Antenna system including a power management and control system

An antenna system may include a reconfigurable array antenna system including a plurality of elements each capable of radiating and receiving electromagnetic energy. The antenna system may also include an electronically reconfigurable power management and control system to selectively power each of the plurality of elements to generate a desired beam pattern.

BACKGROUND OF THE INVENTION

The present invention relates to phased array antennas, and more particularly to an antenna system including a power management and control system.

Phased array antennas may be used for satellite and line-of-sight communications, and other applications related to radar/sensors, electronic warfare (EW) or the like. Radiation patterns or beams from a phased array antenna may typically be controlled or steered electronically by varying the time-delay or phasing of electrical signals to individual transmit and receive elements forming the array antenna without moving any parts. Accordingly, a power management and control system for such antenna systems needs to be efficient particularly in satellite or other space vehicle applications, terrestrial mobile vehicle applications or other applications where capacity may be limited and efficient or optimum use of power is highly desirable. Additionally, such systems are desirably reconfigurable during a mission and systems' reliability can directly impact overall system reliability and performance. For mission critical space applications in particular, electronic subsystems must be able to tolerate a certain amount of single component failures and the failures must be contained from propagating and affecting other circuits or components.

BRIEF SUMMARY OF THE INVENTION

In accordance with an embodiment of the present invention, an antenna system may include a reconfigurable array antenna system including a plurality of elements each capable of radiating and/or receiving electromagnetic energy. The antenna system may also include an electronically reconfigurable power management and control system to selectively power each of the plurality of elements to generate a desired beam pattern without exceeding the system power limits.

In accordance with another embodiment of the present, a power management and control system for an array antenna system may include a host controller to control power to the array antenna system. The power management and control system may also include a beam steering controller to electronically steer the desired beam pattern generable by the array antenna system.

In accordance with another embodiment of the present, invention, a method of controlling antenna elements in an array antenna system may include selectively powering each of a plurality of elements of a reconfigurable phased array antenna system to generate a desired beam pattern within the system's total power allocation. The method may also include managing power consumption in each antenna sub-array of a plurality of antenna sub-arrays in the phased array antenna system.

Other aspects and features of the present invention, as defined solely by the claims, will become apparent to those ordinarily skilled in the art upon review of the following non-limited detailed description of the invention in conjunction with the accompanying figures.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description of embodiments refers to the accompanying drawings, which illustrate specific embodiments of the invention. Other embodiments having different structures and operations do not depart from the scope of the present invention.

FIG. 1is a schematic diagram of an example of an antenna system100including a power management and control system102in accordance with an embodiment of the present invention. The antenna system100may also include a reconfigurable array antenna system104including a plurality of elements106that may be grouped in an array or multiple antenna sub-arrays or modules, such as sub-array108aand sub-array108b. The elements106are capable of being electronically steered for radio frequency communications.

The plurality of elements106may include transmit elements capable of radiating electromagnetic energy or transmitting communications signals, receive elements capable of receiving electromagnetic energy or communications signals, or the elements106may be able to both transmit and receive electromagnetic radiation or signals. The elements106may include Monolithic Microwave Integrated Circuit (MMIC) devices formed or grouped in the antenna sub-arrays108or antenna modules.

As will be described, the antenna system100provides a redundant power management and distribution architecture110for the multiple sub-array, multi-beam phased array antenna system104. The antenna system100may include a host power and control module112, circuit or subsystem and a multi-beam antenna array module114, circuit or subsystem.

The host power and control module112may include a host power converter116to provide step-down power conversion to reduce a line bus voltage to an intermediate voltage. The step-down power conversion may be necessary because of the physical separation between the host controller112and the externally installed array antenna system104. Additionally, a power conversion ratio and low voltage and high voltage current requirements may be optimized for the multi-beam antenna array module114electronics by the host power converter116.

An inline current interruptor118, circuit breaker or similar device may connect the host power converter116to a voltage bus to protect the host power and control module112and its load or array module114. A voltage and current display120may present the host or line side voltage and current for observation by a user or operator or the line side voltage and current may be transmitted to a remote location for monitoring, such as in space vehicle applications.

The host power and control module112may also include an antenna status display122to display a status of the array antenna system104to a user or operator. Alternatively, the antenna status also may be transmitted to a remote location as in space applications.

A delay module124or circuit may be connected between the host power converter116and a host controller126. The host controller126may be connected to a beam steering controller128in the multi-beam antenna array system114by a data bus130. The delay module124may provide proper timing between the host controller126and the beam steering controller128for initial establishment of bus communications over the data bus130.

