BACKGROUND
[1] The present disclosure relates generally to the field of satellite communication.
More specifically, the present disclosure relates to airborne satellite communication. An
electronically scanned array (ESA) is an antenna that can be electronically steered to point in
different directions. As an ESA ages, individual radiating elements can fail. As the individual
elements fail, the radiating performance of the ESA decreases proportionately.
[2] A common sentiment about phased arrays (e.g., ESAs) is that they gracefully
degrade as elements fail. In other words, most ESAs are designed with slow and proportional
performance decay in mind. However, graceful decay does not always occur. Single point
failure modes exist in ESA power supply architectures and controllers, and radiation element
failures can require re-calibration and will reduce gain-to-noise-temperature (G/T) and
effective-isotropic-radiated-power (EIRP) to below acceptable levels.
[3] Various techniques can be used in an attempt to address single point failure modes
and radiation element failures over time. For example, radio-frequency (RF) isolation
techniques can include placing circulators or directional couplers between the phased array
circuitry and the antenna's radiating elements to reduce RF failure mode effects on active
components.
[4] Another solution includes in-position calibration via loop-back testing, calibration
horns, etc. In-position calibration is intended to permit re-caiibration of the ESA to meet
sidelobe requirements but requires a high signal-to-noise-ratio (SNR) for in-position
measurements and complicated pattern synthesis techniques that must be computed on the fly.
The in-position calibration approach places a burden on the back-end radio/radar/sensor
hardware to be able to enable these calibration modes, which may not be possible when
integrating with existing equipment (e.g. a legacy modem).
4831-7910-1513
-2-
Atty. Dkt. No.: 17CR020 (047141-1250)
SUMMARY
[S] In one aspect, embodiments of the inventive concepts disclosed herein are directed to
an apparatus that includes a connector structured to receive mains power from a vehicle, a first
power converter structured to receive and condition the mains power, a second power converter
arranged in parallel with the first power converter and structured to receive and condition the
mains power, a conditioned power connector structured to receive conditioned power from the
first power converter and the second power converter, a first switch arranged between the first
power converter and the conditioned power connector and structured to selectively allow
conditioned power to pass from the first power converter to the conditioned power connector, a
second switch arranged between the second power converter and the conditioned power
connector and structured to selectively allow conditioned power to pass from the second power
converter to the conditioned power connector, and a controller structured to monitor the first
power converter and the second power converter and to operate one of the first switch or the
second switch to provide conditioned power to the conditioned power connector.
[6] In a further aspect, embodiments of the inventive concepts disclosed herein are
directed to an apparatus that includes a plurality of beamformer chips and a plurality of control
buses. Each beamformer chip is associated with at least one radiating element and includes a
control bus interface and a reserve input configured to be remapped into the control bus
interface in the event that a signal within the control bus interface fails. The plurality of control
buses are structured to provide instructions to the plurality of beamformer chips, and each
control bus includes a plurality of primary control paths providing communication from the
control bus to the control bus interface, and a reserve control path structured to be remapped to
provide communication from the control bus to the control bus interface in the event that one of
the plurality of primary control paths fails..
[7] In a further aspect, embodiments of the inventive concepts disclosed herein are
directed to an apparatus that includes an array of active radiating elements, and between about
one percent and about twenty percent reserve radiating elements distributed throughout the
active radiating elements.
-3-
4831-7910-1513
Atty. Dkt.No.: 17CR020 (047141-1250)
[8] In a further aspect, embodiments of the inventive concepts disclosed herein arc
directed to an electronically scanned array system that includes a power supply system, a
radiating element subarray, a plurality of beamformer chips, and a plurality of control buses.
The power supply system includes a connector structured to receive mains power from a
vehicle, a first power converter structured to receive and condition the mains power, a second
power converter arranged in parallel with the first power converter and structured to receive
and condition the mains power, a conditioned power connector structured to receive
conditioned power from the first power converter and the second power converter, a first
switch arranged between the first power converter and the conditioned power connector and
structured to selectively allow conditioned power to pass from the first power converter to the
conditioned power connector, a second switch arranged between the second power converter
and the conditioned power connector and structured to selectively allow conditioned power to
pass from the second power converter to the conditioned power connector, and a controller
structured to monitor the first power converter and the second power converter and to operate
one of the first switch or the second switch to provide conditioned power to the conditioned
power connector. The radiating element subarray includes a plurality of active radiating
elements and between about one percent and about twenty percent reserve radiating elements
distributed throughout the active radiating elements. Each beamformer chip is associated with
at least one radiating element and includes a control bus interface and a reserve input
configured to be remapped into the control bus interface in the event that a signal within the
control bus interface fails. The plurality of control buses are structured to provide instructions
to the plurality of beamformer chips, and each control bus includes a plurality of primary
control paths providing communication from the control bus to the control bus interface, and a
reserve control path structured to be remapped to provide communication from the control bus
to the control bus interface in the event that one of the plurality of primary control paths fails.
