End-fire antenna structure on an aerodynamic system

Abstract

An end-fire antenna structure for an aerodynamic system is disclosed. The antenna structure includes a first patterned metal layer, a second patterned metal layer, and a stack of material layers including the first patterned metal layer and the second patterned metal layer. The first patterned metal layer includes a plurality of parallel slots etched through the metal. The second patterned metal layer includes a tapered radio frequency (RF) feed line having a narrow end coupled to an input / output (I / O) antenna connection. The second patterned metal layer is aligned above the first patterned metal layer so that the tapered RF feed line has a length extending across the plurality of parallel slots. The stack of material layers is flexible so that the stack of material layers is configured to at least partially surround a fuselage of the aerodynamic system.

Description

Technical Field

[0001] The present invention relates to an end-fire antenna structure on an aerodynamic system. Background Art

[0002] Designing various mechanical and electrical components for aerodynamic systems (such as guided projectiles or other flying bodies) is a challenge due to limited space. Such guided aerodynamic systems typically use multiple radio frequency (RF) antennas to transmit and receive radiation in different directions for guidance purposes as well as object identification. Antennas are typically placed in the nose cone area of ​​the guided aerodynamic system to minimize interference from the main body of the aerodynamic system. Multiple antennas in different directions are typically used to transmit or capture RF radiation at different angles. However, it is not always possible or feasible to place antennas in the nose cone. In many applications, other systems or payloads used in the nose cone may interfere with the antenna or make it difficult to share space. Therefore, there are many important issues regarding the design of antennas for aerodynamic systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Features and advantages of embodiments of the claimed subject matter will become apparent as the following detailed description proceeds and with reference to the accompanying drawings, in which:

[0004] Figure 1 An example aerodynamic system configured with a contoured antenna structure according to an embodiment of the present disclosure is shown.

[0005] Figure 2 The present invention is shown in the embodiment of the present invention. Figure 1 Block diagram of the signal processing environment on an example aerodynamic system.

[0006] Figure 3A and Figure 3B A front side view and a back side view of a substrate according to an embodiment of the present disclosure are respectively shown, and in particular, a front side metal pattern and a back side metal pattern on the substrate are shown.

[0007] Figure 4A and Figure 4B A top view and a side view are shown, respectively, of an end-fire antenna design according to an embodiment of the present disclosure.

[0008] Figure 5A and Figure 5B The layer structures of antenna designs according to embodiments of the present disclosure are respectively shown.

[0009] Fig. 6A and Figure 6B is a radiation pattern generated by an end-fire antenna design according to an embodiment of the present disclosure.

[0010] Fig. 7A and Figure 7B The slot geometries for end-fire antenna designs according to embodiments of the present disclosure are shown respectively.

[0011] Figure 8 is a flow chart describing a method of forming an antenna structure around a fuselage of an aerodynamic system according to an embodiment of the present disclosure.

[0012] Although the following detailed description will be made with reference to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent in light of this disclosure. Summary of the invention

[0013] An end-fire antenna structure is disclosed that is particularly suitable for use with an aerodynamic system, such as a guided projectile or other flying body. In one embodiment, the antenna structure is formed on a flexible substrate along with one or more other flexible layers that surround a cylindrical fuselage of the aerodynamic system. In another embodiment, the antenna structure includes two separate metal layers located between a stack of other material layers that together surround a cylindrical fuselage of the aerodynamic system. According to some embodiments, the antenna structure includes a plurality of tapered feed lines that are aligned on corresponding slot arrays to direct radiation to the front of the aerodynamic system. In addition, according to some embodiments, a dielectric layer is used on the outer surface of the antenna to generate leakage surface waves that direct radiation in a forward direction to the front of the aerodynamic system. Many embodiments and variations will be understood in light of this disclosure. DETAILED DESCRIPTION

[0014] General Overview

[0015] As described above, it is often desirable to implement different locations of antennas around an aerodynamic system, rather than just placing the antenna in the nose. In some example cases, the aerodynamic system is a guided munition or projectile, such as a bullet, shell, missile, torpedo, or rocket, to name a few. For many guided munitions or projectiles, the nose region typically carries a specific payload and / or other components, leaving little room for antennas. In this case, please note that the payload carried by the aerodynamic system may vary from application to application and is not necessarily limited to explosives or lethal payloads. For example, the payload may be supplies (e.g., food, equipment), personnel, communication equipment (e.g., providing an airborne communication node over a given area), imaging equipment or other sensor-based equipment (e.g., weather sensors for temperature and humidity, gas sensors, speed sensors), lighting equipment (e.g., illuminating an area with visible light), and surveillance equipment.

[0016] Therefore, the present disclosure provides an antenna structure suitable for an aerodynamic system. In one embodiment, one or more end-fire antennas are mounted around the contour of the fuselage of the aerodynamic system, away from the nose, while directing the radiation in a forward direction (e.g., toward the direction of flight). Generally speaking, an end-fire antenna is a linear or cylindrical antenna structure that emits or outputs its radiation from one end. The direction of maximum radiation is along the axis of the structure (from input to output), and it can be unidirectional or bidirectional. The features of the end-fire antenna structure are described in turn below. In some embodiments, one or more end-fire antennas surround at least a portion of the cylindrical fuselage on a guided projectile (e.g., a guided rocket or missile). One or more end-fire antennas may have different polarizations due to their ground plane orientation, and may exhibit gain shielding due to the presence of an aerodynamic system below the antenna substrate.

[0017] According to some embodiments, an end-fire antenna includes a first patterned metal layer having a tapered feed line and a second patterned metal layer located above the first layer, wherein the second layer includes a plurality of parallel slots aligned above the tapered feed line. Electrical energy propagates along the tapered feed line from its narrow end to its wide end and is coupled through the slots in the second metal layer above and radiated outward. Energy is weakly coupled at the narrow end of the feed line and strongly coupled at the wide end of the feed line. According to some embodiments, the wide end of the tapered feed line is connected to a ground plane via a resistor.

[0018] Each of the first metal layer and the second metal layer can be patterned on two different sides of the same substrate, wherein the substrate is flexible enough to wrap around the outside of the cylindrical fuselage. In some embodiments, the substrate is configured to bend or wrap around substantially any contour shape on the outside of the aerodynamic system. According to some embodiments, a plurality of tapered feed lines with corresponding parallel slots are arranged in a parallel array on the substrate such that the array wraps around the fuselage and transmits or receives radiation directionally (e.g., toward the front of the aerodynamic system).

