Methods, systems and elements for GNSS antennas

Abstract

GNSS antennas are employed in a wide range of civilian and military applications. Whilst low profile, low weight and smaller footprint are of particular importance for many applications a common requirement across all applications is cost reduction. Cost reduction can be achieved for GNSS antennas through manufacturing processes that, for example, reduce waste, reduce assembly piece-part costs, reduce assembly and / or testing time or improve yield against product specification requirements. Accordingly, there are provided design and assembly elements that that support these requirements.

Description

METHODS. SYSTEMS AND ELEMENTS FOR GNSS ANTENNASCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims the benefit of priority to U.S. Provisional Patent Application 63 / 586,674 filed September 29, 2023; the entire contents of which are incorporated herein by reference.FIELD OF THE INVENTION

[0002] This patent application relates to antennas and more particularly to compact global navigation satellite system antennas, antenna elements and antenna assemblies employing coupled dipole resonator elements.BACKGROUND OF THE INVENTION

[0003] As the applications for such GNSS receivers have expanded with low cost GNSS receiver electronics then there is a constant drive for more compact multiband antennas that can be easily integrated into a wide range of portable devices or more generally into mobile platforms and equipment. In addition to being compact these antennas should provide a controlled radiation pattern, namely a uniform coverage of the upper hemisphere of their radiation pattern and circular polarization purity to improve cross-polarization rejection and hence multipath rejection. Further, low profile, low weight and smaller footprint are of particular importance for many applications.

[0004] However, whilst low profile, low weight and smaller footprint are of particular importance for many applications a common requirement across all applications is cost reduction. Cost reduction can be achieved for GNSS antennas through manufacturing processes that, for example, reduce waste, reduce assembly piece-part costs, reduce assembly and / or testing time or improve yield against product specification requirements. Accordingly, it would be beneficial to provide manufacturers of GNSS antenna elements with design and assembly elements that support these requirements.

[0005] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to mitigate limitations within the prior art relating to antennas and more particularly to compact broadband global navigation satellite system antennas, antenna elements and antenna assemblies employing coupled dipole resonator elements.

[0007] In accordance with an embodiment of the invention there is provided an antenna comprising: a printed circuit comprising a dipole element disposed on an insulating substrate with centrally disposed feed connections where metallization of the dipole element at each distal end of the dipole element from the centrally disposed feed connections extends onto protruding extensions of the printed circuit; another printed circuit having a ground plane disposed parallel to and offset from a longitudinal axis of the dipole element by a predetermined offset, and a pair of ground elements, each ground element having a predetermined length and width and metallized upon an insulating substrate and disposed at a distal end of the dipole element; wherein: a first end of each ground element of the pair of ground elements is electrically connected to the ground plane on the another printed circuit; each ground element of the pair of ground elements comprises by a hole in its insulating substrate which is encircled by a metallized region isolated from the ground element metallizations by one or more defined gaps; each metallised protruding extension of the printed circuit board at the distal ends of the dipole element is inserted into the hole of a ground element of the pair of ground elements and the metallization of dipole element at that distal end of the dipole element is directly electrically connected to the metallized region of that ground element of the pair of ground elements; and radiative excitation of each ground element of the pair of ground elements to the metallized region of that ground element of the pair of ground elements via a defined capacitive reactance

[0008] In accordance with an embodiment of the invention there is provided an antenna comprising: a dipole upon a printed circuit; and a pair of ground elements; whereineach ground element of the pair of ground elements is radiatively coupled to a different end of the dipole via a defined capacitive reactance and mechanically connected to the printed circuit.

[0009] In accordance with an embodiment of the invention there is provided an antenna comprising: a printed circuit comprising a dipole element disposed on an insulating substrate with centrally disposed feed connections where metallization of the dipole element at each distal end of the dipole element from the centrally disposed feed connections extends onto protruding extensions of the printed circuit; another printed circuit having a ground plane disposed parallel to and offset from a longitudinal axis of the dipole element by a predetermined offset, and a pair of ground elements, each ground element having a predetermined length and width and metallized upon an insulating substrate and disposed at a distal end of the dipole element; wherein: a first end of each ground element of the pair of ground elements is electrically connected to the ground plane on the another printed circuit; each ground element of the pair of ground elements comprises by a hole in its insulating substrate which is encircled by a metallized region isolated from the ground element metallizations by one or more defined gaps; and each metallised protruding extension of the printed circuit board at the distal ends of the dipole element is inserted into the hole of a ground element of the pair of ground elements and the metallization of dipole element at that distal end of the dipole element is directly electrically connected to the metallized region of that ground element of the pair of ground elements.

[0010] In accordance with an embodiment of the invention there is provided a method of providing an antenna comprising providing a printed circuit comprising a dipole element disposed on an insulating substrate with centrally disposed feed connections where metallization of the dipole element at each distal end of the dipole element from the centrally disposed feed connections extends onto protruding extensions of the printed circuit; providing another printed circuit having a ground plane disposed parallel to and offset from a longitudinal axis of the dipole element by a predetermined offset, andproviding a pair of ground elements, each ground element having a predetermined length and width and metallized upon an insulating substrate and disposed at a distal end of the dipole element; wherein: a first end of each ground element of the pair of ground elements is electrically connected to the ground plane on the another printed circuit; each ground element of the pair of ground elements comprises by a hole in its insulating substrate which is encircled by a metallized region isolated from the ground element metallizations by one or more defined gaps; and each metallised protruding extension of the printed circuit board at the distal ends of the dipole element is inserted into the hole of a ground element of the pair of ground elements and the metallization of dipole element at that distal end of the dipole element is directly electrically connected to the metallized region of that ground element of the pair of ground elements.

[0011] In accordance with an embodiment of the invention there is provided an antenna comprising: a base; a dipole element extending upon a carrier where the dipole element is disposed at a defined distance above the base and extends in a plane horizontal to the base; a ground plane having a portion extending above the dipole element at a defined distance; wherein the dipole element extends along a projection of the carrier; the projection extends through an opening within the ground plane such that the dipole element also extends through the opening; a portion of the dipole element extending through the opening is electrically connected to metallization around the opening; and the metallization around the opening is electrically isolated from the ground plane by a region absent metallization of defined geometry and defined dimensions.

[0012] In accordance with an embodiment of the invention there is provided an antenna comprising: a base; a pair of dipole elements extending upon a carrier radially from an axis perpendicular to the base where the pair of dipole elements are disposed at a defined distance above the base and extending in a plane horizontal to the base from an end towards the axis to a distal end;a ground plane having a first portion extending over a distal end of a dipole element of the pair of dipole elements at a defined distance and a second portion over a distal end of the other dipole element of the pair of dipole elements at the defined distance; wherein the dipole element of the pair of dipole elements extends along a first projection of the carrier and the other dipole element of the pair of dipole elements extends along a second projection of the carrier; the first projection extends through an opening within the first portion of the ground plane such that the dipole element of the pair of dipole elements extends through the opening; the second projection extends through an other opening within the second portion of the ground plane such that the other dipole element of the pair of dipole elements extends through the other opening; a portion of the dipole element of the pair of dipole elements extending through the opening is electrically connected to metallization around the opening; a portion of the other dipole element of the pair of dipole elements extending through the other opening is electrically connected to metallization around the other opening; the metallization around the opening is electrically isolated from the first portion of the ground plane by a region absent metallization of defined geometry and defined dimensions; and the metallization around the other opening is electrically isolated from the second portion of the ground plane by another region absent metallization of other defined geometry and defined dimensions.

