Introduction

Antennas for GNSS (global navigation satellite system) are used for navigation, locating vehicles or other objects, for fleet management or in traffic guidance systems. GPS – as one of the available global satellite services – stands for Global Positioning System and uses a constellation of 24 to 32 satellites in Earth orbit. These transmit radio signals that enable GPS receivers to determine their current location, time and speed. AM/FM and GPS antennas are usually installed at different locations in the vehicle and wired separately. The space requirements and costs for integration are correspondingly high.

Challenge

An existing AM/FM antenna had to be extended with GPS. The volume was allowed to be larger than usual: the entire technology was to fit into the same cone of a normal small roof antenna. The advantages of the intended solution are obvious: it should be possible to easily exchange the antennas, while a smaller volume at the same time results in lower antenna costs.

Another challenge: for a customer, an SDARS antenna was to be mounted recessed in the car roof; however, existing patch antennas do not work with sufficient performance from a small cut-out.

Solution

With the Scarabaeus, a metal frame antenna was developed that is fed and adjusted via several feet. Our Scarabaeus design results in a significantly smaller construction volume in a roof antenna.

Without changing the surface of the vehicle, the antenna combination is fully embedded in a metal cavity and covered by a thick dielectric part of the roof.