(1) Different working frequencies of signals entail distinct requirements for PCBs.
(2) PCBs operating below 1GHz can opt for FR4 due to its low cost and mature multi-layer pressing technology. However, when dealing with low impedance signal input and output (e.g., 50 ohms), meticulous consideration must be given to transmission line characteristic impedance and inter-line coupling during wiring. Nonetheless, a drawback lies in the variability among FR4 plates from different manufacturers and batches, manifested in differing doping levels and dielectric constants ranging from 4.2 to 5.4, leading to instability.
(3) For optical fiber communication products operating above 622Mb/s and small signal microwave transceivers functioning above 1GHz but below 3GHz, modified epoxy resin materials like S1139 are suitable choices. These materials offer relatively stable dielectric constants up to 10GHz, alongside low costs and compatibility with multi-layer pressing processes akin to FR4. Therefore, for tasks such as 622Mb/s data multiplexing branching, clock extraction, small signal amplification, and optical transceivers, these plates are recommended despite their slightly higher production costs compared to FR4 (approximately 4 cents/cm2). However, it’s worth noting that these substrates may not offer the same thickness uniformity as FR4 variants.
Alternatively, one may consider the RO4000 series such as RO4350. However, the prevalent usage domestically is confined to RO4350 double panels. A limitation arises from the incomplete availability of various thicknesses for these plates, hindering convenient production of multi-layer printed boards. For instance, RO4350 plates typically come in 10mil, 20mil, 30mil, and 60mil thicknesses, yet imported varieties are scarce, thereby constraining laminate design options.
(4) Microwave circuits below 3GHz requiring robust signal handling, such as power amplifiers and low noise amplifiers, are best served by double-sided panels akin to RO4350. RO4350 exhibits stable dielectric constants, low loss factors, excellent heat resistance, and processing technology comparable to FR4, albeit at a slightly higher cost (approximately 6 cents more/cm2).
(5) Microwave circuits operating above 10GHz, including power amplifiers, low noise amplifiers, and up/down frequency converters, necessitate boards with heightened performance standards. Thus, it is advisable to employ double-sided boards with performance akin to F4.
(6) Multilayer PCBs for wireless mobile phones demand substrates with low dielectric constants, minimal loss factors, cost-effectiveness, and high dielectric shielding capabilities. Optimal choices include plates exhibiting performance similar to PTFE (e.g., American/European varieties), or a combination of FR4 and high-frequency boards bonded to form a low-cost, high-performance laminate.
(2) PCBs operating below 1GHz can opt for FR4 due to its low cost and mature multi-layer pressing technology. However, when dealing with low impedance signal input and output (e.g., 50 ohms), meticulous consideration must be given to transmission line characteristic impedance and inter-line coupling during wiring. Nonetheless, a drawback lies in the variability among FR4 plates from different manufacturers and batches, manifested in differing doping levels and dielectric constants ranging from 4.2 to 5.4, leading to instability.
(3) For optical fiber communication products operating above 622Mb/s and small signal microwave transceivers functioning above 1GHz but below 3GHz, modified epoxy resin materials like S1139 are suitable choices. These materials offer relatively stable dielectric constants up to 10GHz, alongside low costs and compatibility with multi-layer pressing processes akin to FR4. Therefore, for tasks such as 622Mb/s data multiplexing branching, clock extraction, small signal amplification, and optical transceivers, these plates are recommended despite their slightly higher production costs compared to FR4 (approximately 4 cents/cm2). However, it’s worth noting that these substrates may not offer the same thickness uniformity as FR4 variants.
Alternatively, one may consider the RO4000 series such as RO4350. However, the prevalent usage domestically is confined to RO4350 double panels. A limitation arises from the incomplete availability of various thicknesses for these plates, hindering convenient production of multi-layer printed boards. For instance, RO4350 plates typically come in 10mil, 20mil, 30mil, and 60mil thicknesses, yet imported varieties are scarce, thereby constraining laminate design options.
(4) Microwave circuits below 3GHz requiring robust signal handling, such as power amplifiers and low noise amplifiers, are best served by double-sided panels akin to RO4350. RO4350 exhibits stable dielectric constants, low loss factors, excellent heat resistance, and processing technology comparable to FR4, albeit at a slightly higher cost (approximately 6 cents more/cm2).
(5) Microwave circuits operating above 10GHz, including power amplifiers, low noise amplifiers, and up/down frequency converters, necessitate boards with heightened performance standards. Thus, it is advisable to employ double-sided boards with performance akin to F4.
(6) Multilayer PCBs for wireless mobile phones demand substrates with low dielectric constants, minimal loss factors, cost-effectiveness, and high dielectric shielding capabilities. Optimal choices include plates exhibiting performance similar to PTFE (e.g., American/European varieties), or a combination of FR4 and high-frequency boards bonded to form a low-cost, high-performance laminate.