[0013] In accordance with an embodiment of the invention there is provided an antenna comprising: a base; a first dipole comprising a pair of dipole elements extending upon a first carrier radially from an axis perpendicular to the base where the pair of dipole elements are disposed at a defined distance above the base and extending in a plane horizontal to the base from an end towards the axis to a distal end; a second dipole comprising an other pair of dipole elements extending upon a second carrier radially from the axis perpendicular to the base where the other pair of dipole elements are disposed at a defined distance above the base and extending in a plane horizontal to the base from an end towards the axis to a distal end; a mounting element upon the base comprising:a portion upon which the first carrier and second carrier are mounted orthogonally to one another; and a series of other portions, each other portion extending vertically away from the portion such that it is disposed between a predetermined portion of the first carrier and the second carrier.

[0014] In accordance with an embodiment of the invention there is provided an antenna comprising: a dipole element, on a printed circuit board (PCB) insulating substrate, with centrally disposed feed terminals for connection to a balanced feed network, with metallization of the dipole comprising a first terminal, second terminal, and at each distal end of the dipole element extending onto a third terminal and a fourth terminal; a base ground PCB with planar geometry with metallization providing a ground plane of the antenna having a dimension along the PCB insulating substrate along a longitudinal axis of the dipole element defined in dependence upon a length of the dipole element along the longitudinal axis, the base ground PCB disposed parallel to and offset from the longitudinal axis of the dipole element by a predetermined offset, first and second metallized ground elements metallized on insulating substrates, each said metallized ground element having a first end and a distal second end, each of a predetermined length and width having the first end electrically connected to the base ground PCB at one or more points laterally disposed on the base ground PCB and their second distal end disposed proximate to a distal end of the dipole element; a first predetermined capacitive reactance connected between the third terminal of the dipole element and the second distal end of the first metallized ground element; and a second predetermined capacitive reactance connected between the fourth terminal of the dipole element and the second distal end of the second metallized ground element; wherein a balanced feed network provides identical, antipodal feed signals at the first terminal and the second terminal; and said antenna configuration is effective to provide a miniaturized antenna with an improved, wide bandwidth impedance at said first terminal and second terminal.

[0015] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:

[0017] Figure 1 depicts exemplary cross-section, end elevation and plan view schematics of an inventive broadband antenna according to an embodiment of the invention; employing parasitic elements in conjunction with a dipole;

[0018] Figure 2 depicts exemplary cross-section, end elevation and plan view schematics of an inventive broadband antenna according to an embodiment of the invention employing parasitic elements in conjunction with a dipole;

[0019] Figure 3 depicts an exemplary cross-section schematic of inventive antenna according to an embodiment of the invention employing a dipole element;

[0020] Figure 4 depicts an exemplary cross-section schematic of inventive antenna according to an embodiment of the invention employing a dipole element;

[0021] Figure 5 depicts a perspective view of the inventive circularly polarized (CP) antenna according to the embodiment of the invention depicted in Figure 4;

[0022] Figure 6A depicts an exploded perspective view of an inventive CP antenna according to an embodiment of the invention;

[0023] Figures 6B and 6C depict top views of flexible circuits as may be employed within an inventive CP antenna according to an embodiment of the invention depicted in Figure 6A;

[0024] Figures 6D and 6E depicts perspective views of a distal end of a petal of a flexible circuit engage within an opening within a base substrate of an inventive CP antenna according to an embodiment of the invention depicted in Figure 6A;

[0025] Figure 7A depicts an assembled perspective view of the inventive CP antenna according to an embodiment of the invention depicted in Figure 6A;

[0026] Figure 7B to 7D depict alternate ground plane interconnections for an inventive CP antenna according to an embodiment of the invention depicted in Figure 6A-6E to improve manufacturability and improved assembled antenna reproducibility;

[0027] Figure 8 depicts a cross-sectional view of an assembled inventive CP antenna according to an embodiment of the invention depicted in Figures 6A-6E and 7A-7B;

[0028] Figure 9 depicts a cross-sectional perspective view of an assembled inventive CP antenna according to an embodiment of the invention depicted in Figures 6A to 8 respectively;

[0029] Figure 10 depicts a mounting - tuning element forming part of an inventive CP antenna according to an embodiment of the invention depicted in Figures 6A to 9 respectively;

[0030] Figure 11 depicts a side elevation view of an assembled inventive CP antenna according to an embodiment of the invention depicted in Figures 6 A to 10 respectively;

[0031] Figure 12 depicts a photograph of a mounting between a dipole and carrier with ground plane for inventive CP antenna according to an embodiment of the invention depicted in Figures 6A to 11 respectively to improve manufacturability and improved assembled antenna reproducibility;

[0032] Figure 13 depicts a dipole upon a carrier as employed within an inventive CP antenna according to an embodiment of the invention depicted in Figures 6A to 12 respectively;

[0033] Figure 14 depicts a flexible circuit providing ground planes and support for ground elements of an inventive CP antenna according to an embodiment of the invention depicted in Figures 6A to 13 respectively;

[0034] Figures 15A and 15B depict variations in the mounting - tuning element of Figure 10 as employed within inventive CP antennae as depicted in Figures 6 A to 14 to support improved manufacturability and improved assembled antenna reproducibility; and

[0035] Figure 16 depicts the capacitances and adjusted capacitances from employing a mounting-tuning element as depicted in Figures 10, 15A and 15B; and

[0036] Figure 17 depicts an alternate positioning for metallization and projection for mounting between a dipole and carrier with ground plane for inventive CP antenna according to an embodiment of the invention depicted in Figures 6A to 11 respectively.

[0037] DETAILED DESCRIPTION

[0038] The present description is directed to antennas and more particularly to compact broadband global navigation satellite system antennas, antenna elements and antenna assemblies employing coupled dipole resonator elements.

[0039] The ensuing description provides representative embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the embodiment(s) will provide those skilled in the art with an enabling description for implementing an embodiment or embodiments of the invention. It being understood that various changes can be made in the function and arrangement of elements without departing from the spirit and scope as set forth in the appended claims. Accordingly, an embodiment is an example or implementation of the inventions and not the sole implementation. Various appearances of “one embodiment,” “an embodiment” or “some embodiments” do not necessarily all refer to the same embodiments. Although various featuresof the invention may be described in the context of a single embodiment, the features may also be provided separately or in any suitable combination. Conversely, although the invention may be described herein in the context of separate embodiments for clarity, the invention can also be implemented in a single embodiment or any combination of embodiments. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the invention.

