5G Circulator Magnets

5G has earned much attention due to its application prospect in vehicle networking and industrial IOT. While the development of 5G has also accelerated the mass production of 5G circulator magnets. Circulators, as an essential element of radio-frequency subsystem, have been largely used in wave filter, duplexer, and reflection amplifier of 2G – 4G wireless base station. The network capacity requirement of 5G is much higher than 4G, and Massive MIMO Technology is one of the critical technologies to solve network capacity items. To support Massive MIMO Technology, antenna channel of 5G should be increased to 64-channel from 4-channel and 8-channel. Then consumption of radio-frequency devices rose by several times with the increasing channels. Besides, 5G need more base station density than 4G to achieve the improvement of working band.

Circulator is a radio-frequency passive device of mobile communication field which allows microwave or radio-frequency signal transmits in unidirectional ring. The one-way transmission characteristics are built on the gyromagnetic property of gyromagnetic ferrite. Gyromagnetic ferrite, also know as micro ferrite, is a type of ferrite material which polarization plane constantly rotates around transmission direction when the plane polarized electromagnetic wave travel through the ferrite in one particular direction under high frequency magnetic field. The one-way transmission characteristics are mainly served for mutual isolation between level and level or between level and system of radio-frequency equipment to guarantee working independently, therefore, protect signal source and reduce frequency pulling, interference or unnecessary radiation which will efficiently improve circuit quality.

Isolator is another device that helps electromagnetic wave to achieve one-way transmission. The power is completely transferred to load when electromagnetic wave transfers along the forward direction, then reflected wave from the load generated relatively high attenuation. Such one-way transmission characteristics can apply to isolate the power reflection from the load, and thus protect the signal source. In reality, the circulator can become isolator as long as one of the port connects to termination resistor.

Permanent magnets in circulator can apply the constant direct-current magnetic field to gyromagnetic ferrite, then directly affect working band, temperature stability and other parameters of circulator. Both ferrite and Samarium Cobalt magnets can be utilized as circulator magnets. Ferrite magnets may off-center and cause circulator’s performance become unstable. Ferrite also cannot satisfy the miniaturization demand in 5G circulator at the same time. Therefore, Sm₂Co₁₇ magnets are chosen as 5G circulator magnets even do not have the obvious cost advantage. With the increasing construction of 5G base station in nearly two years, demand for Sm₂Co₁₇ 5G circulator magnets is experiencing explosive growth.