ES2274073T3 - ANTENNA OF DECIMAL BAND CONICAL SLOTS AND MANUFACTURING AND CONFIGURATION PROCEDURES OF THE SAME. - Google Patents

Abstract

An antenna apparatus (10) includes an antenna element (12, 412, 512) that has conductive material with a recess therein. The recess includes a balun hole (36, 536), and a tapered slot (37, 537) communicating at its narrow end with the balun hole. The balun hole is approximately rectangular, has a peripheral edge defined by conductive material, and contains air. The tapered slot has a shape which is optimized as a function of factors that include the balun hole design. Each slot edge follows a predetermined curve other than a first-order exponential curve.

Description

Antenna of conical slots of decimal band and manufacturing procedures and configuration thereof.

Technical Field of the Invention

In general, this invention relates to antennas of conical grooves and, more particularly, to a procedure and a apparatus for obtaining broad band performance on an antenna conical grooves

Background of the invention

During the last decades, the technology of the antennas has experienced an increase in the use of antennas that they use an array of antenna elements, of which an example is a multi-element antenna in phase. Antennas of this type they have many applications in the commercial and defense markets, such as radar and communications systems. In many of these applications, broadband performance is advisable. Some of these antennas are designed so that they can switch between two or more different frequency bands. Therefore in At any given time, the antenna is only working in one of said multiple bands. However, in order to really get broadband operation, the antenna has to be able to function satisfactorily in a single frequency band wide, without the need to switch between two or more bands of different frequencies

A type of antenna element that has been observed that it works well on a multi-element antenna at It is often called a conical groove antenna element. Normally, the frequency at which the antenna operates determines the space between the antenna elements of an element antenna multiple and a conical groove antenna element fits easily within the available space for an antenna element of many multiple element antennas.

European patent application EP 0.343.322 describes an antenna that has a flat conductor and a plane of ground independent of the flat conductor and placed parallel to the same. The ground plane has a groove that extends in transverse to the flat conductor.

US Patent 6,008,770 describes a conical groove antenna that provides a conical pattern that composes using a distribution function of Fermi-Dirac

Tan-huat Chio et al., In the document " Large wideband dual-polarized array of Vivaldi; antennas with radome ", Microwave conference 1999, Asia Pacific Singapore 30 November - 3 December 1999, p. 92-95 (XP010374119), ISBN: 0-7803-5761-2 , describe a conical groove antenna that has two ground planes, with a dielectric between them, to which a tape line feed is provided.

The conical groove antenna elements existing, usually have a bandwidth of, approximately, 3: 1 to 4: 1, although some have a bandwidth which approximates 6: 1. While said antenna elements of Existing conical grooves have generally been suitable for the desired ends have not been satisfactory in all aspects. In this sense, there are applications in which it is advisable that a conical groove antenna element provide broadband performance that involves a band wide near 10: 1 or even larger. The designs and techniques of existing design failed to provide an antenna element of conical grooves that approximates this desired level of broadband performance

Summary of the Invention

From the above, it can be understood that a procedure and an apparatus that contribute, in a conical groove antenna element, at band performance broadband that offers a bandwidth substantially higher than they have the pre-existing conical groove antenna elements.

An aspect of the present invention provides an antenna element as set forth in claim 1.

According to a complementary aspect of the invention a method is provided as set forth in claim 25.

Brief description of the drawings

The present invention will be better understood thanks to the detailed description that appears below, taking into Count the attached drawings, in which:

Figure 1 is a front schematic view Partial of an apparatus that incorporates aspects of the present invention, which includes an antenna element and part of a radome,

Figure 2 is a schematic rear view partial of the apparatus 10,

Figure 3 is a schematic view in section taken along the dividing line 3-3 of Figure 1,

Figure 4 is a front schematic view in partial section of the apparatus of Figure 1, taken along a central plane of it,

Figure 5 is a graph showing the shape of an edge of a groove part that is part of the element of antenna of Figure 1,

Figure 6 is a schematic view in partial perspective showing a part of the back side of the antenna element 12 on an enlarged scale,

Figure 7 is a schematic view in partial perspective showing an enlarged part of outer end of the apparatus of Figure 1,

Figure 8 is a very schematic view of the apparatus of Figure 1, showing a refractive feature  that produce certain dielectric layers of the radome of the same,

Figure 9 is a graph showing the loss of return in the scan of plane E as a function of the frequency of the apparatus of Figure 1,

Figure 10 is a graph showing the return loss in the sweep of the H plane as a function of the frequency of the apparatus of Figure 1,

Figure 11 is a block diagram that shows functional sections of the apparatus of Figure 1,

Figure 12 is a schematic view of a segmented transmission line that serves as a model to analyze a groove line present in the apparatus of Figure 1,

Figure 13 is a schematic view, to scale enlarged, of the end parts of four of the segments of the transmission line of Figure 12 and also shows in lines discontinuous how the number of segments can be tripled by interpolation,

Figure 14 is a schematic view of one of the segments of the transmission line of Figure 12, theoretically represented,

Figure 15 is a flow chart that summarizes an optimization technique that has been used when designing the device Figure 1,

Figure 16 is a front schematic view of an antenna element that is an alternative embodiment of the antenna element of Figure 1,

Figure 17 is a schematic view in perspective of an antenna element that remains another form of alternative embodiment of the antenna element of Figure 1,

Figure 18 is a schematic view in section taken along the dividing line 18-18 of Figure 17 and

Figure 19 is a schematic view from up in partial section of a coaxial tape line that is a component of the antenna element of Figure 17.

Detailed description of the invention

Figure 1 is a front schematic view part of an apparatus 10 that includes an antenna element 12 and part of a radome 13. In the embodiment described, the apparatus 10 is configured for use in an antenna system of multiple elements in phase that is not illustrated. System antenna includes a plurality of antenna elements 12 arranged in a two-dimensional array of rows and columns and includes a radome that extends over all antenna elements, showing a part of said radome in Figure 1 with the number 13.

Figure 2 is a schematic rear view part of the apparatus 10 and Figure 3 is a schematic view in section taken along the dividing line 3-3 of Figure 1. As best seen in Figure 3, the element antenna 12 includes two adjacent and parallel layers 17 and 18 of a dielectric material In the embodiment described, Each dielectric layer has a dielectric constant (Er) of, approximately 3.0. The dielectric layers 17 and 18 are joined each other by means of a thin layer 19 of adhesive film, which is of a type well known in the art. Each of the layers Dielectrics 17 and 18 have a thickness of approximately 20 mils (0.508 millimeters). The adhesive film 19 has a thickness of about 2 to 3 mils (0.0508 to 0.0762 millimeters)

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Figure 4 is a front schematic view in partial section of the apparatus 10, taken along a plane power station that extends between the dielectric layers 17 and 18, with the adhesive film 19 omitted for clarity purposes. The layer dielectric 17 has on the front side thereof a first ground plane 26 (Figure 1), the dielectric layer 18 has in the rear side of it a second ground plane 27 (Figure 2) and the dielectric layer 18 has on the front side of the same a third ground plane defined by three parts independent 28A, 28B and 28C (Figure 4), which, sometimes, in the This specification is collectively called a plane of earth 28.

Each of the ground planes 26 and 27 are layers of electrodeposed metal with a fine gold coating on the outer side thereof to resist corrosion. Every one of the ground planes 26 and 27 has a total thickness that is approximately 1 to 2 mils (0.0254 to 0.0508 millimeters) The ground plane 28 is a metal layer electrodeposing having a thickness of approximately 0.5 to 1 mils (0.0127 to 0.0254 millimeters).

Ground plane 26 has an engraved incoming through it and said incoming includes a part of balun 36 and a slot part 37. The balun part 36 of the recess is, approximately rectangular, except that it has corners that are slightly rounded. It has a dimension of length 38 and a width dimension 39. In the embodiment that is describes, the length dimension 38 is a quarter of the length of desired wave The embodiment of Figures 1 to 4 is optimized for use in a frequency range of, approximately 1.8 GHz to 18 GHz and the length dimension 38 is, about a quarter of the wavelength of a frequency intermediate of approximately 10 GHz. The width dimension 39, of the described embodiment, it is in the range from about a quarter of this wavelength to, approximately three eighths of this wavelength. That is, the width dimension 39 is at least as large as the dimension of length 38, but remains somewhat smaller than a medium of wavelength in order to avoid operating characteristics potentially inadvisable.