[0019] According to an exemplary embodiment of the present disclosure, an antenna structure configured to wrap around the fuselage of an aerodynamic system includes a first patterned metal layer, a second patterned metal layer, and a material layer stack including the first patterned metal layer and the second patterned metal layer. The stack may also include one or more dielectric layers and / or one or more bonding layers, as will be discussed in turn with reference to FIG. 5. The first patterned metal layer includes a plurality of parallel grooves etched through the metal, each parallel groove extending longitudinally along a first direction. The second patterned metal layer includes a tapered radio frequency (RF) feed line having a narrow end and a wide end. The narrow end is coupled to an input / output (I / O) antenna connection. The second patterned metal layer is aligned above the first patterned metal layer so that the tapered RF feed line has a length extending across the plurality of parallel grooves in a second direction substantially perpendicular to the first direction. The material layer stack is flexible so that the material layer stack is configured to wrap around the fuselage of the aerodynamic system.

[0020] According to another example embodiment of the present disclosure, an RF system configured for use on an aerodynamic system includes: a processor configured to generate a digital signal; at least one digital-to-analog converter (DAC) configured to convert the digital signal into an analog signal; a front-end circuit configured to receive and process the analog signal from the DAC to generate an RF signal for transmission; and an antenna structure configured to radiate the RF signal received from the front-end circuit. The front-end circuit can perform any of amplification, up-conversion (mixing) along the transmit direction, down-conversion along the receive direction, modulation along the transmit direction, demodulation along the receive direction, or filtering on the RF signal. The antenna structure includes a first patterned metal layer, a second patterned metal layer, and a material layer stack including the first patterned metal layer and the second patterned metal layer. The stack may also include one or more additional layers (e.g., a dielectric layer, a bonding layer). The first patterned metal layer includes a plurality of parallel grooves etched through the metal, each parallel groove extending longitudinally along a first direction. The second patterned metal layer includes a tapered RF feed line having a narrow end and a wide end. The narrow end is coupled to an input / output (I / O) antenna connection. The second patterned metal layer is aligned over the first patterned metal layer such that the tapered RF feed line has a length extending across the plurality of parallel slots in a second direction substantially perpendicular to the first direction. The material layer stack is flexible such that the material layer stack is configured to wrap around a fuselage of the aerodynamic system.

[0021] According to another example embodiment of the present disclosure, a method of manufacturing an antenna structure configured for use on an aerodynamic system includes: wrapping a sheet having a plurality of dielectric material plates around a fuselage of the aerodynamic system; removing the sheet so that the dielectric material plates remain in corresponding cavities in the fuselage; wrapping a flexible substrate around the fuselage and on the dielectric material plates; and wrapping a dielectric layer around the fuselage and over the flexible substrate. The flexible substrate includes a first patterned metal layer and a second patterned metal layer. The first patterned metal layer includes a plurality of parallel grooves etched through the metal, each parallel groove extending longitudinally along a first direction. The second patterned metal layer includes a tapered RF feed line having a narrow end and a wide end. The narrow end is coupled to an input / output (I / O) antenna connection. The second patterned metal layer is aligned above the first patterned metal layer so that the tapered RF feed line has a length extending across the plurality of parallel grooves along a second direction substantially perpendicular to the first direction.

[0022] The description uses the phrases "in one embodiment" or "in an embodiment," each of which may refer to one or more of the same or different embodiments. In addition, the terms "comprising," "including," "having," etc. as used with respect to the embodiments of the present disclosure are synonymous.

[0023] Aerodynamics System Overview

[0024] Figure 1 An embodiment of an aerodynamic system 100 is shown. As previously described, the aerodynamic system 100 can be a guided projectile of any caliber or type that houses electrical components (e.g., RF communication components or other guidance electronics). In one embodiment, the aerodynamic system 100 is a guided munition, such as a guided missile or rocket (e.g., surface-to-air, air-to-air, or any other guided munition that communicates with an antenna), but other applications may also be apparent.

[0025] According to some embodiments, the aerodynamic system 100 includes a fuselage 102 that acts as a shell or hull to house various elements of the aerodynamic system 100. In some embodiments, the fuselage 102 has a cylindrical shape that produces a substantially circular cross-section. The fuselage 102 may have an outer radius of between about 1.5 inches and 9 inches (e.g., 4.5 inches). According to some embodiments, the antenna structure 104 surrounds at least a portion of the circumference of the fuselage 102. The antenna structure 104 may surround the entire circumference of the fuselage 102. The antenna structure 104 includes an end-fire antenna array having a tapered feed line to direct radiation toward the flight direction of the aerodynamic system 100. The metal outer layer includes an array of parallel slots. Each individual parallel slot has a length along a first direction (curled around the outside of the fuselage 102), and each group of parallel slots is arranged along a second direction substantially perpendicular to the first direction, wherein the second direction is along the length of the aerodynamic system 100 (e.g., in the same direction as the flight direction). As used herein, the term "substantially" when used to describe an angle means within 5 degrees. Thus, for example, if a first direction is substantially perpendicular to a second direction, the angle formed by the intersection of the first direction and the second direction is in the range of 85 degrees to 95 degrees. Each set of parallel slots represents an end-fire antenna with its own tapered feed line (not shown because the feed line is located below the slots), such that the antenna structure 104 includes multiple end-fire antennas oriented along the flight path direction of the aerodynamic system 100. More details on the design and manufacture of end-fire antennas are provided herein.

[0026] The fuselage 102 can have any number of configurations and can be implemented from any number of materials. For example, the fuselage 102 can be a cylinder made from a lightweight material such as titanium or a polymer composite. The fuselage 102 can be a single piece of material, or can be multiple pieces that are formed separately and then joined in a subsequent process. In the latter case, a variety of materials can be used, such as aluminum end caps, a titanium central body portion, and a polymer nose cone in one embodiment. The fuselage 102 generally has a length that extends in the direction of flight (e.g., between the nose cone and the end caps or rear end of the fuselage 102). In a more general sense, the fuselage 102 is not intended to be limited to any particular design or configuration, as will be understood in light of this disclosure.

[0027] In some embodiments, the antenna structure 104 is slightly recessed so that the top surface of the antenna structure 104 is flush with the outer surface of the body 102. The top surface of the antenna structure 104 can be a dielectric material that acts as a radome for the antenna below. In some embodiments, the dielectric material is loaded with polytetrafluoroethylene (PTFE).

[0028] The aerodynamic system 100 may include one or more wings 106 or fins (e.g., tail fins, mid-wings, front fins, movable or controllable fins, fixed fins, and / or any other such guided projectile features). The tilt angle and general orientation of each wing 106 may be independently controlled via a guidance system onboard the aerodynamic system 100 to alter the flight path. In a more general sense, the aerodynamic system 100 is not intended to be limited to any particular set of wings 106 or other fins, and as will be appreciated, some designs may not have any fins.

