RG178 coaxial cable with SMA to I-PEX

The RG178 Coaxial Cable Assembly with SMA to I-PEX Connectors is an essential, high-performance jumper cable designed for seamless RF signal transmission in space-constrained and high-temperature applications. This custom-engineered cable assembly marries the robust, industry-standard SMA (Sub-Miniature A) connector with the ultra-compact I-PEX (also known as U.FL, MHF, or IPX) connector, utilizing the highly flexible and temperature-resistant RG178 coaxial cable. It serves as a vital bridge between integrated circuit boards or internal wireless modules, which often use the tiny I-PEX port, and external antennas or testing equipment that commonly utilize the threaded, secure SMA interface. Engineered for a stable 50 Ohm impedance and operation up to 6 GHz, this assembly is the ideal choice for demanding, miniaturized wireless devices where reliability and minimal signal loss are paramount.

Key Features and Technical Specifications

This cable assembly is specifically designed to overcome the physical and electrical challenges of modern miniaturized RF systems, offering a superior balance of size, flexibility, and performance.

Premium Cable Construction: RG178 Coax

The core of this assembly is the RG178 coaxial cable, known for its exceptional characteristics:

• Ultra-Miniature Diameter: With an outer diameter of approximately 1.8 mm (0.071 inches), the RG178 cable is extremely thin, making it perfect for routing within compact device enclosures and dense circuit boards.

• High-Temperature Rating: The cable's dielectric is made from PTFE (Polytetrafluoroethylene) and the jacket from FEP (Fluorinated Ethylene Propylene), allowing it to maintain stable performance across a wide operating temperature range, typically from −55∘C to +200∘C. This makes it highly reliable in environments where heat generation is a concern.

• Low Signal Attenuation (for its size): Despite its small size, the RG178 utilizes a silver-plated copper conductor and shield, which helps minimize signal loss and provides excellent shielding effectiveness against electromagnetic interference (EMI), ensuring signal integrity for short-distance applications.

• Exceptional Flexibility: The cable’s construction, including a stranded center conductor, provides superior flexibility and a tight bend radius, easing installation in complex mechanical layouts.

Connector Integrity: SMA and I-PEX

The cable assembly features a high-quality connector pair to ensure secure, reliable connections:

• SMA Connector (Standard RF Interface): The SMA end, often a bulkhead jack (female) with a threaded coupling nut, provides a highly durable and stable connection. Its robust design is widely used for connecting to external antennas, access points, instrumentation, or bulkheads, offering high mechanical strength and stable electrical performance up to 6 GHz and often higher.

• I-PEX/U.FL Connector (Ultra-Miniature Interface): The I-PEX (or U.FL) connector is one of the smallest available RF connectors. It is designed for board-level installation, offering a simple snap-on/snap-off mating mechanism. This micro-miniature form factor is crucial for connecting to embedded wireless modules, GPS receivers, and other small PCB components.

Electrical Specifications

Versatile Application Scenarios

The unique combination of the secure SMA interface and the miniature I-PEX connection on a flexible, high-temperature cable makes this assembly indispensable in modern electronic design.

Wireless Communication Systems

This cable is a core component for connecting embedded Wi-Fi, Bluetooth, Zigbee, LoRa, or cellular (2G/3G/4G/LTE/5G) modules to external antennas. This is critical in:

• Mini PCI/PCI-e Cards: Linking the radio module on a mini-PCI or M.2 card (often with I-PEX ports) to a bulkhead SMA connector for an external, high-gain antenna.

• IoT Devices and Gateways: Providing the antenna connection in compact, consumer, and industrial Internet of Things (IoT) sensors, routers, and gateways where board space is severely limited.

• Handheld Radios and Mesh Networks: Connecting internal radio circuits (like those used in Meshtastic or other peer-to-peer communication systems) to rugged external antennas for improved range.

Test and Measurement Equipment

The RG178 cable assembly is frequently used in the lab to connect miniaturized circuit boards or prototypes to larger, standard testing equipment:

• RF Prototyping and Development: Connecting a new RF module (via I-PEX) to a network analyzer or spectrum analyzer (via SMA) for performance testing and calibration.

• Manufacturing Quality Control: Used as a reliable jumper for automated testing jigs to quickly connect and disconnect a Device Under Test (DUT) to test equipment.

Aerospace and Defense

Its high-temperature rating and robust construction are key assets in challenging environments:

• Avionics: Used within aircraft communication and navigation systems where temperature and vibration resistance are non-negotiable.

• Drones and UAVs: Its lightweight, compact form factor is ideal for drone communication links, telemetry, and GPS systems where every millimeter and gram counts.

Conclusion: The Reliable Choice for Miniaturized RF

The RG178 Coaxial Cable Assembly with SMA to I-PEX Connectors delivers a high-quality, practical solution for complex RF interconnect needs. It resolves the classic engineering challenge of connecting ultra-small, integrated wireless components to external, robust antennas or testing infrastructure. By leveraging the flexibility and thermal stability of the RG178 cable, this assembly ensures consistent, low-loss signal integrity across critical high-frequency bands. Whether you are developing the next generation of IoT smart devices, improving the connectivity of a professional radio, or building complex test setups, this RG178 assembly is the definitive, reliable link for your miniaturized wireless architecture.