The host controller126may receive radio frequency (RF) signals or data for controlling the multiple beams that may be generated by the array antenna system104. In the example illustrated inFIG. 1, the host controller126may receive inputs132or RF signals or data for a beam1and a beam2that may be produced by antenna sub-arrays108aand108b, respectively. The system102is scalable to accommodate any number of antenna sub-arrays108and may receive multiple inputs132for controlling different beams from any number of sub-arrays108. The RF signals may be conditioned and transferred by the host controller126to the sub-arrays108via RF signal lines134. Elements106may be selectively controlled within the sub-arrays108and specific sidelobe and antenna beam shapes may be generated by powering up selected sub-arrays108or elements106or powering-down selected sub-arrays108or elements106as will be described in more detail with reference toFIGS. 3A-3D.

For beam pointing, the host controller126may also receive location and navigation data from an inertial navigation system, global positioning system, or other positioning or navigation system via a bus136. The location and navigation data may be conditioned and relayed by the host controller126to the beam steering controller128via the data bus130.

The host power converter116may be connected to at least two antenna power converters136and138that may be in the multi-beam antenna array module114. The two antenna power converters136and138provide redundancy and permit the power management and control system102to be electronically reconfigured for reliably powering the antenna sub-arrays108as further described herein. Each of the antenna power converters136and138may be direct current (DC) to DC power converters. The antenna power converters136and138may convert the intermediate voltage from the host power converter116to suitable operating voltages for the elements106or MMIC devices.

The multi-beam antenna array module114may also include a number of power sequencers140corresponding to the number of antenna sub-arrays108or antenna modules. Accordingly, the multi-beam antenna array module114may include a power sequencer140for every antenna sub-array108. For purposes of simplicity of illustrating and describing the present invention, only two power sequencers140and two antenna sub-arrays108are shown in the exemplary embodiment of the present invention illustrated inFIG. 1. However, the system102is scalable and may include any number of antenna sub-arrays108and corresponding power sequencers140depending upon the expected application or applications of the system102and any spatial limitations of the platform or vehicle with which the system100may be used.

The power sequencers140aand140bmay be respectively connected to the antenna power converters136and138to control a positive voltage supply (Vdd) of each antenna power converter136and138by monitoring a negative output voltage (Vss) of each converter136and138. The positive voltage supply (Vdd) and the negative voltage supply or output voltage (Vss) may be respectively connected from each of the converters136and138to the respective antenna sub-arrays108aand108b. The positive voltage supply (Vdd) may be positive or have a positive polarity relative to a return or common ground142of each of the antenna power converters136and138, and the negative output voltage (Vss) may be negative or negatively polarized relative to the return or common ground142.

Each of the power sequencers140may include a voltage status monitoring module144to respectively monitor the status of each converter's negative output voltage (Vss) to control the application of the positive output voltage (Vdd) to each of the antenna sub-arrays108. Monitoring and measuring the negative output voltage (Vss) prevents excess current drawn by the antenna elements106or MMIC devices which could potentially damage the devices. The voltage status monitor144may generate or cause to be generated a suitable reset signal to hold the positive output voltage (Vdd) off during startup of the antenna system104until the negative output voltage (Vss) is at a proper level to prevent any damage to the antenna elements106or MMIC devices.

Each power sequencer140may also include a power on reset module146. The power on reset module146may generate or cause to be generated a reset signal to hold the positive voltage supply (Vdd) of any one of the converters136or138off, when the converter136or138is coupled to at least one of the antenna sub-arrays108to supply power thereto, in response to the negative output voltage (Vss) of the converter136or138dropping below an acceptable threshold voltage during normal operation of the antenna system100.

Each of the antenna power converters136and138may also include a crowbar switch148or a similar device at the output terminals of the positive voltage supply (Vdd). The crowbar switch148may clamp the positive voltage supply (Vdd) output down before the negative voltage supply (Vss) output during a power down operation to prevent excess current drawn from the positive voltage supply (Vdd) by the antenna elements106or MMIC devices which could potentially damage the devices.

