Dual-band bandpass filter with wide stopband and low insertion loss for GNSS signals

We present the design of a dual-band bandpass filter for GNSS signals based on microstrip open-loop resonators. The filter has two frequency bands intended for the L1 and L2 signals of GPS and GLONASS, and the Galileo open service signal E1. The low insertion loss and the wide stopband achieved make this filter suitable for rejecting out of band interferences in GNSS receivers as a first stage in the RF chain. The filter was implemented and the measurements carried out validate the proposed design, which has only 1.5 dB of insertion loss and about 30 dB out of band attenuation in a wide frequency range.