Patent Description:
In some systems, antenna arrays are used to transmit different high-gain beams in different directions at different times. This may be useful in various applications, such as radars and communication systems. Some approaches use electronic beam steering to change the way in which input signals are provided to antenna arrays in order to modify how the antenna arrays transmit outgoing beams. Other approaches use active switching with field effect transistor (FET) switches combined with multiple phase-tapered splitters, where the switching action of the FETs changes which phase-tapered splitter receives the input signal and thereby changes the resulting beam angle.

<CIT> discloses two beams with equiangular spacing are formed at a single antenna face, and multiple beams are generated by combining a plurality of such faces. This makes it possible to reduce the size of an antenna device and to decrease the wind load sustained by an antenna, whereby it becomes possible to mount many antennas on a single supporting structure and to achieve substantial weight reduction of a supporting structure.

<CIT> discloses a thinned multiple beam phased array antenna.

<CIT> discloses a circular polarization antenna.

<CIT> discloses a planar, low-profile, very wide frequency bandwidth, wide-scan, dual-linear or circular-polarized phased array antenna using integrated stacked-disc radiator tiles.

<CIT> discloses all weather tactical strike system (AWTSS) and method of operation.

This disclosure provides a multi-beam passively-switched patch antenna array.

In a first aspect, an apparatus comprising: multiple patch antenna elements configured to transmit multiple electromagnetic beams in multiple beam directions; multiple inputs each configured to receive one of multiple input signals, each input signal associated with one of the electromagnetic beams; multiple phase-tapered splitters each configured to receive one of the input signals, divide the received input signal into a set of sub-signals, and provide a phase taper that adjusts phases of at least some of the sub-signals in the set of sub-signals, wherein different phase tapers are associated with different ones of the beam directions; and characterized by further comprising multiple <NUM>° hybrid transformers each configured to receive sub-signals associated with different ones of the input signals, isolate the received sub-signals from each other, and provide the isolated sub-signals to one of the patch antenna elements; wherein the patch antenna elements are arranged in four quadrants; the inputs comprise two inputs for each quadrant, wherein one of the inputs for each quadrant is configured to receive a first of the input signals and one other of the inputs for each quadrant is configured to receive a second of the input signals; and the phase-tapered splitters comprise two phase-tapered splitters for each quadrant, wherein one of the phase-tapered splitters for each quadrant is configured to receive the first input signal and one other of the phase-tapered splitters for each quadrant is configured to receive the second input signal.

In a second aspect, a method comprising: receiving a first input signal; dividing the first input signal into a first set of multiple sub-signals and adjusting phases of at least some of the sub-signals in the first set of sub-signals according to a first phase taper; feeding the phase-adjusted first set of sub-signals to multiple patch antenna elements through multiple <NUM>° hybrid transformers; transmitting a first electromagnetic beam in a first beam direction using the patch antenna elements based on the phase-adjusted first set of sub-signals; receiving a second input signal; dividing the second input signal into a second set of multiple sub-signals and adjusting phases of at least some of the sub-signals in the second set of sub-signals according to a second phase taper; feeding the phase-adjusted second set of sub-signals to the patch antenna elements through the <NUM>° hybrid transformers, the <NUM>° hybrid transformers isolating the first and second sets of sub-signals from each another; and transmitting a second electromagnetic beam in a second beam direction using the patch antenna elements based on the phase-adjusted second set of sub-signals; wherein the first and second beam directions are based on the first and second phase tapers, respectively; the patch antenna elements are arranged in four quadrants; the inputs comprise two inputs for each quadrant, wherein one of the inputs for each quadrant is configured to receive the first input signal and one other of the inputs for each quadrant is configured to receive the second input signal; and the phase-tapered splitters comprise two phase-tapered splitters for each quadrant, wherein one of the phase-tapered splitters for each quadrant is configured to receive the first input signal and one other of the phase-tapered splitters for each quadrant is configured to receive the second input signal.

For a more complete understanding of this disclosure, reference is made to the following description, taken in conjunction with the accompanying drawings, in which:.