The multi-beam antenna array module114may also include a redundant power distribution switch150to connect power converters136and138to provide power to antenna status monitor166and the beam steering controller128. An example of a redundant power distribution system that may be used for the redundant power distribution switch150and operation of such a switch or system is described in U.S. Pat. No. 5,654,859, entitled “Redundant Power Distribution System,” issued Aug. 5, 1997 to Fong Shi and in U.S. Pat. No. 7,190,090, entitled “Redundant Power Distribution System,” issued Mar. 13, 2007 to Fong Shi. Both of these patents are assigned to the same assignee as the present invention and are incorporated herein by reference. The redundant power distribution switch150provides redundant power to its loads as long as one of the power converters136or138is in operation.

In another embodiment of the present invention, not shown in the drawings, a power switch may be associated with each antenna sub-array108to connect a chosen one of the at least two converters136and138to selected ones of the antenna sub-arrays104. Each power switch may respectively connect the negative output voltage (Vss) and the positive output voltage (Vdd) of the chosen one of the converters136and138to be operational to the antenna sub-arrays108selected to be powered during a particular mission or operation. The beam steering controller128may control a main power control switch that is connected to each of the power switches associated with each antenna sub-array108and to the negative output voltage (Vss) of each antenna power converter136and138.

Accordingly, the embodiments of the present invention provide a redundant and electronically reconfigurable power management and distribution architecture and control system102for a multiple sub-array multi-beam phased array antenna system104or similar system. The power management, distribution and control system102is capable of isolating a failure and continuing to feed power to the antenna system104. The system104is capable of self reconfiguring at the sub-array level108, simultaneously producing a left hand and a right hand circularly polarized beam pattern152and154, respectively, or either a left hand pattern154or right hand pattern152when only one circular polarization is required. For power conservation, one or more of the total available number of antenna sub-arrays108or beams can be turned off remotely when not needed during a particular mission or operation. The system100can also be easily implemented in other array architectures with more than two simultaneous beams and with multiple sub-arrays.

As previously described, the phased array antenna system104is a redundant design at the sub-array108or module level. The antenna system104may consist of a large number of individual sub-arrays108and may, therefore, be able to lose a small portion of the antenna sub-arrays108or modules, as long as the failed modules do not affect the power and control of the entire system100. Power being supplied to the antenna system104, however, may be the most critical functional block because its reliability has a direct impact on the overall system reliability. For mission critical space applications or similar application, electronic systems must be able to tolerate a single component failure and the failure must be contained from propagating and affecting other components, circuits or subsystems. For cost, weight and performance trade-offs, N numbers of redundant power switches and a minimum of two identical power supplies or converters may be necessary for an N sub-array antenna system to tolerate component failure beyond the antenna sub-array or module level. As described, the redundant power management, distribution and control system102of the embodiments of the present invention are capable of tolerating at least one power supply failure and being able to be reconfigured to maintain operation. Accordingly, should one of the minimum of two DC to DC antenna power converters136and138become inoperable, the other converter may continue to provide uninterruptible power for the loads.

The beam steering controller128may receive beam pointing commands and reconfiguration control commands for sub-array and beam switching from the host controller126. For beam pointing commands and periodic update data, the beam steering controller128may calculate and load the phase shifts or time delays to individual elements106or MMIC devices. Beam forming may be accomplished through a predetermined number of rows and columns of dedicated clock lines156and data lines158. The predetermined number of rows and columns of dedicated clock lines156and data lines158may be dependent upon the number of individual antenna elements106or MMIC devices that may need to be addressed or controlled to provide the desired beam pattern or radiation pattern. For example, an antenna array system similar to the antenna array system200illustrated inFIG. 2may have128elements packaged into sixteen element modules202with eight elements204in each module202. In this example, there may be sixteen clock lines206and sixteen data lines208to address each of the sub-arrays210and212.

For polarization switching, the beam steering controller128may simultaneously send all the control commands via two discrete control lines, beam steering line left (BSL)160and beam steering line right (BSR)162, to the antenna elements106or MMIC devices in the antenna sub-arrays108for the formation of the right hand circular polarized radiation pattern152and the left hand pattern154.

The beam steering controller128may also assert control through discrete power sequencer control lines164from the beam steering controller128to each of the power sequencers140to respectively command and control the positive output voltage (Vdd) from the DC to DC antenna power converters136and138or whichever converter may be active.

The multi-beam antenna array module114may also include an antenna status monitor module166to monitor an operational status of the antenna array system104and to report the operational status to the host controller126. The operational status of the antenna array system104may be presented on the antenna status display122. The operational status that may be displayed may include but is not necessarily limited to operational parameters, such as temperature at various locations on an antenna base plate where the antenna elements106or MMIC based radio frequency (RF) devices are directly attached, power conditions, power consumption of the entire antenna system104, which sub-arrays106are active, or similar information that may be beneficial in monitoring the system performance and controlling the system100.

