Flexible antenna for a personal communications device

#1. Field of the Invention

#The present invention relates to antennas for portable radiotelephones. The invention is more specifically directed to antenna configurations which are disposed within the housing of the hand-held communications equipment.

#2. Description of the Related Art

#FIGS. 1(a), 1(b), and 1(c) show front, side and top views, respectively, of a portable radiotelephone illustrating an antenna configuration according to one embodiment of the present invention.

#FIGS. 2(a) and 2(b) illustrate a relation between the first partial-loop antenna 14 of a portable radiotelephone in FIG. 1 and a user 23 concerning the telephone operating position and distance "h".

#FIG. 3(a) is an explanatory view illustrating the distance "h" from the axis of symmetry of a general loop antenna 17 to a ground plane 9.

#FIGS. 1(a), 1(b), and 1(c) show front, side and top views, respectively, of a portable radiotelephone illustrating an antenna configuration according to one embodiment of the present invention. A portable radiotelephone In the figure has a main housing 11, a microphone 12, a loop antenna 13 (including first and second partial-loop antennas 14 and 15), and a fulcrum or joint 16 for folding up and putting a lid 18 on a surface of the main housing 11. Other numerals in the figure are equivalent to those of the conventional art discussed earlier in FIG. 9 and will not be mentioned here. The lid 18 contains the microphone 12 and the second partial-loop antenna 15. The microphone 12 in this embodiment is located approximately at the center of the circle of the second partial-loop antenna 15, which may make the portable radiotelephone more convenient for operation and minimize possible disturbances of electromagnetic waves caused by using the microphone 12. In this embodiment a matching capacitor 2 Is provided at one end of the axis of symmetry of the second partial-loop antenna 15 with a feeding point 8 at the other. It may be ideal to employ only one matching capacitor as shown in the figure in view of the potential receiving losses caused by providing additional elements.

#The first partial-loop antenna 14 is set at an angle where it receives horizontally polarized radio waves when a portable radiotelephone is held in the upright position, i.e., In a typical telephone operating position. The second partial-loop antenna 15 or the lid 18 is set at an angle where it receives vertically polarized radio waves with respect to the first partial-loop antenna 14, when the lid 18 is fully open or in the telephone operating position. The first partial-loop antenna 14 forms a smaller partial-loop within the bottom plane of the main housing 11 of a portable radiotelephone, while the second partial-loop antenna 15 forms a partial-loop larger than the first partial-loop, within the lid 18. The two partial-loop antennas are joined together at the Fulcrum 16 by conductors 19 to form an apparent solid loop. The ".theta." in the figure indicates an angle which the bottom plane of the main housing, or the first partial-loop antenna 14, should make with the plane of the lid 18 or the second partial-loop antenna 15 when in an open position.

#FIGS. 2(a) and 2(b) illustrate a relation between the first partial-loop antenna 14 of the portable radiotelephone in FIG. 1 and a user 23 concerning the telephone operating position and a distance "h". The directivity of the first partial-loop antenna 14 crosses the body of the user 23 as a virtual ground plane approximately vertically to the user when the user holds a portable radiotelephone in the upright position as shown in the figures. Then the first partial-loop antenna 14 receives vertically polarized radio wave to the user 23 or horizontally to the first partial-loop antenna 14.