<FIG>, described below, and the various embodiments used to describe the principles of the present disclosure are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any type of suitably arranged device or system.

As noted above, in some systems, antenna arrays are used to transmit different high-gain beams in different directions at different times. This may be useful in various applications, such as radars and communication systems. Some approaches use electronic beam steering to change the way in which input signals are provided to antenna arrays in order to modify how the antenna arrays transmit outgoing beams. Other approaches use active switching with field effect transistor (FET) switches combined with multiple phase-tapered splitters, where the switching action of the FETs changes which phase-tapered splitter receives the input signal and thereby changes the resulting beam angle. However, these approaches may require a considerable amount of space to be implemented, which can limit or prevent their use in volume-constrained applications. These approaches also often cannot be used with mono-pulse tracking or permit scaling to arbitrary antenna array sizes. Mono-pulse tracking is a technique used to encode radio frequency (RF) signals to provide accurate directional information, which may be needed or desired in certain applications.

This disclosure provides a multi-beam passively-switched patch antenna array. As described in more detail below, the multi-beam passively-switched patch antenna array includes an array of patch antenna elements and circuitry configured to provide different signals to different antenna elements of the array. The circuitry includes phase-tapered splitters that are used to divide each of multiple input signals into multiple sub-signals, where the sub-signals are provided to different antenna elements of the array. The phase tapering is designed to achieve a desired beam direction for one of multiple output beams produced by the array. The circuitry also includes hybrid transformers that isolate the sub-signals for different input signals from one another prior to reaching the antenna elements of the array. This enables a system to provide one input signal to the circuitry for use in transmitting a beam in a first desired direction and to provide another input signal to the circuitry for use in transmitting another beam in a second desired direction.

In this way, the multi-beam passively-switched patch antenna array supports the transmission of different beams in different directions in a compact package (such as a thin flat package). Moreover, this is accomplished passively in a manner that reduces or eliminates the need for electronic beam steering or active switching. Further, the patch antenna array can be used in mono-pulse tracking applications and can be scaled to arbitrary antenna array sizes. In addition, in some embodiments, the patch antenna array can be fabricated using common printed circuit board (PCB) materials, such as dielectric materials and etched metals, which can significantly reduce the cost and manufacturing requirements of the array.

One or more instances of the multi-beam passively-switched patch antenna array may be used in any suitable applications. Example applications can include various secure (high gain) communications applications, antennas used for seeker applications, and applications in drones or other flight vehicles. Other example applications can include automotive radar applications, such as forward-look and side-look beams in single passive package (utilizing two antennas, one on each side of the vehicle), or applications in <NUM> antennas (utilizing a semi- or non-gimbaled two-beam antenna for communications with two base stations).

<FIG> illustrates an example system <NUM> that uses a multi-beam passively-switched patch antenna array <NUM> in accordance with this disclosure. The patch antenna array <NUM> is positioned in a radome <NUM>, and the patch antenna array <NUM> can be used to transmit multiple beams 106a-106b. In this example, the beams 106a-106b are transmitted from the patch antenna array <NUM> in different directions. For example, the beam 106a is transmitted along a first axis 108a that has a first angle relative to a central axis <NUM> of the patch antenna array <NUM>, and the beam 106b is transmitted along a second axis 108b that has a second angle relative to the central axis <NUM> of the patch antenna array <NUM>. The first axis 108a and the central axis <NUM> may form an angle denoted φ, and the second axis 108b and the central axis <NUM> may form an angle denoted θ. Each angle φ and θ may have any suitable value.

As can be seen here, the patch antenna array <NUM> supports the ability to generate multiple high-gain beams 106a-106b, which are isolated and can be independently activated as described below. The ability to generate different high-gain beams 106a-106b and the ability to passively switch between transmitting the beams 106a-106b can be extremely useful in various applications. Moreover, the patch antenna array <NUM> supports these functions without requiring electronic beam forming or active switching, which can help to reduce the size, weight, and cost of the patch antenna array <NUM>. Further, the patch antenna array <NUM> can be used with mono-pulse tracking applications or other applications. In addition, the patch antenna array <NUM> can independently generate multiple beams 106a-106b that are separated by a fixed angle within any suitable wavelength or frequency band(s).

