Communications: directive radio wave systems and devices (e.g. – With particular circuit – With polarization
Reexamination Certificate
2003-01-17
2004-12-07
Sotomayor, John B. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
With particular circuit
With polarization
C342S157000, C342S158000, C342S174000, C342S372000
Reexamination Certificate
active
06828932
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to active array RF systems and more particularly to a receiver capable of simultaneously receiving N independent RF input signals, which can respectively have different, scan angles and be circularly or linearly, polarized.
BACKGROUND OF THE INVENTION
The prior art describes various active array RF systems useful in a wide range of military and commercial applications for handling circularly and/or linearly polarized signals. For example only, U.S. Pat. No. 6,020,848 describes a phased array antenna system that allows reception of electrically selectable single polarity or simultaneous dual polarity/dual beam signals.
SUMMARY OF THE INVENTION
The present invention is directed to a wideband receiver system capable of simultaneously receiving multiple independent polarized (linearly or circularly) RF input signals from multiple sources within a wide scan angle range. Embodiments of the invention are suitable for a wide range of military and commercial application. The exemplary embodiment described herein is particularly suited for receiving input signals within the X/Ku band, e.g., between 10.9 and 15.35 Ghz.
A preferred receiver in accordance with the invention utilizes first and second linear orthogonal radiators for respectively receiving composite signals RF
X
and RF
Y
. Each of the composite signals can contain multiple independent RF input signals, e.g., F
1
at a frequency of f
1
, F
2
at a frequency of f
2
, . . . FN at frequency fN. The composite signals, RF
X
and RF
Y
, are respectively divided into multiple components, e.g., (where N=4) RF
X1
, RF
X2
, RF
X3
, RF
X4
and RF
Y1
, RF
Y2
, RF
Y3
, RF
Y4
. The RF
X
and RF
Y
components are then uniquely paired and processed in a polarization compensation stage by selective phase shifting based on the known polarization (e.g., left hand circular, right hand circular, linear 0-90°/180°-270°, and linear 90°-180°/270°-360°) of the signals to be received to produce four coherent signals, i.e., RF
XY1
, RF
XY2
, RF
XY3
, RF
XY4
. These four coherent signals are then selectively phase shifted in a scan angle compensation stage to recover the input signals F
1
, F
2
, F
3
, F
4
. The recovered input signals are then preferably band pass filtered.
More particularly, in a preferred embodiment, the composite signal RF
X
is applied to a four way divider which produces the four signals components RF
X1
, RF
X2
, RF
X3
, RF
X4
. Similarly, the composite signal RF
Y
is applied to a four way divider to produce the signal components RF
Y1
, RF
Y2
, RF
Y3
, RF
Y4
. Each signal component contains contributions from the four input signals F
1
, F
2
, F
3
, F
4
. The RF
X
signal components are then respectively passed through controllable 90° phase shift branches and the RF
Y
signal components are respectively passed through controllable 180° phase shift branches. The output of each 90° phase shift branch is uniquely paired with an output from a 180° phase shift branch and then summed in one of four two-way combiners to produce a coherent output. The 90° and 180° phase shift branches are digitally controlled to define a desired polarization angle, i.e., right hand circularly polarized, left hand circularly polarized, or linearly polarized, for each branch pairing. The following table describes an exemplary two bit control of the polarization phase shifters for each branch pairing for each polarity condition:
POLARITY
90° shifter
180° shifter
Right Hand Circular
ON
OFF
Left Hand Circular
ON
ON
Linear 0°-90°/180°-270°
OFF
OFF
Linear 90°-180°/270°-360°
OFF
ON
The coherent outputs of the four two-way combiners, each containing the input signals F
1
, F
2
, F
3
, F
4
, are then respectively applied to four digitally controlled phase shifters to compensate for scan angle. More particularly, the output of the first two-way combiner processing signals RF
X1
and RF
Y1
is applied to a first phase shifter which is digitally controlled to define the scan angle of the input signal F
1
. Similarly, the outputs of the second, third and fourth two-way combiners are respectively applied to the second, third and fourth phase shifters which are respectively digitally controlled to define the scan angles of signals F
2
, F
3
, F
4
. The outputs from the scan angle phase shifters, which comprise the received input signals F
1
, F
2
, F
3
, F
4
, are then preferably passed through band filters respectively tuned to f
1
, f
2
, f
3
, f
4
. A preferred implementation of a receiver in accordance with the invention utilizes multiple substrates configured for stacking into a compact substrate assembly. The preferred substrate assembly includes six substrates or layers configured as follows:
Layer 1=Radiator/Balun Substrate
Layer 2=Low Noise Amplifier (LNA) Substrate
Layer 3=First Circular/Linear Polarization Control Substrate
Layer 4=Second Circular/Linear Polarization Control Substrate
Layer 5=Scan Control Substrate
Layer 6=Regulator Substrate
The substrates are connected vertically preferably using fuzz-button interconnects, and caged via hole technology.
The preferred substrate assembly comprises a sixteen channel device. That is the Radiator/Balun substrate forms a sixteen element matrix in which each element contains orthogonally polarized radiators for supplying composite signals RF
X
and RF
Y
. Each element is coupled through the layers of the stack assembly forming the aforedisccussed receiver to recover four input signals F
1
, F
2
, F
3
, F
4
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Freilich Hornbaker & Rosen
ITT Manufacutring Enterprises, Inc.
Sotomayor John B.
LandOfFree
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