BRIEF DESCRIPTION OF THE FIGURES
[9] Exemplary embodiments will become more fully understood from the following
detailed description, taken in conjunction with the accompanying drawings, wherein like
reference numerals refer to like elements, and:
-4-
4831-7910-1513
Ally. Dkt. No.: 17CR020 (047141-1250)
[10] FIG. 1 is a schematic representation of an ESA power supply system, according to
some embodiments;
[11] FIG. 2 is a schematic representation of a primary supply of the ESA power supply
system of FIG. I, according to some embodiments;
[12] FIG. 3 is a schematic representation of a local supply of the ESA power supply
system of FIG. 1, according to some embodiments;
[13] FIG. 4 is a schematic representation of an orthogonal control bus architecture feeding
an array of radiating elements, according to some embodiments;
[14] FIG. 5 is a schematic representation of a parallel control bus architecture feeding an
array of radiating elements, according to some embodiments;
[15] FIG. 6 is a schematic representation of another orthogonal control bus architecture
feeding multiple arrays of radiating elements, according to some embodiments;
[16] FIG. 7 is a schematic representation of a beamformer chip including bus interfaces
and reserve control lines, according to some embodiments;
[17] FIG. 8 is a front view of an octagonal satellite communication array including
reserve radiating elements, according to some embodiments;
[18] FIG. 9 is a graph showing a gain pattern of an octagonal satellite communication
array that includes no reserve elements, according to some embodiments;
[19] FIG. 10 is a graph showing a gain pattern of the octagonal satellite communication
array of FIG. 8 including reserve elements, according to some embodiments;
[20] FIG. 11 is a top view of a phased array antenna system, according to some
embodiments; and
[21] FIG. 12 is a graph showing sidelobe gain levels of the phased array antenna system
of FIG. 11, according to some embodiments.
-5-
4831-7910-1513
Atty. Dkt.No.: 17CR020 (047141-1250)
DETAILED DESCRIPTION
[22] Following below are more detailed descriptions of various concepts related to, and
-••- implementations of, methods, apparatuses, and systems for electronically scanned arrays
(ESA). The various concepts introduced above and discussed in greater detail below may be
implemented in any number of ways, as the concepts described are not limited to any particular
manner of implementation. Examples of specific implementations and applications are
provided primarily for illustrative purposes.
[23] Referring to the figures generally, the various embodiments disclosed herein relate to
systems, apparatuses, and methods for an ESA that include a primary power supply, transmit
circuit cards, receive circuit cards, a transmit array of radiating elements, and a receive array of
radiating elements. The primary power supply receives main power (e.g., from an aircraft's
power grid), and provides power to two parallel power-factor-correction (PFC) converters that
alter and/or convert the electrical energy to a desirable direct current (DC) voltage (e.g., 48
VDC). The output of each PFC converter is switched so that only one PFC converter is
outputting voltage to the downstream system. In this way, the primary power supply is
protected against single point failures.
[24] Each of the transmit and receive circuit cards are structured to receive power from
the primary power supply (e.g., at 48 VDC) and include a local power supply or power
converter. Each local power supply includes two sets of converter components and each is
switched so that only one set of converter components is providing power to the associated
circuit card and/or array of radiating elements.
[25] In addition to the power supply architecture, a control bus connecting each circuit
card to the associated radiating elements includes a primary control bus and a secondary control
bus. The primary and secondary control busses can be structured either in parallel or
orthogonally and allow for continued operation and control in the event of a single point failure
on the primary control bus.
[26] The arrays of radiating elements themselves include reserve elements that are not
operated or active when the array is new. The reserve elements can be activated as the array
-6-
4831-7910-1513
Arty. Dkt. No.: 17CR020 (047141-1250)
ages. This allows the ESA's performance to continue to meet desired specifications even after
a significant number of individual radiating elements have failed. In addition, the transmit
array and the receive array are constructed in an octagon shape and produce eight primary side
lobes. As a result, the sidelobes each have a lower gain, and sidelobe gain levels are
maintained in an acceptable range even as individual radiating elements fail.