[0040] Reference in the specification to “one embodiment,” “an embodiment,” “some embodiments” or “other embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least one embodiment, but not necessarily all embodiments, of the inventions. The phraseology and terminology employed herein is not to be constmed as limiting but is for descriptive purposes only. It is to be understood that where the claims or specification refer to “a” or “an” element, such reference is not to be constmed as there being only one of that element. It is to be understood that where the specification states that a component feature, stmcture, or characteristic “may,” “might,” “can” or “could” be included, that particular component, feature, stmcture, or characteristic is not required to be included.

[0041] Reference to terms such as “left,” “right,” “top,” “bottom,” “front” and “back” are intended for use in respect to the orientation of the particular feature, stmcture, or element within the figures depicting embodiments of the invention. It would be evident that such directional terminology with respect to the actual use of a device has no specific meaning as the device can be employed in a multiplicity of orientations by the user or users.

[0042] Reference to terms “including,” “comprising,” “consisting” and grammatical variants thereof do not preclude the addition of one or more components, features, steps, integers or groups thereof and that the terms are not to be constmed as specifying components, features, steps or integers. Likewise, the phrase “consisting essentially of,” and grammatical variants thereof, when used herein is not to be constmed as excluding additional components, steps, features integers or groups thereof but rather that the additional features, integers, steps, components or groups thereof do not materially alter the basic and novel characteristics of the claimed composition, device or method. If the specification or claims refer to “an additional” element, that does not preclude there being more than one of the additional element.

[0043] A “feed point” (FP) as used herein and throughout this disclosure relates to or refers to a point at which a microwave track such as those depicted in Figures 2-4 and Figures 6A-8 is coupled to a microwave circuit such as microwave feed network or microwave combining network.

[0044] It would be understood by one of skill in the art that the antennas and antenna elements described with respect to embodiments of the invention below may be formed, for example, as discrete metallic elements, as metallic elements upon a formed or shaped circuit board, as metallic elements upon a substrate, as metallic elements upon a flexible circuit board, or as metallic elements formed upon a flexible substrate without departing from the scope of the invention. Alternatively, the antennas and antenna elements described with respect to embodiments of the invention below may be formed as a single piece part using one or more additive manufacturing methodologies as known in the art.

[0045] It would be understood by one of skill in the art that that the antennas and antenna elements described with respect to embodiments of the invention below may be employed in antennas of varying three-dimensional geometries including, but not limited to, cylindrical, pyramidal, hemispherical, spherical, and fructo-conical without departing from the scope of the invention.

[0046] Table 1 below presents the operating frequencies for single and dual-band GNSS receivers for civilian and military applications. These being Beidou, Galileo, GLONASS, GPS, and NAVIC. Beidou, Galileo, GLONASS and GPS provide dual-band operation in the frequency range 1150MHz-1610MHz. Accordingly, a GNSS antenna supporting both bands is required to support a larger 140MHz bandwidth in the lower band, between approximately 1.160GHz to 1.300GHz, than the approximately 51MHz at the upper band, between approximately 1.559GHz and 1.610GHz. However, as noted above prior art dual band GNSS antenna structures typically provide wider bandwidth operation at the upper band relative to the lower band. Accordingly, the inventors have established GNSS antenna designs that provide improved bandwidth performance in the lower band enabling operational compatibility with multiple GNSS systems.

[0047] Also depicted within Table 1 are the operating frequencies of satellite phone systems which could extend the bandwidth requirements if a dual use antenna was employed.Table 1: Operating Frequencies of GNSS and Satellite Phone Systems (Nearest 1MHz)

[0048] For circularly polarized signals, as employed by GNSS satellites, a pair of antenna elements orthogonally disposed are typically employed where, for a receiver, the wireless signals from the four electrical connections to these two antenna elements are combined within a microwave circuit. Where the four elements are disposed equidistantly then their relative phases may be viewed as 0°, 90°, 180° and 270° respectively. Within the following description single inventive antenna elements are depicted although it would be readily evident to one of skill in the art that these may be employed as the antenna element of a pair of antenna elements to form an antenna for circularly polarized signals.

[0049] Now referring to Figure 1 there are depicted an exemplary cross-section, end elevation and plan view schematics of an inventive Broadband Antenna 100 according to an embodiment of the invention operating according to the principles described above with respect to Figure 1.

[0050] Accordingly, there are depicted the first and second Elements 110A and HOB of the dipole upon a Carrier 160 with tracks to the Feed Point (FP) 120 through an opening in the Ground Plane (GP) 150. The first and second Elements 110A and HOB being disposed above and parallel to the plane of the GP 150 and coupled to the FP 120. Disposed at an end of the first Element 110A distal to the FP 120 is a first Ground Element 130A which is coupled to the Ground Plane 150 and separated from the end of the first Element 110A by a first gap. Disposed at an end of the second Element 110B distal to the FP 120 is a second Ground Element 130B which is coupled to the GP 150 and separated from the end of the second Element 110B by a second gap,. The first gap and second gap are commonly designed to be equal.

[0051] Also depicted, disposed parallel to the first and second Elements 110A and HOB respectively, is a Parasitic Element (PE) 140 where the PE 140 is disposed adjacent to the first and second Elements 110A and HOB respectively further from the GP 150. A first end of the PE 140 is separated from the first Ground Element 130A by a third gap. A second distal end of the PE 140 is separated from the second Ground Element 130B by a fourth gap. The third gap and the fourth gap commonly being equal. As evident in the end elevation the first Ground Element 130A is a conductive surface. The PE 140 metallization as evident from the plan view is upon a Carrier 170. The third gap and the fourth gap are commonly designed to be equal.

[0052] As will become evident from the following description, simulations etc. inventive antenna elements according to embodiments of the invention provide wider bandwidth and improved gain and axial ratio at low elevations compared with other antenna forms of similar size and format such as patch antenna elements, for example.

[0053] For the purposes of explanation it is useful to describe and consider the geometry of the various embodiments of the inventive antenna described herein with reference to the figures of this specification where a PE 140 is employed. Each embodiment may be viewed as comprising an Antenna Loop (AL) which includes the GP 150, the PE 140 which is distal from and substantially parallel to said GP 150, the PE 140 being coupled at each distal end of said PE 140 to the GP 150 with a pair of Ground Elements (GE), first Ground Element 130A and second Ground 130B respectively, where the PE 140 is further coupled to a Dipole, comprising the first Element 110A and second Element 110B. The Dipole further coupled to a balanced Feed Point (FP), FP 120, which are effective in combination to transmit and receive linearly polarized signals over a wide frequency range. Each embodiment is further described in terms of an abstracted Antenna Plane (AP), orthogonal to the GP and disposed at the mid-line of the long axis of the said PE, the mid-point of said PE being defined as the Antenna Center (AC).