[0029] Figure 2 An example RF system 200 is shown that may be used on the airborne aerodynamic system 100 to transmit and / or receive RF radiation. According to some embodiments, the RF radiation is transmitted for guidance and / or homing purposes. The RF system 200 includes a processor 202, a digital-to-analog converter (DAC) 204, an RF front-end circuit 206, an analog-to-digital converter (ADC) 208, and an antenna structure 104. In some cases, any of the processor 202, the DAC 204, the RF front-end circuit 206, or the ADC 208 is implemented as a system-in-package, or a chipset populated on a printed circuit board (PCB), which in turn may be populated in a chassis of a multi-chassis system or other higher-level system, although any number of implementations may be used. The RF system 200 may be part of an electronic device on the airborne aerodynamic system 100 that transmits and / or receives RF signals.

[0030] Processor 202 may be configured to generate and / or receive digital signals for communication or guidance purposes. As used herein, the term "processor" may refer to any device or portion of a device that processes electronic data from registers and / or memory to convert the electronic data into other electronic data that can be stored in registers and / or memory. Processor 202 may include one or more digital signal processors (DSPs), application specific integrated circuits (ASICs), central processing units (CPUs), custom semiconductors, or any other suitable processing devices.

[0031] DAC 204 can be implemented to receive a digital signal from processor 202 and convert the signal into an analog signal that can be sent via antenna structure 104. DAC 204 can be any known type of DAC without limitation. In some embodiments, DAC 204 has a linear range between about 6 GHz and about 12 GHz, and an input resolution in the range of 6 bits to 12 bits, but the present disclosure is not intended to be limited to such specific implementation details.

[0032] According to one embodiment, the RF front-end circuit 206 may include various components designed to filter, amplify and tune selected portions of the received analog signal. The RF front-end circuit may be designed to have a high dynamic range and can be tuned over a wide frequency bandwidth. For example, the RF front-end circuit 204 may include components capable of tuning to a specific frequency range within a signal having a bandwidth in the gigahertz range (such as a bandwidth between 5 GHz and 50 GHz). In some embodiments, the RF front-end circuit 204 modulates the AC signal received from the DAC 204 onto a lower frequency carrier signal. In some embodiments, the RF front-end circuit 204 receives an analog signal from the antenna structure 104 and performs one or more of demodulation, filtering or amplification on the received signal. In some embodiments, the RF front-end circuit 204 includes one or more integrated circuit (IC) chips packaged together in a system-in-package (SIP).

[0033] ADC 208 can be implemented to receive an analog signal from RF front-end circuit 206 and convert the signal into a digital signal that can be received by processor 202 for further analysis. ADC 208 can be any known type of ADC without limitation. In some embodiments, ADC 208 has a linear range between about 6 GHz and about 12 GHz, and an input resolution in the range of 6 bits to 12 bits, but the present disclosure is not intended to be limited to such specific implementation details.

[0034] According to some embodiments, the antenna structure 104 receives an RF signal from the RF front end circuit 206 and transmits the signal out and away from the aerodynamic system 100. The RF signal may be fed into the narrow end of each of a plurality of tapered feed lines arranged together around the fuselage of the aerodynamic system 100. In some embodiments, the antenna structure 104 receives RF radiation impinging on the aerodynamic system 100 and converts the received RF radiation into an analog signal received by the RF front end circuit 206.

[0035] End-fire antenna design

[0036] Figure 3A and Figure 3B 1 shows opposite sides of an example antenna substrate 300 including two patterned metal layers forming an end-fire antenna array according to some embodiments. The antenna substrate 300 includes Figure 3A The first patterned metal layer 302 on the first side of the substrate and the Figure 3BThe second patterned metal layer 306 is shown on the opposite side of the substrate, so that flipping the substrate reveals the first layer or the second patterned metal layer. According to some embodiments, the antenna substrate 300 has a length between about 8 inches and about 9 inches and a height between about 3 inches and about 4 inches. The length of the antenna substrate 300 can be any suitable length to completely surround the fuselage 102 of the aerodynamic system 100. In some embodiments, the substrate is any PCB material that is flexible enough to bend around the circumference of the aerodynamic system 100. The patterned features of the first patterned metal layer 302 and the second patterned metal layer 306 are aligned.

[0037] According to some embodiments, the first patterned metal layer 302 includes a plurality of parallel grooves 304 in which metal has been removed. Each groove 304 can have a length between about 0.5 inches and about 1.0 inches. In some embodiments, the grooves 304 have a length of about 0.8 inches. According to some embodiments, the grooves 304 are arranged in parallel groups across the first patterned metal layer 302. Each group of grooves 304 includes grooves having different widths, wherein the widest groove is located at one end of a given group and the narrowest groove is located at the opposite end of the given group. The grooves between the widest groove and the narrowest groove in a given group have gradually larger widths, as shown in reference Figure 4A According to some embodiments, adjacent groups of slots 304 are spaced apart by a distance between about 0.75 inches and about 1.25 inches. The metal of the first patterned metal layer 302 is electrically grounded to ensure that there are no floating charges that would interfere with RF transmissions.

[0038] According to some embodiments, the second patterned metal layer 306 includes a series of tapered feed lines 308 surrounded by a ground plane 310. As the name implies, the ground plane 310 is electrically grounded to the same ground as the metal of the first patterned metal layer 302. According to some embodiments, each tapered feed line 308 is aligned with a corresponding set of slots 304 such that the length of the tapered feed line 308 extends in a direction substantially perpendicular to the length direction of the slots 304. The antenna input / output (I / O) is coupled to the narrow end of the feed line 308 such that electrical energy propagates along the feed line 308 toward the wide end (during RF transmission) before being dissipated to the ground plane 310 via a resistor connected between the wide end of the tapered feed line 308 and the ground plane 310, as described with reference to FIG. Figure 4B As shown in more detail.

[0039] Although shown as a flat plate for purposes of clarity, antenna substrate 300 is designed to wrap around the fuselage of the aerodynamic system. For an aerodynamic system having a cylindrical fuselage, antenna substrate 300 is designed to wrap around at least a portion of the circumference of the fuselage. In some embodiments, such as Figure 1As shown, the antenna substrate 300 surrounds the entire circumference of the fuselage. According to some embodiments, eight end-fire antennas are shown on the antenna substrate 300 and are arranged in a parallel array. Any number of end-fire antennas can be arranged on the antenna substrate 300. In some embodiments, the number of end-fire antennas on the antenna substrate 300 is a multiple of four.

