Radial Line Slot Antenna Array

Abstract

In some examples, a method for fabricating a switching structure of a radial slot line antenna (RLSA) array using a single semiconductor wafer element comprises forming a set of active switching devices in the wafer element, a position of each active switching device on the wafer element selected according to a predefined configuration representing a slot element layout of the RLSA array, and forming a drive circuit in the wafer element, the drive circuit individually addressing each of the set of active switching devices thereby enabling a selected bias signal to be applied to the set of active switching devices.

Description

[Technical Field]

[0001] The present invention relates to an antenna array. An embodiment relates to a radial slot line antenna array. [Background technology]

[0002] The size, weight, power consumption, and cost of implementing an antenna or antenna array on a platform can be prohibitive, leading to suboptimal deployment, where, for example, certain desired features may be sacrificed in favor of lower-cost or smaller-sized alternatives. For example, active electronically scanned antenna arrays (AESAs) and passive electronically scanned antenna arrays (PESAs) are heavy, expensive, and require large amounts of power to operate and keep cool. Similarly, parasitic reflector-type antennas are large and do not benefit from implementation on some platforms, such as modern aircraft, where (at least) their size may interfere with the platform's aerodynamic profile.

[0003] To reduce cost and size, some antenna structures use a single voltage source to drive the antenna's elements, thereby reducing the structure's physical size and its implementation costs. However, by using only a single voltage source, individual elements cannot be selectively controlled. This therefore limits their use with respect to radiated beams, for example, because the array cannot be scanned. To provide some control over the radiated beam, phase shifters or time delay devices can be employed, but these are generally ferrite-based and therefore lossy, leading to inefficiency. In the case of phase shifters, they are also generally narrow-band. Conversely, a transmitter provided at each antenna element can provide complete control of the radiated beam's phase and amplitude, enabling, for example, scanning. However, such systems are expensive and generally large, for example, as a result of the increased implementation area required for the drive mechanism. Thus, there is often a trade-off between implementing an expensive and / or large / heavy, but efficient and more controllable, antenna and implementing a cheaper and / or smaller / lighter, but less efficient and functionally less useful, antenna. Summary of the Invention

[0004] According to a first aspect of the present disclosure, there is provided a method for fabricating a switching structure for a radial slot line antenna (RLSA) array using a single semiconductor wafer element, the method comprising: forming a set of active switching devices in the wafer element; forming a driver circuit in the wafer element, wherein a position of each active switching device on the wafer element is selected according to a predefined configuration representing a slot element layout of the RLSA array; and the driver circuit individually addresses each of the set of active switching devices, thereby enabling a selected bias signal to be applied to the set of active switching devices.

[0005] Thus, the wafer elements can be fabricated to effectively form large-scale (i.e., wafer-scale) integrated circuits that form the switching structures or surfaces for the antenna array. This eliminates the issues surrounding wafer dicing and packaging and provides improved performance because bond wires are not required to couple the components to control circuits, but the bond wires also add a significant amount of parasitic reactance that can be a source of component failure and that itself has a significant detrimental effect on the performance of the antenna elements.

[0006] In one embodiment of the first aspect, an array of slot elements of the RLSA array can be fabricated on a wafer element by forming a plurality of slots according to a predefined configuration representing the slot element layout of the RLSA array. The array of slot elements of the RLSA array can be fabricated on a substrate structure of the RLSA array. In one example, the substrate structure can be bonded to the wafer element. A plurality of bias control lines can be provided in the wafer element for the set of active switching devices. A plurality of bias control lines can be formed on a control layer. The control layer can be formed in the wafer element. The control layer can be bonded to the wafer element.

[0007] According to a second aspect of the present disclosure, there is provided a radial slot line antenna array comprising: a substrate having a radiating surface of the array; a set of active switching devices integrally formed in a semiconductor wafer element bonded to the substrate, the radiating surface comprising a plurality of slots arranged in a predefined configuration representing the slot element layout of the RLSA array; a plurality of bias control lines integrally formed in the semiconductor wafer element, each switching device being structurally aligned with a respective slot, thereby enabling adjustment of the slot element resonant frequency; and a drive circuit integrally formed in the semiconductor wafer element, the drive circuit configured to individually address the active switching devices, thereby enabling selected bias signals to be applied to the active switching devices using the bias control lines.