In general, it is advisable that the dimension of width 39 be as large as possible within the limitations indicated. However, as a practical matter, when the frequency of operation of a multi-element antenna system in phase increases progressively, the size of the matrix should decrease progressively, because the space available for each element of antenna is approximately a half of the wavelength of the higher operating frequency Therefore, as it decreases progressively the space available for each antenna element 12, the maximum amount of space also decreases progressively available for the width dimension 39 of the balun part 36. Therefore, in Figure 1, the width dimension 39 is, approximately 5% greater than the length dimension 38, but not 50% to 70% higher, due to space limitations imposed by the operating frequency range of the antenna system

Returning to slot part 37 of the incoming of the ground plane 26, the groove part 37 has one end narrow that communicates with the balun part 36 along one of the linear sides of the balun part 36, in a position separated from each end of that linear side. The opposite end of the groove portion 37 is considerably wider than the narrow end The shapes of the edges of the groove part 37 they will be analyzed in more detail in relation to Figure 5.

More specifically, Figure 5 is a graph. showing the shape of an edge of the groove part 37, in which the horizontal axis represents the centerline of the groove, from the end of the balun part 36 to the end of the radome 13. The shaft vertical of Figure 5 represents half the width of the slot, that is, the distance from the edge of the slot to the center line. The edges of the slot part 37 are images spectral of each one of them with respect to the central line of the slot and, therefore, in the graph of Figure 5 only It represents one of these edges.

It will be seen in Figure 5 that the edges of the slot part 37 does not follow a pure exponential curve of first order. On the contrary, the groove edges have a shape that it has been carefully configured to minimize the reflections and reduce the loss of return in a way that facilitates a broad bandwidth greater than 10: 1. The technique that has been used to configure the shape of the groove edge described in detail later. For the moment, just observe certain characteristics of the specific form shown in Figure 5 corresponding to slot part 37. More specifically, you can see that the narrowest part 41 of the slot part 37 is not exactly at the end of the part of groove that joins with the balun part 36, but is separated from this end a small distance. This narrow part 41 It provides an area of greater capacitance. Also, towards opposite end of the groove portion 37, there is a discontinuity 42 considerable, which is discussed below. In addition, each edge of the slot part 37 is something "wavy" in the section from the balun part 36 until discontinuity 42 which is not a random sinuosity, but it is a carefully configured that reduces reflections and loss of return in order to increase bandwidth and improve performance.

In general, the curve shown in Figure 5 can be described, approximately, as a curve first-order exponential that has at least one characteristic of higher order superimposed on the first order characteristic and in fact the specific curve of Figure 5 has a series of higher order characteristics superimposed on the characteristic First order. In this sense, using well-known techniques of curve adaptation, the specific curve shown in the Figure 5 can be expressed in the form of the following equation, in the that the coefficients of the equation are shown in Table 1.

\ text {Half of the width} (x) \ cong \ frac {1} {2} \ sum \ limits ^ {21} _ {i = 0} a_ {i} x ^ {i}

TABLE 1 Coefficients

one

Again referring to Figures 2 and 4, the ground plane 27 has through it an inlet that includes a balun part 43 and a groove part 44 and the plane of land 28 has through it an entree that includes a balun part 46 and a groove part 47. All parts of slot 37, 44 and 47 have the same size and shape, in particular the form described above in relation to Figure 5. In addition, all slot parts 37, 44 and 47 are aligned exactly each other. In a similar way, all parts of balun 36, 43 and 46 have the same size and shape and are aligned exactly each other. Each of the dielectric layers 17 and 18 it has, through them, an opening approximately rectangular, which has the same size and shape as the parts of balun 36, 43 and 46 and that is aligned with the parts of balun 36, 43 and 46. Together, the openings aligned approximately rectangular of the three ground planes and the two layers dielectrics define a balun hole 49 so approximately rectangular that extends completely through of the antenna element 12.

Figure 6 is a schematic view in partial perspective showing a part of the back side of the antenna element 12 on an enlarged scale. Balun opening 49 a through the antenna element 12 is covered with a material electrically conductive, such that a strip 51 of said conductive material extends along the edges of the balun hole The ends of the strip 51 are separated in order and define a groove 52 aligned with the narrow ends of the slot parts 37, 44 and 47. Strip 51 extends between the ground planes 26 and 27 and is electrically coupled to them and also is in electrical contact with the ground plane 28A.

The antenna element 12 also has its opposite side edges coated with an electrically material conductor, so that respective strips 53 and 54 of said conductive material extend the entire length of the elements dielectric, 17 to 18 and also extend between each of ground planes 26 and 27 and are electrically coupled to Each of them. Strip 53 is also in contact electric with the ground plane 28A along its entire length and strip 54 is in electrical contact with each of the planes of land 28B and 28C.

Dielectric layers 17 and 18 have openings respective wedge 57 and 58 through them, which have identical shape and size and that are aligned with each other. The openings 57 and 58 begin at the outer ends of the dielectric elements 17 and 18 and progressively decrease in width in one direction towards the balun hole 49. The conical sides of openings 57 and 58 are separated towards inside from the conical edges of the groove portions 37, 44 and 47. In one direction along the centerline of the parties slot 37, 44 and 47, the inner ends of the openings 57 and 58 are approximately aligned with discontinuity 42 (Figure 5). Discontinuity 42 compensates to some extent a discontinuity of impedance that occurs within the material dielectric due to the start of openings 57 and 58 in their left ends Layer 19 of adhesive film (Figure 3) it has a wedge opening through it that is identical, in size and shape, to openings 57 and 58 and which is aligned with the openings 57 and 58.

The ground plane 28 (Figure 4) also has of the recess that includes the balun part 46 and the groove part 47, an additional recess 66 which is an elongated duct that is extends from an inner end of the dielectric layer 18 around the balun part 46 and joins the narrow end of the groove portion 47. The conduit 66 communicates, along one side, with the balun part 46, however, alternatively, it would be possible for a part of the ground plane 28A to extend among them.

An elongated conductive strip 67 extends to through conduit 66, such that one end is arranged at the inner end of the dielectric layer 18 located in the left side of Figure 1 and the other end extends to through the narrow end of the groove part 47 and is bridged directly to the ground plane 28A. Conductive strip 67 and ground plane 28A are discussed herein. descriptive as if they were physically separate parts, because fulfill different operational functions in the antenna element 12. However, as a practical matter, the ground plane 28A and the conductive strip 67 are simply different integral parts of The same conductive layer.

In relation to Figure 1, a approximately semicircular notch 71 through the ground plane 26 and of the dielectric layer 17, in order to expose a end part of the conductive strip 67, and an end part of each of parts 28A and 28C of the ground plane 28. This allows a contact of a connector arrangement that is not illustrates gear, respectively, with strip 67 and with the parts ground plane 28A and 28C in order to electrically couple the strip conductor 67 of antenna element 12 to a circuit system of the antenna system that is known in the art and that, so Therefore, it is not shown in the drawings. In the case of the element of antenna 12 shown in Figure 1, the circuit system of the antenna system, which is not illustrated, is coupled electrically available to interconnected ground planes by means of the direct gear of a metal frame of the system antenna with one or more of the outer ground planes 26 to 27 and with conductive strips 53 to 54.

The conductive strip 67 acts as an element conductor of the type commonly referred to in the art as a tape line and signal carrier that is transmitting the element of antenna 12 or that is receiving the same. The direct connection between the ground plane 28A and one end of the tape line 67 represents an electrical termination of that end of the line of tape 67. Since tape line 67 ends directly at the ground plane 28, where the tape line 67 extends through of the groove portion 47, the reactances in the comparison with pre-existing devices, in which the line of tape is coupled via a path to the ground plane of the opposite side of a dielectric layer or where the line of tape ends in a type of independent termination structure designed to produce a standing wave resonance.

A plurality of pathways extends through both dielectric layers 17 and 18 in a series of positions different, in order to electrically couple the three planes of land 26 to 28. Three of the roads are identified with reference numbers 76, 77 and 78. The tracks facilitate control exact on the impedance characteristics within the parts of groove 37, 44 and 47 and along the belt line 67 and, they also help reduce or eliminate the degree to which the fields electromagnetic can form parallel modes of waveguides and plates inside the dielectric material. One of the routes that illustrate is identified with reference number 79 and has a diameter slightly larger than the rest of the tracks. Track 79  it is arranged very adjacent to the point at which one end of the tape line 67 ends directly inside the plane part ground 28A and serves to ensure that said end of the line of tape 67 ends directly and safely, not only in the plane of central ground 28, but also in the two ground planes exteriors 26 to 27. It will be noted that a respective row of tracks extends adjacent to each edge of the groove portions 37, 44 and 47, with approximately uniform spaces from each track to the edge of the groove parts and with spaces approximately uniforms between adjacent tracks. Behind each of these rows, along most of their length, there is a additional row of tracks.

