Broadband vertical transition based on LCP multilayer substrate

In this letter, a wideband metal via vertical transition between coplanar waveguide (GCPW) and stripline (SL) ranging from DC to 40 GHz are proposed, and this vertical transition was designed and fabricated in multilayer liquid crystal polymer (LCP) substrate. In order to improve the high-effect harmonic response and the wideband performance, both shielding vias and defected ground structures (DGS) have been introduced in the vertical transition, which suppress high-order mode resonance at 19 GHz and 30 GHz. Measured insertion loss of GCPW-SL-GCPW vertical transition is less than −1 dB, and the return loss is higher than −10 dB in the test frequency band. The results indicate that multilayer LCP technology has a good specification for SOP and wideband communications system applications.