F-Substrate connectors are specialized RF connectors designed to interface directly with planar transmission lines on substrates such as PCBs or hybrid circuits. They are typically used in applications requiring low-profile, surface-level connectivity, often in the microwave and millimeter-wave frequency ranges. These connectors provide a transition between coaxial cables and planar circuits like microstrip or stripline, ensuring minimal signal loss and reflection. F-Substrate connectors are commonly employed in high-frequency testing, aerospace, and compact RF modules where precision, repeatability, and minimal disruption to the signal path are critical.