Figure 7 is a schematic view in partial perspective of the outer end portion of the apparatus 10, on an enlarged scale As best seen in Figure 7, radome 13 includes a dielectric layer 91 that is fixedly coupled to an outer end of the antenna element 12 by means of a adhesive film 92, a second dielectric layer 93 that is fixedly coupled to the dielectric layer 91 by means of a adhesive film 94 and a third dielectric layer 97 which is fixedly coupled to the dielectric layer 93 by means of a Adhesive film 98. Adhesive films 92, 94 and 98 are materials of a type known in the art. Dielectric layer 97 is relatively fine and, mainly, serves as outer protective cover.

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In the embodiment of Figure 7, the dielectric layers 91, 93 and 97 have respective thicknesses of 120 millimeters (3,048 millimeters), 60 millimeters (1,524 millimeters) and 2 mils (0.0508 millimeters) and have constants respective dielectric (Er) of 1.08, 1.3 and 3.6. Alternatively, dielectric layers 91, 93 and 97 could have thicknesses respective of 60 mils (1,524 millimeters), 120 mils (3,048 mm) and 2 mil (0.0508 mm) and respective dielectric constants of 1.3, 1.08 and 3.6. Layers dielectrics 91 and 93 are transmissive to the radiation that is transmitting the antenna element 12 or that is receiving the same. In addition, dielectric layers 91 and 93 produce a degree of refraction of said radiation, as analyzed in more detail later. Dielectric layers 91 and 93 can also produce a degree of impedance matching between the end adjacent wide groove parts located on one side of of the same and the free space located on the other side of the same.

In this regard, and in relation to Figure 4, when an electrical signal is applied to the left end of the tape line 67, the signal moves through the line of tape to its opposite end, on which the tape line is extends transversely through the groove portion 47. In this case, the electrical signal generates an electromagnetic field around of the tape line, which tends to try to scroll in opposite directions within the "slot line" that define slot parts 37, 44 and 47. The slot line increases from impedance, approximately, progressively from the end left of it towards the right end of it, of a impedance of approximately 50 ohms in the area of the line tape 67 at an impedance of approximately 340 to 350 ohms at The wide outer end. Tape line 67 and the system circuits of the antenna system, which is not illustrated, which is coupled are matched, in order to provide an impedance considerable uniform of approximately 50 ohms from the circuit system through tape line 67 to line Slot Free space past the right end of the device 10 has an impedance of approximately 377 ohms for a square unit two-dimensional cell representing spaces uniforms in both directions of the two-dimensional matrix of antenna elements 12 within the element antenna system multiple in phase. The slot line produces a transformation of impedance of a value of approximately 50 ohms at the end left, which is matched to the impedance of the tape line 67, at a value of approximately 360 to 370 ohms at the end right, which closely approximates the impedance of space free.

The use of three ground planes 26 to 28 provides more conductive material along the edges of the slot line that in the preexisting provisions that only they have one or two ground planes, which in turn provides greater capacitance within the groove line. The greatest capacitance allows the narrow end of the groove line to be slightly wider than in pre-existing devices, at time it keeps getting a 50 ohm impedance that is matched to the impedance of tape line 67. To the extent that the narrowest end of the groove line can be extended, the manufacture of ground planes 26 to 28 is simpler, due to the fact that the tolerances that have to do with the Engraving techniques corresponding to ground planes are fixed.

Wedge openings 57 and 58 within the dielectric layers 17 and 18 and the congruent wedge opening inside of the adhesive layer 19, help facilitate said transformation of impedance, reducing the amount of dielectric material and adhesive film disposed within the groove line in the right end of it. Therefore, on the far right of antenna element 12, the impedance within the line of slot will be much closer to the impedance of free space located past the right end of the apparatus 10 of what would occur if openings 57 and 58 and the end were removed right of the groove line was completely filled with dielectric material This is due to the fact that the air has a impedance somewhat higher than the dielectric material and providing openings 57 and 58 replaced by air what would otherwise be dielectric material

As mentioned above, the hole of balun 49 is designed so that the width dimension 39 (Figure 1) is as large as possible in the area where the line of groove joins with the hole of balun 49, until, approximately, three eighths of a desired wavelength. This is intended for provide the greatest discontinuity of impedance possible between the balun hole 49 and the narrow end of the groove line. This great discontinuity is facilitated by the fact that the line of groove joins with the hole of balun 49 through one side of the balun hole 49 which is approximately linear and in a separate position of both ends of said linear side.

In the embodiment described, the Balun hole has an impedance of approximately 300 ohm, which represents a relatively large discontinuity with respect to the 50 ohm impedance of the adjacent end of the slot line As indicated above, the fields electromagnetic generated by tape line 67 where it crosses the slot line will tend to want to move in both directions along the groove line. However, the great impedance discontinuity between balun hole 49 and the left end of the groove line will make the majority of said electromagnetic energy shifts to the right instead of to the left along the groove line and that transmit in free space. To the extent that a part small electromagnetic energy shifts towards the left, the balun hole 49 has a length dimension which is approximately a quarter wavelength (as has been discussed above) and this creates a standing wave of open circuit that also tends to make energy electromagnetic scroll to the right within the line of groove.

As discussed above in relation with Figure 6, the inner edge of the balun hole 49 is coated with a conductive strip 51, except in the groove line. Strip 51 helps prevent electromagnetic fields, present inside the hole of balun 49, enter the material dielectric of layers 17 and 18, which helps increase the width of system band. Therefore, strip 51 helps establish the standing wave or resonance condition with respect to the electromagnetic energy inside the balun hole 49 which, at in turn, helps direct electromagnetic energy to the right inside the groove line. In a way, the balun hole 49 is a tuned inductor hole, which can operate on a 10: 1 bandwidth without electrical or structural adjustment.

In the embodiment described, the Balun hole 49 has no dielectric material inside it. Therefore, the balun hole 49 is filled with air, instead of dielectric material. Regarding a certain frequency, the Wavelength of electromagnetic radiation is greater in air than it would be in dielectric material. Therefore, if Balun hole 49 is made as wide as possible in order to maximize impedance discontinuity between the balun hole and the adjacent end of the groove line, a determined width will be less than half wavelength when the balun hole is filled with air than it would be if The balun hole was filled with dielectric material.

When electromagnetic radiation reaches the right end of antenna element 12, passes through the radome 13 and is issued to free space. As it mentioned above, the dielectric layers 91 and 93 of radome 13 impart a degree of refraction to said dielectric radiation. This refraction is produces with respect to the wave fronts that transmits or receives the antenna system that are oriented at an angle to the calibration line of the antenna system, which is parallel to the center lines of the groove parts of the elements of antenna. The wave fronts that are perpendicular to the line of calibration of the antenna system and, therefore, perpendicular to the center lines of the groove parts of the elements of antenna, they are not subjected to refraction, that is, they can be seen as they experience a refraction of 0º. The following analysis of refraction assumes that the affected wave fronts are oriented at an angle to the calibration line of the antenna system and with respect to the central lines of the parts of slot of the antenna elements.

In this sense, Figure 8 is a very view schematic of the apparatus 10 that includes both the antenna element 12 as radome 13. Arrow 111 represents radiation electromagnetic that is shifting out through the slot line When the radiation passes through the surface of contact between the antenna element 12 and the dielectric layer 91, it refracts to a degree that moves in one direction slightly different, as schematically indicated in Figure 8 with arrow 112. Similarly, when radiation passes to across the contact surface between the dielectric layer 91 and the dielectric 93, experiences a higher degree of refraction than further increases its angle, as indicated schematically with the arrow 113. Subsequently, when said radiation passes through the contact surface between the dielectric layer 93 and the space free, refracts a little more, so that it moves in a slightly larger angle, as indicated schematically with the arrow 114. Said refraction within radome 13 allows the apparatus 10 function more effectively over a sweep angle broader, which in the embodiment described is of, approximately 50º to 60º. In a way, refraction makes a part of the radiation transmitted to each edge of the angle of sweep have an effective power level higher than it would be without such refraction.