[0040] Figure 4A FIG. 4 is a top view of an example end-fire antenna 400 including the first patterned metal layer and the second patterned metal layer shown in FIG. 3 according to some embodiments. Note that Figure 4A The specific elements shown in the drawings are not necessarily drawn to scale and are primarily for descriptive purposes. The slots 304 are aligned on the corresponding tapered feed lines 308 as described above, such that the tapered feed lines 308 extend in a direction substantially perpendicular to the length direction of the slots 304. Note that the slots 304 exist in a first plane and the tapered feed lines 308 exist in a parallel second plane below the first plane.

[0041] According to some embodiments, the width of each slot 304 increases in a direction from the narrow end of the feed line 308 to the wide end of the feed line 308. In some embodiments, the narrowest slot 401 is aligned closest to the narrowest end of the tapered feed line. The widest slot 403 is aligned closest to the widest end of the tapered feed line 308. According to some embodiments, the width of the narrowest slot 401 is between 0.01 and 0.07 inches, while the width of the widest slot 401 is between 0.08 and 0.18 inches. In one embodiment, the narrowest slot is approximately 0.04 inches wide, while the widest slot 403 is approximately 0.13 inches wide. Some slot designs may be different from Figure 4A For example, some of the grooves may have the same width or be arranged at different spacings from each other. Fig. 7A and Figure 7B Some other example slot designs are provided.

[0042] According to some embodiments, the slots 304 are arranged so that they have approximately 1 / 4 wavelength spacing between adjacent slots. Thus, the designed spacing between the slots can be application dependent and vary according to the RF radiation wavelength of interest. In some embodiments, the slots 304 are designed to have a spacing between 1 / 2 wavelength and 1 / 4 wavelength between adjacent slots.

[0043] According to some embodiments, the antenna I / O 402 is disposed at the narrowest end of the tapered feed line 308. The antenna I / O may represent any type of coupling, such as a wire soldered to the tapered feed line 308. An analog signal to be transmitted as RF radiation is applied to the tapered feed line 308 via the antenna I / O 402. During signal transmission, weaker coupling occurs at the narrower end of the tapered feed line 308 due to the overlap of the narrower portion of the tapered feed line 308 with the thinner slot, while stronger coupling occurs at the wider end of the tapered feed line 308 due to the overlap of the wider portion of the tapered feed line 308 with the wider slot. In addition, the RF signal received by the end-fire antenna will generate an electrical signal received at the antenna I / O 402 along the tapered feed line 308.

[0044] According to some embodiments, end-fire antenna 400 is disposed above cavity 404. In some embodiments, cavity 404 is disposed in an outer surface of a fuselage of an aerodynamic system such that end-fire antenna 400 (as part of a flexible antenna substrate) wraps around the fuselage and is located above cavity 404. Cavity 404 is electrically grounded to the same ground as ground plane 310 of first patterned metal layer 302 and second patterned metal layer 306.

[0045] As described above, according to some embodiments, the wide end of the tapered feed line 308 terminates with a resistor 406 connected to the electrical ground plane 310. The resistor 406 may have a resistance between about 10 ohms and 50 ohms. In some embodiments, the resistor 406 has a resistance of about 30 ohms. According to some embodiments, the resistance of the resistor 406 is selected so as to eliminate or significantly reduce any reverse waves formed through the tapered feed line 308. The resistor 406 may be made of any standard resistor material, such as carbon, metal oxides or nitrides, or ceramics, to name a few examples.

[0046] Figure 4BA cross-sectional view of a first patterned metal layer and a second patterned metal layer taken through plane A-A' is shown according to some embodiments. The space between the first patterned metal layer 302 and the second patterned metal layer with the tapered feed line 308 and the ground plane 310 below can include a substrate having the first patterned metal layer 302 located on the top surface of the substrate and the tapered feed line 308 and the ground plane 310 located on the bottom surface of the substrate. The resistor 406 is coupled between the wide end of the tapered feed line 308 and the ground plane 310. According to some embodiments, the tapered feed line 308 is closer to the first patterned metal layer 302 then to the ground surface 407 of the cavity 404, thereby achieving better RF coupling with the slot 304. Although not shown for clarity, the cavity 404 can be filled with a dielectric material, which can be the same dielectric material used between the first patterned metal layer and the second patterned metal layer. In some other embodiments, the dielectric material within cavity 404 has a lower dielectric constant than the dielectric constant of the antenna substrate having the first patterned metal layer and the second patterned metal layer on opposite sides of the antenna substrate. According to some embodiments, a separate cavity 404 is used under each end-fire antenna 400 (e.g., for each end-fire antenna shown across substrate 300) to avoid mutual coupling under the slot and corruption of any radiated RF pattern.

[0047] According to some embodiments, conductive connection 408 can be made to electrically connect ground plane 310 with first patterned metal layer 302. Conductive connection 408 can be a via (e.g., a plated through hole) filled with a conductive material that extends across the thickness of the antenna substrate. In some other embodiments, conductive connection 408 represents one or more metal traces or wires used to connect ground plane 310 with first patterned metal layer 302.

[0048] Figure 5A A cross-sectional view of a material layer stack 500 is shown that forms an antenna structure for a fuselage that surrounds an aerodynamic system, according to one embodiment. The material layer stack 500 can be disposed on an outer metal surface 502 of the fuselage. According to some embodiments, the material layer stack 500 includes a first patterned metal layer 302 and a second patterned metal layer 306 on either side of an antenna substrate 504. Any dielectric material or multiple layers of dielectric material can be used for the antenna substrate 504. In some embodiments, the antenna substrate 504 is a laminate substrate having a thickness of approximately 500 microns (e.g., Rogers RT / duroid 5880 high frequency laminate, which is a PTFE composite material reinforced with glass microfibers, for example only). In some embodiments, the antenna substrate 504 has a dielectric constant between approximately 1.75 and approximately 2.25.

[0049] The material layer stack 500 also includes a lower dielectric layer 506 sandwiched between the second patterned metal layer 306 and the outer metal surface 502 of the fuselage. According to some embodiments, the lower dielectric layer 506 is used to fill the cavity in the fuselage, so that the outer metal surface 502 represents the ground surface 407 of the cavity, such as Figure 4B As shown. The lower dielectric layer 506 may have a lower dielectric constant than the antenna substrate 504. For example, the lower dielectric layer 506 may have a dielectric constant between 1 and 1.2. In some embodiments, the lower dielectric layer 506 has a thickness of about 2.5 mm. In some embodiments, the lower dielectric layer 506 includes polymethacrylimide (PMI).

