FR4 substrate and Rogers RO4350B high-frequency microwave substrate are two mainstream circuit board base materials in the electronic industry, which are hugely different in dielectric constant, dielectric loss, temperature stability, frequency adaptation range, mechanical property and application field. FR4 is the most universal general-purpose circuit substrate, while RO4350B is a professional high-performance high-frequency special substrate customized for radio frequency and microwave signal transmission.

In terms of core electrical performance parameters, FR4 glass fiber epoxy resin substrate has a fixed dielectric constant ranging from 4.2 to 4.4, with large fluctuation range and poor uniformity. Its dielectric loss is relatively high, and the signal attenuation loss will rise sharply when working in high-frequency band above 1GHz, which is easy to cause signal distortion, phase offset and transmission efficiency reduction. RO4350B high-frequency substrate is made of reinforced hydrocarbon ceramic composite material, with stable and accurate dielectric constant stably maintained at 3.48, ultra-low stable dielectric loss, extremely low signal transmission attenuation in high-frequency and microwave frequency bands, excellent phase consistency and signal integrity, which can ensure long-distance stable transmission of high-frequency radio frequency signals without distortion.

In terms of high temperature resistance and environmental stability, the glass transition temperature of ordinary FR4 substrate is relatively low. Under continuous high-temperature working environment, the material is prone to thermal expansion deformation, dielectric parameter drift and insulation performance decline, and its weather resistance and damp heat resistance are general, easily affected by external temperature and humidity changes to interfere with circuit electrical performance. RO4350B high-frequency material has excellent thermal dimensional stability, low thermal expansion coefficient, stable physical and electrical properties in wide temperature range, strong resistance to high temperature aging, damp heat erosion and chemical corrosion, and its electrical parameters will not fluctuate obviously with changes in external working environment, which fully meets the long-term stable working requirements of high-frequency communication equipment in harsh environments.

In terms of processing performance and production cost, FR4 substrate has mature production technology, simple circuit board processing flow, easy drilling, etching, pressing and welding operation, sufficient raw material supply and low market price, which is the preferred substrate for most low-frequency digital circuits and ordinary analog circuits. RO4350B high-frequency substrate has strict requirements for production processing technology, high precision requirements for board making, difficult hole processing and line production, low production efficiency, expensive raw material price and high comprehensive board making cost, so it is not suitable for ordinary low-frequency circuit mass production.

In practical application scenarios, FR4 substrates are widely used in consumer electronic mainboards, household appliance control boards, industrial low-frequency control circuits, ordinary communication low-speed signal boards and various civilian universal printed circuit boards, focusing on cost performance and basic circuit conduction functions. RO4350B high-frequency substrates are specially used in 5G communication base station radio frequency modules, microwave radar circuits, satellite communication equipment, high-frequency antenna boards, wireless radio frequency signal transceivers and aerospace high-frequency electronic systems, focusing on high-frequency signal transmission accuracy, low loss performance and high environmental stability, which are irreplaceable core base materials in the field of high-frequency wireless communication.