High-impedance amplifier enabling an easy implementable interface for a diversity system of window-printed antennas

For FM radio reception in cars a high-impedance amplifier concept represents a lean interface between antennas and the radio, enabling an easy integration of different antenna structures with low development effort. Results of the frequency responses in the European and Japanese FM band of an optimized high-impedance amplifier in combination with several measured window antennas with different impedance behavior are presented. In order to highlight the advantages of the high-impedance amplifier concept, the results are compared to those of a standard 50-Ohm amplifier using the same antennas. In contrast to the 50-Ohm amplifier, which requires a matching network for each antenna structure, it is possible to apply just one single high-impedance amplifier for various window-printed antennas occurring in a diversity system. The investigations show the great flexibility and applicability of the high-impedance amplifier, since the number of conditions to be met is significantly reduced.