Compact SIW filter with asymmetric frequency response for C-band wireless applications

In this paper, the design of a low-loss compact filter with asymmetric response for 5.15-5.35 GHz wireless local area network (WLAN) applications is presented. The proposed filter implements a cross-coupled trisection topology that enables to conveniently add a transmission zero at the upper-side in order to reject strong interferers that could come from the close UNII-2e and UNII-3 bands (i.e. between 5.47-5.825 GHz). The filter is based on capacitively loaded circular coaxial resonators embedded into a dielectric material following a substrate integrated waveguide (SIW) approach. The designed filter shows good electromagnetic performance in terms of losses and out-of-band rejection while greatly reducing the device size.