[27] Referring now to FIG. 1, an electronically scanned array (ESA) 100 includes a
primary power supply 104 arranged within a vehicle (e.g., an aircraft), an externa! power
distribution circuit 108 arranged outside the vehicle and receiving conditioned power from the
primary power supply 104, four receive subarrays 112 each receiving power from the external
power distribution circuit 108 and powering a set of radiating elements 116, and four transmit
subarrays 120 each receiving power from the external power distribution circuit 108 and
powering a set of radiating elements 124. In some embodiments, the external power
distribution circuit 108 is omitted and power is provided to the receive subarrays 112 and the
transmit subarrays 120 from the primary power supply 104. For example, the external power
distribution circuit 108 may be omitted when the primary power supply 104 is located outside a
pressure vessel (e.g., the body of an aircraft). In some examples, more than four or less than
four transmit and receive subarrays 112, 120 are included. Four of each subarray 112, 120 are
shown for exemplary purposes only.
[28] Each of the receive subarrays 112 includes a beamforming network 128 and four
circuit cards 132, each circuit card 132 including a local power source or power converter.
Similarly, each of the transmit subarrays 120 includes a beamforming network 136 and four
circuit cards 140, eacii circuit card 140 including a local power source or power converter. In
some embodiments, the beamforming networks 128 of the receive subarrays 112 include
amplifiers, low noise filters, splitters, and phase shifters or time delays designed to receive
signals or data beams via the receive radiating elements 116. In some embodiments, the
beamforming networks 136 of the transmit subarrays 120 include amplifiers, low noise filters,
combiners, and phase shifters or time delays designed to transmit signals or data beams via the
transmit radiating elements 124. In some embodiments, the beamforming networks 128, 136
control the polarity of signals, a time delay, a phase shift, or other aspects required for desirable
-7-
4831-7910-1513
Atty. Dkt.No.: 17CR020 (047141-1250)
beamforming. In some embodiments, each subarray 112, 120 includes less than four or more
than four circuit cards 132, 140.
[29] Referring now to FIG. 2, the primary power supply 104 receives mains power (e.g.,
115 VAC) at a connector 144, passes the mains power through an EMI filter 148, before
splitting in parallel to a first power factor correction (PFC) converter 152a and a second PFC
converter 152b. Each PFC converter I52a,b adjusts the power factor of the mains power
supply and transforms the voltage to a desired direct current voltage (e.g., 48 VDC).
Downstream of the first PFC converter 152a is a first solid state current breaker (SSCB) 156a,
and downstream of the second PFC converter 152b is a second SSCB 156b. The first SSCB
156a and the second SSCB 156b are controlled by a primary power source control 160. The
primary power source control 160 communicates with diagnostic features in each PFC
converter 152a,b and sensors 164 (e.g., current sensors) to determine a health of each of the
PFC converters 152a,b and the associated power transmission circuits. In some embodiments,
the primary power source control 160 closes the first SSCB 156a so that conditioned power is
provided by the first PFC converter 152a. Should the primary power source control 160
determine that a problem has occurred with the first PFC converter 152a or the associate power
transmission circuitry, then the first SSCB 156a is opened, and the second SSCB 156b is closed
so that power is provided by the second PFC converter 152b. The parallel arrangement of the
PFC converters I52a,b and the SSCBs 156a,b reduces the likelihood of a single point failure
rendering the primary power supply 104 inoperable. In some embodiments, other sensors may
be used to determine if current and/or conditioned power is being provided from the PFC
converters 152a,b.
[30] Downstream of the SSCBs 156a,b, an energy storage device 168 (e.g., a capacitor, a
battery, etc.) is structured to receive and store conditioned power from one of the PFC
converters 152a,b. The energy stored within the energy storage device 168 can be used to
bridge a momentary drop out of power, supplement or replace the conditioned power provided
by the PFC converters I52a,b during times of high energy usage, or provide longer term
operation among other advantages. In some embodiments, a ship or aircraft's power drops out
or fails momentarily. These drop outs are typically characterized by the ship or aircraft
manufacturer, and occur as often as once per hour, for a duration of 50 to 250 milliseconds
-8-
4831-7910-1513
Atty. Dkt.No.: 17CR020 (047141-1250)
during normal flight as power is reconfigured on the aircraft. Playing through these momentary
interruptions is desirable, so the computer doesn't need to reboot and the data link is not lost. A
conditioned power connector 172 provides a connection point for the external power
distribution circuit 108 or a power bus structured to connect directly to the subarrays 112, 120.