[0054] An inventive Circularly Polarized Antenna (CP) is realized with two such inventive linearly polarized antenna elements such as depicted in Figure 1 with a common GP 150, with a first antenna loop (AL) and a second AL each orthogonal to the other and both orthogonal to the GP 150, with a common AC, and a summing means for summing the electric signals generated at each of the two FPs in phase quadrature for a receiver.

[0055] For consideration and computation, a plane, Circularly Polarized (CP) wave can be decomposed as two linearly polarized waves with common Poynting vectors, in phase quadrature, with the rotational direction (right or left) of the vector sum of the superimposed waves determined by the sign of the quadrature phase difference. Further, for any circularly polarized plane wave, the decomposition axis for the E-M fields of the linearly polarized wavesis arbitrary; any choice is equally valid. Further, all azimuthal angles relative to the GP 150 are equivalent so that extrapolation and generalization of effects derived by consideration of incident waves “square to” the AP is valid.

[0056] The basis for the improved gain and axial ratio at low elevations can be appreciated by one of skill in the art by separately considering plane linearly polarized waves incident at various Poynting vectors and configurations of field axes on an inventive linearly polarized antenna according to an embodiment of the invention or an inventive circularly polarized antenna comprised of two orthogonal linear polarized antennas according to another embodiment of the invention.

[0057] In a first case, consider a plane linearly polarized wave incident on an inventive antenna according to an embodiment of the invention with its Poynting vector parallel to both the GP 150 and the PE 140, the incident wave being further characterized as having its associated E- field orthogonal to the GP 150. The associated H-field would thus be parallel to the GP 150 and orthogonal to the AP, so that the AL would contain the incident plane linearly polarized wave magnetic flux and an electromagnetic field (emf) would be generated as a result of the induced loop current which would be coupled to the antenna FP 120. The E field of the incident plane linearly polarized wave being orthogonal to the PE 140 would not thus contribute to the received signal.

[0058] In a second case, consider a plane linearly polarized wave incident on an inventive antenna according to an embodiment of the invention with its Poynting vector parallel to the GP 150 and orthogonal to the PE 140, the incident wave being further characterized as having its associated E-field parallel to the PE 140. An emf would thus be induced in the PE and coupled to the antenna FP. As the associated H-Field of the incident plane linearly polarized wave is parallel to the AP, no current would be induced in the AL by the H-Field, which thus would not contribute to any received signal.

[0059] In a third case, consider a plane linearly polarized wave incident on an inventive antenna according to an embodiment of the invention such that the Poynting vector is orthogonal to both the GP 150 and the PE 140, the incident wave further characterized as having an E-field orthogonal to the AP. Consequently, no constructive emf would be induced in the PE 140, and because the incident wave H-field would be parallel to the AP no current would be induced in the AL, so that no signal power would be coupled to the antenna FP.

[0060] In a fourth case, consider a plane linearly polarized wave incident on an inventive antenna according to an embodiment of the invention such that the Poynting vector is orthogonal to the GP 150 and orthogonal to the PE 140, with the incident wave furthercharacterized as having an E-field parallel to the PE 140. An emf would thus be induced in the PE and coupled to the antenna FP. In addition, the AL would contain the associated magnetic flux and also generate an emf that would be coupled to the antenna FP, so that both of the associated E and H fields contribute to the received signal.

[0061] A CP antenna, such as might be utilized to receive signals from a satellite, can be realized using two linearly polarized antennas orthogonally disposed with respect to each other and the GP 150, each linearly polarized antenna being according to an embodiment of the inventive antenna previously described, with the PEs of the respective antennas, linear, planar or three dimensional elements, disposed above (and parallel to) the GP 150.

[0062] In a fifth case, a CP wave incident on a CP antenna, with a Poynting vector at zenith (directly overhead in typical use) orthogonal to the GP 150 and, for convenience, the E-field axis of a first component wave of the CP wave further considered as parallel to the PE 140 of a first one of the antenna elements, the first linearly polarized component wave component of the CP wave would be incident on the first antenna according the fourth case described above, so that both the E and H fields of both components each contribute to the signal generated at the first FP. Similarly, the second linear component wave of the CP wave would be incident on the second, orthogonal antenna according to the fourth case described above sot that the received signal at the second FP of the second antenna element would include contributions by both the E-field and H-field of the second component of the CP wave.

[0063] In a sixth case, of a CP wave incident on a CP antenna, with a Poynting vector parallel to the GP 150 (on the horizon in typical use) and parallel to the PE 140 of a first linearly polarized antenna, and with the E-field axis of a first component wave of the CP wave considered orthogonal to the GP 150, only the H-Field would contribute the received signal at the first FP and by similar argument, the received signal at the second FP would be only be contributed by the E-Field of the second component of the CP wave. Thus with appropriate dimensions, the magnetic and electric responses may be made equal for CP waves incident at the horizon, which is effective to reduce the axial ratio of the CPO antenna at the horizon.

[0064] It will be appreciated that the third case considered above shows that each axis of a circularly polarized antenna realized with two linearly polarized orthogonal antenna elements according to embodiments of the invention is electrically isolated from the other, a necessary condition for reception of CP signals.

[0065] Referring to Figure 2 there are depicted an exemplary cross-section, end elevation and plan view schematics of an inventive Broadband Antenna 200 according to an embodiment of the invention operating according to the principles described above with respect to Figure 1.

[0066] Accordingly, there are depicted the first and second Elements 210A and 21 OB of the dipole upon a Carrier 260 with tracks to the Feed Point (FP) 220 through an opening in the Ground Plane (GP) 250. The first and second Elements 210A and 210B being orthogonal to and parallel to the plane of the GP 250 and coupled to the FP 220. Disposed at an end of the first Element 210A distal to its connection to the FP 220 is a first Ground Element 230 A which is coupled to the Ground Plane 250 and separated from the end of the first Element 210A by a first gap. Disposed at an end of the second Element 210B distal to the end connecting to the FP 220 is a second Ground Element 230B which is coupled to the GP 250 and separated from the end of the second Element 210B by a second gap. The first gap and second gap are commonly designed to be equal.

[0067] Also depicted is a Parasitic Element (PE) 240 where a first end of the PE 240 is separated from the first Ground Element 230A by a third gap. A second distal end of the PE 240 is separated from the second Ground Element 230B by a fourth gap. The third gap and the fourth gap are commonly designed to be equal. As depicted the first Ground Element 230A, PE 240 and second Ground Element 230B are now all disposed upon a common carrier 270 which is shaped to provide a curved profile.

[0068] Within the embodiments of the invention described above with respect to Figures 1 and 2 the structure has been described with a parasitic element, e.g. Parasitic Element 140 in Figure 1 or Parasitic Element 240 in Figure 2, further from the ground plane, e.g. Ground Plane 150 or Ground Plane 250, than the dipole. However, it would be evident to one of skill in the art that the antenna structures described and depicted according to embodiments of the invention may also be implemented the parasitic element closer to the ground plane than the dipole.