[0008] In one implementation of the second aspect, at least some of the set of active switching devices may comprise microelectromechanical system (MEMS) switches. The MEMS switches may comprise charge-controlled or field-controlled MEMS switches. At least some of the MEMS switches may comprise cantilever, bridge, or diaphragm-type MEMS. At least some of the set of active switching devices may comprise varactor diodes and / or memory capacitors. The drive circuit may comprise at least one high-voltage driver configured to supply a high-voltage bias signal. The radiating surface may comprise a metal layer interposed between and bonded to the semiconductor wafer element and the substrate.

[0009] Embodiments of the present invention will now be described, by way of example only, with reference to the following figures. [Brief explanation of the drawings]

[0010] [Figure 1] Schematic of an RLSA array according to an example. [Figure 2] 1 is a schematic diagram of a radial slot line antenna array according to an example. [Figure 3] 1 is a schematic diagram of a portion of an RLSA array according to an example. [Figure 4] 1 is a schematic diagram of a lithography process used on a wafer element, according to an example. [Figure 5] 1 is a flowchart of a method for fabricating a switching structure for a radial slot line antenna array using a single semiconductor wafer element, according to an example. [Figure 6] 1 is a flowchart of a method for fabricating a switching structure for a radial slot line antenna array using a single semiconductor wafer element, according to an example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Exemplary embodiments are described below in sufficient detail to enable those skilled in the art to embody and implement the systems and processes described herein. It is important to understand that embodiments may be provided in many alternative forms and should not be construed as limited to the examples set forth herein.

[0012] Accordingly, while the embodiments may be modified in various ways and take various alternative forms, specific embodiments thereof are shown in the drawings and will be described in detail below by way of example. There is no intention to limit the invention to the particular forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims are to be covered. Elements of exemplary embodiments will, where appropriate, be consistently designated by the same reference numerals throughout the drawings and detailed description.

[0013] The terms used herein to describe embodiments are not intended to be limiting. The articles "a," "an," and "the" are singular in that they have a single referent; however, the use of the singular in this document does not exclude the presence of more than one referent. In other words, elements referred to in the singular can be counted as one or more unless the context clearly dictates otherwise. Furthermore, it will be understood that the terms "comprises," "comprising," "includes," and / or "including," as used herein, specify the presence of stated features, items, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, items, steps, operations, elements, components, and / or groups thereof.

[0014] Unless otherwise defined, all terms (including technical and scientific terms) used herein should be interpreted as customary in the art. It will be further understood that commonly used terms should also be interpreted as customary in the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0015] A radial line slot antenna (RSLA) is a low-cost antenna structure that includes a radiating element, a cavity, a background plate, and a feed for supplying a signal to the radiating element. The radiating element and background plate typically comprise a pair of metal disks, such as aluminum, copper, brass, or molybdenum, separated by a cavity, thereby forming a parallel-plate waveguide that is fed at its center by a feed or waveguide transition, which may be, for example, a coaxial feed. The cavity between the parallel plates may be filled with a low-permittivity substrate, such as a dielectric material or a slow-wave structure. This can help prevent the formation of grating lobes in the far-field pattern. Together with the radiating element and background plate, the cavity acts as a circular waveguide that guides the signal from the feed as it propagates radially.

[0016] A RLSA typically comprises multiple through slots or apertures in a radiating element, nominally configured as multiple slot pairs, each pair effectively acting as an antenna element of the RLSA, such that all of the multiple slot pairs of a radiating element form an array antenna. The slot pairs are arranged in a predetermined pattern configured to generate a fixed beam at a given frequency in a given polarization, and the slots of a slot pair are typically positioned relative to each other so that their major axes are orthogonal to each other. The slot orientation can be determined by analyzing the field vectors propagated by each slot in the array; it is common to consider the slots of a slot pair as in-phase and out-of-phase, and then use a cumulative sum of these sets of slots to achieve the desired polarization.

