The **MA28FCA-R** is a specialized high-frequency coaxial connector, specifically a **2.8mm (K-type compatible) Female to SMA Female adapter**. These components are critical in RF (Radio Frequency) and microwave engineering for bridging different connector standards while maintaining signal integrity at high frequencies. --- ### 1. Technical Specifications The "2.8mm" designation refers to the inner diameter of the outer conductor. These connectors are designed to operate well into the millimeter-wave spectrum. | Feature | Specification | | :--- | :--- | | **Connector Type A** | 2.8mm (K-Type) Female | | **Connector Type B** | SMA Female | | **Frequency Range** | DC to 26.5 GHz (Typical) / up to 40 GHz | | **Impedance** | 50 Ohms | | **Body Material** | Stainless Steel (Passivated) | | **Contact Material** | Beryllium Copper (Gold Plated) | | **VSWR** | ≤ 1.20:1 (Frequency dependent) | --- ### 2. Key Electronic Components & Construction #### A. The Dielectric (Insulator) The internal spacing between the center pin and the outer shell is filled with a low-loss dielectric, usually **Air** or **PTFE (Teflon)**. In 2.8mm connectors, air dielectrics are common to minimize signal attenuation and phase shifting at high frequencies. #### B. Center Contacts * **Material:** Usually Beryllium Copper for its excellent spring properties and conductivity. * **Plating:** Hard gold plating is used to ensure low contact resistance and to prevent oxidation over thousands of mating cycles. #### C. Interface Geometry The 2.8mm interface is precision-engineered to be mechanically compatible with **SMA** and **3.5mm** connectors. However, the 2.8mm version offers a higher "cutoff frequency," meaning it can carry higher-frequency signals without the electromagnetic waves breaking down into unwanted "modes." --- ### 3. Common Applications Due to its precision and frequency range, the MA28FCA-R is used in specific high-tech environments: 1. **Test and Measurement:** Connecting a high-frequency Signal Generator (using 2.8mm) to a Device Under Test (DUT) that uses standard SMA. 2. **Telecommunications:** 5G infrastructure testing where frequencies exceed the 18 GHz limit of standard SMA connectors. 3. **Aerospace & Defense:** Radar systems and satellite communication modules requiring ruggedized, high-performance interconnects. --- ### 4. Handling Precautions * **Torque:** Always use a calibrated torque wrench. Over-tightening can deform the internal pins. * **Cleanliness:** At 26.5GHz+, a microscopic piece of dust can act as a huge impedance mismatch. Use compressed air or isopropyl alcohol to clean the interfaces. * **Alignment:** Ensure the pins are perfectly centered before threading to avoid "stubbing" the female socket.