Modular narrowband dipole antenna

Abstract

A narrowband dipole antenna module comprising: a housing including a base having an internally defined opening and a hollow support column extending from the opening [A1] and having a plurality of antenna openings defined within the hollow support column; a circuit assembly configured to be inserted into the housing, the circuit assembly comprising: an input printed circuit board having a transmit connector and a receive connector on the input printed circuit board; a matching printed circuit board having a lumped element matching component and a plurality of terminal blocks on the matching printed circuit board; a pair of coaxial feed lines connected between the input printed circuit board and the matching printed circuit board, each having a coil formed inside such that the feed line functions as a balun; and at least one rigid support member connected between the input printed circuit board and the matching printed circuit board such that the terminal block is adjacent to the antenna opening when the circuit assembly is inserted into the housing; and a plurality of antenna elements configured to be connected to the terminal block.

Description

Technical Field

[0001] The present disclosure relates to a narrowband dipole antenna.

Background Art

[0002] The pendant crossed dipole is a well-understood antenna structure. However, this approach is costly, complex, difficult to tune, prone to overheating at high power, and may cause environmental problems.

[0003] The inventors have determined the need for an improved antenna design that addresses these cost, power, tuning, and environmental realities through several new means without sacrificing performance.

Summary of the Invention

[0004] One aspect of the present disclosure provides a narrowband dipole antenna module, which includes a housing comprising a base having an internally defined opening, and a hollow support extending from the opening in the base, the hollow support having a plurality of antenna openings defined within the hollow support near the distal end of the hollow support, and a circuit assembly configured to be inserted into the housing, the circuit assembly comprising an input printed circuit board having a transmit connector and a receive connector for connecting to an antenna drive circuit on the input printed circuit board, a matching printed circuit board having a lumped element matching component and a plurality of terminal blocks, each terminal block configured to receive an antenna element, The circuit assembly includes a pair of coaxial feed lines connected between an input printed circuit board and a matching printed circuit board, each of which has a coil formed inside so that the pair of coaxial feed lines function as a balloon; and at least one rigid support member connected between the input printed circuit board and the matching printed circuit board for holding the matching printed circuit board at a fixed distance from the input printed circuit board such that when the input printed circuit board is mounted on the lower surface of a base plate, the terminal block on the matching printed circuit board is adjacent to the antenna opening in a hollow support; and a plurality of antenna elements configured to be received through the antenna opening and connected to the terminal block. In some embodiments, one of the pair of coaxial feed lines has a clockwise coil formed inside, and the other of the pair of coaxial feed lines has a counterclockwise coil formed inside.In some embodiments, the matching printed circuit board has a first surface facing the input printed circuit and a second surface opposite to the first surface, the second surface having a terminal block mounted on the second surface, and includes a pair of power line landing pads for connecting to a pair of coaxial power lines, each power line landing pad including an annular ring on the first surface of the matching printed circuit board for connecting to the outer conductor of one of the power lines, and plated through-holes extending from inside the annular ring on the first surface to the second surface of the matching printed circuit board for connecting to the inner conductor of the power line. In some embodiments, the narrowband dipole antenna module further comprises isolator elements for each of a plurality of antenna apertures, the isolator element having a projection extending from a first side of the isolator element configured to engage with one of the antenna apertures, and a recess on a second side of the isolator element for receiving one of the antenna elements, the recess having an aperture extending from the first side of the isolator element within the recess to allow the antenna element to directly engage with the terminal block. In some embodiments, the narrowband dipole antenna module further comprises a first sealing ring between the first side of each isolator element and the housing for forming a seal between the isolator element and the housing, and a second sealing ring between the second side of each isolator element and the antenna element for forming a seal between the isolator element and the antenna element. In some embodiments, the terminal block is configured to hold the antenna element at a 45-degree angle from the longitudinal axis of the hollow support. In some embodiments, multiple antenna apertures include four antenna apertures, multiple terminal blocks include four terminal blocks, and multiple antenna elements include four antenna elements.

