A compact filtering power divider with low-pass response and wide harmonic suppression

This article presents a miniaturized filtering power divider with low-pass behavior and a wide attenuation band. The proposed FPD has an operating frequency (f(o)) of 1.52 GHz with a relative stopband rejection of 165% and an electrical circuit size of (0.25 lambda(g) x 0.14 lambda(g)). The microstrip structure responsible for low-pass filter response is modeled using two rectangular-shaped open resonators (ORs) loaded with multiple sections of the interdigital capacitor. The low-pass filter operates at a cut-off frequency of 1.56 GHz and passband insertion loss of 0.35 dB. The output ports are connected with a 100 omega isolation resistor to obtain good isolation in the passband. The two dissimilar defected ground structures are introduced in the ground plane for achieving circuit miniaturization and wide harmonic suppression up to 15 GHz. The electromagnetic simulated results of both the low-pass filter and FPD show a well-matched behavior with the experimental ones. The proposed FPD is suitable for GPS applications.