In some embodiments, the patch antenna array <NUM> may represent a circular patch antenna array, and the beams 106a-106b may represent circularly-polarized beams. In particular embodiments, the beam 106a may have a "right hand" circular polarization, and the beam 106b may have a "left hand" circular polarization (or vice versa). Note, however, that other designs and operations of the patch antenna array <NUM> may be used.

In this example, the system <NUM> additionally includes at least one signal source <NUM> and a controller <NUM>. The at least one signal source <NUM> represents a source of input electrical signals that are provided to the patch antenna array <NUM>, where the input signals provide RF power used to generate the beams 106a-106b. A single source <NUM> may generate multiple input signals, or different sources <NUM> may generate different input signals. Each signal source <NUM> represents any suitable structure configured to generate RF power used to generate at least one beam of electromagnetic energy. The controller <NUM> controls the operation of the signal source(s) <NUM> in order to control which input signal is provided to the patch antenna array <NUM> at any given time. For instance, the controller <NUM> may cause one input signal to be provided to the patch antenna array <NUM> (so that a first beam 106a is produced) and then cause another input signal to be provided to the patch antenna array <NUM> (so that a second beam 106b is produced). The controller <NUM> may switch back and forth between the input signals as needed or desired. The controller <NUM> includes any suitable structure configured to control operation of at least part of the system <NUM>. For example, the controller <NUM> may include one or more processing devices, such as one or more microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), or discrete elements.

Although <FIG> illustrates one example of a system <NUM> that uses a multi-beam passively-switched patch antenna array <NUM>, various changes may be made to <FIG>. For example, one or more instances of the patch antenna array <NUM> may be used in any other suitable applications or systems. Also, the number of patch antenna arrays <NUM>, the number of antenna elements in each patch antenna array <NUM>, the size of each patch antenna array <NUM>, and the size(s) of the antenna elements in each patch antenna array <NUM> can be selected in order to support desired operation in a specific application.

<FIG> illustrates an example multi-beam passively-switched patch antenna array <NUM> in accordance with this disclosure. For ease of explanation, the patch antenna array <NUM> shown in <FIG> may be described as being used in the system <NUM> of <FIG>. However, the patch antenna array <NUM> may be used in any other suitable manner.

As shown in <FIG>, the patch antenna array <NUM> includes patch antenna elements <NUM>. Each patch antenna element <NUM> is configured to receive an electrical signal and to radiate electromagnetic energy based on the received signal and/or to receive electromagnetic energy and provide an electrical signal based on the received electromagnetic energy. Each patch antenna element <NUM> may be formed from any suitable material(s), such as one or more metals or other conductive material(s). Each patch antenna element <NUM> may also be formed in any suitable manner, such as by depositing and etching the material(s) forming the patch antenna element <NUM>. In some embodiments, the patch antenna elements <NUM> may be formed on a printed circuit board. Each patch antenna element <NUM> may further have any suitable size, shape, and dimensions. In this example, the patch antenna elements <NUM> are generally circular, although other shapes may be used. Note that the patch antenna array <NUM> can be designed to provide a large antenna gain for each of the beams 106a-106b produced by the patch antenna array <NUM>, such as an antenna gain of about <NUM> decibels or more. However, the antenna gain can vary depending on various factors, such as the number of antenna elements <NUM> in the array <NUM> and the size of the array <NUM>. The patch antenna elements <NUM> may be separated from one another by any suitable material(s), such as one or more oxides, insulators, or other dielectric material(s).

The patch antenna elements <NUM> are positioned over a stack <NUM> of additional layers. The stack <NUM> includes circuitry that can be used as described below to provide electrical signals to the patch antenna elements <NUM>. The electrical signals can be processed using the circuitry in order to cause the patch antenna elements <NUM> to generate and radiate different beams 106a-106b in desired directions.

