tracker. active units, in contrast, include a powered amplifier that boosts the power of the signal.
The latter is typically more expensive and more difficult to install, but it can also be installed further away from your GPS unit than a passive antenna can. A passive antenna should, generally speaking, be installed with no more than three feet of coaxial cable between it and the GPS unit. Active antennas, in contrast, can be installed much further away, and are therefore better suited for use with larger vehicles.
GPS dielectric antennas (DRAs)
DRAs rely on radiating resonators that can transform guided waves into unguided waves (RF signals). GPS dielectric antennas make use of ceramic and plastic materials characterized by high permittivity and high factor. The main advantages of GPS combination antennas of this type include:
- Compared to proportionately sized metallic antennas whose size is proportional to , DRAs are characterized by a smaller form factor
- Due to the absence of conducting material, DRAs are characterized by high radiation efficiency. This characteristic makes them very suitable for applications at very high frequencies, such as in the range from 30 GHz to 300 GHz. As a matter of fact, at these frequencies, traditional metallic antennas suffer from higher conductor losses
- DRAs can be characterized by a large impedance bandwidth if the dimensions of the resonator and the material dielectric constant are chosen properly.
- DRAs can be excited using different techniques which is helpful in different applications and for array integration.
- The gain, bandwidth, and polarization characteristics of a DRA can be easily controlled using different design techniques.
