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1. When designing, the substrate telecommunications engineer has selected the appropriate dielectric constant, dielectric thickness, and copper foil thickness based on the required impedance. Therefore, when accepting an order, it is necessary to verify carefully to ensure that all design requirements are met. 2. Precision requirements for transmission line fabrication: For the transmission of high-frequency signals, very strict requirements are placed on the characteristic impedance of the printed conductors; thus, the precision required for manufacturing the transmission lines is generally ±0.02 mm (transmission lines with a precision of ±0.01 mm are also common). The edges of the transmission lines must be extremely smooth, with no minor burrs or gaps allowed. 3. Coating requirements: The characteristic impedance of high-frequency microwave board transmission lines directly affects the quality of microwave signal transmission. The value of the characteristic impedance is related to the thickness of the copper foil; this is especially true for microwave substrates with via metallization. The thickness of the coating not only affects the total thickness of the copper foil but also influences the precision of the conductors after etching. Therefore, the thickness and uniformity of the coating must be strictly controlled. 4. Requirements regarding mechanical processing: Firstly, the material used for high-frequency microwave boards differs significantly from the epoxy glass fiber cloth material used in printed circuit boards in terms of mechanical processing ； Secondly, the processing precision required for high-frequency microwave boards is much higher than that for printed circuit boards; generally, the dimensional tolerance is ±0.1 mm (for higher precision levels, it is usually ±0.05 mm or -0.1 mm to 0 mm). 5. Requirements for characteristic impedance: As discussed earlier, characteristic impedance is a fundamental requirement for high-frequency microwave circuits; failing to meet this requirement renders all efforts pointless.