To extend the scope of application and enhance the functionality of wireless LANs, it is essential to increase the performance of high frequency components such as signal send/receive modules included in wireless communication equipment. Hitachi Cable provides various wireless-related products, and this article describes its compound semiconductors and antennas that are incorporated into wireless devices.
Comprised of GaAs wafers and epitaxial wafers that are essential for higher-speed wireless access
| Shift to compound semiconductors for higher performance At the heart of a wireless communication device is a high-frequency circuit called a "front-end module." This module includes a power amplifier and a send/receive timing switch, which significantly influence communications performance. With a shift to higher-speed wireless LAN standards such as IEEE802.11a and 11g in recent years, it is necessary to further increase performance of the power amplifier and switch. For example, the standards 11a and 11g use a communication scheme called "OFDM modulation." To exploit the strength of this scheme, it is very important to ensure high power amplifier output linearity and high switch isolation performance. In addition, related to the handling of high frequency signals, there are several issues to address: measures to control heat generation, increase in durability and reliability of the devices, and reduction of power consumption. To meet the requirements, manufacturers are replacing conventional silicon semiconductors with those made of compounds such as gallium arsenide (GaAs). GaAs compound semiconductors are superior to silicon semiconductors in operation speed, noise reduction, and resistance to high frequencies. |
 Gallium arsenide (GaAs) compound semiconductors |
From design of epitaxial structure to volume production
Hitachi Cable is one of the leading manufacturers providing GaAs compound wafers and epitaxial wafers for semiconductor devices. We have a track record in providing wafers for high-frequency circuits that extends back to the early days of mobile phones. Using our accumulated technological expertise and skills, we hold a large share of the market for GaAs compound wafers and epitaxial wafers for wireless LAN modules, which are now in increasing demand.
In cooperation with device manufacturers and foundries, Hitachi Cable can carry out the entire process, from design of optimum epitaxial layers based on uses and requirements to prototyping and volume production. This is our major strength. Since we carry out the entire wafer production process, we can quickly deliver wafers with optimum epitaxial structures based on customer needs.
We shall continuously contribute to the advancement of wireless technology such as mobile phones and wireless LANs by providing high-quality GaAs wafers and epitaxial wafers to meet customer needs.
