Communications: radio wave antennas – Antennas – With radio cabinet
Reexamination Certificate
1999-05-28
2001-03-13
Le, Hoanganh (Department: 2821)
Communications: radio wave antennas
Antennas
With radio cabinet
C343S7000MS, C455S090300
Reexamination Certificate
active
06201501
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to antennas and, more particularly, to compact, lightweight antennas for mobile communications devices.
BACKGROUND OF THE INVENTION
As mobile telephone technology has advanced, the phone developers have concentrated on making the phone smaller so that more volume and weight could be set aside for battery storage, while keeping the overall form-factor of the phone to be pocket-sized. With the advent of new long-life battery storage technologies and low power digital modulation, the phone has been reduced to a size and battery life that is more than adequate in both departments. Now that these problems are effectively solved, an interest to adding new features to the phone beyond ordinary telecommunications has developed. Among these features is the accurate locating technology afforded by GPS receivers.
Adding a GPS receiver to a mobile phone permits dual use of many of the phone's current parts: embedded CPU, DSP, battery, user interface. Unfortunately, cellular downlink signals are different enough from GPS downlink that an entirely different antenna and filtering arrangement may be needed. For example, GPS downlink signals are typically circularly polarized, whereas cellular signals are not. Moreover, since dual antennas are needed, each antenna must be oriented so that while the mobile phone is positioned for each specialized use, as few phone parts and external obstacles are interposed between the external radio source and the phone antenna.
Since a mobile station such as a mobile phone must be highly miniaturized in order to provide its current functionality, designers adding new features must use as little real estate on the main circuit board as possible. Current generation circular polarized patch antennas, as described, for example, in the paper, “Compact Microstrip Antenna Loaded with Very High Permittivity Superstrate”, Chih-Yu Huang and Jian-Yi Wu, IEEE Antennas and Propagation Society International Symposium 1998, Jun. 21-26 1998, Atlanta Ga., may occupy as little as a square 20 mm on a side. This type of antenna, and others that lack holes are continuous conductor type antennas. Because GPS depends on line-of-sight (LOS) operation between the satellite(s) and the receiver, the GPS receive antenna must be on the top of the mobile station while employed for its locating function—which means for purposes of human-readable output, the mobile station's display must be situated on the same side as the antenna. Furthermore, the GPS antenna must be on the distant end, as opposed to the end that is grasped. Moreover, on that same side, the antenna competes for space with display, keyboard, microphone and speaker as principal front-side mobile phone components.
Deploying the GPS antenna on a flip or a boom causes its own problems. A flip requires extra enclosing hardware, as well as a resilient path for conductors to carry signals between the flip and the main phone. More parts thus produce higher cost, greater weight, lower reliability among other problems. The same problems apply to any other component that is deployed on a flip or boom.
OBJECTS OF THE INVENTION
It is therefore an object of this invention to provide an improved antenna for a mobile communications device that overcomes the foregoing and other problems.
Another object and advantage of this invention is to provide an auxiliary antenna for a mobile communications device that may be configured and hidden within the device while not disturbing significantly the functions of a basic cellular antenna.
It is a further object and advantage of this invention to provide an antenna that is transparent to sound so that sound devices may operate near the ground-plane of the antenna.
It is a further object and advantage of this invention to provide an antenna that can be situated between a speaker and a user's ear without changing the typical speaker location on the upper longitudinal middle of the front side of the phone.
It is a further object to provide an elliptically polarized antenna operating close to a non-polarized antenna such that both may be housed in a common enclosure.
SUMMARY OF THE INVENTION
The present invention provides a antenna that is compatible with the form of portable mobile devices. The antenna configuration includes a conducting portion that is flat and generally rectangularly shaped. The antenna maybe configured so the conducting portion of the antenna configuration may be mounted within a mobile station between a speaker and an earpiece. Slots may be implemented in each side to permit the conducting portion to operate like a microstrip antenna having dimensions much larger, but still with high levels of gain with respect to the desired frequencies. At least one hole may be implemented in the conducting portion to aid in sound transmission from the speaker to the earpiece. The implementation of a hole in the approximate center of the conducting portion has virtually no effect in the gain of the antenna since the central region for a continuous antenna having a rectangular shape (or with slots) is a voltage minimum.
In an embodiment of the invention, a mobile phone is provided a flat GPS antenna which has a hole through the central region. The hole is located just above a speaker or other input/output device, wherein the speaker is mounted on a printed circuit board (PCB), and the GPS antenna is set-off from the PCB, yet still enclosed within a case or casing of the mobile phone. The case has an earpiece which has holes located near to the GPS antenna hole. A cellular antenna is mounted below the PCB to permit reception and transmission of cellular frequencies. The GPS antenna, speaker, and cellular antenna are located on the part of the mobile phone that is the distant end, i.e. the remaining part of the mobile phone is for grasping and other handling by a person. In alternative embodiments, the cellular antenna may be any other type of antenna usually for cellular communications such as extendable, stub antennas or antennas embedded in flip portions of a mobile station.
Similar performance with a two-feed circularly polarized microstrip antenna can be achieved, while making the size of the two-feed antenna as small as the size of the single-feed arrangement. It is also quite common to generate elliptical polarization by using two feed points to excite two orthogonal modes on the patch with a 90 degrees phase difference between their excitations.
In another embodiment of the invention, the antenna generates elliptical polarization by using two blunt opposite corners of the patch. The placement of the feedpoint at the end of a slot is needed to provide the elliptical polarization. Enhanced performance occurs by putting a high permittivity superstrate over the patch as well as between the patch and the ground plane. The longest dimension is about 20 mm, which appears electrically as a half wavelength (about 9.5 cm for 1575 MHz GPS signals).
REFERENCES:
patent: 5410323 (1995-04-01), Kuroda
patent: 5710987 (1998-01-01), Paulick
patent: 6025802 (2000-02-01), Eggleston et al.
Huang, Chih-Yu and Wu, Jian-Yi,Compact Microstrip Antenna Loaded with Very High Permittivity Superstrate, Feb. 1998, pp. 680-683, IEEE, 1998.
Arkko Aimo
Lehtola Antero
Pankinaho Ilkka
Le Hoang-anh
Nokia Mobile Phones Limited
Rivers Brian T.
Rolnik Robert C.
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