Each antenna power converter136and138may include a positive voltage (Vdd) On/Off control168for the converter's main output voltage. The power sequencer136or138may control the positive output voltage (Vdd) using the On/Off control168by monitoring the status of the converter's negative output voltage (Vss). As previously described, the positive output voltage (Vdd) may be positive with respect to the return or common ground of the converter136or138, and the negative output voltage (Vss) may be negative with respect to the same return of the same converter.

In accordance with an embodiment of the present invention, the power management and control system102and reconfigurable array antenna system104may be mounted to a vehicle170. The vehicle170may be an aerospace vehicle, such as an aircraft, satellite, spacecraft or similar vehicle, a terrestrial vehicle, watercraft or other vehicle.

FIG. 2is a block diagram of an exemplary array antenna system200in accordance with an embodiment of the present invention. The array antenna system200may be used for the array antenna system104ofFIG. 1. The array antenna system200may include multiple array channels210and212that may generate multiple radiation beams. Only two array channels210and212(beam1and beam2respectively) are illustrated in the exemplary system200inFIG. 2for purposes of explaining the present invention. The array channels210and212may be identical. Each of the two array channels210and212may contain128antenna elements204or radiation means that may be packaged into16modules202. Each module202may include8antenna elements204that may be arranged in a 2×4 configuration or some other configuration that may be appropriate for the intended purpose or application of the antenna system200. Each antenna element204may be capable of providing two independent radio frequency (RF) channels that may each include a MMIC low-noise amplifier and phase shifter, an RF transmission line and a shared radiating element (not shown inFIG. 2). These two RF channels in each antenna module202may form dual beams with dual polarizations, such as one for a left-hand circular polarized radiation pattern and the other for a right-hand circular polarized radiation pattern similar to radiation patterns152and154previously described with reference toFIG. 1. All the128elements204in each array channel210and212may be controlled by eight digital clock lines206and sixteen digital data lines208. The clock lines206and the data lines208may be arranged in an orthogonal manner for individual element addressing and control.

A DC power distribution network214and a RF distribution network216may also be embedded in each array channel210and212to distribute electrical power to each of the elements204and to transmit or receive RF signals to or from each of the elements204depending upon whether the element is transmitting or receiving signals. The power distribution network214may include positive output voltage (Vdd) lines218, negative output voltage (Vss) lines220and return (RTN) lines222or common ground of the antenna power converters, such as converters136and138inFIG. 1.

Those skilled in the art will recognize that the exemplary antenna systems100and200shown inFIGS. 1 and 2, respectively, illustrate a configuration for dual sub-array, dual-beam applications. The array architecture and power management, distribution and control system of the embodiments of the present invention described herein can be scaled to larger size arrays or systems. The configuration can be extended to full scale large arrays made of N×N sub-arrays, and variations may be adapted to other applications.

FIGS. 3A-3Dare illustrations of examples of methods or different schemes300a-300dfor selectively powering antenna sub-arrays302of a phased array antenna system304a-304dfor sidelobe and beam shaping control in accordance with embodiments of the present invention. In addition to being reconfigurable the power management and control system of the embodiments of the present invention may provide power-efficient beam sidelobe and beam shape control for better antenna beam profile control. A conventional method of controlling antenna sidelobes is to use attenuators in the RF signal paths within the antenna modules. With this traditional approach the antenna still consumes the same DC power even though the RF signal is being attenuated.

For an antenna aperture made up of a significant number of sub-arrays302, as shown inFIGS. 3A-3D, sidelobe and beam shape control is possible if power to each sub-array302can be selectively turned on or off by host commands, such as commands from the host controller126inFIG. 1. This new method reduces overall heat load and DC power consumption in the antenna304, which may be important for some applications, such as space based mission critical communications where power conservation is often required.

By turning on and off the antenna sub-arrays302as illustrated in the exemplary schemes300a,300band300c, the active portion of the antenna aperture may be rounder and thus can generate a beam profile or radiation pattern closer to that of an often desirable circular aperture. By turning on and off the antenna sub-arrays302as illustrated in the exemplary scheme300d, the antenna aperture may be rounder and with a density taper, thus enabling an additional degree of freedom in terms of power conservation. Those skilled in the art will recognize that other beam configurations or patterns may be available by controlling which sub-arrays are turned on or off.