[0050] The material layer stack 500 also includes an upper dielectric layer 508 located above the first patterned metal layer 302. According to some embodiments, the upper dielectric layer 508 acts as a radome layer to protect the other layers of the material layer stack 500 from environmental influences. According to some embodiments, the upper dielectric layer 508 has a relatively high dielectric constant (e.g., higher than the dielectric constant of the antenna substrate 504), thereby generating leakage surface waves along the top surface of the first patterned metal layer 302. The leakage surface waves will guide the radiation forward to the front of the aerodynamic system. In some embodiments, the upper dielectric layer 508 has a dielectric constant between 2.75 and 3.25. In some embodiments, the upper dielectric layer 508 has a thickness of about 1 mm. The thickness of the upper dielectric layer 508 can be designed to be approximately 1 / 4 wavelength of the RF radiation of interest, and can therefore be changed according to the application. In some embodiments, the upper dielectric layer 508 includes a Teflon-based polymer.

[0051] According to some embodiments, glue layer 510 is used to bond certain layers together within material layer stack 500. For example, material layer stack 500 includes glue layer 510 between first patterned metal layer 302 and upper dielectric layer 508, between second patterned metal layer 306 and lower dielectric layer 506, and between lower dielectric layer 506 and outer metal surface 502. Any adhesive material can be used for glue layer 510. In some embodiments, the adhesive material used in glue layer 510 has a dielectric constant between about 3.25 and about 3.75. Glue layer 510 can have a thickness between about 100 microns and 200 microns.

[0052] Figure 5BA cross-sectional view of another material layer stack 501 constituting an antenna structure of a fuselage wrapping aerodynamic system according to an embodiment is shown. Material layer stack 501 may be disposed on an outer metal surface 502 of the fuselage. According to some embodiments, material layer stack 501 differs from material layer stack 500 in having first patterned metal sheet 512 and second patterned metal sheet 514 as separate metal sheets instead of patterned metal layers on substrate 504. Therefore, some layers in material layer stack 501 are similar to layers in material layer stack 500 and use the same numerical labels.

[0053] According to some embodiments, material layer stack 501 includes more glue layers 510 to fix first patterned metal sheet 512 and second patterned metal sheet 514 compared to material layer stack 500. In some embodiments, material layer stack 501 includes a thin layer of polyimide adjacent to first patterned metal sheet 512 and between first patterned metal sheet 512 and glue layer 510, and material layer stack 501 includes a thin layer of polyimide adjacent to second patterned metal sheet 514 and between second patterned metal sheet 514 and glue layer 510.

[0054] The material layer stack 501 also includes a middle portion dielectric layer 516 sandwiched between the first patterned metal sheet 512 and the second patterned metal sheet 514. The middle portion dielectric layer 516 can have a lower dielectric constant than the antenna substrate 504. For example, the middle portion dielectric layer 516 can have a dielectric constant between 1 and 1.2. The middle portion dielectric layer 516 can be the same dielectric material as the lower dielectric layer 506. In some embodiments, the middle portion dielectric layer 516 has a thickness of about 1 mm.

[0055] Fig. 6A and Figure 6B Comparison of RF radiation characteristics of different slotted end-fire antenna designs according to some embodiments. Fig. 6A A transmission radiation pattern 602 is shown away from the slotted surface of the first patterned metal layer 302. Because the first patterned metal layer 302 acts as a finite metal ground plane, the radiation pattern 602 radiates away from grazing angles along the first patterned metal layer 302. Because the antenna structure is located behind and away from the front of the aerodynamic system, directing the gain more to the front of the aerodynamic system is advantageous for homing applications.

[0056] Figure 6BAnother transmitted radiation pattern 604 is shown away from the slotted surface of the first patterned metal layer 302 including a dielectric layer, such as the upper dielectric layer 508. The presence of the upper dielectric layer 508 slows down the speed of the surface waves and causes the surface waves to gradually radiate as leaky waves during propagation along the first patterned metal layer 302. The slowed surface waves cause the radiation pattern 604 to radiate closer to the surface at a lower angle, thereby directing gain to the front of the aerodynamic system.

[0057] In some embodiments, the thickness of the upper dielectric layer 508 is less than or equal to 1 / 2 of the wavelength of the transmitted RF radiation. Although the discussion so far describes a dielectric material used as the top layer of a material stack to produce leakage surface waves, other materials can also be used to produce similar effects. For example, a layer of magnetic material can also cause leakage surface waves. In some other embodiments, a corrugated metal pattern increases inductance, which can cause leakage surface waves.

[0058] As described above, according to some embodiments, the slots 304 on the first patterned metal layer 302 can be varied to achieve a dual-band series-fed end-fire design. Slots having the same length can provide a single-band design for a given wavelength range. By varying the length of some slots, the antenna can be used to transmit or receive different frequency bands.

[0059] Fig. 7A An example slot design that can be used to replace the slots 304 on the first patterned metal layer 302 is shown. The slot design includes a first plurality of slots 702 having a first length and a second plurality of slots 704 having a second length that is shorter than the first length. Each of the second plurality of slots 704 alternates with one of the first plurality of slots 702. By alternating different slot lengths alone, two different frequency bands can be used. According to some embodiments, the first frequency band associated with the first plurality of slots 702 is approximately twice the frequency of the second frequency band associated with the second plurality of slots 704. According to some embodiments, the width of at least the first plurality of slots 702 increases along the length of the end-fire antenna, similar to the increasing width of the slots 304. In some embodiments, more than one second plurality of slots 704 is included between each pair of first plurality of slots 702. Increasing the number of shorter slots between pairs of longer slots increases the ratio between the frequency bands. For example, if two shorter slots (second plurality of slots 704) are provided between each pair of longer slots (first plurality of slots 702), the two frequency bands will have a ratio of 3:1.

[0060] Figure 7BAnother example slot design that can be used to replace the slots 304 on the first patterned metal layer 302 is shown, the two creating two different frequency bands. The slot design includes a first plurality of slots 706 having a first length and a second plurality of slots 708 having a second length shorter than the first length, wherein the first plurality of slots 706 are located in a first slot group, the first slot group is adjacent to a second slot group, and the second slot group includes the second plurality of slots 708. In some embodiments, the first plurality of slots 706 are aligned on the wider portion of the tapered feed line, and the second plurality of slots 708 are aligned on the narrower portion of the tapered feed line, which is located on a separate metal layer below the first patterned metal layer 302, as shown in reference Figure 5B In some embodiments, the length of the second multi-slot 708 becomes longer and longer in the direction of the first multi-slot 706. In some embodiments, the cavity under the end-fire antenna is shaped to accommodate different slot lengths (e.g., the cavity is wider under the first multi-slot 706 and narrower under the second multi-slot 708).

