Communications: directive radio wave systems and devices (e.g. – Directive – Including a steerable array
Reexamination Certificate
2001-10-05
2003-05-06
Tareza, Thomas H. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Including a steerable array
Reexamination Certificate
active
06559797
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to multiple beam communication systems and more particularly, to a method and apparatus for digitally controlling a received signal that is manipulated by a digital beam former.
BACKGROUND OF THE INVENTION
Current commercial high altitude communication devices having conventional multiple beam architectures, which use multipatch antennas, incorporate digital beam forming (DBF) techniques. Multipatch antennas receive and convert communication signals into received signals. Multipatch antennas are also very useful in forming multiple simultaneous beams covering a large field of view (FOV).
Now referring to
FIG. 1
, a block diagrammatic view of a receiving circuit
10
of a conventional high altitude communication device is shown. Typical mobile satellite payloads have a multipatch antenna
12
. The multipatch antenna
12
includes a plurality of patches
14
, each patch
14
receives communication signals
16
. Each patch
14
is preferably used only once in receiving communication signals
16
to prevent signal to noise degradation.
The configurations of the patches
14
affect the optimization of multipatch antenna axial ratio (AR). Typical multipatch antennas usually have a poor AR. With a good design, 2 db AR over a large FOV is commonly accepted. For limited FOV applications such as a geosynchronous orbit satellite, grouping patches
14
with proper orientation significantly improves the AR to 0.2 db or less.
Orientations of the patches
14
also affect the amount of created grating lobes. The patches
14
have element patterns. When element patterns overlap grating lobes are created. Grating lobes reduce multipatch antenna directivity and gain as known in the art.
The patches
14
are combined in even numbered groups by combining networks
18
to form array elements
19
. The combining networks
18
convert the communications signals
16
into combined signals
20
. Each combining network
18
is connected to several components for signal-conditioning the combined signals
20
prior to connecting to a digital beam former
22
. The combining networks
18
are connected to a plurality of low noise amplifiers (LNAs)
24
, which amplify the combined signals
20
to form received signals
26
. The LNAs
24
are connected to a plurality of downconverters
28
. The downconverters
28
convert the high frequency received signals
26
to baseband or intermediate frequency (IF) signals
30
. The baseband signals
30
are then transformed into digital signals
32
by analog-to-digital (A/D) converters
34
.
Now referring to
FIG. 2
, a schematic view of sample array element
19
and a combining network
18
, which together optimize axial ratio and prevent grating lobes is shown. The communication signals
16
are received by patches
14
and combined by 3 db hybrids
36
and circular ring hybrids
38
to form the combined signals
20
. The patches
14
are oriented 90° in sequence. The 3 db hybrids
36
are at 90° and the circular ring hybrids
38
are at 180°. The 3db hybrids
36
and the circular ring hybrids
38
cause signal losses due to their internal characteristics.
Now referring to
FIG. 3
, a block diagrammatic view of the multipatch antenna
12
showing the positioning of the array elements
19
is shown. The patches
14
are positioned to minimize overlapping of element patterns, thereby, suppressing grating lobes and maximizing gain. By orienting the patches
14
and array elements
19
so that spacing between patches
14
is approximately equal to half the wavelength of the received signal
26
and spacing between array elements
19
is approximately equal to the wavelength of the received signal
26
, grating lobes can be prevented.
In high altitude communication devices there is a continuing effort to decrease the amount of components in the system thereby decreasing the size and weight of the system, decreasing hardware, decreasing costs, decreasing power consumption, and increasing efficiency.
In space systems, where up to thousands of array elements may be used, a reduction in satellite payload components may cause tremendous savings. In other communication systems, in which many array elements are used the savings in cost, weight, and power will also be increased.
Therefore a need exists to reduce the number of components in the high altitude communication device. Also a need exists to produce a high altitude communication device having zero grating lobes, good axial ratio, and a reduced amount of signal loss over existing high altitude communication device.
SUMMARY OF THE INVENTION
The forgoing and other advantages are provided by a method and apparatus of digitally controlling a received signal within a high altitude communication device. The high altitude communication device uses a first array element comprising a plurality of patches and a second array element comprising a plurality of patches. The first array element and the second array element are for receiving communication signals. A patch in the first array element is shared by the second array element.
A method of digitally controlling received signals within a high altitude communication device is provided. The method includes clocking an array element and receiving communication signals. The communication signals are converted to digital baseband signals by the plurality of grouping networks. The plurality of grouping networks also transforms the digital baseband signals into digital combined signals.
The present invention has several advantages over existing signal controlling techniques. One advantage of the present invention is that it reduces the number of high altitude communication device components by eliminating the use of hybrids and combining networks. The reduction in components reduces weight and saves space within a high altitude communication device. Furthermore, the reduction in components reduces costs involved in production and implementation of satellite systems.
Another advantage of the present invention is that it minimizes signal losses due to the elimination of the hybrids and combining networks.
Yet another advantage of the present invention is that an arbitrary number of patches may be grouped together as opposed to a fixed hardwired even amount of patches.
Moreover, the present invention eliminates grating lobes and optimizes the high altitude communication device axial ratio. The present invention also reduces A/D dynamic range requirements and may be easily calibrated and recalibrated.
Therefore, a high altitude communication device having a minimal number of components, which can digitally control received signals, is possible due to the stated method advantages. The present invention itself, together with further objects and attendant advantages, will be best understood by reference to the following detailed description, taken in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
For a more complete understanding of this invention reference should now be had to the embodiments illustrated in greater detail in the accompanying figures and described below by way of example.
In the figures:
FIG. 1
is a block diagrammatic view of a receiving circuit of a conventional high altitude communication device.
FIG. 2
is a schematic view of an array element in conjunction with a combining network of a conventional high altitude communication device.
FIG. 3
is a block diagrammatic view of a multipatch antenna of a conventional high altitude communication device showing positioning of array elements.
FIG. 4
is a perspective view of a communication system, utilizing a method and apparatus for sampling communication signals according to the present invention.
FIG. 5
is a block diagrammatic view of a high altitude communication device in accordance with the present invention.
FIG. 6
is a block diagrammatic view of a receiving circuit of a high altitude communication device in accordance with the present invention.
FIG. 7
is a block diagrammatic view of a multipatch antenna of a mobile satellite payloa
Duraiswamy V. D.
Hughes Electronics Corporation
Mull Fred H
Sales M. W.
Tareza Thomas H.
LandOfFree
Overlapping subarray patch antenna system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Overlapping subarray patch antenna system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Overlapping subarray patch antenna system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3055081