BLACKSBURG, Va., Sept. 12, 1996 -- Antennas for hand-held radios and cellular phones can be safer and perform better, Virginia Tech electrical engineer Warren Stutzman has demonstrated.
Stutzman along with co-inventor J. Randall Nealy received a patent on July 30, 1996, #5,541,609 for a high-performance, low radiation-hazard antenna for hand-held devices operating at 1900 megahertz (MHz) and above. These frequencies are now being pioneered to provide more communications to supplement the crowded cellular telephone bands that operate at 800 MHz.
With conventional antennas, the signal is transmitted in all directions and part of it is lost due to absorption by the user's head. Stutzman's and Nealy's "Safetenna" eliminates transmission in the direction where the signal would be blocked by the user's head, thereby avoiding potentially harmful absorption of power by the user's body.
Tests of Safetenna demonstrate that total radiated power is unchanged by the presence of the operator; thus, reduction of the overall radiated power by a factor of three that is typical of conventional antennas is avoided. In addition, there are no gaps in the directional properties of Safetenna as there are with conventional antennas. That is, conventional antennas experience a signal reduction by a factor of 60 due to the user's head being in the way.
"The goal of improved performance for communication is in harmony with safety; there is no trade-off," explains Stutzman, who is a faculty member in the Center for Wireless Telecommunications at Virginia Tech.
Safetenna is available for licensing from Virginia Tech Intellectual Properties Inc.