1. Field of the Invention
The present invention relates to a portable phone and, more particularly, to a flip cover and antenna assembly coupled to a main housing of such a portable phone.
2. Description of Related Art
Portable cellular phones, which typically transmit and receive signals at a frequency of approximately 900 Megahertz, are well known and have been utilized for the last several years. Recently, however, it has become important for a second mode of communication, i.e., satellite, to be employed in areas where cellular communication is unavailable due to the lack of necessary cellular towers or stations. Such satellite communication occurs at frequencies within the L-band, and generally in the range of 1.0 to 30.0 Gigahertz.
It is recognized that separate antennas are necessary for cellular and satellite mode communication since cellular antennas are linearly polarized and satellite antennas are circularly polarized. A further difference is that the satellite communication mode involves a directional component, where link margin is increased when the satellite antenna is pointed toward the satellite, and the cellular mode communication mode does not. Thus, the positioning of the satellite antenna in the portable phone is very important, as is the construction of the satellite antenna.
Flip covers for portable phones have generally been used to protect the keypad or display and has only extended over part of the phone base. In certain applications, though, a flip cover has been utilized to house an antenna (e.g., U.S. Pat. Nos. 5,337,061, 5,258,892, 5,014,346, and 5,170,173). As will be seen herein, each of the antennas disclosed in these patents is of a different construction than the satellite antenna of the present invention. Additionally, the mechanical coupling of the flip cover to the main housing in such patents involves rotation about a single axis between an open and closed position.
It has been found that the form of antenna desired for satellite mode communication is a radiating patch element, which presents certain electrical and structural challenges when positioned within a flip cover of a portable phone. In particular, the gain for such types of antennas needs to be increased for acceptable performance, as does control over the radiation patterns thereof. The radiating patch elements must also be adequately secured within the flip cover housing to maintain stability and consistency. At the same time, the overall aesthetic impression of a portable phone including such a flip cover and antenna assembly must remain pleasing to the user.
In light of the foregoing, a primary object of the present invention is to provide a flip cover and antenna assembly for a portable phone capable of operating in satellite and/or cellular communication modes.
Another object of the present invention is to provide a flip cover and antenna assembly for a portable phone which maximizes the gain of the antenna element in such flip cover.
Yet another object of the present invention is to provide a flip cover and antenna assembly for a portable phone which maintains the overall look, feel and impression of the portable phone.
Still another object of the present invention is to provide a flip cover and antenna assembly which is compatible with rotation about two separate axes.
Another object of the present invention is to provide a flip cover and antenna assembly for a portable phone which maintains structural integrity when used in the operating environment.
These objects and other features of the present invention will become more readily apparent upon reference to the following description when taken in conjunction with the following drawing.
In accordance with the present invention, a flip cover and antenna assembly for a portable phone is disclosed as being rotatably coupled to a main housing thereof. The flip cover and antenna assembly includes a first flip cover housing, a second flip cover housing matable with the first flip cover housing, and an antenna element positioned between the first and second flip cover housings. The antenna element further includes a ground plane having a first surface and a second surface, with at least one radiating patch element bonded to the ground plane first surface. A dielectric foam is positioned over any remaining area of the ground plane first surface. The first and second flip cover housings have flanges which extend from at least a portion thereof to wrap around corresponding edges of the main housing, which enables extensions of the ground plane to be provided conforming to the flanges. The ground plane may also be patterned in order to control the radiation pattern thereof and minimize RF interaction with the portable phone and its user. The flip cover and antenna assembly may also include a second antenna in the form of a printed circuit antenna or a monopole antenna.