Providing wedge openings 57 and 58 in the dielectric layer of the antenna element 12 allows the use of lower dielectric constants for dielectric layers 91 and 93 of radome 13 of what they would be. This, in turn, reduces the degree in which electromagnetic energy deviates in surface waves transverse within the dielectric layers, for example as schematically indicated with an arrow of dashed lines 117, which in turn reduces or prevents an effect that is sometimes called sweep blindness

While the previous analysis of refraction is has presented in the context of transmitted radiation, experts in matter they will recognize that the radiation received is also subject to refraction. For example, in Figure 8, the number of reference 121 schematically represents radiation that is being approaching the antenna element 12 at an angle to the center line of the groove parts of the antenna element 12. When said radiation passes through radome 13 and enters the antenna element 12, the radiation is refracted progressively, as indicated schematically with arrows 122, 123 and 124, until the radiation is shifting through the part of slot of the antenna element 12, approximately, parallel to the center line.

Figure 9 is a graph showing the loss return depending on the frequency, corresponding to the form of embodiment of Figures 1 to 8, of which in the art known as sweeping the plane E. Since the loss of return is A standard way of expressing the amount of reflection is It is advisable that the loss of return be as low as possible. Be you will notice that the apparatus 10 provides a loss of return that continuously below -10dB for a sweep width 60º over a bandwidth of approximately 1.8 GHz at approximately 17.5 GHz. Those skilled in the art will recognize that, expressed according to another industrial standard, the form of embodiment of Figures 1 to 8 provides a bandwidth of at minus 10: 1 for -9.5dB (VSWR less than 2).

Figure 10 is a graph similar to Figure 9, but that shows a loss of return from what is commonly known in the art as sweeping the H plane. Figure 10 shows that the apparatus 10 provides a return loss of -10dB at through a scan width of 45º to 50º of a frequency of, approximately 3.5 GHz at a frequency greater than 18 GHz.

While the previous analysis has been presented mainly in the context of signals that the apparatus 10 of Figure 1, apparatus 10 is equally suitable for its use in the reception of electromagnetic signals. The experts in the matter they will understand thanks to the previous transmission analysis signal how the device 10 would work for the purpose of receiving signal.

The advantageous performance characteristics, such as those reflected in Figures 9 and 10, are partly due to the shape determined for the edges of the groove portions 37, 44 and 47, which together serve as the slot line of the antenna element 12. An explanation of how the shape of the edges of the parts of groove.

In this regard and in relation to Figures 1 and 4, the apparatus 10 is conceptually divided into three sections functional in order to carry out an analysis that determines a Optimal shape for the edges of the groove parts. Plus specifically, a functional section is called balun and corresponds approximately to the hole of balun 49 and the line of conductive tape 67. The following functional section is called the groove and corresponds approximately to the part of the part of slot extending from the hole of balun 49 to the discontinuity 42 of the left end of wedge openings 57 and 58. The third functional section 203 is called the final piece and corresponds approximately to the part of the apparatus 10 located at the right of discontinuity 42, in particular, from the end left of the wedge openings 57 to 58 to the right side of the outer dielectric layer 97.

Figure 11 is a diagram showing three blocks 201 to 203, which respectively represent the three functional sections that have been previously analyzed, specifically, the balun, groove and end piece sections. Together, blocks 201 to 203 represent apparatus 10 of the Figure 1, as schematically indicated with a dashed line in Figure 11. Each of blocks 201 to 203 is represented as a two-port element, which includes a port with two terminals on the left side and another port with two terminals on the right side. Adjacent ports of adjacent blocks They are coupled to each other. The final piece 203 has the port of right side coupled to an additional block 208, which schematically represents the impedance of free space arranged above the right end of the apparatus 10 of the Figure one.

As is known in the art, each of the two-port blocks, such as those represented by numbers  201 to 203, can be represented with what is commonly called a matrix [ABCD]. For example, focusing on block 202 of the Figure 11, which represents the slot, the left port has a voltage V_ {X} and a current I_ {X} and the right port has a voltage V_ {Y} and a current I_ {Y}. The relationship between sayings ports can be expressed with the following equation, in which the Subscript "S" identifies the slot section:

2

Similarly, and still referring to the Figure 11, the total transfer function for the apparatus 10 is can represent with a single matrix [ABCD], as follows:

3

in the that

4

and in which the subscripts "APP", "B", "S" and "EP" refer to the device 10, to balun section 201, to slot section 202 and to the end piece section 203, respectively.

Before trying to determine an optimal way for the edges of the groove, the balun and the final piece (which correspond to blocks 201 and 203) are designed in order to achieve appropriate design goals. For example, as has analyzed above, balun hole 49 (Figure 1) has various aspects, such as the shape, size and absence of dielectric material, which are intended to achieve the objective of design of a great discontinuity of impedance between the hole of balun and the groove line, which, in turn, maintains a width of wide band for antenna element 12. Possible configurations design for both the balun and the final piece can be rigorously analyze with an existing software program to Determine the expected performance characteristics. A The appropriate software program for this task is the commercialized by Ansoft Corporation, Pittsburg, Pennsylvania with the name High Frequency Structure Simulator (HFSS).

Once the physical design of the balun section and the final part section, are determined several matrices [ABCD] suitable for each. In this sense, the apparatus 10 is designed for use over a range of desired frequencies The operating characteristics of the balun section will be different at different frequencies and the operating characteristics of the final part section will be different at different frequencies. Consequently, they are selected several predetermined frequencies, which are distributed in the Desired frequency range. Subsequently, a respective different [ABCD] matrix for balun section 201 corresponding to each selected frequency and a respective different [ABCD] matrix for the final part section 203 corresponding to said frequency.

In the art, suitable techniques are known. to determine a matrix [ABCD] from a physical design. As an example, the parameters that represent the physical design are they can provide a known software program that, subsequently, you can calculate a transfer function form known in the art as a matrix [S]. The program of HFSS computer mentioned above is suitable for this work From that moment, the matrix [S] can be convert to a corresponding [ABCD] matrix, using techniques known math

Going back to slot section 202 of the Figure 11, an aspect of the present invention is to provide a technique in which the part of the groove line corresponding to the block 202 is represented by a model that is a line of transmission that has the same size and shape as the slot, the transmission line having the form of a series of segments of adjacent transmission line. For example, Figure 12 is a schematic view of a model that is a transmission line 241, formed of a plurality of N contiguous rectangular segments SEG1, SEG2, SEG3, ... SEGN. In Figure 12 there are 40 segments and, therefore therefore, N = 40. The center line of the groove is indicated schematically with the number 243, and the outer ends of the N segments, taken together, represent the edges of the groove. All segments have the same length in one direction parallel to the center line 243, but have several widths different in a direction transverse to the center line 243. The segments of Figure 12 do not necessarily represent the form of exact slot shown in Figure 5, but can be consider representative of one of a number of different ways that are evaluated to determine which form would serve as the form Optimum shown in Figure 5.

In order to determine an optimal way for groove edges, the normal length value for all Segments SEG1 to SEGN, as well as the respective width values of N vary selectively and independently and performance of the apparatus 10 is evaluated for each of said configurations of the segmented transmission line, in a way that explains more in detail later. It should be borne in mind that the N number of segments does not vary. Therefore, if the value varies normal length for segments, the total length of the segmented transmission line and therefore the length Total slot it represents. Therefore, part of what is optimize is the length of the slot itself.

Since the normal length and widths respective of the N segments vary independently, the optimization process is increasingly complex and takes more time if the value of N. is increased As a result, the selection of the value of N implies conflicting considerations. In particular, On the one hand, it is advisable to have a value of N relatively wide so that the ends of the segments provide a Good resolution of the definition of groove edges. For another side, it is advisable to have a relatively small value of N at in order to reduce the computational complexity involved in evaluating different configurations of the transmission line model segmented Regarding an antenna element of the type to be described with the number 12 in the embodiment of the Figures 1 to 8, it has been observed that a value of N in the range of, approximately 40 to 60 provides a good balance between these Two conflicting considerations.