[0069] Now referring to Figure 3 there are depicted an exemplary cross-section schematic of inventive Antenna 300 according to an embodiment of the invention.

[0070] Referring to Antenna 300 in Figure 3 the first Dipole Element 330A and second Dipole Element 330B of the dipole are disposed on a first side of a Carrier 320, for example a PCB. By employing a Carrier 320 with a higher dielectric constant than air the separation between the dipole and the first and second Ground Elements 360A and 360B can be reduced whilst maintaining the desired coupling characteristics between the dipole and the first and second Ground Elements 360 A and 360B thereby allowing the height of Antenna 300 to be reduced. The Carrier 320 is supported at its centre by a Feed 340 which has the feed lines for the first and second Dipole Elements 330 A and 330B of the dipole where the electricalconnections between these feed lines and the first and second Elements 330 A and 330B of the dipole have been omitted for clarity.

[0071] The first and second Ground Elements 360A and 360B are disposed at the periphery of the Antenna 300 and are formed from another Carrier or Carriers upon which is disposed a Ground Plane 310. Within other embodiments of the invention the Ground Plane 310 may be employed without a Carrier or Carriers such that the first and second Ground Elements 360A and 360B are simply discrete Ground Planes 310. Optionally, the Ground Planes 310 may be disposed on the inner surface of each of the first and second Ground Elements 360 A and 360B.

[0072] The first Ground Element 360 A extends over the first Dipole Element 330 A for a predetermined distance such that the Ground Plane 310 extends over the first Dipole Element 330 A for another predetermined distance which may be the same as the predetermined distance or different. Similarly, the second Ground Element 360B extends over the second Dipole Element 330B for a predetermined distance such that the Ground Plane 310 extends over the second Dipole Element 330B for another predetermined distance. In this manner the microwave / RF performance of the first and second Dipole Elements 330A and 33B are adjusted in dependence upon the degree of overlap of the Ground Plane 310 to them such that the antenna gain of the Antenna 300 is enhanced for the desired operating frequencies and / or enhanced for specific ranges of elevation. For example, the Antenna 300 may be designed to operate upon the uplink and / or downlink bands of a GNSS system such as INMARSAT where a pair of dual orthogonal Antennae 2000 are employed to support the required right-hand circular polarization. For INMARSAT the uplink frequency band is 1626.5 - 1660.5 MHz whilst the downlink frequency band is 1525.0 - 1559.0 MHz such that these sit either side of the GPS LI signal operating at 1.563-1.587 GHz.

[0073] Referring to Figure 4 there are depicted an exemplary cross-section schematic of inventive Antenna 400 according to an embodiment of the invention. Within Antenna 400 the first Dipole Element 330A and second Dipole Element 330B of the dipole disposed on the Carrier 320 in Figure 3 have been replaced with the first and second Elements 110A and HOB of the dipole upon the Carrier 160 of Antenna 100. The first and second Elements 110A and HOB being coupled to the FP 120.

[0074] In either instance the design of the Antennae 300 and 400 in Figures 3 and 4 respectively are without a parasitic element, e.g. Parasitic Element 140 in Figure 1 or Parasitic Element 240 in Figure 2. The inventors having established that embodiments of the invention based upon the design methodology of Antennae 100 and 200 in Figures 1 and 2 may be employed to address applications with a first range of performance requirements and / or a firstrange of mechanical requirements whereas the design methodology of Antennae 300 and 400 in Figures 3 and 4 may be employed to address applications with a second range of performance requirements and / or a second range of mechanical requirements. Within other applications with a third range of performance requirements and / or a third range of mechanical requirements both the design methodologies of Antennae 100 and 200 respectively and Antennae 300 and 400 respectively may be employed to meet the target requirements.

[0075] Each embodiment is further described in terms of an abstracted Antenna Plane (AP), orthogonal to the GP 350, and disposed at the mid-point of the long axis of each of the dipoles formed from the first and second Elements 110A and HOB, mid-point being defined as the Antenna Center (AC). An inventive Circularly Polarized Antenna (CP) is realized with two such inventive linearly polarized antenna elements such as depicted in Figure 4 with a common GP 350, with a first antenna loop (AL) and a second AL each orthogonal to the other and both orthogonal to the GP 350, with a common AC, and a summing means for summing the electric signals generated at each of the two FPs in phase quadrature for a receiver (or a splitting means for generating phase quadrature offset electrical signals for each of the FPs for a transmitter).

[0076] For consideration and computation, a plane, Circularly Polarized (CP) wave can be decomposed as two linearly polarized waves with common Poynting vectors, in phase quadrature, with the rotational direction (right or left) of the vector sum of the superimposed waves determined by the sign of the quadrature phase difference. Further, for any circularly polarized plane wave, the decomposition axis for the E-M fields of the linearly polarized waves is arbitrary; any choice is equally valid. Further, all azimuthal angles relative to the GP 150 are equivalent so that extrapolation and generalization of effects derived by consideration of incident waves “square to” the AP is valid.

[0077] The basis for the improved gain and axial ratio at low elevations can be appreciated by one of skill in the art by separately considering plane linearly polarized waves incident at various Poynting vectors and configurations of field axes on an inventive linearly polarized antenna according to an embodiment of the invention or an inventive circularly polarized antenna comprised of two orthogonal linear polarized antennas according to another embodiment of the invention.

[0078] In a first case, consider a plane linearly polarized wave incident on an inventive antenna according to an embodiment of the invention with its Poynting vector parallel to both the GP 350 and the first and second Elements 110A and HOB, the incident wave being further characterized as having its associated E-field orthogonal to the GP 350. The associated H-field would thus be parallel to the GP 350 and orthogonal to the AP, so that the AL would containthe incident plane linearly polarized wave magnetic flux and an emf would be generated as a result of the induced loop current which would be coupled to the antenna FP 120. The E field of the incident plane linearly polarized wave being orthogonal to the first and second Elements 110A and 1 lOBwould not thus contribute to the received signal.

[0079] In a second case, consider a plane linearly polarized wave incident on an inventive antenna according to an embodiment of the invention with its Poynting vector parallel to the GP 350 and orthogonal to the first and second Elements 110A and HOB, the incident wave being further characterized as having its associated E-field parallel to the first and second Elements 110A and HOB. An emf would thus be induced in the first and second Elements 110A and 1 lOBand coupled to the antenna FP. As the associated H-Field of the incident plane linearly polarized wave is parallel to the AP, no current would be induced in the AL by the Il- Field, which thus would not contribute to any received signal.

[0080] In a third case, consider a plane linearly polarized wave incident on an inventive antenna according to an embodiment of the invention such that the Poynting vector is orthogonal to both the GP 350 and the first and second Elements 110A and 110B, the incident wave further characterized as having an E-field orthogonal to the AP. Consequently, no constructive emf would be induced in the first and second Elements 110A and HOB, and because the incident wave H-field would be parallel to the AP no current would be induced in the AL, so that no signal power would be coupled to the antenna FP.