[31] Referring now to FIG. 3, a local power supply in the form of a local power converter
174 includes a first isolated input 178a and a second isolated input I78b that are structured to
receive power from the primary power supply 104. In some embodiments, where the local
power converter 174 is associated with a receive circuit card 132, the isolated power inputs
178a,b receive about 48 VDC and about 2.0 Amps of power. In some embodiments, where the
local power converter 174 is associated with a transmit circuit card 140, the isolated power
inputs 178a,b receive about 48 VDC and about 2.0 Amps of power. In some embodiments, the
isolated power inputs 178a,b receive mains power, or the already conditioned power received at
the isolated power inputs 178a,b can be considered mains power for the system. In some
embodiments, other voltage or current ratings may be provided, as desired to meet required
specifications.
[32] A first isolating switch or first SSCB 182a is arranged downstream of the first
isolated power input 178a and a fust EMI filter stage 186a is arranged downstream of the first
isolating SSCB I82a. Downstream of the first EMI filter stage 186a is a first local power
supply 190a that provides a local voltage and current arranged to be used by the associated
circuit card 132. A second isolating switch or second SSCB 182b is arranged downstream of
the second isolated power input 178b and a second EMI filter stage 186b is arranged
downstream of the second isolating SSCB 182b. Downstream of the second EMI filter stage
186b is a second local power supply 190b that provides a local voltage and current arranged to
be used by the associated circuit card 132. In some embodiments, the local power supplies
190a,b provide 2.5 VDC, 3.3 VDC, or another voltage, as desired. In some embodiments,
multiple different voltages are provided.
[33] Downstream of the first local power supply 190a is a first connection switch or first
connection SSCB 194a structured to selectively interrupt power transmission from the first
isolated power input 178a and the first local power supply 190a to the circuit card 132. A
4831-7910-1513
Atty. Dkt. No.: 17CR020 (047141-1250)
second connection switch or second connection SSCB 194b is positioned downstream of the
second local power supply 190b and is structured to selectively interrupt power transmission
from the second isolated power input 178b and the second local power supply 190b to the
circuit card 132. A local control 198 controls the arrangement (e.g., open or closed) of the
isolation SSCBs 182a,b and the connection SSCBs 3 94 a,b. The local control 198 is in
communication with sensors 202 (e.g., current and voltage sensors) arranged between each
local power supply 190a,b and each connection SSCB 194a,b. In some embodiments, the
sensors 202 are a power supply monitor and include current sensing elements and voltage
sensing elements. In some embodiments, the sensors 202 include more than one sensing
component.
[34] The local control 198 operates the isolation SSCBs 182a,b and the connection
SSCBs 194a,b to provide power from one isolated power input 178a,b and one associated local
power supply 190a,b at any given time to the circuit card 132. The inclusion of two isolated
power inputs I78a,b and two local power supplies 190a,b structured on two independent power
transmission paths reduces the likelihood of a single point failure on one power transmission
path interrupting operation of the circuit card 132. If the focal control 198 determines that one
power transmission path has failed (e.g., the sensor 202 indicates no current), then the failed
power transmission path is shut down by opening the associated isolation SSCB 182a,b and the
connection SSCB 194a,b. Power transmission is restored by closing the other isolation SSCB
I82a,b and connection SSCB I94a,b.
[35] In some embodiments, each circuit card 132, 140 includes a local power converter
174 and the beamforming networks 128, 136 and associated radiating elements 116, 124 can be
operated when the local power converters 174 are functional. The inclusion of parallel power
transmission paths increases the operational availability of the subarrays 112, 120 and
decreases the incidence of single point failures shutting down a system. Within the context of
this application, availability means the ability to be functionally operational given a failure or
sequence of failures. In some embodiments, equipment life is proportional to temperature and
environmental conditions as well as design margins, and reliability is proportional to
component count, etc.