[0005] Another aspect of the present disclosure provides a method for assembling a narrowband dipole antenna, the method comprising assembling a circuit assembly, the circuit assembly comprising: an input printed circuit board having a transmit connector and a receive connector for connecting to an antenna drive circuit on the input printed circuit board; a matching printed circuit board having a lumped element matching component and a plurality of terminal blocks, each terminal block configured to receive an antenna element; and a pair of coaxial feed lines connected between the input printed circuit board and the matching printed circuit board, each of the pair of coaxial feed lines having an internal structure such that the pair of coaxial feed lines function as a balun. The circuit assembly includes a pair of coaxial feed lines having coils, and at least one rigid support member connected between the input printed circuit board and the matching printed circuit board for holding the matching printed circuit board at a fixed distance from the input printed circuit board, and inserting the circuit assembly into a housing, wherein the housing includes a base having an internally defined opening, and a hollow support column extending from the opening in the base, the hollow support column having a plurality of antenna openings defined within the hollow support column near the distal end of the hollow support column, so that when the input printed circuit board is mounted on the underside of the base plate, terminal blocks on the matching printed circuit board are adjacent to the antenna openings in the hollow support column, and inserting the circuit assembly into a housing, wherein a plurality of antenna elements are connected to the plurality of terminal blocks.

[0006] Further aspects of this disclosure and details of exemplary embodiments are described below. [Brief explanation of the drawing]

[0007] The following figures illustrate embodiments, where similar reference figures refer to similar parts. The embodiments shown in the accompanying figures are illustrative and not limiting.

[0008] [Figure 1] An exemplary narrowband cross-dipole antenna module according to one embodiment of the present disclosure is shown. [Figure 1A] Figure 1 shows an exemplary narrowband cross-dipole antenna module from a different angle. [Figure 2] Figure 1 shows a partially disassembled assembly diagram of the circuit assembly of the narrowband dipole antenna module. [Figure 3] Figure 1 shows the housing and circuit assembly of a narrowband dipole antenna module, with the circuit assembly positioned to be inserted into the housing. [Figure 4] Figure 1 shows a partially disassembled assembly diagram of the narrowband dipole antenna module. [Figure 5] Figure 1 shows an exemplary matching circuit board for a narrowband dipole antenna module. [Figure 5A] Figure 5 shows a top view of an exemplary matching circuit board. [Figure 5B] Figure 5 shows a bottom view of an exemplary matching circuit board. [Figure 5C] Figure 5 shows a magnified view of a portion of an exemplary matching circuit board. [Modes for carrying out the invention]

[0009] In general, this disclosure discloses a narrowband dipole antenna having a mechanically robust modular structure that is easy to assemble and less expensive than typical existing antenna designs. The exemplary embodiment shown in the figure is configured as a cross-narrowband dipole antenna having four hanging antenna elements, but other embodiments may have different numbers and configurations of antenna elements. Some embodiments of this disclosure provide antenna modules particularly suitable for use with 1D or 2D phased array radar systems operating in the UHF band, but the antenna modules of this disclosure can also be used with other types of radar systems and frequency bands.

[0010] Herein, this disclosure will be described more fully with reference to the drawings illustrating various exemplary embodiments of the disclosure. This disclosure can be embodied in many different forms and should not be construed as necessarily limited to the exemplary embodiments disclosed herein. Rather, the exemplary embodiments are provided so as to ensure that this disclosure is thorough and complete, and so as to fully convey the various concepts of the disclosure to those skilled in the art.

[0011] To simplify and clarify the diagrams, reference figures may be repeated between figures to indicate corresponding or similar elements. A great deal of detail is provided to help understand the examples described herein. The examples can be practiced without these details. In other examples, well-known methods, procedures, and components are not described in detail to avoid obscuring the examples described.