Various existing techniques are known for produce independent variation of a series of parameters of a selective mode in order to optimize a specific characteristic. Such a technique is usually known in the art as Nelder-Mead's technique. There are programs of commercially available software that implements the technique Nelder-Mead, of which an example is the program MATLAB® marketed by The MathWorks of Natick, Massachusetts. Programs of this type provide the ability to Nelder-Mead generic and may be provided with input data for a specific application that causes the program apply the generic principles of that application specific. Since in the art the techniques of Nelder-Mead, are not described in detail in the Present descriptive report. On the contrary, to facilitate a understanding of the present invention, a brief is provided general perspective

In particular, a program that implements Nelder-Mead techniques is able to vary several parameters in an intelligent way according to the principles of Nelder-Mead, while evaluating a characteristic That is going to be optimized. In general, configurations of parameters, which usually improve the specific characteristic, to configurations that do not improve the feature and preferred configurations are used to predict other new configurations that can possibly provide even further improvement of the specific characteristic.

In the context of the present invention, select an initial slot shape, for example, in which the groove edges simply follow an exponential curve of first order. Subsequently, a line model of segmented transmission of the type shown in Figure 12 to model said initial slot shape using N segments in which N is approximately 40 to 60. Both the respective widths of the segments as the normal length of the segments vary from independently using Nelder-Mead techniques in order to find a plurality of different configurations of the segmented transmission line, which each represents a different slot shape. For each configuration of this type, Evaluate the performance of that configuration.

In this regard, in order to evaluate the performance, the number of segments of the model is tripled by interpolation. For example, Figure 13 is a schematic view, on an enlarged scale, of the end parts of four of the segments of the transmission line shown in the part upper right of Figure 12. The solid lines of Figure 13 correspond directly to the segments shown in the Figure 12. The dashed lines in Figure 13 show how to triples the total number of line segments from N to 3N. By For example, two points 261 and 262 are identified by interpolation in uniformly separated positions along a straight line that extends between two points 263 and 264, which are in respective corners of two of the N segments that are shown in Figure 12. Subsequently, each of the points 261 to 264 is a corner of a new respective segment that has a length that is one third of the length of each of the N segments shown in Figure 12. It should be taken into account that, although 3N segments are now available to evaluate performance, Nelder-Mead techniques are not use to vary independently the widths of all 3N segments, but only the widths of the N segments that are shown in Figure 12. The other two thirds of the segments they have widths that depend directly on the N widths originals, instead of widths determined by a Totally independent variation.

For a given 3N configuration segments, for example, as represented by the lines discontinuous in Figure 13, system performance is evaluated as follows. Each of the 3N segments is treated as An independent transmission line. In relation to the Figure 14, a theoretical transmission line has a length el, corresponding to the uniform dimension of each of the 3N segments in a direction parallel to the center line 243 (Figure 12) of the slot. In addition, the theoretical transmission line of the Figure 14 has an impedance Z_ {SEG} and, in the case of each of the 3N segments shown in Figure 13, said impedance depends on one or more different factors. In first place, depends on the width of the segment in one direction transversal to the central line 243. In addition, and in relation to the apparatus 10 shown in Figure 1, depends on whether there is material inside the slot and, if so, the characteristics of said material.

For example, the embodiment of the Figure 1 has parts of the dielectric layers 17 and 18 that are arranged inside the groove and the dielectric layers have impedance characteristics that vary with frequency, including For a given width. On the contrary, if the parts of the dielectric layers 17 and 18 located within the slot, so that the slot was filled with air, the impedance characteristic would vary with width but not with the frequency, because the air impedance does not vary with the frequency.

As is evident in Figure 14, the line theoretical transmission can be modeled as an element of two ports of the type that has been previously analyzed and therefore its characteristics can be represented with a matrix [ABCD]. In the case of one of the 3N rectangular segments shown in Figure 14, the matrix [ABCD] corresponding to a segment Specific ideal without loss would be defined as follows:

5

in the that

? = \ frac {2 \ pi} {\ lambda}

j = \ sqrt {-1}

In these equations, one should take into account that the value of the wavelength λ may vary not only depending on the frequency, but also depending on the type of material present inside the groove. For example, for a determined frequency, the wavelength will have a value if there is dielectric material inside the groove (as in the form of embodiment of Figure 1), but will have a different value if the slot contains air instead of dielectric material.

For a selected frequency, it is determined a respective [ABCD] matrix for each of the 3N segments. By therefore, a matrix [ABCD] is determined, for the entire line of segmented transmission, as follows:

6

Therefore, referring to the Figure 11, a matrix [ABCD] can be determined for the entire apparatus of Figure 1, identified with the subscript "APP", which includes the antenna element 12 and the radome part 13, of the next way.

7

Still referring to Figure 11, it recognize that this matrix [ABCD] for the antenna element is You can express in the following standard way:

8

This matrix equation can be returned to write in the form of two non-matrix equations, as follows:

V_ {IN} = AV_ {FS} + BI_ {FS}

I_ {IN} = CV_ {FS} + DI_ {FS}

in which A, B, C and D are of 9 .

Still referring to Figure 11 and, in particular, to block 208 of the right end of it is fine known that the voltage is equal to impedance current. For the therefore, V_ {Fs} = I_ {FS} \ cdot Z_ {FS}. Substituting this in the two previous equations by V_ {IN} and I_ {IN} you get what next:

V_ {IN} = I_ {FS} (AZ_ {FS} + B)

I_ {IN} = I_ {FS} (CZ_ {FS} + D)

in which A, B, C and D are of 10 .

Next, suppose that Z_ {SYS} represents the impedance of the entire system shown in the Figure 11, which includes both apparatus 10 and block 208, according to seen from the port on the left side of Figure 11. It will recognize that:

Z_ {SYS} = \ frac {V_ {IN}} {I_ {IN}} = \ frac {AZ_ {FS} + C} {CZ_ {FS} + D}

in which A, B, C and D are of eleven .

As mentioned earlier, the item of antenna 12 of Figure 1 is coupled to an antenna system which is not illustrated, for example, by means of a cable. System antenna supplies electrical signals to the input port of the left side of Figure 11 and from it. Let's suppose Z_ {0} represents the characteristic impedance of the cable that is not Illustrates and other circuit systems of the antenna system. The usual in the art is to design said circuit systems and cable so that all impedances are matched, to thereby provide a line of impedance really constant without reflection. In the embodiment described, said characteristic impedance Z_ {0} has a value of 50 ohm

For a system of the type shown in the Figure 11, it is known in the art that the proportion of the voltage reflected with respect to the incident voltage at the port you can express with the following equation:

Z = \ frac {A_ {SYS} - Z_ {0}} {Z_ {SYS} + Z_ {0}}

It is also well known in the art that, using a reflection value R determined from the equation above, the associated return loss RL can be determined at from the following equation:

RL = 20 \ log_ {10} \ (| R |)

The performance evaluation procedure which has been analyzed above is typical of a frequency specific. For a given groove shape, it is necessary perform said evaluation independently for each of a series of different frequencies distributed over a range of desired frequencies This will result in a series of different RL return loss values calculated for that specific slot shape at respective different frequencies and such values of the loss of return RL can be presented in chart shape similar to Figures 9 and 10.

In addition, the previous analysis has focused on How to evaluate a proposed slot shape. In order to find one optimally, it is necessary to evaluate in a similar way a series of different slot shapes and compare the results of said assessments to determine which slot shape the optimal performance Several different criteria can be used to perform this evaluation and these criteria can be used in independent way or in combination. Next they will be analyzed some examples of these criteria, but it should be recognized that The present invention is not limited to these criteria specific.

A first criterion involves a determination of the maximum return loss value RL calculated for a form of determined slot. It could be selected as the optimal design the groove shape that has the lowest maximum RL value. Alternatively, all slot shapes could be identified evaluated with a maximum return loss value RL less than a specific value (such as -10 dB) and, subsequently, could be comparatively evaluate the forms of this group using others criteria

A second criterion would be to determine the value maximum, for each slot shape, of the absolute value of the calculated reflection R. The groove design could be selected with said lower maximum value as the optimal design. Alternatively, all slot shapes could be selected. evaluated for which said maximum calculated value is less than a specific value and subsequently could be evaluated comparatively the groove shapes of that group using others criteria

The two criteria that have been analyzed previously they usually focus on a single maximum point of the reflection R or loss of return RL. Other criteria could take more than an average approach to performance in the interval of desired frequencies. For example, a third criterion would be to add the absolute reflection values R calculated to several frequencies for a given slot design, as follows:

\ sum \ limits ^ {\ int_ {max}} _ {\ int = \ int_ {min}} | R _ {\ int} |

A fourth criterion, which is a variation of third criterion, would be to add the squares of the absolute values of reflection R calculated at various frequencies for a form of certain slot, as follows:

\ sum \ limits ^ {\ int_ {max}} _ {\ int = \ int_ {min}} | R _ {\ int} | ^ {2}

Figure 15 is a flow chart that summarizes The optimization technique discussed above. Plus specifically, in block 301, both the design of the balun and the of the final piece are optimized and finalized. Subsequently determine the transfer functions of both balun and the final piece, for each of a plurality of frequencies default distributed over a desired frequency range. As discussed above, each of these functions of transfer can be represented in the form of a matrix [ABCD]

Then, in block 302, select an initial slot form in order to "granar" the routine of optimization In the embodiment described, it is select the initial groove shape to be a curve pure exponential first order, however alternatively it would be possible to use another initial slot form. Then in the block 303, the selected slot shape is modeled as a line  of segmented transmission, in the way it has been analyzed above in relation to Figures 12 and 13. Subsequently, in block 306, the lowest of the frequencies is selected Default interval.

