A compact wideband filter with absorption and sharp rejection

This paper presents a multilayered ultra-wideband (UWB) filter simultaneously featuring two unique characteristics, i.e., absorbing out-of-band signals and suppressing 5.8GHz interference. The former enables the UWB transmitter to operate with high stability, and the latter disables this transmitter to interfere other 5.8 GHz wireless devices. The proposed filter is with a compact size of 13×11 mm2, and achieves in-band transmission in lower UWB band between 3 and 5 GHz, high interference suppression at 5.8 GHz, as well as good absorption of out-of-band reflections below 2.8 GHz.