A micromachined separable RF connector fabricated using low-resistivity silicon

A micromachined separable RF connector is demonstrated using low-resistivity silicon as the substrate material. The design is based around a two-part device, containing pins capable of deflections perpendicular to the substrate plane. Thick SU-8 dielectric is used to reduce lossy substrate coupling and mechanical interlocking is introduced to ensure robust attachment to the substrate during fabrication and in service. Anisotropic wet etching is used to generate alignment features, which allow precise self-alignment between respective parts during mating. Test components were fabricated to allow single-sided probing, revealing a dc contact resistance of 44 m and an insertion loss of 3.5 dB at 8.5 GHz; the latter being stable over at least 100 mating cycles. The insertion loss effectively represents the response of two connector pairs in series, leading to a value of approximately 1.8 dB for a single pair. Isolation between adjacent lines is >35 dB at 8.5 GHz, indicating good crosstalk rejection between neighbouring pins. The concept is amenable to meet the future needs of high-density, high-frequency connectors, enhancing the options for integrating MEMS devices with CMOS circuitry. (Some figures in this article are in colour only in the electronic version)