In the 5G era, antenna miniaturization is a rigid need. According to the 5G development plan, the 5G frequency band can be divided into two major frequency bands, Sub-6GHz and millimeter wave. The channel capacity and signal transmission rate have increased significantly, and higher requirements are put forward on the number and performance of antennas. In terms of quantity, on the one hand, mobile phones supporting 5G communication also support all communication frequency bands of 4G/3G/2G. The realization of WiFi, Bluetooth, GPS, NFC and other functions also requires corresponding antennas, so the original antennas need to be retained. On the other hand, Massive MIMO technology achieves the purpose of increasing transmission channels by increasing the number of base station and mobile terminal antennas. The number of corresponding mobile phone antennas will also evolve from the current 2 or 4 to 8 or even 16, and the number of stand-alone antennas has greatly increased . At the same time, trends such as thin, thin, miniaturized, and full-screen smart phones have placed new requirements on the structure and form of mobile phones, and the loading space for antennas is getting smaller and smaller. Therefore, antenna miniaturization is the primary task.
LCP has excellent performance and has become a key material for 5G devices. LCP (Liquid Crystal Polymer, liquid crystal polymer) has good electrical properties, very stable dielectric properties in the high frequency range below 110GHz, and at the same time has better flexibility characteristics. Compared with traditional PI soft boards, LCP soft boards The bending radius is smaller, the number of bending resistance is more, the shape can be freely designed, and it is more suitable for the needs of high frequency, high speed and miniaturization.
In Sub 6GHz, each antenna signal needs a radio frequency transmission line to be transmitted to the radio frequency front end. The substantial increase in the number of antennas has brought an increase in the demand for radio frequency transmission lines. Traditional coaxial cables have low transmission loss and can be used for high-frequency signal transmission, but their size is too large to meet the design requirements of terminal manufacturers. The LCP soft board can carry multiple transmission lines in a 3-layer structure of only 0.2mm, which can ensure extremely low transmission loss while reducing the volume. It is expected to replace the traditional coaxial cable and become the mainstream solution in the future, bringing more space to the mobile phone. High utilization rate. In 2017, Apple used two LCP antennas and four LCP soft boards (upper antenna, lower antenna, relay cable, 3D Sensing camera) for the first time in iPhoneX. According to Appleinsider report, the number of LCP antennas in iPhone XS/XR/XS MAX increased to 6, LCP is leading a new wave of mobile phone antenna materials in the 5G era.
The accelerated penetration of LCP soft boards has driven the demand for BTB (Board to Board) connectors to increase accordingly. The BTB connector is mainly used to realize the connection of PCB or the connection of PCB and soft board. It is generally used in a pair of male (Plug) and female (Receptacle). The male connector is generally soldered to the FPC cable end, and the female connector is soldered. At the board end, it is mainly composed of the following parts:
Plastic shell (Housing): fix all terminals, play a fixed and insulating role;
Terminal (Contact): Contact conduction current;
Shell post: used for grounding and product fixation to prevent electromagnetic interference;
Other accessories: solder paste, Mylar, Cover…
BTB connector connects two FPCs
Benefiting from the changes in 5G signal transmission methods, BTB connectors are expected to usher in both volume and price increases. At present, BTB connectors in mobile phones are mainly used in modules such as battery, main and auxiliary boards, front and rear cameras, side keys, speakers, fingerprint recognition, etc. Each mobile phone requires about 10 sets of BTB connectors, and BTB connectors are more valuable , It is about 4-5 times of traditional coaxial cable. In the future, with the increasing demand for radio frequency connectors and the accelerated replacement of coaxial cables.