Microcoax

Microcoax refers to a category of ultra-small coaxial cables designed to carry RF signals in constrained spaces. They are used in medical devices, aerospace instrumentation, and high-density electronics where a low-profile, flexible interconnect is required. Microcoax cables aim to combine the advantages of traditional coax—shielding, controlled impedance, and repeatable performance—with a greatly reduced diameter.

Construction and specifications

A microcoax cable typically consists of a central conductor (often copper or copper-clad steel), a dielectric insulator (commonly PTFE or FEP), a shielding system (foil plus braided conductor or a combination thereof), and an outer jacket made from fluoropolymers or similar materials. Outer diameters commonly range from about 0.6 to 1.6 millimeters, and the characteristic impedance is usually 50 ohms or 75 ohms. The dielectric and shielding are selected to maintain impedance accuracy, minimize loss, and provide adequate shielding against EMI. These cables are engineered to withstand repeated flexing and small bend radii without significant degradation of electrical performance.

Performance and considerations

Compared with larger coax, microcoax cables exhibit higher attenuation per unit length at a given frequency due to their reduced cross-section. They offer good shielding when properly constructioned, enabling stable impedance and predictable microwave behavior up to several gigahertz, depending on the exact materials and geometry. Connectorization requires specialized micro-miniature terminations to preserve impedance and reliability.

Applications and markets

Microcoax is commonly found in endoscopic and catheter-based medical devices, MRI and other medical imaging wiring, small-form-factor RF assemblies in aerospace and defense, and compact high-frequency interconnects in consumer electronics and test equipment. The technology prioritizes small size, flexibility, and reliable RF performance in tight spaces.