Abstract
This paper presents the design of miniaturized substrate integrated waveguide (SIW) filters implemented in LTCC technology (Low-Temperature Co-fired Ceramic) for 10-GHz applications. In order to miniaturize the size of the circuit and to improve its performance, multilayered structure and the LTCC technology are employed to design and fabricate the filter. The SIW structures are based on a combline topology
completely embedded into HL2000 substrate, showing good Q-factor and improved selectivity. The cavity resonator shows a very compact implementation, and the resulting estimated Q-factor and resonance frequency are 150 and 11.65 GHz, respectively. To demonstrate the feasibility of this approach, we have considered the design of a 2-pole filter based on a a pair of combline resonators, coupled by means of a magnetic iris, whose EM response shows an estimated inserion loss of 2 dB at
10.8 GHz, and a return loss better than 15 dB with an equi-ripple fractional bandwidth (FBW) of 3:25% (or absolute bandwidth of 350 MHz). The designed SIW structures show advantages in terms of compactness, and reduce concerns on potential radiation issues.