In some embodiments, the patch antenna array <NUM> may be divided into quadrants 206a-206d or other sections, and input signals can be provided to different quadrants of the patch antenna array <NUM> (although this need not be the case). In the example shown in <FIG>, each quadrant 206a-206d includes twenty-six patch antenna elements <NUM>, although other numbers of patch antenna elements <NUM> may be used. The use of quadrants 206a-206d may, in some applications, support the use of mono-pulse tracking, which often involves the use of four channels (one per quadrant) along with the use of phases of +<NUM>° and -<NUM>° in opposite quadrants.

In this example, the patch antenna array <NUM> additionally includes at least one projection <NUM> extending from the stack <NUM>. The projection <NUM> may be used to help ensure that the patch antenna array <NUM> is installed with a correct orientation in a larger device or system. For example, installing the patch antenna array <NUM> upside down or otherwise rotated in the system <NUM> of <FIG> would cause the beams 106a-106b to radiate from the patch antenna array <NUM> in the wrong directions. The projection <NUM> can help to ensure that the patch antenna array <NUM> is installed in a proper orientation so that the beams 106a-106b radiate from the patch antenna array <NUM> in the desired directions. Note, however, that any other suitable mechanism may be used to identify a proper orientation of the patch antenna array <NUM>. Also note that the ability to rotate the patch antenna array <NUM> may be desired in some cases.

While the patch antenna array <NUM> here is shown as having a generally flat circular disc shape, the patch antenna array <NUM> may have any other suitable form. Also, the patch antenna array <NUM> may be packaged in any suitable manner. For example, the patch antenna array <NUM> may be shaped like a circular disc and have a diameter of about <NUM> inches (about <NUM> millimeters) or less and a thickness of about <NUM> inches (about <NUM> millimeters) or less. However, these are examples only, and other packages for the patch antenna array <NUM> may be used.

Although <FIG> illustrates one example of a multi-beam passively-switched patch antenna array <NUM>, various changes may be made to <FIG>. For example, the sizes, shapes, and dimensions of the patch antenna array <NUM> and each of its individual components may vary as needed or desired. Also, the patch antenna array <NUM> may include any suitable number and arrangement of patch antenna elements <NUM>.

<FIG> illustrates an example functional architecture <NUM> of a multi-beam passively-switched patch antenna array <NUM> in accordance with this disclosure. For ease of explanation, the functional architecture <NUM> shown in <FIG> may be described as being used in the system <NUM> of <FIG> with a patch antenna array <NUM> having the form shown in <FIG>. However, the functional architecture <NUM> may be used with any other suitable patch antenna array and in any other suitable system.

As shown in <FIG>, the patch antenna array <NUM> is configured to receive multiple input signals 302a-302b. The input signals 302a-302b represent the electrical signals that provide RF power used to generate the beams 106a-106b, respectively, transmitted by the patch antenna array <NUM>. For example, the input signals 302a-302b may represent signals generated by the signal source(s) <NUM>. In order to produce one beam 106a, the input signal 302a can be provided to the patch antenna array <NUM>. In order to produce another beam 106b, the input signal 302b can be provided to the patch antenna array <NUM>. This enables passive switching of the patch antenna array <NUM> by controlling which input signal 302a or 302b provides RF power to the patch antenna array <NUM>. In some embodiments, this control can be provided by the controller <NUM> controlling which input signal 302a or 302b is provided to the patch antenna array <NUM> by the signal source(s) <NUM>.