[0017] FIG. 1 is a schematic diagram of an example RLSA array. The RLSA array includes a radiating element 101, a cavity 105, a background plate 103, and a coaxial feed 107. A plurality of slots 109 are provided within the radiating surface 101. The slots 109 form discontinuities within the radiating surface. Thus, a signal from the feed 107 generates a voltage across the slot. The wall 111 may be a conductive material, may be open, or may be terminated with a lossy material. There are numerous ways in which the slots can be arranged within the radiating element, and the methods described herein do not depend on the overall slot pattern. For example, a two-dimensional spiral slot array may be used. In the example of FIG. 1, the RLSA array is shown in the form of a single-layer structure. However, such an array may be implemented with a dual-layer feed structure.

[0018] According to one example, the resonance of at least one of the multiple slots can be controlled or changed by adjusting or selecting the capacitance value of a variable capacitance device disposed across the slot. That is, the resonant frequency of the slot can be tuned by changing the capacitance of the slot. Because the beam pattern of an RLSA changes depending on the activity state of the slot, various beam patterns can be generated using various combinations of capacitance of one or more slots to vary the degree to which the slot resonates. Thus, given a desired beam pattern of the array, a slot activation configuration can be used to define a set of slots that are switched on or off (or in a semi-active state of radiation). The radiation state of a slot is, in one example, defined by the capacitive reactance of the slot in question. Such a value can be selected to effectively prevent the slot from being radiating, radiating at its maximum value, or somewhere between these extremes. Thus, when tuning the resonant frequency of a slot, the value of the antenna gain for a given combination of capacitance values ​​associated with the slots of the array results in a beam pattern due to coupling between the slots in their various activity states.

[0019] According to one example, slots may be switched on or off, or provided in a semi-active state, for example, by applying a capacitance selected from one of a plurality of values, which may be discrete. Thus, a desired beam pattern to be emitted by the array may involve a slot activation configuration in which some of the slots radiate at a first level, some of the slots radiate at a second level, and so on. The first level may correspond to the slots being effectively off, and the second level may correspond to the slots being effectively on and radiating at or near resonance. Intermediate between these states, various other levels of slot activity may be provided in which the slots radiate below resonance but are not "off," depending on a predominant value of capacitance for one or more slots.

[0020] In one example, the resonant frequency of the slot can be adjusted or selected using an active switching device. The active switching device can include any of a microelectromechanical system (MEMS) switch, a varactor diode, and a memory capacitor. The MEMS can be a radio frequency MEMS (RF MEMS). In one example, the RF MEMS is a capacitive RF MEMS. That is, the contact interface of the RF MEMS can be, for example, capacitive. In one example, the capacitive RF MEMS can be biased below its pull-in voltage to enable control over the resonance of the slot on which the capacitive RF MEMS is disposed. Thus, as described above, the capacitance can be selected from one of a plurality of values, which can be, for example, discrete values, thereby ultimately enabling beam steering using the RLSA. In one example, the RF MEMS used can be, for example, a capacitive MEMS or a cantilever-type MEMS.

[0021] Reference herein to a MEMS switch is not intended to be limiting, but merely represents, by way of example, one of many active switching devices that may be implemented.

[0022] Typically, MEMS switches are fabricated on dies that are part of a semiconductor wafer, which can be, for example, up to about 300 mm in diameter. There can be hundreds to thousands of dies on a single wafer, depending on the size of the die. Dies can range from 1 or 2 mm to tens of mm. To allow for packaging, dies are removed from the wafer by dicing the wafer by scribing and breaking, etching (deep reactive ion etching), sawing, or laser cutting. Once removed from the wafer, the dies can then be packaged. The individually packaged dies are then bonded into structures to provide the desired functionality.