Next, in block 307, it is determined a respective frequency transfer function selected for each of the segments of the line segmented transmission In the embodiment described, each of said transfer functions may be in the form of a matrix [ABCD], as discussed above. These various transfer functions for different segments are combine to obtain a single transfer function for all the segmented transmission line. In the embodiment that described, it is also a matrix [ABCD], as has been analyzed above.

Subsequently, the control passes from block 307 to block 308. For the current slot shape and frequency selected, the transfer functions of the section are used of balun, groove section and end piece section for calculate and save a reflection value and a loss value of return, in a way that has been previously described. Later, in block 311, it is determined whether the frequency selected in that moment is the highest frequency of the interval. If not, in block 312 the next highest of the predetermined frequencies and control returns to block 307 to analyze the performance of the current slot design in said Recently selected frequency.

On the contrary, if in block 311 you determines that the current slot shape has been evaluated for all the predetermined frequencies of the interval, the control goes to block 313, in which all reflection values are used and return loss values of the current slot shape for evaluate the system performance for that form of slot. Subsequently, these evaluations are saved.

Next, in block 316, it is evaluated whether The optimal form has been found. That determination involves the use of performance criteria of the type that has been analyzed previously. In addition, it depends on whether the techniques of Nelder-Mead, which have been analyzed above, have reached a point where several forms of different slot and it seems that the optimal way could be a way that has already been evaluated, rather than in a way that has not yet been evaluated. In general, a series of groove shapes will be evaluated before making a decision in block 326 that has been Identified the optimal slot shape.

When in block 316 it is determined that not yet an optimal groove shape has been located, the control goes to the block 317, in which a form of new and different groove, by varying the widths of the N segments and / or the normal length of the N segments. The blocks 316 and 317 basically represent a specific application of the known Nelder-Mead techniques that have been analyzed above. On the contrary, if at some point it determines in block 316 that a groove shape has been determined optimal, the evaluation procedure is terminated and ends in block 318.

Figure 16 is a schematic front view of an antenna element 412 which is an embodiment alternative of antenna element 12 of Figure 1. Normally, the antenna element 412 of Figure 16 would be used with a radome of the type shown with the number 13 in Figure 1, however in Figure 16 the radome is omitted. The antenna element 412 of the Figure 16 is substantially identical to antenna element 12 of the Figure 1, except for the differences discussed below.

More specifically, both the two layers dielectric as the adhesive film of antenna element 412 is extend out past the ends of the three planes of earth, being able to see one of the dielectric layers with the number 417 and being able to see one of the ground planes with the number 426. Each of the upper and lower side edges of the element antenna 412 has a coating that extends from the left end of the antenna element to the right ends of the ground planes. Said edge coating does not extend all over the right end of the antenna element 412.

Each of the dielectric layers has a wedge opening in them, of which one can be seen with the number 457. It will be noted that the left end of each opening wedge is located to the right of the right ends of the ground planes, which include the ground plane 426. That is, the wedge openings of the dielectric layers are not arranged within the groove line that define the grooves of the planes of Earth. Accordingly, the edges of the groove portions of the antenna element 412 does not have a discontinuity comparable to the shown with the number 42 in Figure 1, because the discontinuity 42 is due to the fact that the wedge opening 57 of Figure 1 is disposed within the groove line.

Although it cannot be easily seen in Figure 16, the edges of the groove parts of the ground planes do not they follow an exponential curve of the first order but they have higher order effects that give them a somewhat corrugated, in a manner similar to that described above in relationship with the embodiment of Figure 1. The procedure that has been used to determine the shape of the edges of groove of the embodiment of Figure 16 is similar to procedure described above for the form of embodiment of Figure 1 and, therefore, is not described again in detail. In addition, the operation of the embodiment of Figure 16 is similar to the operation of the embodiment of Figure 1 and, therefore, is not explained again in detail.

Figure 17 is a schematic view in perspective of an antenna element 512 which is a form of additional alternative embodiment of antenna element 12 of the Figure 1. The antenna element 512 includes a body 514 that is Made of a single metal plate. An entree is provided to through the metal plate and includes a part of balun 536 in shape of a rectangular hole and an elongated groove part 537 which communicates at its narrow end with the balun part 536. In general, the balun part 536 and the groove part 537 have sizes and shapes that are comparable to those that have been analyzed above in relation to the embodiment of the Figure 1. In this sense, the edges of the groove portion 537 do not follow simply an exponential first order curve, but they include higher order effects that give the edges a somewhat shaped wavy The shape of the edges is determined by a procedure similar to the one discussed above in relation to the embodiment of Figure 1 and said procedure is not described again in detail.

An important difference is that the part of Slot 537 contains air instead of a dielectric material. The effects of the groove part having air instead of a material Dielectric have already been analyzed in detail previously. He antenna element 512 includes a 561 coaxial tape line that it has an electrically conductive outer shell that is fixedly attached to the front of the plate 514 by medium of a conductive epoxy adhesive of a known type.

Figure 18 is a schematic sectional view. of the 561 coaxial tape line taken along the line 18-18 of Figure 17. As shown in Figure 18, coaxial tape line 561 includes two layers adjacent dielectric 563 and 564, with a line of conductive tape 567 arranged between them. Throughout most of its length, tape line 567 has a width that is substantially less than the width of the dielectric layers 563 and 564, so that the dielectric layers 563 and 564 make the times of a layer of insulating material that extends coaxially around tape line 567.

A cover 569 of an electrically material conductor extends completely around the layers Dielectric 563 and 564. As mentioned above, in the Figure 17, cover 569 is physically and electrically coupled to the metal plate 514 by means of a conductive epoxy adhesive of a known type, which is not shown separately in the drawings.

Figure 19 is a schematic view from top in partial section of coaxial tape line 561, taken along a plane defined by the upper surface of the tape line 567, and showing an end part of the line of coaxial tape 561 which is located in the end zone narrow of groove portion 537 (Figure 17). In relation to Figures 17 and 19, the conductive cover 569 has a separation annul 572 that extends completely around the line of coaxial tape 561. The separation 572 is aligned with the part of slot 537 and allows the current inside the tape line 567 generate electromagnetic fields that can leave the cover 569 and extend into slot portion 537.

Approximately in the middle of the separation 572, tape line 567 begins to progressively expand to the width, which serves as a transition surface of an approximately rectangular end portion 573 of which three sides electrically engage cover 569. One way with the number 574 extends through the conductive tape line between opposite sides of cover 569 and is coupled electrically to the end portion 573 of the tape line 567. Therefore, in reality, the end of tape line 567 is bridged directly to a ground plane defined by the plate metal 514 (Figure 17), in order to produce an electrical termination of tape line 567.

A technique to manufacture the tape line Coaxial 561 is as follows. Dielectric material 564 is manufactured and subsequently a metal layer is deposited on the part top of it. Subsequently, the metal layer is etched photolithographically, in a known way, in order to extract parts selected from it, such that the remaining parts define tape line 567 with its end portion 573. Subsequently, dielectric layer 563 is formed on the layer dielectric 564 and tape line 567. Next, a cylindrical hole through the dielectric layers and the layer of metal, in a position where track 574 is to be formed. Subsequently, this provision is immersed in a tank of chemical coating, so as to form cover 569 on all outside of it and in order to form track 574 inside of the cylindrical hole. The annular mask prevents the material conductor covers the interior of the separation zone 572. A Once the coating is finished, the mask is removed in order to leave  discovered the separation 572. Subsequently, the assembly resulting is attached to metal plate 514 using an adhesive Conductive epoxy, as discussed above.