[0081] In a fourth case, consider a plane linearly polarized wave incident on an inventive antenna according to an embodiment of the invention such that the Poynting vector is orthogonal to the GP 350 and orthogonal to the first and second Elements 110A and 110B, with the incident wave further characterized as having an E-field parallel to the first and second Elements 110A and 110B. An emf would thus be induced in the PE and coupled to the antenna FP. In addition, the AL would contain the associated magnetic flux and also generate an emf that would be coupled to the antenna FP, so that both of the associated E and H fields contribute to the received signal.

[0082] A CP antenna, such as might be utilized to receive signals from a satellite, can be realized using two linearly polarized antennas orthogonally disposed with respect to each other and the GP 350, each linearly polarized antenna being according to an embodiment of the inventive antenna previously described, with the PEs of the respective antennas, linear, planar or three dimensional elements, disposed above (and parallel to) the GP 350.

[0083] In a fifth case, a CP wave incident on a CP antenna, with a Poynting vector at zenith (directly overhead in typical use) orthogonal to the GP 350 and, for convenience, the E-fieldaxis of a first component wave of the CP wave further considered as parallel to the first and second Elements 110A and HOB of a first one of the antenna elements, the first linearly polarized component wave component of the CP wave would be incident on the first antenna according the fourth case described above, so that both the E and H fields of both components each contribute to the signal generated at the first FP. Similarly, the second linear component wave of the CP wave would be incident on the second, orthogonal antenna according to the fourth case described above sot that the received signal at the second FP of the second antenna element would include contributions by both the E-field and H-field of the second component of the CP wave.

[0084] In a sixth case, of a CP wave incident on a CP antenna, with a Poynting vector parallel to the GP 350 (on the horizon in typical use) and parallel to the first and second Elements 110A and HOBof a first linearly polarized antenna, and with the E-field axis of a first component wave of the CP wave considered orthogonal to the GP 350, only the H-Field would contribute the received signal at the first FP and by similar argument, the received signal at the second FP would be only be contributed by the E-Field of the second component of the CP wave. Thus with appropriate dimensions, the magnetic and electric responses may be made equal for CP waves incident at the horizon, which is effective to reduce the axial ratio of the CPO antenna at the horizon.

[0085] It will be appreciated that the third case considered above shows that each axis of a circularly polarized antenna realized with two linearly polarized orthogonal antenna elements according to embodiments of the invention is electrically isolated from the other, a necessary condition for reception of CP signals.

[0086] Now referring to Figure 5 there is depicted a perspective view of the inventive Antenna 500 according to an embodiment of the invention which employs a pair of Antenna 400, as depicted in Figure 4, mounted orthogonally in order to provide an antenna operating upon circularly polarized signals.

[0087] A first antenna element, a first instance of Antenna 400, comprises a first dipole formed from a first Dipole Element 520A and a second Dipole Element 520B which are orthogonal to and parallel to a Ground Plane (GP) 540. The first Dipole Element 520A and the second Dipole Element 520B being coupled to a first Feed Point via one or more means as known in the art. The first Dipole Element 520A is coupled to first Feed 560 and the second Dipole Element 520B is coupled to a second Feed, not visible within the perspective view, where the first Feed 560 and second Feed comprise external connections for the Feed Point of the dipole. Also depicted in association with the first Dipole Element 520A and the secondDipole Element 520B are a first Ground Element 510A and a second Ground Element 51 OB. The first Ground Element 510A and second Ground Element 520 A extend over the first Dipole Element 520A and the second Dipole Element 520B respectively and are each coupled to the Ground Plane 540. The first Ground Element 510A and second Ground Element 520 A are depicted as being directly electrically coupled to the Ground Plane 540 but these may, within other embodiments of the invention, be electromagnetically coupled.

[0088] A second antenna element, a second instance of Antenna 400, comprises a second dipole formed from a third Dipole Element 550A and a fourth Dipole Element 550B which are orthogonal to and parallel to a Ground Plane (GP) 540. The third Dipole Element 550Aand the second Dipole Element 520B being coupled to a second Feed Point via one or more means as known in the art. The third Dipole Element 550A is coupled to third Feed 570 and the fourth Dipole Element 550B is coupled to a fourth Feed, not visible within the perspective view, where the third Feed 570 and fourth Feed comprise external connections for the second Feed Point of the dipole. Also depicted in association with the third Dipole Element 550A and the fourth Dipole Element 550B are a third Ground Element 510C and a fourth Ground Element 510D. The third Ground Element 510C and fourth Ground Element 520D extend over the third Dipole Element 550A and the fourth Dipole Element 550B respectively and are each coupled to the Ground Plane 540. The third Ground Element 510C and fourth Ground Element 520D are depicted as being directly electrically coupled to the Ground Plane 540 but these may, within other embodiments of the invention, be electromagnetically coupled.

[0089] Within the embodiments of the invention described above with respect to Figures 1 to 5 the antenna structure may be designed and intended to be implemented such that the first gap and third gap are equal such that the second gap and fourth gap are equal or the first gap and third gap are different such that the second gap and fourth gap are different. In each instance the antenna structure is designed and intended to be implemented such that the first gap and second gap are equal and the third gap and fourth gap are equal. However, it would be evident to one of skill in the art that manufacturing tolerances may result in the first gap and second gap being unequal and / or the third gap and fourth gap being unequal for a single axis of a CP antenna, such as depicted in Figure 5. Further, the first gap and / or second gap may be different between one axis of the CP antenna and the other as well as the third gap and / or fourth gap may be different between one axis of the CP antenna and the other.

[0090] Accordingly, as will become evident with respect to embodiments of the invention described below the inventors have established techniques to address these manufacturing tolerances and their resulting impact on the antenna performance.

[0091] Referring to Figure 6A there is depicted an exploded perspective View 600A of an inventive CP antenna according to an embodiment of the invention. As depicted the CP Antenna 600 comprises a flexible circuit (FLEX) 610 which provides a physical support for the ground plane elements of the first and second Ground Elements 360A and 360B associated with each of the orthogonal dipoles, namely first Dipole 630A and second Dipole 630B. Accordingly, the FLEX 610 has four ground planes on each end arm of the FLEX 610. A Support 620 is disposed between the pair of assembled orthogonal dipoles, first Dipole 630A and second Dipole 630B which engages features on the upper surfaces of each of the first Dipole 630A and second Dipole 630B to retain them in position at the Support 620. Other features on the lower edges of each of the first Dipole 630A and second Dipole 630B engage with corresponding features on the Base 650 to retain the first Dipole 630A and second Dipole 630B in position orthogonally to one another. The interlocking design of the first Dipole 630A and second Dipole 630B and the combination of Base 650 and Support 620 also provide for the first Dipole 630A and second Dipole 630B to be orthogonal to the Base 650. The Base 650 comprising the lower ground plane, e.g., GP 350 in Figure 3, such as upon the lower surface distal to that the antenna elements are assembled upon. The first Dipole 630A and second Dipole 630B also engage with Mounting 640 which aids assembly and thereby improves manufacturability but also as outlined below can provide tuning for improved antenna performance reproducibility.