[0023] According to one example, instead of fabricating active switching devices, such as capacitive RF MEMS, on a die and then dicing and packaging them, wafer elements can be fabricated to form a large integrated circuit that forms the switching structure of the RLSA. Such a switching structure can include, for example, a substrate with a metal ground plane having several etched slots thereon. The slots can be rectangular or have another shape to resonate at the desired frequency of RF radiation. In one example, the primary operating frequency can include bands within the X, Ku, K, and Ka bands (as defined by the IEEE). The wafer elements can be, for example, 4- to 8-inch wafers, although other wafer sizes can also be used.

[0024] According to one example, in addition to the slots, several bias control lines may be provided for applying actuation voltages to the active switching devices, along with semiconductor transistors or alternative equivalent switches located adjacent to the active switching devices. This location need not be uniform across the array to aid in lithography processes. For example, this allows individual capacitive RF MEMS to be turned on or off across the surface of the RLSA. In one example, these elements are fabricated on a single wafer element, thereby avoiding the need for wafer dicing and packaging, thus providing an improvement over existing methods of packaging large quantities of switches and then reflow soldering the semiconductor devices or packaged MEMS onto a printed circuit board (PCB), typically at a pitch no different from that of the bare die fabricated on the wafer. Furthermore, improved performance results because bond wires are not used to couple the components to the control circuitry. The bond wires used when packaging bare die into a format that can be directly soldered to a PCB add a significant amount of parasitic reactance, which, while being a source of component failure, can also significantly and detrimentally affect the performance of the antenna elements used for tuning. Furthermore, tuning can be undertaken across the wafer surface in the fabrication process to ensure that the tunable capacitance is uniform across the array, and to account for and correct for fabrication variations in the wafer fabrication process that can mean that devices fabricated in the center of the wafer will be different from devices on the edge of the wafer. Such tuning is difficult when discrete components are used.

[0025] FIG. 2 is a schematic diagram of a radial slot line antenna array according to an example. In particular, the example of FIG. 2 is a schematic diagram of an exploded view of components of a radial slot line antenna array according to an example. A substrate 207, such as a printed circuit board (PCB), is provided. In the example of FIG. 2, the substrate 207 comprises a radio frequency (RF) feed structure 209 of the RLSA array. A radiating surface 205 of the array comprises a plurality of slots arranged in a predefined configuration representing the slot element layout of the RLSA array. In one example, the radiating surface 205 defining the slot layer may be formed on the substrate 207 and may comprise a metal layer. A control layer 203 comprises a plurality of bias control lines. In one example, the bias control lines comprise metallized control tracks. The bias control lines may be formed on the substrate 207. A semiconductor wafer element 201 is provided. The element 201 comprises an active wafer. In one example, either or both of the radiating surface 205 and the control layer 203 may be integrally formed within the element 201. Alternatively, element 201 may be bonded to any one or all of emitting surface 205, control layer 203, and substrate 207.

[0026] According to one example, a set of active switching devices is integrally formed within the semiconductor wafer element 201. Each switching device is formed within the wafer element 201 at a selected location, thereby structurally aligning the switching device with a respective slot in the radiating surface 205. Thus, the element 201 includes a set of active switching devices aligned with the slots in the radiating surface 205, thereby enabling adjustment of the slot element resonant frequency. Drive circuitry for individually addressing the active switching devices is integrally formed within the semiconductor wafer element 201. In one example, the drive circuitry is configured to individually address the active switching devices, thereby enabling selected bias signals to be applied to the active switching devices using bias control lines in the control layer 203. In one example, the active switching devices can include any one or more of varactor diodes, MEMS switches, or memory capacitors. The drive circuitry may be, for example, a simple transistor configured to drive a relatively simple switching device such as a varactor diode, or may be a more complex sub-circuit comprising, for example, a MOSFET of a high-voltage driver when driving a MEMS device.

[0027] 2 , element 201 may be bonded to substrate 207. In one example, either or both of layers 203, 205 may be fabricated separately or as part of either substrate 207 or element 201. Thus, either or both of layers 203, 205 may be interposed between and bonded to element 201 and other layers of a structure, such as substrate 207. That is, slot layer 205 may be manufactured or fabricated on substrate 207 or as part of wafer-scale IC (WSIC) 201. Similarly, control layer 203 may be manufactured or fabricated on substrate 207 or as part of WSIC 201.