The operation of antenna element 512 of Figures 17 to 19 is generally similar to that of the element of antenna 12 of Figure 1. Therefore, it is considered to be unnecessary detailed independent performance analysis of the antenna element 512 and therefore omitted.

The present invention provides a series of technical advantages One of these technical advantages is the result of the absence of dielectric material in the balun hole, of such that the hole contains air. Since the air has a dielectric constant lower than that of the dielectric material, the air has an impedance higher than that of a dielectric material, and the wavelength of a given frequency is greater by the air than in a dielectric material. Therefore, for a determined physical width of the balun hole, the width effective electrical is less for air than for a material dielectric. This in turn means that the electrical width effective is much less than 8/2 for air than for a material dielectric, which reduces unwanted effects. An advantage Additional occurs when the inner edge of the balun hole is a driver, for example due to the fact of providing a coating, because it helps increase the bandwidth of the balun hole containing the electric fields of the hole. In the case of an antenna element with layers of a material dielectric, the leading edge of the hole prevents the fields electrical extend into the dielectric material around the orifice.

Another advantage occurs when the hole Balun has a generally rectangular shape, because it helps create a sharp discontinuity of impedance between the orifice of balun and the associated end of the groove line. With a abrupt discontinuity of impedance, the electric fields of the narrow end area of the groove see the balun hole as, approximately, an open circuit through an interval of desired frequencies, which gives the balun hole a width of relatively broad band. A related advantage occurs when the rectangular balun hole has no material dielectric and the edge of the balun hole is conductive, because the bandwidth of the balun hole increases even more. The hole The resulting balun is actually a conductive hole Tuned.

Another advantage results from the fact provide more than two ground planes and the completion of the tape line directly on one of said ground planes, because it facilitates a relatively broad bandwidth for the balun hole When the balun hole is approximately rectangular, does not contain dielectric material, has edges conductors, is associated with two or more ground planes and is associated with a tape line termination on a ground plane, the bandwidth independent of the balun hole can be, approximately 8: 1.

Another advantage, which implies a greater width of band, occurs when a balun hole of this type is used with a slot that has a shape that has been optimized using techniques according to the invention. At low frequencies, the hole of Balun is inductive and the slot is capacitive. However, when the optimization technique is used to achieve a match conjugated balun hole and groove, both cooperate to provide good performance even at low frequencies, of a somewhat analogous to the resonance of an RLC circuit Tuned. In particular, they can provide a bandwidth decimal (10: 1) capable of a scanning volume of plane E of ± 60 ° and the plane H of ± 50 °.

Provide three or more ground planes too can provide another advantage, helping to minimize reactances in the tape line to the transition surface of the groove line. In addition, provide three or more planes of earth increases the amount of conductive material present along of the groove edges, thereby increasing the capacitance, which in turn allows the narrow end of the groove to be more large. When the narrow end of the groove is wider, it is easier to manufacture the groove while still getting a low impedance of approximately 50 ohms for the end narrow groove. This is because the tolerances of the Engravings are basically fixed and the Engraving of the narrow end of the groove.

Another advantage occurs when the line of tape ends directly on one of the ground planes, because this, in reality, provides a real physical short circuit to a ground plane, compared to the pre-existing techniques that basically they try to emulate or approach a physical short circuit creating a standing wave resonance. The elements of antenna that have been described provide a line of tape for the transition surface of the groove line with a ratio of transformation that approaches the unit and with reactances of minimum dispersion

Claims (34)

