With the deployment of 5G and the outlook toward 6G, flexible printed circuits (FPC) are facing more stringent requirements in high‑frequency, high‑speed signal transmission, and dielectric constant (Dk) and dielectric loss factor (Df) are key parameters determining signal attenuation and time delay. This paper reviewed the current state and application challenges of key insulating materials for FPC, focusing on the performance advantages, modification strategies, and industrialization progress of modified polyimide (MPI) and liquid crystal polymer (LCP) as high‑frequency dielectric substrates. It also analyzed the challenges in formulation design, filler selection and process compatibility of modified polyimide and polyolefin systems used for high-frequency pure adhesive films. In addition, the potential of low‑Dk/Df polymers such as fluorinated resins was evaluated, the trade-offs among electrical properties, processability and cost were discussed, and suggestions for future research and industrialization pathways of high-frequency FPC materials were proposed.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |