High-frequency PCBA manufacturing specializes in producing printed circuit boards and assemblies that operate at radio frequencies (RF) above 300 MHz or microwave frequencies above 3 GHz—critical for applications like 5G base stations, satellite communication systems, radar devices, and wireless routers. This process requires strict control over material selection, trace design, and manufacturing tolerances to ensure minimal signal loss, low crosstalk, and stable performance at high frequencies.

　　Material selection is the foundation of high-frequency PCBA manufacturing. Standard FR-4 substrates are unsuitable for high frequencies due to their high dielectric loss (Df > 0.02 at 1 GHz). Instead, specialized materials with low dielectric constant (Dk) and low dielectric loss are used:

　　PTFE (Teflon)-based substrates (e.g., Rogers RO4350B) with Dk = 3.48 and Df = 0.0037 at 10 GHz, ideal for 5G and radar applications;

　　Ceramic-filled PTFE substrates (e.g., Rogers RO4003C) for better mechanical stability and lower cost;

　　LCP (Liquid Crystal Polymer) substrates for ultra-high frequencies (above 60 GHz) and flexible high-frequency PCBs.

　　Trace design and fabrication require extreme precision to maintain signal integrity. High-frequency traces must be designed with controlled impedance (typically 50Ω or 75Ω) to match the impedance of components and connectors, preventing signal reflection. This is achieved by:

　　Calculating trace width and spacing based on substrate thickness and dielectric constant (e.g., a 50Ω trace on a 0.8mm RO4350B substrate requires a width of ~1.2mm);

　　Using smooth, uniform copper traces (electroplated copper with Ra < 0.5μm) to reduce skin-effect loss (a phenomenon where high-frequency signals travel along the surface of traces);

　　Minimizing trace length and avoiding sharp bends (which cause signal reflections) by using 45° angles or curved paths.

　　Manufacturing processes are optimized to avoid signal degradation:

　　Drilling: Laser drilling is used for microvias to minimize hole size and reduce parasitic capacitance;

　　Plating: Thin, uniform gold plating (0.5–1μm) is applied to traces and connectors to reduce contact resistance and improve corrosion resistance;

　　Assembly: Components (e.g., RF ICs, antennas, filters) are placed with high accuracy (±0.01mm) to ensure proper alignment with traces, and reflow soldering profiles are adjusted to prevent damage to heat-sensitive RF components.

　　Testing for high-frequency PCBs goes beyond standard electrical tests. It includes:

　　Network analyzer testing to measure S-parameters (reflection, transmission, and isolation) across the operating frequency range;

　　Time-domain reflectometry (TDR) to detect impedance mismatches;

　　Thermal testing to ensure performance stability under high-power operation.

　　High-frequency PCBA manufacturing is essential for telecommunications, aerospace, and defense industries. While it is more costly than standard PCBA manufacturing (materials alone can be 3–5 times more expensive), it enables the reliable operation of high-frequency electronic systems that are critical to modern communication and sensing technologies.