[0028] Thus, according to one example, the active switching devices defining the switching surface of an RLSA array can be manufactured or fabricated as WSICs. This reduces processing steps in the transfer of the switching components to the product, minimizes unwanted parasitic artifacts as a result of packaging, and allows for trimming and tuning of the devices on the wafer to enable a more electrically uniform surface. In addition, it provides the ability to create larger RLSA arrays because the WSIC surface can be tessellated, thus reducing the number of processing and packaging steps required and therefore reducing the cost of the product. For example, a single large PCB can be manufactured, and the WSICs can then be arranged in a grid on the PCB surface. This is particularly advantageous for larger antennas, for example, for use in SATCOM, where greater gain and therefore a larger diameter are required.

[0029] In one example, for example, the substrate 207 comprising a PCB may be manufactured using conventional PCB manufacturing techniques, or alternatively using machined material.

[0030] Thus, according to one example, a set of active switching devices may be fabricated in or on an entire semiconductor wafer element and then bonded onto the top surface of a PCB substrate (with intermediate layers, such as, for example, layer 205 and / or layer 203, if applicable). Alignment of wafer element 201 with substrate 207 may be achieved with extremely high tolerances. In one example, wafer element 201 may be positioned over the entire top surface of substrate 207, thereby covering all slots. In some implementations, wafer 201 may be a silicon wafer. Thus, wafer 201 may have a high dielectric constant, Er=10. Considering that wafer 201 may be on the order of about 200-400 μm thick, this may have the effect of detuning the slots. According to one example, to prevent this from occurring, deep reactive ion etching (DRIE) may be utilized, for example, to remove silicon substrate near the slots. DRIE can also be used to mitigate mismatches in the wafer's coefficients of thermal expansion (CTE) or stress points.

[0031] FIG. 3 is a schematic diagram of a portion of an RLSA array according to one example. In the example of FIG. 3, radiating surface 205 is provided on substrate 207. Slots 305 are provided in radiating surface 205, and corresponding active switching devices (not shown for clarity) are provided in wafer element 303. In the example of FIG. 2, drive circuitry in the form of transistors is shown. For example, in the case of MEMS switches, the control circuitry would be more complex, but would ultimately depend on the type of MEMS switch. As can be seen in FIG. 3 and as explained above, a portion of wafer element 303 has been removed near slot 305.

[0032] In one example, forming the slot layer 205 on the wafer means that through-silicon vias 309 can be provided to connect pads on the bottom of the wafer to pads on the top. As mentioned above, the slot layer 205 can be fabricated on a PCB. In another example, the slot layer 205 can be fabricated from a metal such as aluminum or molybdenum, which can be plated. Using this as the slot layer 205 means that the slot layer 205 can be bonded directly to the silicon wafer 201, especially in the case of molybdenum, where the CTE of the material is matched. Thus, active switching devices and control circuits can be fabricated on or within the wafer 201. Therefore, it is not necessary to connect control devices fabricated on the wafer to control lines fabricated on the substrate 207. Capacitive coupling exists between the control devices and the slot layer 205.

[0033] According to one example, the driver circuitry and active switching devices may be fabricated using standard CMOS foundry processing techniques, thereby enabling electronic trimming, self-testing, redundancy, and reconfiguration that cannot be achieved in packaging devices placed directly on PCB 207. In one example, multi-level metallization may be applied to the top of the driver switching device pairs as part of the CMOS process. Additionally, metallization of the edges of wafer element 303 may be performed, for example, by sputtering copper onto the silicon wafer surface. This may be a process that supplements the initial CMOS process and may be completed, for example, according to the flowchart of FIG. 6.

