Terahertz monolithic integrated coplanar band‐pass filter based on slotline mode

Abstract

In this letter, a terahertz monolithic integrated planar band-pass filter based on coplanar waveguide (CPW) resonators has been proposed. By adopting the feeding line in form of a slotline, the need for air-bridges in traditional CPW filters is eliminated, achieving good integrability and reducing fabrication difficulty. To further improve the filtering performance, the defected ground structure is used in the design, introducing a finite transmission zero at the lower sideband. The filter is manufactured on the semi-insulation silicon carbide (SiC) substrate, to fit the existing advanced GaN-on-SiC monolithic integration system. Measurement reveals the fractional band-width of 5.7% at the center frequency of 279 GHz, with an insertion loss of 5.1 dB. With a volume of 500 × 400 × 50 μm (0.45 × 0.36 × 0.045 λ 0 ), the proposed filter improves the performance of the planar filter operating at the terahertz band effectively.