NTT Develops Fingertip-sized Millimeter Wave Dish Antenna

May 12, 2009 18:42 Hiroki Yomogita, Nikkei Electronics

Nippon Telegraph and Telephone Corp (NTT) developed a compact antenna module for 60GHz wireless communications.

Based on a multilayer ceramic substrate technology, the company realized a millimeter wave parabolic antenna with a size of only 12mm². The new antenna reportedly has performance comparable to that of an array antenna. It is intended for use in mobile phones and networks among home audio-video electronics.

With this antenna module, NTT prototyped a wireless transmission system with the maximum transmission rate of 10Gbps, and will exhibit it at Wireless Technology Park 2009, which runs from May 12 to 13, 2009, at Pacifico Yokohama in Kanagawa Prefecture, Japan.

The new parabolic antenna module is designed for 60GHz wireless communications and measures 12 x 12 x 1mm. By utilizing the multilayer structure of a low temperature co-fired ceramic (LTCC) substrate, the company simulated the mirror structure of a parabolic antenna in the module substrate.

Because the antenna module has RF circuit components for millimeter wave communications on its back side, it also works as an RF circuit module. When combined with a baseband processing circuit, a MAC circuit, etc, the module can be utilized for the millimeter wave band wireless communications.

The new antenna ensures a gain of 16dBi, which is equivalent to that of an array antenna. The antenna module has an operating bandwidth of 57-66GHz and a beam angle of 20°.

The company not just enhanced the packaging technology but also made improvements to the signal transmission method. During transmission, the module divides a 10Gbps signal into multiple frequency channels and wirelessly transmits them in parallel. NTT's prototype system ensures a transmission rate of 10Gbps by transmitting four channels in parallel (2.5Gbps per channel).

While the prototype system uses QPSK for the primary modulation method, the data transmission rate can be further enhanced by utilizing a higher order modulation scheme such as the 16-level QAM, the company said. The prototype system is compliant with a transmission method that is presently being standardized by the 802.15.3c working group.

Based on the new antenna module, NTT intends to develop a 1cc-class ultrasmall wireless module, aiming at a power consumption of about 500mW and a component price of ¥10,000 (approx US$102) or lower. Also, in order to mount the module in mobile phones, etc, the company plans to further reduce the size, the power consumption and the component price.

For indoor wireless transmission, the company expects to install multiple antenna modules in a home.

"When performing millimeter wave transmission in a home, we may be faced with difficulties such as the directness of millimeter waves," said Kazuhiro Uehara, senior research engineer, supervisor and group leader at the Wireless Systems Innovation Laboratory of NTT. "By developing a compact millimeter wave module and installing it in plural locations in a house, signal transmission can be continued through a different transmission path even if an obstacle is located on one of the paths."

Furthermore, the company expects to use the module for wirelessly connecting flat-screen TVs and set-top boxes so that HDTV images can be exchanged between them.

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