Each input signal 302a-302b is provided to a respective phase-tapered splitter 304a-304b. The phase-tapered splitters 304a-304b divide the input signals 302a-302b into sets of sub-signals 306a-306b, respectively. For example, each phase-tapered splitter 304a-304b may equally or unequally divide one of the input signals 302a-302b into the sub-signals 306a-306b (which may have equal or unequal power). Each phase-tapered splitter 304a-304b can also adjust the phases of the sub-signals 306a-306b so that the resulting beams 106a-106b produced by the patch antenna array <NUM> are transmitted in desired directions. This can be accomplished in various ways, such as by designing the phase-tapered splitters 304a-304b so that the sub-signals 306a-306b travel through conductive paths of different lengths before reaching the patch antenna elements <NUM>. The phase taper provided by each phase-tapered splitter 304a-304b translates into the beam angle of the resulting beam 106a-106b. Thus, for instance, the beam 106a at an angle φ can be produced by the phase-tapered splitter 304a providing an electrical phase taper denoted α per row of patch antenna elements <NUM>, and the beam 106b at an angle θ can be produced by the phase-tapered splitter 304b providing an electrical phase taper of β per row of patch antenna elements <NUM>. The phase-tapered splitters 304a-304b may also generate circular polarizations in different directions ("right hand" versus "left handed") for the different beams 106a-106b. Each phase-tapered splitter 304a-304b includes any suitable structure configured to split an input signal and adjust phases of the resulting sub-signals.

One of the sub-signals 306a can be provided to each patch antenna element <NUM> of the patch antenna array <NUM>, and one of the sub-signals 306b can be provided to each patch antenna element <NUM> of the patch antenna array <NUM>. Prior to reaching the patch antenna element <NUM>, each pair of one sub-signal 306a and one sub-signal 306b is provided to a <NUM>° hybrid transformer <NUM>. Depending on which input signal 302a or 302b is being received, the <NUM>° hybrid transformer <NUM> allows one of the sub-signals 306a or 306b to be provided to the associated patch antenna element <NUM> of the patch antenna array <NUM>. The <NUM>° hybrid transformer <NUM> also splits the received sub-signal 306a or 306b (typically equally), provides one portion of the received sub-signal 306a or 306b to one input of the patch antenna element <NUM>, and provides another portion of the received sub-signal 306a or 306b to another input of the patch antenna element <NUM>. The two portions of the sub-signal 306a or 306b are out-of-phase, namely one portion of the sub-signal 306a or 306b is <NUM>° out-of-phase with the other portion of the sub-signal 306a or 306b. Overall, the <NUM>° hybrid transformer <NUM> provides isolation between the two sub-signals 306a, 306b and ensures that one sub-signal does not affect the other. Each <NUM>° hybrid transformer <NUM> includes any suitable structure configured to isolate sub-signals and ensure that the sub-signals are out-of-phase.

Note that the components illustrated in a dashed box <NUM> can be replicated multiple times, such as once for each antenna element <NUM> in a quadrant 206a-206d or other portion of the patch antenna array <NUM>. All of these antenna elements <NUM> may be fed by outputs of the same phase-tapered splitters 304a-304b. A dashed box <NUM> in <FIG> indicates that the phase-tapered splitters 304a-304b may be implemented in a different portion of the patch antenna array <NUM>, such as in other layers of the patch antenna array <NUM>, although this need not be the case. The dashed box <NUM> also indicates that the phase-tapered splitters 304a-304b may be replicated multiple times, such as once for each quadrant 206a-206d or other portion of the patch antenna array <NUM>, where each is used with its own set of hybrid transformers <NUM> and antenna elements <NUM>. In those embodiments, the same input signals 302a-302b may be provided to each set of phase-tapered splitters 304a-304b.

Although <FIG> illustrates one example of a functional architecture <NUM> of a multi-beam passively-switched patch antenna array <NUM>, various changes may be made to <FIG>. For example, each of the phase-tapered splitters 304a-304b may be used to feed any suitable number of patch antenna elements <NUM>. Also, the components of the patch antenna array <NUM> may have any suitable layout or arrangement of components.

<FIG> illustrate an example layout of a multi-beam passively-switched patch antenna array <NUM> in accordance with this disclosure. For ease of explanation, the layout shown in <FIG> may be described as being used to implement the functional architecture <NUM> of <FIG> for a patch antenna array <NUM> having the form shown in <FIG>, which is used in the system <NUM> of <FIG>. However, the layout may be used with any other suitable patch antenna array and functional architecture and in any other suitable system.