1. An antenna element (12) that has a dielectric layer (18), an electrically conductive layer (28) and a elongated conductive element (67), in which the dielectric layer (18) has a hole (49) through it, the layer electrically conductive (28) is disposed adjacent to a surface of said dielectric layer (18), said conductive layer (28) having a Incoming recorded therein that includes a balun part (46) and a conical groove part (37), said groove part (47) having a narrow end that communicates with said balun part (46) and said balun part (46) being aligned with said hole (49) through said dielectric layer (18) and the element being elongated conductor (67) directly connected to said layer conductive (28) and in the same plane as the same, extending said conductive layer (28), generally, transversely with respect to said slot part (47) in the area of said end strait thereof, in which said hole (49) through said dielectric layer (18) has substantially the same size and such that said balun part (46) of said recess of said layer conductive (28), the element including a conductive layer additional (27) that has an additional entrant in it, said additional entrant including an additional balun part (43) and including an additional slot portion (44) that is communicates, at one end, with said additional balun part (43), said slot portions (44, 47) of said size recess being and similarly and being substantially aligned with each other and said additional balun portion (43) having substantially the same shape and size as said hole (49) through said layer dielectric (18) and being aligned with it. 2. An antenna element (12) according to the claim 1, which includes a conductive strip (51) which is extends along an edge of said hole (49) of said dielectric layer (18), except in the area of said groove parts (44, 47), and that is in electrical contact with each of said conductive layers (27, 28). 3. An antenna element (12) according to the claim 1, which includes two additional conductive layers (26,  27) said conductive layers (26, 27) being substantially in parallel to each other, which includes an additional dielectric layer (17) said dielectric layers (17, 18) being substantially in parallel to each other and to said conductive layers (26, 27, 28) and each of said dielectric layers being arranged (17, 18) between a respective pair of said conductive layers (26/28, 27/28), wherein said additional dielectric layer (17) has through the same a hole (49), said holes (49) being through said dielectric layers (17,18) of substantially the same size and form and being aligned with each other and in which each of said additional conductive layers (26, 27) have an entrant therein additional, including each of said additional entrant a additional balun part (36, 43) and including a groove part additional (37, 44) that communicates, at one end, with said part of additional balun (36, 43) thereof, said parts being groove (37, 43, 47) of each of said conductive layers (26, 27, 28) of similar size and shape and being substantially aligned each other, and said balun parts being (36, 43, 46) of each of said conductive layers (26, 27, 28) of similar size and shape and being aligned with each other and with said holes (49) through said dielectric layers (17, 18). 4. An antenna element (12) according to claim 3 which includes a conductive strip (51) which is extends along the edges of said holes (49) of said dielectric layers (17, 18), except in the area of said parts of groove (37, 44, 47) of said conductive layers (26, 27, 28), and that is in electrical contact with each of said conductive layers (26, 27, 28). 5. An antenna element (12) according to claim 1, wherein said slot portion (47) has edges on opposite sides of it that each follows a predetermined curve other than a first exponential curve order. 6. An antenna element (12) according to claim 5, wherein said predetermined curve of each one of said edges is configured to facilitate reduction at minimum return loss of electromagnetic signals induced within said slot portion (47) through said elongated conductive element (67). 7. An antenna element (12) according to claim 1, wherein said balun part (46) has a form that facilitates an important and abrupt discontinuity of impedance between said slot part (47) and said balun part (46), including said form of said part of balun (46) said part of balun (46) that has an approximately straight side, said one end of said slot part (47) communicating with said balun part (46) in a position between the ends of said straight side of said balun part (46). 8. An antenna element (12) according to claim 7, wherein said debalun part (46) has a shape that is approximately rectangular. 9. An antenna element (12) according to claim 8, wherein said balun part (46) has, in a first direction generally parallel to said an end of said slot part (47), a dimension that is approximately a quarter of a selected wavelength and has, in a second direction substantially perpendicular to said first direction, a second dimension that is at least a quarter of said wavelength selected and that is less than one half of said selected wavelength 10. An antenna element (12) according to the claim 7, wherein said slot portion (47) has edges on opposite sides of it that each follows a curve default other than an exponential curve of first order. 11. An antenna element according to the claim 10, wherein said predetermined curve for each one of said edges is configured to facilitate reduction at minimum return loss of electromagnetic signals induced within said slot portion (47) through said elongated conductive element (67). An antenna element (12) according to claim 1, wherein the dielectric layer (18) is a first dielectric layer (18) of a pair of a first and a second dielectric layer (17, 18) extending approximately parallel to each other, in which the conductive layer (28) is a first conductive layer (28) of a set of a first, a second and a third conductive layer (28, 27, 26) that extend, approximately, in parallel with each other and said first and second dielectric layers (17, 18), said first dielectric layer (18) being located between said first and second conductive layers (28, 27) and said second dielectric layer (17) being located between said first and third dielectric layers (28, 26), each of said first, second and third conductive layers (28, 27, 26) having an inlet therein that includes a balun part (36, 43, 46) and a slot part (37, 44, 47) that communicates, at one end, with the balu part n (36, 43, 46) thereof, said groove portions (37, 44, 47) being each of said first, second and third conductive layers (28, 27, 26) of similar size and shape and being substantially aligned with each other and said balun portions (36, 43, 46) of each of said first, second and third conductive layers (28, 27, 26) of similar size and shape and being aligned with each other, a plurality of conductive tracks (76, 77, 78) extending through openings of said first and second dielectric layers
tricas (17, 18) for electrically coupling said first, second and third conductive layers (28, 27, 26) to each other. 13. An antenna element (12) according to the claim 12, wherein said elongated conductive element (67) is disposed between said first and second dielectric layers (17, 18) and has an end portion that extends through said groove portion (47) of said first conductive layer (28) and is electrically connected directly to said first layer conductor (28) of said one end of said slot portion (47) of the same. 14. An antenna element (12) according to the claim 13, wherein said first conductive layer (28) it has an additional elongated entree in it that communicates, in one end, with said slot part (47) and in which said elongated conductive element (67) extends through said Additional incoming 15. An antenna element (12) according to the claim 5, wherein said predetermined curve for each one of these edges is configured according to characteristics of said balun part (46) and of said groove part (47) for facilitate the minimization of signal return loss electromagnetic induced within said slot part (47) by means of said conductive element (67). 16. An antenna element (12) according to the claim 5, which includes an additional structure arranged adjacent to one end of said slot portion (47) separated from said one end thereof and in which said predetermined curve is configured based on characteristics of said part of balun (46), of said slot part (47) and of said structure additional to facilitate the minimization of loss of return of electromagnetic signals induced within said part of groove (47) by means of said elongated conductive elements (67). 17. An antenna element (12) according to the claim 5, wherein said predetermined curve includes a first and second exponential characteristics that entail respective different exponential powers. 18. An antenna element (12) according to the claim 5, wherein said predetermined curve includes a plurality of exponential characteristics that entail respective different exponential powers. 19. An antenna element (12) according to the claim 5, wherein said conductive layer (28) includes two electrically conductive layers (28, 27) arranged on sides opposite of said dielectric layer (18), said layers having conductive (28, 27) respective incoming in them that are aligned with each other and that each includes a balun hole (49) which is part of said balun part (46, 43) and a groove that is part of said slot part (47, 44) and wherein said layers conductive (28, 27) include a plurality of tracks (76, 77, 78) that each extends between said conductive layers (28, 27) to through said dielectric layer (18), said dispositions being arranged tracks (76, 77, 78) near each edge of each of said parts slot (47, 44) in separate positions along the same. 20. An antenna element (12) of the claim 1, wherein said slot portion (47) has a width that is narrower in a first section of said part of slot (47) located near said one end thereof, having said slot part (47) a second and a third sections that they are arranged on opposite sides of said first section and that each one has a width greater than the width of said first section. 21. An antenna element (12) according to the claim 1, further comprising: a refractive layer (91) which extends approximately perpendicular to a line center of said slot part (47) in a past position said additional end of said slot part (47), said layer being of refraction (91) made of a material that is transmissive to the refraction of electromagnetic signals of a range of selected frequencies that move in one of two directions opposite along said groove portion (47) and producing said refraction. 22. An antenna element (12) according to the claim 1, which includes an additional layer (93) which is extends approximately perpendicular to said center line of said slot portion (47) and that is disposed adjacent to said refractive layer (91) on one side thereof separated from said slot portion (47), said additional layer (93) being made of a material that is transmissive to the refraction of the signals electromagnetic of said selected frequency range that are moving in one of these two directions opposite to along said slot part (47) and that produces said refraction. 23. An antenna element (12) according to the claim 2, wherein said refractive and additional layers (91, 93) are respective parts of a radome (13). 24. An antenna element (12) according to claim 1, wherein said refractive layers and additional (91, 93) have dielectric constants that are different. 25. A method, comprising the steps of: creating a hole (49) through a dielectric layer (18), manufacturing an electrically conductive layer (28) adjacent to a surface of said dielectric layer (18), said layer having conductive (28) an inlet engraved therein that includes a balun part (46) and a conical groove part (47), said groove part (47) having a narrow end communicating with said balun part (46 ) and said balun part (46) being aligned with said hole (49) through said dielectric layer (18) and forming an elongated conductive element (67) in direct contact with said conductive layer (28) and in the same plane that the same, said elongated conductive element (67) extending, generally, transversely with respect to said slot part (47) in the area of said narrow end, in which said creation stage is carried out such that said hole (49) through said dielectric layer (18) t it has substantially the same size and shape as said balun part (46) of said recess of said conductive layer (28), including the step of manufacturing an additional conductive layer (27) having an additional recess therein, including said recess additionally an additional balun part (43) and including an additional slot part (44) which communicates, at one end, with said additional balun part (43), said slot parts (44, 47) being of said recess of similar size and shape and being substantially aligned with each other and having said additional balun part (43) substantially the same size and shape as said hole (49) through said dielectric layer (18) and being aligned with the
same. 26. A procedure according to claim 25, which includes the step of manufacturing a strip conductor (51) extending along an edge of said orifice (49) of said dielectric layer (18), except in the area of said groove parts (44, 47), and which is in electrical contact with each of said conductive layers (28, 27). 27. A procedure according to claim 25, wherein said balun part (46) is formed with a form that facilitates a large and abrupt discontinuity of impedance between said slot part (47) and said balun part (46), including said form of said part of balun (46) said part of balun (46) that has an approximately straight side, said one end of said slot part (47) communicating with said balun part (46) in a position between the ends of said straight side of said balun part (46). 28. A procedure according to claim 27, wherein the creation step is carried out of  such a way that said balun part (46) has a shape that is, approximately rectangular. 29. A procedure according to claim 28, wherein said creation step is carried out  such that said balun part (46) has, in a first direction generally parallel to said one end of said part slot (47), a dimension that is approximately a quarter of a selected wavelength and has, in a second direction substantially perpendicular to said first direction, a second dimension that is at least a quarter of said length of selected wave and that is less than a medium of said length of selected wave 30. A procedure according to claim 25, further comprising: providing the layer dielectric (18) as a first and second dielectric layers (18, 17) that extend approximately parallel to each other, manufacture the conductive layer (28) as a first, a second and a third conductive layers (28, 27, 26) that extend, approximately, in parallel with each other and to said first and second dielectric layers (18, 17), said first layer being located dielectric (18) between said first and second conductive layers (28, 27) and said second dielectric layer (17) being located between said first and third dielectric layers, form in each of said first, second and third conductive layers (28, 27, 26) a respective inlet that includes a balun part (46, 43, 36) and a slot part (47, 44, 37) that communicates, at one end, with the balun part (46, 43, 36) thereof, said parts being slot (47, 44, 37) of each of said first, second and third conductive layers (28, 27, 26) of similar size and shape and being substantially aligned with each other and said parts being of balun (46, 43, 36) of each of said first, second and third conductive layers (28, 27, 26) of similar size and shape and being aligned with each other, form a plurality of pathways conductors (76, 77, 78) that extend through openings of said first and second dielectric layers (18, 17) for coupling electrically with each other said first, second and third layers conductive (28, 27, 26). 31. A procedure according to claim 30, wherein said manufacturing step is carried to carried out in such a way that said elongated conductive element (67) is disposes between said first and second dielectric layers (18, 17) and has an end part that extends through said part slot (47) of said first conductive layer (28) and is connected electrically directly to said first conductive layer (28) of said one end of said slot part (47) thereof. 32. A procedure according to claim 25, wherein said slot portion (47) is formed with  a width that is narrower in a first section of said slot part (47) located near said one end thereof, said slot part (47) having a second and a third sections that are arranged on opposite sides of said first section and that each has a width greater than the width of said first section. 33. A procedure according to claim 25, further comprising: forming a layer of refraction (91) that extends approximately perpendicularly to a center line of said slot part (47) in a position said additional end of said slot part (47) passed, said refractive layer (91) being made of a material that is transmissive to the refraction of electromagnetic signals from a selected frequency range that travel in one of two opposite directions along said slot part (47) and that produce such refraction. 34. A procedure according to claim 33, which includes the step of forming an additional layer  (93) which extends approximately perpendicular to said center line of said slot part (47) and which is arranged adjacent to said refractive layer (91) on one side thereof separated from said slot portion (47), said layer being additional (93) made of a material that is transmissive to the refraction of the electromagnetic signals of said range of selected frequencies that are moving in one of said two opposite directions along said slot part (47) and that produces such refraction.