[0034] In a CMOS process, lithography is used to create individual dies on a wafer. Thus, in a CMOS process, the steppers used in the lithography process use a 4:1 or 5:1 reduction in the optics. This generally means that only a small portion of the wafer can be patterned at any one time. However, according to one example, a 4:1 stepper lithography process can be used to create the dies on the wafer 303. A 1:1 process can then be used to bond the individual dies with metal layers, i.e., tracks that connect the switches together. To minimize the number of dies required in the lithography process, design compromises can be made in which the locations of the dies and capacitive components are variously positioned around each radiating element.

[0035] In examples where MEMS switches are implemented, a void may be created in the wafer, for example, by stacking additional structures on top of the device to create a sealed cavity for the MEMS.

[0036] FIG. 4 is a schematic diagram of a wafer element according to one example. In the example of FIG. 4, wafer element 401 comprises multiple dies 403. Each die, colored black, may comprise an active switching device. These are coupled together using bias control lines 405 in the example of FIG. 4. Thus, wafer 401 is sparsely populated but does not require dicing in post-processing stages. Furthermore, as explained above, all drive, tuning, and self-test electronics may be included along with the active switching devices, meaning that any wafer-to-wafer variations may be accounted for in the manufacturing process.

[0037] FIG. 5 is a flowchart of a method for fabricating a switching structure for a radial slot line antenna array using a single semiconductor wafer element, according to one example. In block 501, a set of active switching devices is formed within the wafer element. As described above, the location of each active switching device on the wafer element can be selected according to a predefined configuration 503 representing the slot element layout of the RLSA array. In block 505, drive circuits are formed. In one example, the drive circuits can be formed, for example, by doping the wafer element and can depend on the active switching devices and the resulting drive circuits required. The drive circuits are configured to individually address each of the set of active switching devices, thereby allowing selected bias signals to be applied to the set of active switching devices, for example, using bias control lines.

[0038] 6 is a flowchart of a method for fabricating a switching structure for a radial slot line antenna array using a single semiconductor wafer element, according to an example. In block 601, an array of slot elements of the RLSA array is fabricated on the wafer element by forming a plurality of slots according to a predefined configuration representing the slot element layout of the RLSA array. In block 603, a plurality of bias control lines in the wafer element are formed for a set of active switching devices.

[0039] The foregoing description has been provided to enable those skilled in the art to best utilize various aspects of the exemplary embodiments disclosed herein. This exemplary description is not intended to be exhaustive or to be limited to any precise form disclosed. Many modifications and variations are possible without departing from the spirit and scope of the present disclosure. The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. In determining the scope of the present disclosure, reference should be made to the appended claims and their equivalents. The following is a summary of the claims as originally filed: [C1] 1. A method for fabricating a switching structure for a radial slot line antenna (RLSA) array using a single semiconductor wafer component, comprising: forming a set of active switching devices within the wafer element, and a location of each active switching device on the wafer element is selected according to a predefined configuration representing a slot element layout of the RLSA array; forming a drive circuit within the wafer element, the drive circuit individually addressing each of the set of active switching devices, thereby enabling selected bias signals to be applied to the set of active switching devices; A method for providing [C2] The method of C1, further comprising fabricating an array of slot elements of the RLSA array on the wafer element by forming a plurality of slots according to the predefined configuration representing the slot element layout of the RLSA array. [C3] The method of C1, further comprising fabricating an array of slot elements of the RLSA array on a substrate structure of the RLSA array. [C4] The method of C3, further comprising bonding the substrate structure to the wafer element. [C5] The method of any one of C1 to C4, further comprising forming a plurality of bias control lines within the wafer element for the set of active switching devices. [C6] The method of any one of C1 to C5, further comprising forming a plurality of bias control lines on the control layer. [C7] The method of C6, wherein the control layer is formed within the wafer element. [C8] The method of C6, further comprising bonding the control layer to the wafer element. [C9] A radial slot line antenna array, comprising: a substrate having a radiating surface of the array, the radiating surface having a plurality of slots arranged in a predefined configuration representing a slot element layout of the RLSA array; a set of active switching devices integrally formed within a semiconductor wafer element bonded to said substrate, each switching device structurally aligned with a respective slot, thereby enabling tuning of the slot element resonant frequency; a plurality of bias control lines integrally formed within the semiconductor wafer element; a driver circuit integrally formed within the semiconductor wafer element and configured to individually address the active switching devices, thereby enabling selected bias signals to be applied to the active switching devices using the bias control lines; and A radial slot line antenna array comprising: [C10] The radial slot line antenna array of C9, wherein at least some of the set of active switching devices comprise microelectromechanical system (MEMS) switches. [C11] The radial slot line antenna array of C10, wherein the MEMS switch comprises a charge-controlled or field-controlled MEMS switch. [C12] 12. The radial slot line antenna array of claim 10 or 11, wherein at least some of the MEMS switches comprise cantilever, bridge or diaphragm type MEMS. [C13] The radial slot line antenna array of C9, wherein at least some of the sets of active switching devices comprise varactor diodes and / or memory capacitors. [C14] 14. The radial slot line antenna array of any one of claims C9 to 13, wherein the drive circuit comprises at least one high voltage driver configured to provide a high voltage bias signal. [C15] A radial slot line antenna array as described in any one of C9 to 14, wherein the radiating surface comprises a metal layer interposed between the semiconductor wafer element and the substrate and bonded to the semiconductor wafer element and the substrate.

