LTCC implementation for compact CSIW resonators with strong coupling for advanced filters in 5G applications

A compact coaxial SIW resonator and filter in multi-layer LTCC technology with Green Tape Dupont material is developed. Compact resonators with strong coupling to implement narrow- and moderate-bandwidth filters are proposed. High-order filters have been designed, implemented and tested with excellent results. An insertion loss of less than 0.4 dB (measured Q-factor > 400) for a 3-pole filter and 0.52 dB (0.56 dB connectorized, measured Q-factor > 440) for a 4-pole filter is demonstrated. The fractional bandwidth of the 4 pole filter is almost 262 MHz @ 3 GHz and 8.8%.