[0092] Now referring to Figure 6B there is depicted a top View 600B of the FLEX 610 in planar form prior to being shaped over the first Dipole 630A, second Dipole 630B and Support 620 and being attached to the Base 650 with first and second Tabs 615A and 615B inserted into Openings 655 within the Base 650. The variant of the FLEX 610 depicted in Views 600A and 600B in Figures 6A and 6B respectively comprising a pair of first Tabs 615A and a second Tab 650B. The second Tab 650B being slightly longer than the first Tabs 615A and with an opening through it alt6hough within other embodiments of the invention the design of each tab of the set of tabs at the distal end of a petal of the FLEX 610 may be that of the first Tab 615A or second Tab 615B.

[0093] Referring to Figure 6C there is depicted a top View 600C of a Flexible Circuit 610B which is a variant of the FLEX 610 depicted in Figures 6A and 6B. The Flexible Circuit 610B has a pair of Shaped Tabs 615C at the distal end of each petal. As evident from Figures 6D and 6E these Shaped Tabs 615C are inserted into Openings 655 within the Base 650. These are shaped such that Shaped Tabs 615C can be inserted and then the flexibility in Flexible Circuit 610B pushes the petals towards the outer rim of the Base 650 and therein the Openings 655wherein projection on the outer edge of the Openings 655 engage with the Shaped Tabs 615C such that the distal ends of the petals of the Flexible Circuit 61 OB are retained in position and do not spring back out of the Openings 655.

[0094] Now referring to Figure 7A there is depicted an assembled perspective view of the inventive CP antenna according to an embodiment of the invention as depicted in Figure 6A. Accordingly, the FLEX 610, Support 620, first Dipole 630A, second Dipole 630B and Mounting 640 are depicted assembled to the Base 650.

[0095] The lower edges of each arm of the FLEX 610 are depicted with mechanical structures similar to those depicted within PCT / CA2020 / 051188 by the inventors (published as WO / 2021 / 046,635) to provide PCBs for the dipole(s) which support a mounting having metallization for the ground elements disposed upon it such that the ground planes on the FLEX 610 can be soldered directly to the ground plane on the lower surface of Base 650.

[0096] Optionally, the FLEX 610 may have additional mechanical structures such as described and depicted by the inventors within U.S. Provisional Patent 63 / 499,088 which provide mechanical engagement between the FLEX 610 and the first Dipole 630A and / or second Dipole 630B.

[0097] Referring to Figure 7B to 7D there are depicted alternate ground plane interconnections for an inventive CP antenna according to an embodiment of the invention depicted in Figures 6A-6E to improve manufacturability and improved assembled antenna reproducibility. As depicted the lower edge of the FLEX 610 has three projections (tabs) with metallization that extend through the Base 650. In Figure 7A only the central tab is soldered to the Base Ground Plane 655 on the lower side of the Base 650. In contrast in Figure 7C the outer tabs are both connected whilst in Figure 7D only one of the outer pair of tabs is connected.

[0098] Accordingly, adjustments of the soldering connections from the ground plane on the FLEX 610 to the Base Ground Plane 655 result in different paths for the high frequency currents flowing in the antenna within the respective AL of the antenna incorporating this ground plane on the FLEX 610, the Base Ground Plane 655 and the associated feed and first / second elements of the dipole. These soldering connection based adjustments, by virtue of adjusting the AL of an arm of a dipole, thereby provide some tuning of that arm of the dipole, namely the one of the first Element 110A and second Element HOB according to which end of the Carrier 160 the solder connections are being adjusted. It would be evident therefore that different soldering connections may be employed for each of the first Element 110A and second Element HOB on one dipole and that these may be similar to or different to those employed for the first Element 110A and second Element 110B of the other orthogonal dipole.

[0099] Within other embodiments of the invention the number of tabs and their positions relative to a centre line or other reference point of the ground metallization may be varied in different antenna designs to provide different tuning options and configurations.

[0100] Referring to Figure 8 there is depicted a cross-sectional view of an assembled inventive CP antenna according to an embodiment of the invention depicted in Figures 6A-6E and 7A-7D respectively. Accordingly, the cross-section is along the axis of the first Dipole 630A which is accordingly face-on in Figure 8. The upper linking element of the second Dipole 630B which sits atop the first Dipole 630A is evident in the upper middle of Figure 8. The Support 640 depicted in Figure 6 has been omitted for clarity. The first Dipole 630 A has openings within its lowest edge that fit over the Mounting 640 which is also assembled onto the Base 650. At the upper end of the first Dipole 630A there are Projections 810 which fit through Openings 820 within the FLEX 610. As will become evident from Figures 12 to 14 which are described below the Projections 810 have metallization forming part of the respective dipole elements of the first Dipole 630 A, such as first and second Elements 110 and HOB respectively in Figure 1, supporting soldering of a metallization pattern on the FLEX 610 to a Projection 810 thereby forming a mechanical interface between the first Dipole 630A and the FLEX 610.

[0101] A similar cross-section orthogonal to that in Figure 8 and offset from the centre line of the antenna is depicted in Figure 9. Accordingly, second Dipole 630B is depicted spanning across with the vertical section of first Dipole 630A centrally disposed relative to the second Dipole 630B. The first Dipole 630A extending vertically through the Mounting 640. In this cross-section the Support 620 is depicted which provides a mechanical alignment of the upper edges of the first Dipole 630 A and second Dipole 630B relative to one another. The alignment of the first Dipole 630A and second Dipole 630B also being provided by the Mounting 640 and their tabs fitting into slots within the Base 650. Also evident are the Projection 810 and Opening 820 although the metallization on the FLEX 610 is omitted for clarity.

[0102] Referring to Figure 10 there is depicted a mounting - tuning element forming part of an inventive CP antenna according to an embodiment of the invention depicted in Figure 6A to 9 respectively. The mounting, such as Mounting 640 in Figure 6, has orthogonal slots and features to engage the dipoles, such as first Dipole 630A and second Dipole 630B respectively in Figure 6A. As will become evident from the description below the specific design and / or material of the mounting - tuning element provides for some tuning and / ordecoupling of the pair of orthogonal dipoles, such as first Dipole 630A and second Dipole 630B respectively in Figure 6.

[0103] Now referring to Figure 11 there is depicted a side elevation view of an assembled inventive CP antenna according to an embodiment of the invention depicted in Figures 6A to 10 respectively. Again the Support 620 has been omitted for clarity. Accordingly, to the left there is depicted a first Projection 810A on a Dipole 1110 is depicted projecting through an opening with within the FLEX 610. Dipole 1110 may, for example, be first Dipole 630A in Figure 6A, second Dipole 630B in Figure 6A or Carrier 160 in Figure 1 with the first and second Elements 110A and HOB respectively.