-10-
4831-7910-1513
Atty. Dkt.No.: 17CR020 (047141-1250)
[36] Referring now to FIG. 4, a subarray control system 206 includes sixty-four radiating
elements 210, sixteen beamfonner chips 212 each controlling four radiating elements 210, a
subarray controller 214 structured to control the beamfonner chips 212, a set of primary control
buses 218, and a set of secondary control buses 222. In some embodiments, the beamfonner
chips 212 are SiGe chips. In some embodiments, the beamfonner chips 212 can be created
using CMOS (e.g., RF CMOS, SOI CMOS) and/or other integrated circuit processes. In some
embodiments, the subarray controller 214 is a field programmable gate array (FPGA). On
some embodiments, the subarray controller 214 is an application specific integrated circuit
(ASIC), or another type of control block architecture. In some embodiments, each of the
primary control buses 218 and the secondary control buses 222 is a serial interface bus.
[37] The primary control buses 218 and the secondary control buses 222 are arranged
orthogonally relative to one another such that each beamfonner chip 212 can be controlled by
either a primary control bus 218 or a secondary control bus 222. In some embodiments, if the
primary control bus 218 providing communication between the subarray controller 214 and the
beamformer chips 2I2-I through 212-4 fails, then the four secondary control buses 222
arranged in communication with the beamformer chips 212-1 through 212-4 are assigned to
carry the needed information. In some embodiments, more than sixty four or less that sixty
four radiating elements 210 are included. For example, in some embodiments, five-hundredtweive
radiating elements 210 are included. In some embodiments, more than sixteen or less
than sixteen beamfonner chips 212 are included. In some embodiments, more than four or less
than four primary control buses 218 and secondary control buses 222 are included. In some
embodiments, the number of secondary control buses 222 may be different than the number of
primary control buses 218.
[38] Referring now to FIG. 5, a subarray control system 226 includes similar parts to the
subarray control system 206 described above and includes sixty-four radiating elements 230,
sixteen beamformer chips 234 each controlling four radiating elements 230, a subarray
controller 238 structured to control the beamformer chips 234, a set of primary control buses
242, and a set of secondary control buses 246. The primary control buses 242 and the
secondary control buses 246 are arranged in parallel so that if one primary control bus 242
-11-
4831-7910-1513
Atty. Dkt.No.: 17CR020 (047141-1250)
fails,- the corresponding parallel secondary control bus 246 can be re-mapped to deliver
information to the beamformer chips 234.
[39] Referring now to FIG. 6, a subarray control system 250 includes a first subarray 254
including sixty-four radiating elements, a second subarray 258 including sixty-four radiating
elements, sixteen beamformer chips 262 associated with the first subarray 254, sixteen
beamformer chips 266 associated with the second subarray 258, a first subarray controller 270,
a first set of primary control buses 274, a first set of secondary control buses 278, a second
subarray controller 282, a second set of primary control buses 286, a second set of secondary
control buses 290, a third subarray controller 294, a third set of primary control buses 298, a
third set of secondary control buses 302. Each subarray controller 270, 282, 294 communicates
with more than one subarray 254, 258. For example, the second subarray controller 282 is in
communication with the first subarray 254 via the second set of secondary control buses 290,
and the second subarray 258 via the second set of primary control buses 286. This arrangement
allows broken or failed control buses to be remapped to other controllers while maintaining
operation. For example, if one of the first set of primary control buses 274 were to fail, the
second set of secondary control buses 290 can be remapped to provide the desired information.
In another example, if the first subarray controller 270 were to fail, the second set of secondary
control buses 290 can be remapped to control the first subarray 254 without the need for the
first subarray controller 270. A large array of subarray controllers can be setup with orthogonal
or parallel control bus redundancies so that a robust set of subarrays can be provided that will
resist single point failures of both individual control buses and subarray controller failures.
[40] Referring now to FIG. 7, a subarray controller or beamformer chip 303 that includes
a set of primary inputs or a primary control interface bus, a secondary set of inputs or a
secondary control interface bus, and a spare set of inputs. The set of primary inputs can include
a primary clock input 304, a primary data input 305, and a primary frame input 306. The set of
secondary inputs can include a secondary frame input 307, a secondary data input 308, and a
secondary clock input. The spare inputs can include a first spare input 310 and a second spare
input 311. The primary clock input 304 is structured in communication with a first multiplexer
312, the primary data input 305 is structured in communication with a second multiplexer 313,
the primary frame input 306 is structured in communication with a third multiplexer 314, the
-12-
4831-7910-1513
Atty. Dkt.No.: 17CRO20 (047141-1250)
' secondary frame input 307 is structured in communication with a fourth multiplexer 315, the
secondary data input 308 is structured in communication with a fifth multiplexer 316, and the
secondary clock input 309 is structured in communication .with a sixth multiplexer 317. In
some embodiments, the primary data input 305 and the secondary data input 308 arc split into
separate receive data and transmit data inputs and additional multiplexers are included to accept
the data inputs.