[0012] Various terms used herein may mean direct or indirect, full or partial, temporary or permanent acts or omissions. For example, when an element is said to be “in,” “connected to,” or “combined with” another element, that element may be directly present in the other element, connected to it, or there may be intermediate elements involving indirect or direct transformations. Conversely, when an element is said to be “directly connected” or “directly combined” with another element, there are no intermediate elements.

[0013] The various postoperative procedures used herein are for illustrative purposes only and are not intended to necessarily limit the disclosure. As used herein, the various singular forms “a,” “an,” and “the” are also intended to include the various complex forms unless otherwise expressly indicated in a particular context. As used herein, the various terms “comprises,” “includes,” “comprising,” or “including” specify the presence of a declared feature, component, step, operation, element, or component, but do not exclude the presence or addition of one or more other features, components, steps, operations, elements, components, or groups thereof.

[0014] As used herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or as is evident from the context, “X adopts A or B” is intended to mean any of a set of natural inclusive substitutions. In other words, if X adopts A, then X adopts B, or if X adopts both A and B, then “X adopts A or B” is true in either of the above cases.

[0015] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as those generally understood by those skilled in the art to which this disclosure belongs. Various terms, such as those defined in general dictionaries, should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an ideal and / or overly formal sense unless expressly defined herein.

[0016] Furthermore, relative terms such as “downward,” “below,” “upward,” and “top” may be used herein to describe the relationship of one element to another, as shown in the accompanying set of illustrative drawings. Such relative terms are intended to encompass different directions of the technology shown, in addition to the directions shown in the accompanying set of illustrative drawings. For example, when a device in the accompanying set of illustrative drawings is turned over, various elements described as being on the “below” side of other elements will be oriented on the “upward” side of other elements. Similarly, when one device in the illustrative drawings is turned over, various elements described as being “below” or “below” other elements will be oriented on the “upward” side of other elements. Thus, the various illustrative terms “downward” and “below” can encompass both upward and downward directions.

[0017] As used herein, the terms “about” or “substantially” refer to a variation of ±10% from the nominal value / term. Such variation is always included in any given value / term provided herein, regardless of whether such variation specifically refers to any given value / term.

[0018] Terms such as "first," "second," etc., may be used herein to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not necessarily be limited by such terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Accordingly, the first element, component, region, layer, or section considered below may be referred to as the second element, component, region, layer, or section without departing from the various teachings of this disclosure.

[0019] The features described with respect to specific exemplary embodiments can be present in and / or combined with various other exemplary embodiments, and can be sub-combined. Also, different aspects and / or elements of the exemplary embodiments can be further combined and sub-combined in a similar manner as disclosed herein. Furthermore, some exemplary embodiments can be components of a larger system, individually and / or collectively, and other procedures can take precedence over their use and / or otherwise modify their use. Additionally, many steps can be required before, after, and / or concurrently with the exemplary embodiments as disclosed herein. Note that at least as disclosed herein, any and / or all methods and / or processes can be at least partially implemented via at least one entity in any manner.

[0020] Exemplary embodiments of the present disclosure are described herein with reference to the explanatory diagrams of the idealized embodiments (and intermediate structures) of the present disclosure. Thus, for example, variations from the various illustrated shapes as a result of manufacturing techniques and / or tolerances can be expected. Therefore, the various exemplary embodiments of the present disclosure should not be construed as necessarily limited to the various specific shapes of the regions illustrated herein, but can include, for example, deviations in shape resulting from manufacturing.

[0021] As disclosed herein, any and / or all elements can be formed from the same structurally continuous parts, such as being single units, and / or can be manufactured and / or connected separately, such as assemblies and / or modules. As disclosed herein, any and / or all elements can be manufactured via any manufacturing process, regardless of additive manufacturing, subtractive manufacturing, and / or any other type of manufacturing. For example, some manufacturing processes include three-dimensional (3D) printing, laser cutting, computer numerical control routing, milling, pressing, stamping, vacuum forming, hydroforming, injection molding, lithography, and the like.

