A Surface-Mountable Suspended Integrated Strip-Line Technology Using Castellated Vias

Air-suspended packaging techniques have long been desired due to their low-loss, low dispersion, and wideband-capable attributes. However, many, if not all, of the proposed air-suspended technologies over the years have been focused on stand-alone connectorized component design or assume the air cavity will be integrated into a multilayer printed circuit board (PCB) stack-up. However, given the modern-day trend to reduce cost, size, weight, and power, there is a need for air-suspended technologies that can be used in standard PCB assembly processes. In this letter, a novel method of surface mounting the suspended integrated strip-line (SISL) technology is proposed. A castellated via is used as the signal transition from the carrier board to the SISL component to make surface mounting easy and accessible. A wideband thru-line is designed, simulated, fabricated, and measured in the proposed surface-mount technology (SMT) SISL packaging to demonstrate its feasibility. The simulated and measured results agree very well over the 1–6-GHz frequency band validating the design over critical frequency bands. While the proposed method is only shown here for a thru-line, the generalized concept applies to any and all components that can be designed using traditional SISL design procedures.