Claims

1. 1. A method for fabricating a switching structure for a radial slot line antenna (RLSA) array using a single semiconductor wafer component, comprising: forming a set of active switching devices within the wafer element, and a location of each active switching device on the wafer element is selected according to a predefined configuration representing a slot element layout of the RLSA array; forming a drive circuit within the wafer element, the drive circuit individually addressing each of the set of active switching devices, thereby enabling selected bias signals to be applied to the set of active switching devices; A method for providing

2. 2. The method of claim 1, further comprising fabricating an array of slot elements of the RLSA array on the wafer element by forming a plurality of slots according to the predefined configuration representing the slot element layout of the RLSA array.

3. The method of claim 1 , further comprising fabricating an array of slot elements of the RLSA array on a substrate structure of the RLSA array.

4. The method of claim 3 further comprising bonding the substrate structure to the wafer element.

5. The method of claim 1 , further comprising forming a plurality of bias control lines within the wafer element for the set of active switching devices.

6. The method of claim 1 , further comprising forming a plurality of bias control lines on the control layer.

7. The method of claim 6 , wherein the control layer is formed within the wafer element.

8. The method of claim 6 further comprising bonding the control layer to the wafer element.

9. A radial slot line antenna array, comprising: a substrate having a radiating surface of the array, the radiating surface having a plurality of slots arranged in a predefined configuration representing a slot element layout of the RLSA array; a set of active switching devices integrally formed within a semiconductor wafer element bonded to said substrate, each switching device structurally aligned with a respective slot, thereby enabling tuning of the slot element resonant frequency; a plurality of bias control lines integrally formed within the semiconductor wafer element; a driver circuit integrally formed within the semiconductor wafer element and configured to individually address the active switching devices, thereby enabling selected bias signals to be applied to the active switching devices using the bias control lines; and A radial slot line antenna array comprising:

10. 10. The radial slot line antenna array of claim 9, wherein at least some of the set of active switching devices comprise micro-electromechanical system (MEMS) switches.

11. The radial slot line antenna array of claim 10 , wherein the MEMS switch comprises a charge-controlled or field-controlled MEMS switch.

12. The radial slot line antenna array of claim 10 , wherein at least some of the MEMS switches comprise cantilever, bridge or diaphragm type MEMS.

13. 10. The radial slot line antenna array of claim 9, wherein at least some of said sets of active switching devices comprise varactor diodes and / or memory capacitors.

14. 10. The radial slot line antenna array of claim 9, wherein the drive circuitry comprises at least one high voltage driver configured to provide a high voltage bias signal.

15. 10. The radial slot line antenna array of claim 9, wherein said radiating surface comprises a metal layer interposed between said semiconductor wafer element and said substrate and bonded to said semiconductor wafer element and said substrate.

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