As shown in <FIG>, a layer <NUM> of the patch antenna array <NUM> is used for input/output and includes a substrate <NUM> and multiple input/output (I/O) connectors 404a-<NUM>. The substrate <NUM> may be formed using a printed circuit board or other electrically-insulative material(s). Each I/O connector 404a-<NUM> can be used to couple the patch antenna array <NUM> to a larger device or system and to receive an input signal from or provide an output signal to the larger device or system. Each I/O connector 404a-<NUM> represents any suitable structure configured to receive or provide an electrical signal. Each I/O connector 404a-<NUM> can be formed from any suitable conductive material(s), such as one or more metals, and in any suitable manner, such as deposition and etching. In some embodiments, the I/O connectors 404a-<NUM> are configured to mate with spring connectors used in the larger device or system.

Note that there are eight I/O connectors 404a-<NUM> in this example, which may be used to provide two input signals 302a-302b to each of four quadrants 206a-206d of the patch antenna array <NUM>. For instance, the I/O connectors 404a-404d may be used to provide the same input signal 302a to the four quadrants 206a-206d of the patch antenna array <NUM>, and the I/O connectors 404e-<NUM> may be used to provide the same input signal 302b to the four quadrants 206a-206d of the patch antenna array <NUM>. However, the layer <NUM> of the patch antenna array <NUM> can support any suitable number of inputs/outputs in any suitable arrangement.

As shown in <FIG> and <FIG>, two layers <NUM> and <NUM> of the patch antenna array <NUM> are used for implementing the phase-tapered splitters 304a-304b. The layer <NUM> includes a substrate <NUM> and multiple electrical traces <NUM>, and the layer <NUM> includes a substrate <NUM> and multiple electrical traces <NUM>. The electrical traces <NUM> and <NUM> can be electrically coupled to corresponding I/O connectors 404a-<NUM> and to other structures using conductive stubs or vias. The electrical traces <NUM> and <NUM> act as splitters to divide the input signals 302a-302b into different sets of sub-signals. This is accomplished by having multiple parallel pathways electrically coupled to each of the I/O connectors 404a-<NUM>. The desired phase shifts may be obtained using, for instance, electrical traces <NUM> and <NUM> of different lengths.

Each electrical trace <NUM> and <NUM> represents any suitable pathway configured to transport an electrical sub-signal. Each electrical trace <NUM> and <NUM> can be formed from any suitable conductive material(s), such as one or more metals, and in any suitable manner, such as deposition and etching. Each electrical trace <NUM> and <NUM> includes multiple connection points <NUM> and <NUM>, which represent areas where the electrical traces <NUM> and <NUM> can be coupled to other layers of the patch antenna array <NUM> using the conductive stubs or vias.

As shown in <FIG>, another layer <NUM> of the patch antenna array <NUM> includes a substrate <NUM> and multiple hybrid transformers <NUM>. The hybrid transformers <NUM> can be electrically coupled to corresponding connection points <NUM> and <NUM> in the layers <NUM> and <NUM> using the conductive stubs or vias. The substrate <NUM> may be formed using a printed circuit board or other electrically-insulative material(s). Each hybrid transformer <NUM> receives one sub-signal 306a and one sub-signal 306b produced by the layers <NUM> and <NUM> at different times. Each hybrid transformer <NUM> also splits the received sub-signal 306a or 306b (depending on which input signal 302a or 302b is currently being received) and isolates the sub-signals 306a and 306b from each other.

As shown in <FIG>, a top layer <NUM> of the patch antenna array <NUM> includes the patch antenna elements <NUM> and a substrate <NUM>. The substrate <NUM> may be formed using a printed circuit board or other electrically-insulative material(s). Also shown in <FIG> is the phase taper used in the patch antenna array <NUM> in order to achieve desired beam directions. In this example, the phase taper increases moving up each row of patch antenna elements <NUM>, where each row above the first row has an additional phase taper of Δα or Δβ (depending on whether the input signal 302a or 302b is being received) relative to the adjacent lower row. The specific values used as the additional phase tapers Δα and Δβ can vary based on the specific angles φ and θ being created. Any suitable phase tapers may be used here to achieve desired beam directions.