[41] The first spare input 310 is structured in communication with each of the
multiplexers 312, 313, 314, 315, 316, 317. The second spare input 311 is also structured in
communication with each of the multiplexers 312, 333, 314, 315, 316, 317. In some
embodiments, more than two or less than two spare inputs are included. In some embodiments,
the first spare input 310 is structured in communication with only the multiplexers receiving
signals from the primary inputs, and the second spare input 311 is structured in communication
with only the multiplexers receiving signals from the secondary inputs.
[42] The first multiplexer 312, the second multiplexer 313, and the third multiplexer 314
are structured in communication with a control bus interface or first serial interface block 318.
The fourth multiplexer 315, the fifth multiplexer 316, and the sixth multiplexer 317 are
structured in communication with a control bus interface or second serial interface block 319.
The first serial interface block 318 and the second interface block 319 are structured in
communication with a control register block 320. The control register block 320 communicates
with the multiplexers to control the data flow provided to the serial interface blocks 318, 319.
A first control path 321 provides communication with the first multiplexer 312, a second
control path provides communication with the second multiplexer 313, a third control path 323
provides communication with the third multiplexer 314, a fourth control path 324 provides
communication with the fourth multiplexer 315, a fifth control path provides communication
with the fifth multiplexer 316, and a sixth control path 326 provides communication with the
sixth multiplexer 317.
[43] Each of the multiplexers 312, 313, 314, 315, 316, 317 is arranged to receive three
inputs (e.g. the first multiplexer 312 receives an input from the primary clock input 304, the
first spare input 310, and the second spare input 311) and output one of the three data inputs to
-13-
4831-7910-1513
Atty. Dkt.No.: 17CR020 (047141-1250)
the associate serial interface block 318, 319. Which of the three data inputs is passed along is
controlled via the associate control path (e.g., the first control path 321 in the case of the first
multiplexer 312).
[44] In operation, during normal functioning when no components have failed, the control
register 320 receives the signals from the primary clock input 304, the primary data input 305,
and the primary frame input 306. The control register 320 then communicates the received
signals so that the associated radiating elements can be controlled. In the event of an input
failure (e.g., the Primary clock input 304 fails), the control register 320 is controlled to receive
and process signals from the secondary clock input 309, the secondary data input 308, and the
secondary frame input 307 via the second serial interface block 319. The first spare input 310
is then remapped to provide the signal originally associated with the primary clock input 304.
The control register 320 communicates with the first multiplexer 312 via the first control path
321 to select the signal from the first spare input 310 to be passed along to the first serial
interface block 318. After the first spare input 310 has been remapped and the first multiplexer
adjusted, then the control register again receives the signals from the first serial interface block
318 and continues normal operation. Similarly, the second spare input 311 can be remapped
and used to replace another failed input. In some embodiments, the secondary inputs can be
used as a replacement for the primary inputs.
[45] The beamformer chip 303 has many advantages when used in a subarray and a
plurality of arrays are including in an assembly. For example, each beamformer chip
incorporates two or more control bus interfaces, each beamformer chip incorporates zero or
more reserve or spare inputs which may be remapped to either/any control bus input in the
event of a signal failure within a given bus, at the array level there are many control buses
where each beamformer chip is connected to as many buses as it implements interfaces for, at
the array level each control bus incorporates zero or more reserve signal paths, buses or lines
which may be used as backups for the bus signals should a failure occur, at the array level the
control buses may be arranged in an orthogonal manner relative to a given chip, and at the
assembly level (multiple arrays), the control buses may be arranged to extend across array
boundaries.
-14-
0-1513
Ally. Dkt.No.: 17CR020 (047141-1250)
[46] Referring now to FIG. 8, an antenna array 330 defines an octagonal shape. The array
330 is populated with active radiating elements 334 and reserve radiating elements 338
dispersed randomly throughout the array 330. Active radiating elements 334 are used by an
associated beamforming netwoik to transmit and receive signals. In some embodiments, about
ten percent (10%) of the total number of radiating elements are reserve radiating elements 338
that are not operational when the array 330 is new. In some embodiments, between about one
percent and about twenty percent of the total number of radiating elements are reserve radiating
elements 338. In some embodiments, the array 330 is divided into tiles or sub tiles, and an
even number of reserve radiating elements 338 are positioned in each sub tile. In some
embodiments, the array 330 includes four sub tiles. In some embodiments, the array 330 can
include more than four or less than for sub tiles. For example, three, six, eight, or nine sub tiles
can be realized. In some embodiments, the reserve radiating elements 338 are positioned
randomly within each sub tile. In some embodiments, the reserve radiating elements 338 are
positioned in an even distribution throughout each sub tile. In some embodiments, active
radiating elements and reserve radiating elements may be included on an array of a different
shape. For example, square or rectangular arrays can include active radiating elements and
reserve radiating elements.
