Design, Fabrication and Measurement of a GPS-Galileo Dual-Passband Filter

This paper presents the design, fabrication and measurement of a GPS-Galileo dual-passband filter. The applied synthesis methodology is based on a frequency transformation of the Chebyshev low-pass prototype, and unlike most of conventional synthesis methodologies allows us to design dual-passband filters as classical coupled-resonator filters. The filter is designed and fabricated in microstrip technology which offers a very cost effective device with reduced size and weight. The measured insertion loss is about 2 dB in the lower band and 3.5 dB in the higher band. Lower insertion loss is possible using resonators with higher unloaded quality factor, for example cavity resonators, but on the other hand this type of resonators presents much higher cost, size and weight.