A compact self-packaged lumped-element coupler using substrate integrated suspended line technology

This paper proposes a new compact self-packaged lumped-element coupler using substrate integrated suspended line (SISL) technology. The proposed SISL lumped coupler is implemented by using multilayer printed circuit boards (PCBs), transitions from SISL to conductor backed coplanar waveguide (CBCPW) and a second-order lumped-element coupler topology. The fabricated coupler has a compact size of 0.025λg×0.11λg, a measured broad bandwidth of 33.3% at the center frequency of 1.18 GHz. Moreover, with the benefit of SISL technology, the proposed SISL lumped coupler is self-packaged and features low cost and light weight.