[0061] Figure 8 8 is a flow chart of an example method 800 for manufacturing an end-fire antenna structure (e.g., antenna structure 104) around a fuselage of an aerodynamic system according to an embodiment of the present disclosure. Although the methods described herein may appear to have a specific order of operations, other embodiments may not be limited thereto. Therefore, the order of operations may vary between embodiments, as will be apparent from this disclosure.

[0062] Method 800 begins at box 802, where a sheet is wrapped around a fuselage of an aerodynamic system, the sheet having a dielectric material plate attached to the sheet. According to some embodiments, the dielectric material plate is shaped to fit within a cavity formed in the fuselage so that a given dielectric material plate fits within a corresponding cavity. The dielectric material plate can be the same as the lower dielectric layer 506 that is part of the material layer stack 500. Therefore, the dielectric material plate can be a PMI with a dielectric constant between 1 and 1.2. The dielectric material plate can be loosely bonded to the sheet so that they can be easily separated when the sheet is peeled from the fuselage. According to some embodiments, the sheet is any epoxy-based material, such as AF126 sheet epoxy from 3M (Maplewood, MN).

[0063] The method 800 continues at block 804 where the sheet is peeled away from the fuselage, leaving behind the plates of dielectric material. According to some embodiments, each plate of dielectric material is left within a respective cavity around the circumference of the fuselage.

[0064] The method 800 continues to block 806 where an antenna substrate (e.g., antenna substrate 300) is wrapped around the fuselage over the plates of dielectric material. According to some embodiments, the antenna substrate is wrapped so that each end-fire antenna on the antenna substrate is aligned over a corresponding plate of dielectric material. For example, if eight end-fire antennas are arranged in parallel on the antenna substrate, eight plates of dielectric material will be disposed around at least a portion of the circumference of the fuselage so as to align with each of the eight end-fire antennas on the antenna substrate. After wrapping the antenna substrate around at least a portion of the circumference of the fuselage, a clamshell bracket may be applied around the outside of the antenna substrate to secure it in place and allow any adhesive to finish curing.

[0065] The method 800 continues to block 808 where a top dielectric layer is wrapped around the body and over the antenna substrate. According to some embodiments, the top dielectric layer serves as a radome structure for the antenna substrate below and can be the same as the upper dielectric layer 508 that is part of the material layer stack 500. Thus, the top dielectric layer can include a Teflon-based polymer having a dielectric constant between 2.75 and 3.25. After wrapping the top dielectric layer around at least a portion of the antenna substrate below, a clamshell standoff can be applied around the outside of the top dielectric layer to secure it in place and allow any adhesive to finish curing.

[0066] Many specific details are set forth herein to provide a thorough understanding of the embodiments. However, those of ordinary skill will appreciate that the embodiments can be practiced without these specific details. In other cases, well-known operations, components, and circuits are not described in detail to avoid obscuring the embodiments. It is understood that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments. In addition, although the subject matter has been described in a language specific to structural features and / or method actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described herein. On the contrary, the specific features and actions described herein are disclosed as example forms for implementing the claims.

[0067] Further Example Implementations

[0068] The following examples relate to further embodiments, from which numerous permutations and configurations will be apparent.

[0069] Embodiment 1 is an antenna structure configured to wrap around a fuselage of an aerodynamic system, the fuselage having a length along a first direction. The antenna structure includes a first patterned metal layer, a second patterned metal layer, and a stack of material layers including the first patterned metal layer and the second patterned metal layer. The first patterned metal layer includes a plurality of parallel grooves etched through the metal, each parallel groove extending longitudinally in a second direction perpendicular to the first direction. The second patterned metal layer includes a tapered radio frequency (RF) feed line having a narrow end and a wide end, the narrow end coupled to an input / output (I / O) antenna connection, wherein the second patterned metal layer is aligned on the first patterned metal layer so that the tapered RF feed line has a length extending across the plurality of parallel grooves in the first direction. The stack of material layers is flexible so that the stack of material layers is configured to at least partially wrap around the fuselage of the aerodynamic system.

[0070] Embodiment 2 includes the subject matter of embodiment 1, wherein the material layer stack is configured to surround the entire circumference of the fuselage.

[0071] Embodiment 3 includes the subject matter of embodiment 1 or 2, wherein the material layer stack comprises: a first dielectric layer located between a first patterned metal layer and a second patterned metal layer; and a second dielectric layer located above the first patterned metal layer, such that the first patterned metal layer is sandwiched between the first dielectric layer and the second dielectric layer.

[0072] Embodiment 4 includes the subject matter of embodiment 3, wherein the second dielectric layer has a higher dielectric constant than the first dielectric layer.

[0073] Embodiment 5 includes the subject matter of Embodiment 3 or 4, wherein the first dielectric layer comprises polymethacrylimide (PMI) and the second dielectric layer comprises polytetrafluoroethylene (PTFE).

[0074] Embodiment 6 includes the subject matter of any of Embodiments 1-5, wherein the first patterned metal layer is located on a front side of the flexible substrate and the second patterned metal layer is located on a back side of the flexible substrate.

[0075] Embodiment 7 includes the subject matter of Embodiment 6, wherein the material layer stack includes a dielectric layer over the first patterned metal layer, wherein the dielectric layer has a higher dielectric constant than the flexible substrate.

[0076] Embodiment 8 includes the subject matter of Embodiment 6 or 7, further comprising one or more plated through vias connected between the first patterned metal layer and the second patterned metal layer.

[0077] Embodiment 9 includes the subject matter of any of Embodiments 1-8, wherein the plurality of parallel grooves each have the same length.

[0078] Embodiment 10 includes the subject matter of embodiment 9, wherein the plurality of parallel slots have widths that increase along a first direction, such that the wide end of the tapered RF feed line is aligned on a slot having the largest width among the plurality of parallel slots, and the narrow end of the tapered RF feed line is aligned on a slot having the smallest width among the plurality of parallel slots.

[0079] Embodiment 11 includes the subject matter of any of Embodiments 1-10, wherein the plurality of parallel grooves comprises a first groove set having a first length and a second groove set having a second length shorter than the first length.

[0080] Embodiment 12 includes the subject matter of embodiment 11, wherein the grooves in the first groove set alternate with the grooves in the second groove set along the first direction.

[0081] Embodiment 13 includes the subject matter of embodiment 11, wherein the first slot set is adjacent to the second slot set.

[0082] Embodiment 14 includes the subject matter of any of Embodiments 1-13, wherein the second patterned metal layer includes a ground plane, and wherein the antenna structure further includes a resistor coupled between the tapered RF feed line and the ground plane.