[0022] Figures 1 and 1A illustrate an exemplary antenna module 100 according to an embodiment of the present disclosure. This antenna module 100 is designed to generate circular polarization using drooping elements to reduce scan loss and be used within a phased array system, following a conventional crossed dipole structure. The antenna module includes a housing 102 having a base 104 for attachment on a support structure, such as a support structure of a transceiver module, and a hollow strut 106 extending from the base 104. Four antenna elements 150 extend downward at an angle of 45 degrees from an opening 108 at a distal end of the hollow strut 106. A circuit assembly 110 is received within the hollow strut 106 and provides a connection between the antenna elements 150 and an antenna drive circuit, such as a 50-ohm radar phased array radar system.

[0023] The crossed dipole structures of Figures 1 and 1A can use non-orthogonal structures or single dipole structures. However, the crossed dipole structure can be used with orthogonal feeding to generate circularly polarized radiation from the antenna. Thus, unless otherwise specified, references to dipole antenna structures include both crossed dipole structures and single dipole structures.

[0024] As shown in Figures 2 and 3, the circuit assembly 110 includes an input printed circuit board 112 and a matching printed circuit board 130, which is held by a rigid support member 120 at a fixed distance from the input printed circuit board 112 and electrically connected by a pair of coaxial power supply lines 122 and 124. In the illustrated example, the circuit assembly 110 is configured to be inserted into a hollow support column 106 which may have a square cross-section, so that the matching printed circuit board 130 is generally square, and the rigid support member 120 includes a pair of rods connected to opposite corners of the matching printed circuit board 130, but other embodiments may have different configurations of the matching printed circuit board 130 and the rigid support member 120.

[0025] The input printed circuit board 112 includes a transmit connector 114, a receive connector 116, a hybrid coupler 118, and a feed trace with a 1 M ohm resistor for dissipating static electricity. The coaxial feed lines 122 and 124 each have a first end connected to the input printed circuit board 112 and a second end connected to the matching printed circuit board 130. The coaxial feed lines 122 and 124 include coil portions 126 and 128 formed within the coaxial feed lines near the second ends, so that the coaxial feed lines 122 and 124 can function as inductive baluns, preventing current imbalance between dipole branches and ensuring a symmetrical radiating antenna pattern. The hybrid coupler 118 may be capable of feeding both dipoles in a perpendicular phase difference state. In some embodiments, the coaxial feed lines 122 and 124 each have coils wound 10 times to form coil portions 126 and 128. In some embodiments, one of the coil portions 126 and 128 is formed as a clockwise coil, and the other of the coil portions 126 and 128 is formed as a counterclockwise coil to prevent coupling.

[0026] The second ends of the coaxial feed lines 122 and 124 are connected to landing pads 132 and 134 on the matching printed circuit board 130. In some embodiments, as illustrated by the exemplary embodiments shown in Figures 5, 5A, 5B, and 5C, the landing pads 132 and 134 each include annular rings 132A / 134A on the underside of the matching printed circuit board 130 for connection to the outer conductors of the feed lines 122 / 124, and plated through-holes 132B / 134B extending upward on the matching printed circuit board 130 for connection to the inner conductors of the feed lines 122 / 124. The drooping of the antenna element 150 and the careful selection of the height of the antenna element 150 above the ground plane, facilitated by the modular design of the antenna assembly according to this disclosure, tend to lower the feed point impedance.

[0027] The embodiment may be configured to adjust the size or shape of various elements, including an antenna element 150, a hollow support 106, and other components of different sizes and shapes that enable tuning of a modular narrowband dipole antenna for a specific application or required frequency. Adjustment may be achieved by having interchangeable components of different sizes. The embodiment may also allow for various element sizes or lengths that are adjustable, for example, by sliding or other means for adjusting length or height. These different-sized components may be in a set that can be conveniently swapped in the field when the application changes or when experiments use antenna configurations of different heights, widths, and lengths, enabling real-time tuning of the system.

