Miniaturized Substrate Integrated Waveguide 5g Ltcc Bandpass Filter Exploiting Capacitive Loaded Cavities

In this article, a compact bandpass filter with a pair of transmission zeros exploiting capacitive loaded cavities is presented. The proposed filter structure is mainly composed of coplanar waveguide (CPW) feeding structures and four substrate integrated waveguide (SIW) resonators. The size of the filter has been greatly reduced due to the capacitive loaded circle metallic septum and the vertical coupling of stacked cavities in three dimensional structures by low temperature co-fired ceramic technology. The filter not only achieves the advantages of high-selectivity, a much wider upper stopband bandwidth, but also realizes a miniaturized volume of 3.35 x 2.10 x 0.66 mm(3). The simulated and measured results show the bandpass filter achieves a center frequency of 28 GHz with 3 dB fractional bandwidth of 8%. The filter is suitable for application in 5G wireless communication.