Hitachi Cable, Ltd. has announced the successful development of a compact coupler designed for the TransferJet*1 short-range, high-speed wireless transfer system. The company will begin shipping samples in fall 2010.

TransferJet is a short-range, high-speed wireless transfer technology standardized by the TransferJet Consortium. In place of ordinary antennas that transmit and radiate electromagnetic waves, this technology is based on a coupler, a transmitting/receiving antenna based on inductive electric waves. The system offers numerous advantages: high speeds comparable to the UWB*2 (Ultra-Wide Band) system and the simplicity of the NFC*3 (Near-Field Communication) system adopted by FeliCa.*4 These benefits allow users to transfer data at rates of up to 560 Mbps simply by bringing two devices incorporating couplers within several cm of each other. Allowing quick, easy, cable-free transfers of large data volumes, including image, audio, and video data, the technology is expected to find applications in various digital products, including TVs, PCs, digital cameras, and mobile phones.

Hitachi Cable has produced internal wireless-communication antennas for notebook PCs and other mobile equipment for many years. To expand its product lineup and operations in this business segment, Hitachi Cable has concluded a license agreement for TransferJet with Sony Corporation and developed a TransferJet-compatible compact coupler. Hitachi Cable has supplied this product to customers since December 2009.

The compact coupler recently developed by Hitachi Cable is a board-edge-radiating type that provides transmitting/receiving performance sufficient for mobile devices in which space limitations tend to be tight, like digital cameras. Hitachi Cable will begin shipping samples in fall 2010.

The newly-developed board-edge-radiating type coupler measures no more than 0.3 mm in thickness. Conventional board-top-surface-radiating types perform wireless communications via the board top panel (20 mm × 20 mm). In contrast, the new board-edge-radiating type allows wireless communication via the board edge (25 mm × 0.3 mm or less), increasing board mounting flexibility and facilitating incorporation of the coupler into compact devices such as digital cameras. As with conventional board-top-surface-radiating types, the radiating element can be constructed from standard components (e.g., double-layer printed circuit boards), making the new coupler easy to mass-produce at low cost. Using thin film (e.g., FPC; Flexible Printed Circuits) as a substrate will also make it possible to produce a compact coupler measuring no more than 0.1 mm in thickness.

Hitachi Cable will continue to develop smaller and thinner couplers and expand its lineup with the goal of increasing annual sales of compact couplers to 300 million yen in fiscal 2012.

*1	TransferJet is a trademark of Sony Corporation.
*2	UWB (Ultra-Wide Band) refers to a wireless communication method that transmits and receives data using a frequency band of 500 MHz and higher.
*3	NFC (Near-Field Communication) refers to a wireless communications technology designed for bilateral communications between two devices at transfer rates of 100 to 400 kbps over very short distances (around 10 cm).
*4	FeliCa is a registered trademark of Sony Corporation.

Specifications of the compact coupler

Item		Specification
External dimensions	Width	25×10(mm)
	Thickness	0.1~0.3(mm)
Frequency		4.20~4.76(GHz)
Coupling strength		|S21|>-25(dB)
Flatness (when coupled)		<3.0(dB)
Non-coupling strength		|S21|<-50(dB)
Sample price		1,000 yen/unit (Min. 5 units)

Reference: Compact coupler types classified by radiating direction

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External view of compact coupler

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TransferJet Consortium website

• http://www.transferjet.org/en/index.html