[0028] Antenna modules according to some embodiments of the present disclosure are configured such that the feed point impedance is close to 50 ohms, and the remaining matching can be achieved on a matching printed circuit board 130 using a single capacitor and separate inductors for each dipole element. Since the differential feed point impedance of each dipole is nominally 50 ohms, this makes it possible for the circuit assembly according to the present disclosure to feed each dipole using a 50-ohm transmission line. Converting a single-ended 50-ohm input to a balanced antenna drive circuit can be achieved using a balun. Since everything in this exemplary embodiment is 50 ohms, a 50-ohm coaxial cable can be used for the feed lines 122 / 124 that form the balun. The balun distributes and separates the current that flows into and out of the dipole elements. The current flowing through the coaxial shield excites one element, while the current on the central conductor excites the other half of the dipole. The balun ensures that the current in the inner and outer conductors of the coaxial feed line is balunned so that the dipole radiates in the desired pattern. The isolation function is achieved by establishing impedance outside the coaxial shield. Coiling the coaxial feed line near the dipole feed point exemplifies the inductance needed to prevent current flow along the outside of the coaxial shield. In some embodiments, the resulting inductive reactance is at least 10 times the characteristic impedance of the feed, or about 500 ohms, in an exemplary 50-ohm system. Providing a pair of coiled coaxial cables for horizontal (H) and vertical (V) feeds can achieve improved cost and power operation compared to more complex balun structures such as balanced-unbalanced transformers or parallel-line baluns. Coiled cables are inexpensive to manufacture and, due to their inherently low losses, can handle up to 1000 watts while simultaneously functioning as high-impedance chokes for shielding current.In many applications, the coiled power supply cable balun structure according to this disclosure exhibits significant overheating up to the maximum Curie point, as observed at 1000W using ferrite; therefore, it is preferable to simply place a ferrite choke on a linear power supply cable. In some embodiments, efficiency is optimized by using a PTFE coaxial balun structure and only one matching component per element.

[0029] The matching printed circuit board 130 may include a lumped element matching component connected between terminal blocks 140 to match the impedance of the antenna element 150 to the impedance of the antenna drive circuit. For example, in an exemplary embodiment having a 50-ohm antenna drive circuit, the lumped element matching component can be adjusted to bring the impedance at the feed point of the antenna element 150 as close to 50 ohms as possible. In embodiments configured for use in a 50-ohm system, the matching network can reduce reflected power and improve efficiency. The aforementioned matching network is problematic at high power levels due to potentially large inefficiencies, and quarter-wavelength conversion is extremely large at UHF. In the antenna according to this disclosure, a low-ESR PCB-based differential matching network, a high-power lumped component on the matching printed circuit board 130, directly feeds the antenna element 150 through the terminal blocks 140. This allows both dipoles to be fed simultaneously using their own matching networks, enabling a modular design that tunes directly at the element feed point. This same PCB-based design can be employed at any frequency by re-selecting the lumped element component.

[0030] Further details of the structure and steps in an exemplary method of assembly are illustrated in Figures 3 and 4. Once the circuit assembly 110 is assembled, it is inserted into the housing 102. In the illustrated example, the housing 102 includes a hollow support column 106 formed from a square tube stock with a welded base 104. As shown in Figure 3, a spacer element 105 may be positioned on studs extending from the base 104, and the input printed circuit board 112 is mounted on studs extending from the base 104. Once the circuit assembly 110 is secured in the housing 102, the terminal block 140 will be exposed within the hollow support column 106 through openings 108. As shown in Figure 4, in some embodiments, isolator elements 152 (which may be made of, for example, Delrin / polyoxymethylene or other suitable material) are positioned within each opening 108 before the antenna elements 150 are screwed into the exposed terminal block 140. In some embodiments, each isolator 152 has a projection 153 extending from a first side of each isolator configured to engage with one of the antenna apertures, and a recess 151 on a second side of each isolator for receiving one of the antenna elements 150, the aperture at the base of the recess 151 extending to the first side of the isolator element to allow a screw-in connector extending from the antenna element 150 to directly engage with the terminal block 140. In some embodiments, a first sealing ring 154 is located between the first side of each isolator element 152 and the housing, and a second sealing ring 156 is located between the second side of each isolator element 152 and the antenna element 150, so that the isolators and O-rings form an environmental seal protecting the circuit assembly 110. The completed antenna module 100 can then be mounted on a transceiver module having similarly sealed interface surfaces protected from environmental hazards.