[0083] Embodiment 15 includes the subject matter of embodiments 1-14, wherein the plurality of parallel trenches is a first group of parallel trenches, and the first patterned metal layer includes multiple groups of parallel trenches, each trench in the multiple groups of parallel trenches being parallel to each other.

[0084] Embodiment 16 includes the subject matter of Embodiment 15, wherein the second patterned metal layer comprises a plurality of tapered RF feed lines, wherein each tapered RF feed line of the plurality of tapered RF feed lines is aligned over a corresponding set of parallel grooves of the plurality of sets of parallel grooves.

[0085] Embodiment 17 includes the subject matter of any of Embodiments 1-16, further comprising a dielectric material between the material layer stack and the fuselage.

[0086] Embodiment 18 includes the subject matter of Embodiment 17, wherein the body has a cavity and the dielectric material is disposed within the cavity.

[0087] Embodiment 19 is a guided munition comprising the antenna structure of any one of embodiments 1-18.

[0088] Embodiment 20 is an RF system configured for an aerodynamic system. The RF system includes: a processor configured to generate a digital signal; at least one digital-to-analog converter (DAC) configured to convert the digital signal into an analog signal; a front-end circuit configured to receive the analog signal from the DAC and perform amplification, up-conversion, modulation, or filtering of the analog signal to provide a transmission signal; and an antenna structure configured to radiate the transmission signal received from the front-end circuit. The antenna structure includes a first patterned metal layer, a second patterned metal layer, and a stack of material layers including the first patterned metal layer and the second patterned metal layer. The first patterned metal layer includes a plurality of parallel grooves etched through the metal, each parallel groove extending longitudinally in a first direction perpendicular to a second direction, and the second direction is along the length of the aerodynamic system extending between the nose cone and the tail end. The second patterned metal layer includes a tapered radio frequency (RF) feed line having a narrow end and a wide end, the narrow end coupled to an input / output (I / O) antenna connection, wherein the second patterned metal layer is aligned on the first patterned metal layer so that the tapered RF feed line has a length extending across the plurality of parallel grooves in the second direction. The material layer stack is flexible such that the material layer stack is configured to at least partially surround a fuselage of the aerodynamic system.

[0089] Embodiment 21 includes the subject matter of Embodiment 20, wherein the material layer stack is configured to surround the entire circumference of the fuselage.

[0090] Embodiment 22 includes the subject matter of embodiment 20 or 21, wherein the material layer stack includes: a first dielectric layer located between a first patterned metal layer and a second patterned metal layer; and a second dielectric layer located above the first patterned metal layer, such that the first patterned metal layer is sandwiched between the first dielectric layer and the second dielectric layer.

[0091] Embodiment 23 includes the subject matter of Embodiment 22, wherein the second dielectric layer has a higher dielectric constant than the first dielectric layer.

[0092] Embodiment 24 includes the subject matter of Embodiment 22 or 23, wherein the first dielectric layer comprises polymethacrylimide (PMI) and the second dielectric layer comprises polytetrafluoroethylene (PTFE).

[0093] Embodiment 25 includes the subject matter of any of Embodiments 20-24, wherein the first patterned metal layer is located on a front side of a flexible printed circuit board (PCB) and the second patterned metal layer is located on a back side of the flexible PCB.

[0094] Embodiment 26 includes the subject matter of Embodiment 25, wherein the material layer stack comprises a dielectric layer above the first patterned metal layer, wherein the dielectric layer has a higher dielectric constant than the flexible PCB.

[0095] Embodiment 27 includes the subject matter of Embodiment 25 or 26, wherein the antenna structure further comprises one or more plated through vias connected between the first patterned metal layer and the second patterned metal layer.

[0096] Embodiment 28 includes the subject matter of any of Embodiments 20-27, wherein the plurality of parallel grooves each have the same length.

[0097] Embodiment 29 includes the subject matter of embodiment 28, wherein the plurality of parallel slots have widths that increase along a second direction, such that the wide end of the tapered RF feed line is aligned over the slot having the largest width among the plurality of parallel slots, and the narrow end of the tapered RF feed line is aligned over the slot having the smallest width among the plurality of parallel slots.

[0098] Embodiment 30 includes the subject matter of any of Embodiments 20-29, wherein the plurality of parallel grooves comprises a first groove set having a first length and a second groove set having a second length shorter than the first length.

[0099] Embodiment 31 includes the subject matter of Embodiment 30, wherein the grooves in the first groove set alternate with the grooves in the second groove set along the second direction.

[0100] Embodiment 32 includes the subject matter of Embodiment 30, wherein the first slot set is adjacent to the second slot set.

[0101] Embodiment 33 includes the subject matter of any of Embodiments 20-32, wherein the second patterned metal layer includes a ground plane, and wherein the antenna structure further includes a resistor coupled between the tapered RF feed line and the ground plane.

[0102] Embodiment 34 includes the subject matter of any of Embodiments 20-33, wherein the plurality of parallel trenches is a first set of parallel trenches, and the first patterned metal layer includes multiple sets of parallel trenches, each trench in the multiple sets of parallel trenches being parallel to each other.

[0103] Embodiment 35 includes the subject matter of Embodiment 34, wherein the second patterned metal layer comprises a plurality of tapered RF feed lines, each tapered RF feed line of the plurality of tapered RF feed lines being aligned over a corresponding set of parallel grooves of the plurality of sets of parallel grooves.

[0104] Embodiment 36 includes the subject matter of any of Embodiments 20-35, wherein the aerodynamic system is a guided munition.

[0105] Embodiment 37 includes the subject matter of embodiment 36, wherein the transmission signal is a homing signal for guiding the guided munition.

[0106] Embodiment 38 includes the subject matter of any of Embodiments 20-37, wherein the antenna structure further comprises a dielectric material located between the material layer stack and the body.

[0107] Embodiment 39 includes the subject matter of Embodiment 38, wherein the body has a cavity and the dielectric material is disposed within the cavity.

[0108] Embodiment 40 is a method of manufacturing an antenna structure configured for an aerodynamic system. The method includes: wrapping a sheet having a plurality of dielectric material plates around a fuselage of the aerodynamic system; removing the sheet so that the dielectric material plates remain within corresponding cavities in the fuselage; and wrapping a flexible substrate around the fuselage and over the dielectric material plates. The flexible substrate includes: a first patterned metal layer on a first surface of the flexible substrate, wherein the first patterned metal layer includes a plurality of parallel grooves etched through the metal, each parallel groove extending longitudinally in a first direction; and a second patterned metal layer located on a second surface of the flexible substrate opposite the first surface, wherein the second patterned metal layer includes a tapered radio frequency (RF) feed line having a narrow end and a wide end, the narrow end coupled to an input / output (I / O) antenna connection, wherein the second patterned metal layer is aligned with the first patterned metal layer so that the tapered RF feed line has a length extending across the plurality of parallel grooves in a second direction substantially perpendicular to the first direction. The method also includes wrapping a dielectric layer at least partially around the fuselage and over the flexible substrate.