[47] The effective-isotropic-radiated-power (EIRP) of the array 330 and the gain of the
array 330 are proportional to the number of active radiating elements 334 that are functional.
As the array 330 ages, individual active radiating elements 334 will fail and no longer be
operational. This failure leads to a reduction of the EIRP and gain. The inclusion of the
reserve radiating elements 338 allows the operator or controller of the array 330 to activate
reserve radiating elements 338 in response to failure of active radiating elements 334. In some
embodiments, a controller identifies the nearest reserve radiation element 338 to a failed active
radiating element 334 and remaps the control paths, buses or lines so that the nearest reserve
radiating element 338 is activated. In some embodiments, the inclusion of about ten percent
(10%) reserve radiating elements 338 doubles the MTBF of the array 330.
[48] Referring now to FIG. 9, an octagonal array similar to the array 330 and including
only active radiating elements (i.e., no reserve radiating elements) will produce a radiation
pattern with a strong central lobe and eight side lobes that are about thirty decibels (-30 dB)
-15-
4831-7910-1513
Atty. Dkt.No.: 17CR020 (047141-1250)
lower than the central lobe. A standard square or rectangular array will typically include four
side lobes. Increasing the number of side lobes has the effect of spreading the side lobe energy
or radiation field so that each individual side lobe has a lower energy.
[49] Referring now to FIG. 10 a radiation pattern produced by the array 330 when new
and including about ten percent (10%) reserve radiating elements 338 is shown. The graph of
FIG. 10 shows that the reserve radiating elements 338 introduce some pattern artifacts, but the
energy of the side lobes is still acceptably low and the artifacts do not negatively affect the
strong central lobe. Testing has shown that the radiation pattern and pattern artifacts remain
constant as active radiating elements 334 fail and reserve radiating elements 338 are activated.
[50] Referring now to FIG. 11, a satellite communication system 342 includes a transmit
array 346, a receive array 350, and a control module 354 that controls the transmit array 346
and the receive array 350. Each of the transmit array 346 and the receive array 350 are
octagonal in shape and provide the benefits described above with respect to FIG. 9. FIG. 12
shows a gain pattern produced by the octagonal arrays in comparison to a side lobe gain mask
required by the FCC. As clearly shown in FIG. 12, the side lobe noise levels produced by these
octagonal arrays are well below the required levels.
[51] While the detailed drawings, specific examples, detailed algorithms and particular
configurations given describe preferred and exemplary embodiments, they serve the purpose of
illustration only. The inventions disclosed are not limited to the specific forms and reticles
shown. For example, the methods may be performed in any of a variety of sequence of steps.
The hardware and optical configurations shown and described may differ depending on the
chosen performance characteristics and physical characteristics of the electronically scanned
array and processing devices. For example, the type of system components and their
interconnections may differ. The systems and methods depicted and described are not limited
to the precise details and conditions disclosed. The specific mechanical components and
operations are shown in a non-limiting fashion. Furthermore, other substitutions,
modifications, changes, and omissions may be made in the design, operating conditions, and
arrangement of the exemplary embodiments without departing from the scope of the invention
as expressed in the appended claims.

WHAT IS CLAIMED IS:
1. An apparatus, comprising:
a connector structured to receive mains power from a vehicle;
a first power converter structured to receive and condition the mains power;
a second power converter arranged in parallel with the first power converter and
structured to receive and condition the mains power;
a conditioned power connector structured to receive conditioned power from the first
power converter and the second power converter;
a first switch arranged between the first power converter and the conditioned power
connector and structured to selectively allow conditioned power to pass from the first power
converter to the conditioned power connector;
a second switch arranged between the second power converter and the conditioned
power connector and structured to selectively allow conditioned power to pass from the second
power converter to the conditioned power connector; and
a controller structured to monitor the first power converter and the second power
converter and to operate one of the first switch or the second switch to provide conditioned
power to the conditioned power connector.