[0031] Antenna modules constructed by specific embodiments of this disclosure offer improvements in addressing environmental issues, tuning, and productivity. In exemplary embodiments, electronic components, including a hybrid input PCB, a coiled balun feed line, and a differential matching PCB, can be pre-assembled within an electronic submodule. This submodule is then inserted into a welded and anodized antenna strut. Finally, the antenna elements are screwed into a terminal block on a matching PCB having dedicated insulators and lubricated O-rings to ensure a securely fixed environmental seal. The base of the antenna is bolted into a transceiver module having similarly environmentally sealed interfaces. The resulting antenna is mechanically robust and easy to assemble. In addition, in antenna modules constructed by this disclosure, tuning the antenna element length is very simple, as it involves only removing an existing antenna element 150 and replacing it with a new antenna element, or replacing one or more other components, such as the housing 102 or a portion thereof. For example, the housing 102 may consist of separate components such as a hollow support 106, an opening 108, and a base 104 having different sizes, shapes, or materials. The interchangeable nature of certain embodiments allows for the efficient generation of narrowband antennas and on-site tuning, resulting in better, more efficient antenna performance and cost savings. Embodiments may also allow the hollow support 106 to adjust its height and change the beam shape, for example, by using a bracket (not shown). This embodiment may be optimized for frequency range, center frequency, input impedance, beam shape, and efficiency in the interaction between a 1D phased array antenna and a 2D phased array antenna. Embodiments may also use hybrid inputs for orthogonal signals.

[0032] It will be understood that a great many specific details are included to provide a complete understanding of the typical embodiments described herein. However, it will be understood by those skilled in the art that the embodiments described herein can be practiced without these specific details. For example, different low-cost balloon designs can be made by forming a choke using high-power coupled inductors on a PCB. Other embodiments may also use non-coaxial two-wire cables, such as twisted pair. In other cases, well-known methods, procedures, and components have not been described in detail so as not to obscure the embodiments described herein. Furthermore, this specification should not be considered to limit the scope of the embodiments described herein in any way, but rather to simply describe embodiments of the various exemplary embodiments described herein.

[0033] This specification provides numerous exemplary embodiments of the subject matter of the present invention. Although each embodiment represents a single combination of the elements of the invention, the subject matter of the present invention is considered to encompass all possible combinations of the disclosed elements. Thus, if one embodiment includes elements A, B, and C, and a second embodiment includes elements B and D, the subject matter of the present invention is also considered to encompass other remaining combinations of A, B, C, or D, even if not expressly disclosed.

[0034] In light of the foregoing disclosure, many changes and modifications are possible to the exemplary embodiments described herein, as will be obvious to those skilled in the art. While many typical aspects and embodiments have been considered above, those skilled in the art will recognize certain modifications, rearrangements, additions, and subcombinations thereof. Accordingly, the appended claims below, and the claims introduced thereafter, should be construed to include all such modifications, rearrangements, and subcombinations as reasonably inferred by those skilled in the art. The scope of the claims should not be limited by the embodiments described in the examples, but the broadest interpretation that is consistent with the foregoing disclosure should be given.

[0035] This disclosure can be embodied in other specific forms without departing from its intent or essential characteristics. The embodiments described should be considered in all respects as merely illustrative and non-limiting.

