Daido Steel Co., Ltd. (President: Takashi Ishiguro) has developed the permalloy*3 foil STARPAS® with the world's highest level of noise suppression effect against the magnetic noise from kHz to MHz band, and we started selling it in January. The noise band has been difficult to be solved so far among increasing electromagnetic wave noise*2 in communication, IoT device*1, electrification of automobiles and popularization of autonomous driving.
STARPAS® is the foil products which thickness is between 10 and 30 micrometers made of MEN®PC-2S with our highest permeability *4 material, and their relative permeability*5 at 100kHz is more than 4,800 (2.7 times or more of MEN®PC 2S with a thickness of 100 micrometers) and one at 1MHz is more than 1,400 (3.9 times or more of the material above), which has the world's highest level of magnetic noise suppression effect.
In addition, because STARPAS® is provided as hoop or sheet, it can be easily stamped and formed to various shapes, and has superior workability. Therefore it can be stuck on the apparatus which wants to evade the influence of a device and the noise that an electromagnetic wave noise generates. The use as the laminated seat through the insulating material is possible, too.
1．Background
In the recent information-oriented society, a lot of digital devices are used by the evolution of the mobile communication system and the spread of IoT apparatuses. ICs for these devices have some issues on EMC*6 which they are operated at a high frequency and lower supply voltage. Therefor the electromagnetic wave noise is easily emitted and susceptible to noise from other sources due to low power consumption. In addition, EMC environment against the electromagnetic wave noise to devices is becoming more stringent by wireless charging.
On the other hand, it is also known that the electromagnetic wave noise emitted from inverters for drive motors affects the radio reception performance and the motion of control ECU*7 in automobiles. And in ADAS, it is getting more important to suppress noise, due to higher volume and higher speed transmit data from various sensors in the future.
Usually, passive components*8 such as cores, electromagnetic wave absorbers and shield are used to remove the noise for these measures. However, it is not enough to remove the noise (mainly magnetic noise) below several tens of MHz by sintered ferrite which is conventional electromagnetic wave absorber material. So higher permeability electromagnetic wave absorber material has been demanded.
With the downsizing of the mobile device, high-density implementation of the IC advances. Therefore, the form of the electromagnetic wave noise suppression diversifies. As the shielding method has changed from entire circuits to specific ICs package, thinner electromagnetic wave absorber material is required to realize compact ICs package with easy pasting up. Sintered ferrite has some issues in thickness and workability (bending, stamping and pasting up). Nano crystalline ribbons also has some problems that it is too brittle to be handed and bended after magnetic annealing. Therefore, the thin magnetic noise suppression materials with high permeability at less than several tens of MHz and also easy to be attached on devices are required. In general, the permeability of the material decreases accompany with increase of frequency or decrease of thickness. However, a thin STARPAS® maintains high permeability without paying big sacrifice even at high frequencies.
2. Products Lineup
| Product name | Thickness | Relative permeability at 100 kHz | Relative permeability at 1 MHz |
| STARPAS®-10PC2S | 10μm | 5,200 | 3,500 |
| STARPAS®-20PC2S | 20μm | 5,000 | 2,000 |
| STARPAS®-30PC2S | 30μm | 4,800 | 1,400 |
| Manufacturable shape | Hoop material, and sheet |
| Manufacturable dimensions | Thickness: 10μm, 20μm, and 30μm, width: 100mm or less |
Glossary
＊1 IoT device
Anything connected to Internet. It has sensor and communication functions.
＊2 Electromagnetic wave noise
Electromagnetic wave from the alternating current, which is not intended to be generated.
＊3 Permalloy
One of soft magnetic materials (It sticks to a magnet and loses its magnetism when the magnetic field is removed) and it is an alloy of iron-nickel having the highest permeability among them.
＊4 Permeability
A numerical value representing the magnetism, which indicates the ease of magnetization of a material (ease of magnetic flux passage). Proportional constant representing the relationship between the strength of the magnetic field and the magnetic flux density. One index of magnetic shield performance.
＊5 Relative permeability
Relative permeability Relative ratio by vacuum permeability (4πx10-7 H/m)
＊6 EMC
Electromagnetic compatibility. Electromagnetic resistance or non-interference of electric equipment.
＊7 ECU
Electronic controllers.
＊8 Passive component
Passive component Capacitors, resistors, coils, and other components