2. The apparatus of claim 1, wherein if the controller determines that the first power
converter has failed, the first switch is opened and the second switch is closed so that the
second power converter is in communication with the conditioned power connector.
3. The apparatus of claim I, wherein if the controller determines that the first power
converter has failed, the first switch is opened and the second switch remains closed so that the
first power converter is no longer in communication with the conditioned power connector.
4. The apparatus of claim 1, further comprising a first isolating switch positioned upstream
of the first power converter, and a second isolating switch positioned upstream of the second
power converter, wherein the first isolating switch and the second isolating switch are actuated
by the controller to selectively isolate the first power converter or the second power converter.
5. The apparatus of claim 1, wherein the first power converter and the second power
converter each comprise a local power supply providing a plurality of voltages.
6. The apparatus of claim 1, wherein more than two power converters are connected in
parallel to loads via switches associated with each power converter.
7. An apparatus comprising:
a plurality of beamformer chips, each associated with at least one radiating element and
including a control bus interface and a reserve input configured to be remapped into the control
bus interface in the event that a signal within the control bus interface fails; and
a plurality of control buses structured to provide instructions to the plurality of
beamformer chips, and each including
a plurality of primary control paths providing communication from the control
bus to the control bus interface, and
a reserve control path structured to be remapped to provide communication from
the control bus to the control bus interface in the event that one of the plurality of primary
control paths fails.
8. The apparatus of claim 7, wherein the control buses are arranged in an orthogonal
manner.
9. The apparatus of claim 7, wherein each control bus communicates with a first subarray
of beamformer chips and a second subarray of beamformer chips.
10. An apparatus comprising:
an array of active radiating elements; and
between about one percent and about twenty percent reserve radiating elements
distributed throughout the active radiating elements.
11. The apparatus of claim 10, wherein the reserve radiating elements are divided between
four sub tiles.
12. The apparatus of claim 10, wherein the reserve radiating elements are divided between a
plurality of sub tiles and are distributed evenly within each sub tile.
13. The apparatus of claim 10, wherein the reserve radiating elements are activated as the
active radiating elements fail.
14. The apparatus of claim 10, wherein the array defines an octagonal shape.
15. An electronically scanned array system comprising:
a power supply system comprising:
a connector structured to receive mains power from a vehicle,
a first power converter structured to receive and condition the mains power,
a second power converter arranged in parallel with the first power converter and
structured to receive and condition the mains power,
a conditioned power connector structured to receive conditioned power from the
first power converter and the second power converter,
a first switch arranged between the first power converter and the conditioned
power connector and structured to selectively allow conditioned power to pass from the first
power converter to the conditioned power connector,
a second switch arranged between the second power converter and the
conditioned power connector and structured to selectively allow conditioned power to pass
from the second power converter to the conditioned power connector, and
a controller structured to monitor the first power converter and the second power
converter and to operate one of the first switch or the second switch to provide conditioned
power to the conditioned power connector;
a radiating element subarray comprising a plurality of active radiating elements, and
between about one percent and about twenty percent reserve radiating elements distributed
throughout the active radiating elements;
a plurality of beamformer chips, each associated with at least one radiating element and
including a control bus interface and a reserve input configured to be remapped into the control
bus interface in the event that a signal within the control bus interface fails; and
a plurality of control buses structured to provide instructions to the plurality of
beamformer chips, and each including
a plurality of primary control paths providing communication from the control
bus to the control bus interface, and
a reserve control path structured to be remapped to provide communication from the
control bus to the control bus interface in the event that one of the plurality of primary control
paths fails.
16. The electronically scanned array system of claim 15, wherein the power supply system
further comprises a first sensor positioned between the first power converter and the first
switch, the controller structured in communication with the first sensor.
17. The electronically scanned array system of claim 15, wherein the power supply system
further comprises an energy storage device in selective communication with the first power
converter and the second power converter and positioned downstream of the first switch and
the second switch.
18. The electronically scanned array system of claim 15, wherein the power supply system
further comprises a first isolating switch positioned upstream of the first power converter, and a
second isolating switch positioned upstream of the second power converter, wherein the first
isolating switch and the second isolating switch are actuated by the controller to selectively
isolate the first power converter or the second power converter.
19. The electronically scanned array system of claim 15, wherein the control buses are
arranged in an orthogonal manner.
20. The electronically scanned array system of claim" 15, wherein each control bus
communicates with a first subarray of beamformer chips and a second subarray of beamformer
chips.