Claims

1. A narrowband dipole antenna module, A housing comprising: a base having an internally defined opening; and a hollow support column extending from the opening in the base, wherein the hollow support column has a plurality of antenna openings defined within the hollow support column near its distal end; A circuit assembly configured to be inserted into the housing, wherein the circuit assembly is An input printed circuit board, wherein the input printed circuit board has a transmit connector and a receive connector for connecting to an antenna drive circuit, A matching printed circuit board comprising a centrifugal element matching component and a plurality of terminal blocks, each terminal block configured to receive an antenna element, on the matching printed circuit board, A pair of coaxial power supply lines connected between the input printed circuit board and the matching printed circuit board, each of the pair of coaxial power supply lines having a coil formed inside such that the pair of coaxial power supply lines function as a balloon, A circuit assembly including at least one rigid support member connected between the input printed circuit board and the matching printed circuit board for holding the matching printed circuit board at a fixed distance from the input printed circuit board such that the terminal block on the matching printed circuit board is adjacent to the antenna opening in the hollow support when the input printed circuit board is mounted on the lower surface of the base plate, A narrowband dipole antenna module comprising a plurality of antenna elements, which are received through the antenna opening and configured to be connected to the terminal block.

2. The narrowband dipole antenna module according to claim 1, wherein one of the pair of coaxial feed lines has a clockwise coil formed inside, and the other of the pair of coaxial feed lines has a counterclockwise coil formed inside.

3. The narrowband dipole antenna module according to claim 1, wherein the matching printed circuit board has a first surface facing the input printed circuit and a second surface opposite to the first surface, having the terminal block mounted on the second surface, and includes a pair of feed line landing pads for connecting to the pair of coaxial feed lines, each feed line landing pad including an annular ring on the first surface of the matching printed circuit board for connecting to the outer conductor of one of the feed lines, and a plated through-hole extending from inside the annular ring on the first surface to the second surface of the matching printed circuit board for connecting to the inner conductor of the feed line.

4. The narrowband dipole antenna module according to claim 1, further comprising an isolator element for each of the plurality of antenna apertures, wherein the isolator element has a projection extending from a first side surface of the isolator element configured to engage with one of the antenna apertures, and a recess on a second side surface of the isolator element for receiving one of the antenna elements, the recess having an aperture extending from the first side surface of the isolator element within the recess for enabling the antenna element to directly engage with the terminal block.

5. The narrowband dipole antenna module according to claim 4, further comprising: a first sealing ring between the first side surface of each isolator element and the housing, for forming a seal between the isolator element and the housing; and a second sealing ring between the second side surface of each isolator element and the antenna element, for forming a seal between the isolator element and the antenna element.

6. The narrowband dipole antenna module according to claim 1, wherein the terminal block is configured to hold the antenna element at an angle of 45 degrees from the longitudinal axis of the hollow support column.

7. The narrowband dipole antenna module according to claim 6, wherein the plurality of antenna openings include four antenna openings, the plurality of terminal blocks include four terminal blocks, and the plurality of antenna elements include four antenna elements.

8. The narrowband dipole antenna module according to claim 1, wherein the hollow support column is configured to be adjustable in height.

9. The narrowband dipole antenna module according to claim 1, wherein the plurality of antenna elements are configured to be adjustable in length.

10. A method for assembling a narrowband dipole antenna, wherein the method is Assembling a circuit assembly, wherein the circuit assembly includes: an input printed circuit board having a transmit connector and a receive connector for connecting to an antenna drive circuit on the input printed circuit board; a matching printed circuit board having a lumen element matching component and a plurality of terminal blocks, each terminal block configured to receive an antenna element on the matching printed circuit board; a pair of coaxial feed lines connected between the input printed circuit board and the matching printed circuit board, each of the pair of coaxial feed lines having a coil formed inside so that the pair of coaxial feed lines function as a balun; and at least one rigid support member connected between the input printed circuit board and the matching printed circuit board for holding the matching printed circuit board at a fixed distance from the input printed circuit board. Inserting the circuit assembly into a housing, wherein the housing includes a base having an internally defined opening and a hollow support extending from the opening in the base, the hollow support having a plurality of antenna openings defined within the hollow support near its distal end, so that when the input printed circuit board is mounted on the underside of the base plate, the terminal block on the matching printed circuit board is adjacent to the antenna openings in the hollow support, A method comprising connecting multiple antenna elements to the multiple terminal blocks.