While not shown here, one or more additional layers would typically be used in the patch antenna array <NUM>. For example, one or more intermediate layers of dielectric material(s), routing electrical pathways, or other components of the patch antenna array <NUM> may be positioned between the layers <NUM> and <NUM>, between the layers <NUM> and <NUM>, between the layers <NUM> and <NUM>, and/or between the layers <NUM> and <NUM>. The conductive stubs or vias connecting adjacent ones of the layers <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> can pass through the dielectric material(s) forming the intermediate layers. Also, one or more protective layer or other layers may coat the exposed surfaces of the top and bottoms layers <NUM> and <NUM>. In addition, any of the electrical pathways in any of the layers (or intermediate layers) may include tuning stubs, which represent conductive portions of electrical pathways that can be modified (such as trimmed) to adjust the electrical pathways (from the perspective of the electrical signals being transported) as needed to achieve impedance matching between RF transitions.

In addition, note that the design of the patch antenna array <NUM> enables its fabrication in various ways, including the use of standard PCB processing techniques. Thus, for example, each layer <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be formed by obtaining a suitable printed circuit board and depositing metal(s) or other material(s) on the printed circuit board, etching the metal(s) or other material(s) as needed, and/or attaching components to the printed circuit board. Of course, the patch antenna array <NUM> may be fabricated in any other suitable manner, and this disclosure is not limited to any particular fabrication technique.

All of the various layers <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> here include one or more notches <NUM>. In this example, the patch antenna array <NUM> includes one notch <NUM> in a specified position. As with the projection <NUM>, the notch or notches <NUM> may be used to help ensure that the patch antenna array <NUM> is installed with a correct orientation in a larger device or system, which may help to avoid installing the patch antenna array <NUM> in an improper orientation that causes the beams 106a-106b to radiate in undesired directions.

Although <FIG> illustrate one example of a layout of a multi-beam passively-switched patch antenna array <NUM>, various changes may be made to <FIG>. For example, the sizes, shapes, and dimensions of the patch antenna array <NUM> and each of its individual components may vary as needed or desired. Also, a patch antenna array <NUM> designed in accordance with this disclosure may have any other suitable layout, whether or not implemented using this type of stacked multi-layer approach.

It may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The phrase "associated with," as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

The description in the present application should not be read as implying that any particular element, step, or function is an essential or critical element that must be included in the claim scope. The scope of patented subject matter is defined only by the allowed claims.

Claim 1:
An apparatus comprising:
multiple patch antenna elements (<NUM>) configured to transmit multiple electromagnetic beams (106a-106b) in multiple beam directions;
multiple inputs each configured to receive one of multiple input signals (302a-302b), each input signal (302a-302b) associated with one of the electromagnetic beams (106a-106b);
multiple phase-tapered splitters (304a-304b) each configured to receive one of the input signals (302a-302b), divide the received input signal (302a-302b) into a set of sub-signals (306a-306b), and provide a phase taper that adjusts phases of at least some of the sub-signals (306a-306b) in the set of sub-signals (306a-306b), wherein different phase tapers are associated with different ones of the beam directions; and
characterized by further comprising multiple <NUM>° hybrid transformers each configured to receive sub-signals (306a-306b) associated with different ones of the input signals (302a-302b), isolate the received sub-signals (306a-306b) from each other, and provide the isolated sub-signals (306a-306b) to one of the patch antenna elements (<NUM>);
wherein the patch antenna elements (<NUM>) are arranged in four quadrants;
the inputs comprise two inputs for each quadrant, wherein one of the inputs for each quadrant is configured to receive a first of the input signals (302a-302b) and one other of the inputs for each quadrant is configured to receive a second of the input signals (302a-302b); and
the phase-tapered splitters (304a-304b) comprise two phase-tapered splitters (304a-304b) for each quadrant, wherein one of the phase-tapered splitters (304a-304b) for each quadrant is configured to receive the first input signal (302a) and one other of the phase-tapered splitters (304a-304b) for each quadrant is configured to receive the second input signal (302b).