Claims

1. An antenna structure configured to wrap around a fuselage of an aerodynamic system, the fuselage having a length along a first direction, the antenna structure comprising: a first patterned metal layer, wherein the first patterned metal layer comprises a plurality of parallel grooves etched through the metal, each of the parallel grooves extending longitudinally in a second direction perpendicular to the first direction; a second patterned metal layer, wherein the second patterned metal layer includes a tapered radio frequency (RF) feed line having a narrow end and a wide end, the narrow end coupled to an input / output (I / O) antenna connection, wherein the second patterned metal layer is aligned over the first patterned metal layer such that the tapered radio frequency (RF) feed line has a length extending across the plurality of parallel slots in the first direction; and A material layer stack, including the first patterned metal layer and the second patterned metal layer, is flexible such that the material layer stack is configured to at least partially surround the fuselage of the aerodynamic system.

2. The antenna structure according to claim 1, characterized in that: The material layer stack is configured to surround the entire circumference of the fuselage.

3. The antenna structure according to claim 1, characterized in that: The first patterned metal layer is located on the front side of the flexible substrate, and the second patterned metal layer is located on the back side of the flexible substrate.

4. The antenna structure according to claim 3, characterized in that: The material layer stack includes a dielectric layer located above the first patterned metal layer, wherein the dielectric layer has a higher dielectric constant than the flexible substrate. 5 . The antenna structure of claim 3 , further comprising one or more plated through holes connected between the first patterned metal layer and the second patterned metal layer.

6. The antenna structure according to claim 1, characterized in that: The plurality of parallel slots have increasing widths along the first direction, such that the wide end of the tapered RF feed line is aligned above a slot having the largest width among the plurality of parallel slots, and the narrow end of the tapered RF feed line is aligned above a slot having the smallest width among the plurality of parallel slots.

7. The antenna structure according to claim 1, characterized in that: The second patterned metal layer includes a ground plane, and wherein the antenna structure further includes a resistor coupled between the tapered radio frequency (RF) feed line and the ground plane.

8. The antenna structure of claim 1, further comprising a dielectric material located between the material layer stack and the body.

9. The antenna structure according to claim 8, characterized in that: The body has a cavity, and the dielectric material is disposed within the cavity.

10. A radio frequency system configured for use in an aerodynamic system, the radio frequency system comprising: a processor configured to generate a digital signal; at least one digital-to-analog converter (DAC) configured to convert the digital signal into an analog signal; A front-end circuit configured to receive the analog signal from the digital-to-analog converter and perform any one of amplification, up-conversion, modulation or filtering on the analog signal, thereby providing a transmission signal; and An antenna structure configured to radiate the transmission signal received from the front-end circuit, wherein the antenna structure includes a first patterned metal layer, wherein the first patterned metal layer includes a plurality of parallel grooves etched through the metal, each of the parallel grooves extending longitudinally in a first direction perpendicular to a second direction along a length of the aerodynamic system extending between the nose cone and the tail end, a second patterned metal layer, wherein the second patterned metal layer includes a tapered radio frequency (RF) feed line having a narrow end and a wide end, the narrow end coupled to an input / output (I / O) antenna connection, wherein the second patterned metal layer is aligned over the first patterned metal layer such that the tapered radio frequency (RF) feed line has a length extending across the plurality of parallel slots in the second direction, and A material layer stack, including the first patterned metal layer and the second patterned metal layer, is flexible such that the material layer stack is configured to at least partially surround a fuselage of the aerodynamic system.

11. The radio frequency system according to claim 10, characterized in that: The material layers are stacked up to surround the entire circumference of the fuselage.

12. The radio frequency system according to claim 10, characterized in that: The first patterned metal layer is located on a front side of a flexible printed circuit board (PCB), and the second patterned metal layer is located on a back side of the flexible printed circuit board (PCB).

13. The radio frequency system according to claim 12, characterized in that: The material layer stack includes a dielectric layer located above the first patterned metal layer, wherein the dielectric layer has a higher dielectric constant than the flexible printed circuit board.

14. The radio frequency system according to claim 12, characterized in that: The antenna structure also includes one or more plated through holes connected between the first patterned metal layer and the second patterned metal layer.

15. The radio frequency system according to claim 10, characterized in that: The plurality of parallel slots have increasing widths along the second direction, such that the wide end of the tapered RF feed line is aligned above a slot having the largest width among the plurality of parallel slots, and the narrow end of the tapered RF feed line is aligned above a slot having the smallest width among the plurality of parallel slots.

16. The radio frequency system according to claim 10, characterized in that: The second patterned metal layer includes a ground plane, and wherein the antenna structure further includes a resistor coupled between the tapered radio frequency (RF) feed line and the ground plane.

17. The radio frequency system according to claim 10, characterized in that: The plurality of parallel grooves are a first group of parallel grooves, and the first patterned metal layer includes a plurality of groups of parallel grooves, each of the plurality of groups of parallel grooves being parallel to each other.

18. The radio frequency system according to claim 10, characterized in that: This aerodynamic system is the guided munition.

19. The radio frequency system according to claim 18, characterized in that: The transmission signal is a homing signal for guiding the guided munition.

20. A method of manufacturing an antenna structure configured for use in an aerodynamic system, the method comprising: wrapping a sheet having a plurality of panels of dielectric material around a fuselage of the aerodynamic system; removing the sheet material thereby leaving the plate of dielectric material within the corresponding cavity in the fuselage; A flexible substrate is wrapped around the body and the dielectric material plate, wherein the flexible substrate includes a first patterned metal layer located on the first surface of the flexible substrate, wherein the first patterned metal layer includes a plurality of parallel grooves etched through the metal, each of the parallel grooves extending longitudinally in a first direction, and a second patterned metal layer on a second surface of the flexible substrate opposite the first surface, wherein the second patterned metal layer includes a tapered radio frequency (RF) feed line having a narrow end and a wide end, the narrow end coupled to an input / output (I / O) antenna connection, wherein the second patterned metal layer is aligned with the first patterned metal layer such that the tapered radio frequency (RF) feed line has a length extending across the plurality of parallel slots in a second direction substantially perpendicular to the first direction; and A dielectric layer is at least partially surrounded around the body and over the flexible substrate.

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