11. The method according to claim 10, wherein one of the pair of coaxial power supply lines has a clockwise coil formed inside, and the other of the pair of coaxial power supply lines has a counterclockwise coil formed inside.

12. The method according to claim 10, wherein the matching printed circuit board has a first surface facing the input printed circuit and a second surface opposite to the first surface, the second surface having the terminal block mounted on the second surface, and a pair of power line landing pads for connecting to the pair of coaxial power lines, each power line landing pad including an annular ring on the first surface of the matching printed circuit board for connecting to the outer conductor of one of the power lines, and plated through-holes extending from inside the annular ring on the first surface of the matching printed circuit board to the second surface for connecting to the inner conductor of the power line.

13. The method according to claim 10, wherein connecting the plurality of antenna elements further comprises connecting an isolator element to each of the plurality of antenna apertures, the isolator element having a projection extending from a first side of the isolator element configured to engage with one of the antenna apertures, and a recess on a second side of the isolator element for receiving one of the antenna elements, the recess having an aperture extending from the first side of the isolator element within the recess for enabling the antenna element to directly engage with the terminal block.

14. The method according to claim 13, further comprising connecting the plurality of antenna elements a first sealing ring between the first side surface of each isolator element and the housing, which is for forming a seal between the isolator element and the housing, and a second sealing ring between the second side surface of each isolator element and the antenna element, which is for forming a seal between the isolator element and the antenna element.

15. The method according to claim 10, wherein the terminal block is configured to hold the antenna element at an angle of 45 degrees from the longitudinal axis of the hollow support column.

16. The method according to claim 10, wherein the plurality of antenna openings include four antenna openings, the plurality of terminal blocks include four terminal blocks, and the plurality of antenna elements include four antenna elements.

17. It is a system, A housing comprising: a base having an internally defined opening; and a hollow support extending from the opening in the base, wherein the hollow support has a plurality of defined antenna openings within the hollow support near its distal end, and the height of the hollow support is configured to be adjustable. A circuit assembly configured to be inserted into the housing, wherein the circuit assembly is An input printed circuit board, wherein the input printed circuit board has a transmit connector and a receive connector for connecting to an antenna drive circuit, A matching printed circuit board comprising a centrifugal element matching component and a plurality of terminal blocks, each terminal block configured to receive an antenna element, on the matching printed circuit board, A pair of coaxial power supply lines connected between the input printed circuit board and the matching printed circuit board, A circuit assembly including at least one rigid support member connected between the input printed circuit board and the matching printed circuit board for holding the matching printed circuit board at a fixed distance from the input printed circuit board such that the terminal block on the matching printed circuit board is adjacent to the antenna opening in the hollow support when the input printed circuit board is mounted on the lower surface of the base plate, A system comprising a plurality of antenna elements, which are received through the antenna opening and configured to be connected to the terminal block, wherein the length of the antenna elements is configured to be adjustable.

18. The system according to claim 17, wherein each of the pair of coaxial feed lines has a coil formed inside such that the pair of coaxial feed lines function as a balun.

19. The system according to claim 18, wherein one of the pair of coaxial power supply lines has a clockwise coil formed inside, and the other of the pair of coaxial power supply lines has a counterclockwise coil formed inside.

20. The system according to claim 17, wherein the plurality of antenna openings include four antenna openings, the plurality of terminal blocks include four terminal blocks, and the plurality of antenna elements include four antenna elements.

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