Communications: radio wave antennas – Antennas – With support for antenna – reflector or director
Reexamination Certificate
1999-02-10
2001-03-06
Le, Hoanganh (Department: 2821)
Communications: radio wave antennas
Antennas
With support for antenna, reflector or director
C343S7000MS, C343S878000
Reexamination Certificate
active
06198460
ABSTRACT:
The present application relates to an antenna support structure particularly for in-door applications as well as to a wireless indoor communication system using such an antenna support structure.
Wireless indoor communication systems according to the state of the art usual use omnidirectional antennas, which are not well suited in the case of communication between different floors, and which are radiating electromagnetic power in all directions. Therefore a part of the radiated electromagnetic power gets always lost, produced multipath effects and interferes with other independent communication systems in the neighborhood.
However, the use of high frequencies for in-door communication systems represents an attractive solution for wireless in-door communication. The user requirements for in-door applications are still growing due to the availability of data and digital video services. The availability of larger bandwidths of data and digital video services. The availability of larger bandwidths at frequency higher than 1 GHz offers a high data rate applications. Frequency bands of 2,4 GHz, 5 to 6 GHz, 24 GHz, 17 GHz, 19 GHz, 40 GHz, and 60 GHz among others are considered throughout the world as to be a possible carrier for modulated transmission signals.
The propagation in in-door environments is usually divided in two groups: light of sight (LOS) communication and non-light of sight (NLOS) communication. The frequencies above 10 GHz are usually considered to be more suitable for LOS communication because of the higher physical attenuation (propagation properties) of the higher carrier frequencies.
The critical components of high frequency systems are the antennas. They can significantly increase of decrease the performance of the entire in-door communication system. In the case of higher frequency (higher than 10 GHz) the number of antenna radiation sub-elements can be larger so that theoretically multi-element arrays can be applied, wherein classic phased arrays, adaptive antennas or smart antennas can be used. At lower frequencies the number of the applied antenna elements has to be decreased due to the larger geometrical size of the radiation elements. A typical working scenario within one cell in the case of NLOS communication includes communication between different rooms which can also be a different floor levels, as it is shown in FIG.
1
.
In
FIG. 1
the reference number
10
designates one cell of a wireless in-door communication system. In every room of the different floors at least one mobile portable terminal
11
is placed. The four rooms shown in
FIG. 1
are belonging to the same wireless in-door cell, which can be for example a private network. To enable the terminal
11
in room
1
to communicate with the other mobile or portable terminals
11
in respectively the other rooms, the antenna loops (beams)
12
of the antenna system associated with the terminal in room
1
has to be directed in all of the directions respectively to the other mobile or portable terminals
11
in the other rooms.
According to the scenario as shown in
FIG. 1
it is very likely that communication between different floors can have a big importance, particularly if the used frequency is below 10 GHz. The scenario in
FIG. 1
can represent a local high data rate communication system. Due to the very complex propagation properties in the NLOS working case in due to the relatively large wall attenuation and limited transmission power, the proper choice of the antenna system has an crucial importance, particularly if so-called ISM (Industrial, Scientific, Medical) bands with restricted transmission power are considered. Resulting from a simple theoretical consideration it follows that an antenna gain of 7 to 12 dB (printed antennas, 1 or 2 couples of printed radiation elements) instead of the antenna gain of 0-1 dB (classic monopole metal like antennas) can significantly improve the quality of the communication of the wireless in-door communication system, and allow a larger back-off of the transmitter, which is necessary if specific modulation schemes like OFDM or other spread spectrum modulation schemes are used.
Thereby one problem is how to direct the in-door antenna system to the directions such as to have the maximum system gain. The approach of using electrically scanned antennas is theoretically very attractive, however, in practice this approach can not provide for optimum solution for an in-door use as a lot of radiation elements are needed for a good scanning. However, in in-door use there might not be enough place considering the used wavelength. Furthermore such electrically scanned antennas according to the state of the art are expensive and the scanning angles are very limited.
Antennas for in-door communication systems according to the state of the art are usually monopole antennas having an omni directional vertical polarization, or they are based on different microstrip technologies with planar assemblies. A typical product as it is known from the state of the art is for example shown in an advertising folder “The Suhner planar antenna wireless communication in the 1,7-2,5 GHz range” of Huber+Suhner AG, Radio Transmission Department, Herisau, Switzerland. Said known 2,4 GHz (ISM band) planar antenna as a linear and circular polarization.
Furthermore radio LAN an antennas for 5,8 GHz (ISM band) have been proposed. Both proposed antennas have in common that their radiation zone is fixed, once the antennas are mechanically screwed or glowed to a base surface. However, due to the complicated propagation properties in in-door environments it is difficult to predict directly the optimum direction, and it can be desirable to transmit and radiate in some specific direction, e.g. to radiate in one time slot in one direction to a target user in the upper floor to communicate in another time slot with another user who is placed in one of the rooms in the neighborhood, which requires an horizontal radiation pattern.
The object of the present application is to provide for an antenna support structure particularly to support a plurality of planar antenna sub-systems. The preferred application of the proposed antenna support structure lies in the field of in-door wireless transmission systems.
The object of the invention is achieved by means of the features of claim
1
.
According to the present invention therefore an antenna support structure for at least three directional antenna sub-systems is proposed. The antenna support structure thereby comprises at least four panels adapted to support respectively one of the antenna subsystems. The panels include a main panel as well as at least three secondary panels being placed respectively adjacent to the main panel. The secondary panels are attached by hinge means to the main panel. Thereby the secondary panels can be individually adjusted in a predetermined angle to the main panel.
The main panel can be rotatable relatively to a base point of the antenna support structure.
The antenna sub-system can be preferably planar antenna arrays.
Furthermore electrical and/or mechanical adjustment means can be provided to adjust and fixed respectively the angle between one of the secondary panels and the main panel.
An antenna control unit can be provided controlling the electrical adjustment means. the mechanical adjustment means can be used for a coarse positioning by the user.
The main panel can be adapted to support an antenna sub-system, for example a planar antenna sub-system array.
The main panel can have a triangular shape and one of the secondary panels can be respectively hinged to one of the sides of the main panel.
The secondary panels can also have a triangular shape.
Alternatively the main panel can have an essentially rectangular shape.
Furthermore mechanical and/or electrical rotation drive means for adjusting and fixing the rotation angle of the main panel relatively to the base point of the antenna support structure can be provided.
The hinge means connecting respectively a secondary panel to the main panel can be adapted to
Frommer William S.
Frommer Lawrence & Haug, LLLP.
Le Hoang-anh
Polito Bruno
Sony International (Europe) GmbH
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