SoftBank Corp developed antenna technology which broadens the use cases for terahertz (THz) spectrum, demonstrating the reliability of the band to support connected vehicles during a field trial in Tokyo.

In a statement, the operator explained it transmitted 300GHz signals to vehicles in verification tests by limiting the communication area to roads, which prevented power dispersion.

SoftBank developed a compact, proprietary cosecant pattern antenna, also known as a constant height pattern, which allows for maintaining high antenna gain while ensuring a system with constant power reception. The design aims to send more radio energy in a specific direction.

Given the shorter wavelength of THz spectrum, the company was able to reduce the height of antennas for the base station and terminal to about 1.5cm from 2.9cm for a typical 2.4GHz receiver.

Although tests were limited to 140m due to road length restrictions, the operator believes since there was enough power to reach the cell-edge, even longer-distance coverage is possible.

Due to significant propagation loss in the THz band, the company said the spectrum is generally only used for fixed wireless access and NFC. Researchers have tested a narrow beam of high-gain antennas to extend communication distance to make THz communication more practical.

Because THz airwaves have a wider frequency band than the mmWave band used in 5G, the spectrum holds promise for ultra-high-speed wireless communication for the beyond 5G and 6G era, SoftBank stated.