초록 ▼

A portable telephone has an antenna structure that directs radiated energy away from the user's head. In one embodiment, the telephone employs an internal transmission antenna, and a metallic surface is interposed between the antenna and the user's head. The metallic surface is spaced apart from the

A portable telephone has an antenna structure that directs radiated energy away from the user's head. In one embodiment, the telephone employs an internal transmission antenna, and a metallic surface is interposed between the antenna and the user's head. The metallic surface is spaced apart from the radiating element of the transmission antenna by one-quarter of the effective wavelength, so as to maximize the reflection of energy away from the user's head. The metallic surface is preferably non-planar to disperse the reflected radiation over a wider area than would be the case with a planar surface. In an alternative embodiment, a pair of spaced-apart planar array transmission antennas are used to preferentially steer the radiated power away from the telephone user's head.

대표청구항 ▼

1. A portable telephone comprising: a radio frequency transmitter having an operating frequency; a radio frequency antenna coupled to the transmitter; a non-planar metallic shield spaced apart from the antenna so as to be disposed between the antenna and a user of the portable telephone; and a

1. A portable telephone comprising: a radio frequency transmitter having an operating frequency; a radio frequency antenna coupled to the transmitter; a non-planar metallic shield spaced apart from the antenna so as to be disposed between the antenna and a user of the portable telephone; and a layer of dielectric material disposed in a space between said radio frequency antenna and said non-planar metallic shield; wherein a distance between said non-planar metallic shield and said radio frequency antenna is substantially equal to 1/4 of an effective wavelength of a space containing the dielectric material. 2. The portable telephone of claim 1 wherein the non-planar metallic shield is curved. 3. The portable telephone of claim 1 wherein the non-planar metallic shield is folded. 4. The portable telephone of claim 1 wherein the non-planar metallic shield is corrugated. 5. The portable telephone of claim 1 wherein the antenna comprises a dipole. 6. The portable telephone of claim 1 further comprising a radiation monitor. 7. The portable telephone of claim 1 wherein the antenna comprises a dipole. 8. The portable telephone of claim 1 wherein the antenna comprises a cross dipole. 9. The portable telephone of claim 1 wherein the antenna comprises a patch antenna. 10. The portable telephone of claim 1 wherein the antenna comprises a cross patch antenna. 11. A portable telephone comprising: a radio frequency transmitter having an operating frequency; a radio frequency antenna coupled to the transmitter; a layer of dielectric material disposed on at least a portion of said radio frequency antenna; and a metallic shield disposed on said layer of dielectric material so as to be positioned between the antenna and a user of the portable telephone; wherein the metallic shield is spaced apart from the antenna by a distance approximately equal to 1/4 of an effective wavelength in the dielectric material of said operating frequency. 12. The portable telephone of claim 11 wherein the metallic shield is non-planar. 13. The portable telephone of claim 11 wherein the antenna comprises a dipole. 14. The portable telephone of claim 11 further comprising a radiation monitor. 15. A portable telephone comprising: a radio frequency transmitter having an operating frequency; a radio frequency antenna coupled to said radio frequency transmitter; a layer of dielectric material disposed on at least a portion of said radio frequency antenna; said layer of dielectric material having a prescribed dielectric constant; and a metallic shield disposed on said layer of dielectric material and positioned between said radio frequency antenna and a user of the portable telephone; wherein a distance between said metallic shield and said radio frequency antenna is a predetermined fraction of an effective wavelength of a space containing the dielectric material. 16. The portable telephone of claim 15, wherein said dielectric constant is selected such that said predetermined fraction is 1/4 of said effective wavelength. 17. The portable telephone of claim 15, wherein said dielectric constant is 100. 18. The portable telephone of claim 15, wherein said dielectric constant is greater than 100. 19. The portable telephone of claim 15, wherein the distance between said metallic shield and said radio frequency antenna is 0.75 cm or less. 20. The portable telephone of claim 15, wherein the dielectric constant is 50. 21. The portable telephone of claim 15, wherein the dielectric constant is greater than 50.