[0104] To the right a second Projection 810B of an orthogonal dipole is depicted projecting through an Opening 820 within the FLEX 610. Disposed around the Opening 820 is a first Metallization 1120. The first Metallization 1120 being separated from the ground plane (GP) Metallization 1140 of the FLEX 610 by FLEX Opening 1130 within the GP metallization such that the first Metallization 1120 is electrically isolated from the GP Metallization 1140.

[0105] However, by soldering the metallization on the second Projection 810B to the first Metallization 1120 the FLEX 610 is mechanically coupled to the carrier of that dipole. The capacitance of the dipole element, which includes the metallization on the second Projection 810B, to the GP Metallization 1140 is therefore defined by the design, e.g., dimensions and geometry, of the FLEX Opening 1130 between the first Metallization 1120 and the GP Metallization 1140. Accordingly, the design depicted in addition to mechanically linking each dipole to the FLEX 610 also allows the capacitance from each dipole element to ground to controlled with improved reproducibility during antenna manufacturing.

[0106] Referring to Figure 12 there is depicted a photograph of this mounting between a dipole, specifically the Projection 810, and a carrier (e.g., the insulating underlying mechanical support of FLEX 610) upon which is formed the GP Metallization 1140 for the inventive CP antenna according to an embodiment of the invention depicted in Figures 6A to 11 respectively. Solder 1210 between the Projection 810 and the metallization around the opening being evident. As noted the design approach improves manufacturability and provides improved assembled antenna reproducibility by mechanically defining the capacitance between a dipole element and the ground plane upon the FLEX 610.

[0107] Evident within Figure 12 are additional Marks 1220 within the GP Metallization 1140. These allow for an adjustment of the FLEX Opening 1130 either post-manufacturing of the FLEX 610 or post- assembly of the antenna. This being achieved, for example, by mechanical scribing of the GP Metallization using the Marks 1220 as guides. Alternatively,laser cutting, laser ablation etc. may be employed. In this manner the capacitance from a dipole element to ground can be adjusted post-assembly for example.

[0108] Now referring to Figure 13 there is depicted a dipole upon a carrier as employed within an inventive CP antenna according to an embodiment of the invention depicted in Figures 6 A to 12 respectively. As depicted the dipole comprises first Element 1330 which extends from a first Projection 810A to first Feed 1340 and a second Element 1360 which extends from a second Projection 810B to a second Feed 1350. The first Feed 1340 and second Feed 1350 coupling to Feed Connections 1320 and 1330 respectively which form a Feed Point (FP) to the dipole.

[0109] Referring to Figure 14 there is depicted a flexible circuit, e.g. FLEX 610 in Figure 6 A, which provides the ground planes (e.g. GP Metallization 1140 in Figure 11) and mechanical support of these. The flexible circuit supporting ground elements of an inventive CP antenna according to an embodiment of the invention depicted in Figures 6 to 13 respectively. The insert depicts the Opening 820, first Metallization 1120, FLEX Opening 1130 and GP Metallization 1140 in each arm. Accordingly, opposing pairs of these arms are employed with each dipole of the pair of dipoles of the CP antenna.

[0110] Now referring to Figures 15A and 15B there are depicted variations in the mounting - tuning element of Figure 10 as employed within inventive CP antennae as depicted in Figures 6 A to 14 to support improved manufacturability and improved assembled antenna reproducibility. Within Figure 15A a first Mount 1510 is depicted which provides equivalent mechanical support of the dipoles as Mounting 640 in Figure 6. Similarly in Figure 15B a second Mount 1520 is depicted similarly provides equivalent mechanical support of the dipoles as Mounting 640 in Figure 6.

[0111] First Mount 1510 has a first gap, Hr, between its upper edge and the lower edge of the metallization of the dipole elements. Second Mount 1520 has a second gap, H2, between its upper edge and the lower edge of the metallization of the dipole elements. Accordingly, the first Mount 1510 and second Mount 1520 cover different portions of the vertical feeds, e.g., first Feed 1340 and second Feed 1350 in Figure 13.

[0112] It is known that production of elements for antennas such as the inventive CP antenna depicted and described with respect to Figures 1 to 15B results in variability from the different tolerances of the different manufacturing processes as well as those arising from assembly processes. Accordingly, the inventors established that the centre of a dipole relative to mechanical centre of the antenna varies according to the mechanical tolerances of cutting / isolating the carrier for the dipole. Similarly, tolerances of forming the Base 650 and the FLEX610 coupled with the mechanical offsets of the dipole elements upon their carrier result in offsets of the dipoles relative to the CP antenna and FLEX 610.

[0113] Within Figures 6A to 15B the projection upon the carrier supporting the dipole element metallization which is electrically connected to the metallization around the opening within the FLEX 610 through which the projected extends is depicted as being at the upper distal ends of the dipole elements. In Figure 17 the projection is at the lower distal end but it would be evident that other designs may be employed without departing from the scope of the invention. Such designs may include multiple projections and openings within the FLEX 610 in some embodiments of the invention where one or all such multiple projections and openings are employed. Optionally, one or a subset may be employed to provide adjustment of antenna performance.

[0114] The embodiments of the invention described and depicted with respect to Figures 6A to 15B and 17 may, with respect to an alternative description, be viewed as comprising a printed circuit, another printed circuit and a pair of ground elements. The printed circuit comprising a dipole element disposed on an insulating substrate with centrally disposed feed connections where metallization of the dipole element at each distal end of the dipole element from the centrally disposed feed connections extends onto protruding extensions of the printed circuit.

[0115] The another printed circuit having a ground plane disposed parallel to and offset from a longitudinal axis of the dipole element by a predetermined offset. With respect to the pair of ground elements then each ground element has a predetermined length and width and is metallized upon an insulating substrate and is disposed at a distal end of the dipole element. The insulating substrate may be common to the pair of ground elements of they may within another embodiment of the invention be a pair of insulating substrates.

[0116] A first end of each ground element of the pair of ground elements is electrically connected to the ground plane on the another printed circuit. Each ground element of the pair of ground elements comprises by a hole in its insulating substrate which is encircled by a metallized region isolated from the ground element metallizations by one or more defined gaps. Each metallised protruding extension of the printed circuit board at the distal ends of the dipole element is inserted into the hole of a ground element of the pair of ground elements and the metallization of the dipole element at that distal end of the dipole element is directly electrically connected to the metallized region of that ground element of the pair of ground elements. Optionally, the protruding extension of the printed circuit board at the distal ends of the dipole element may project through the hole of the ground element of the pair of ground elements associated with it.

[0117] The one or more defined gaps between the metallized region of each ground element and the ground element defines a characteristic capacitance between each dipole of the dipole element and ground such that manufacturing and / or assembly variations of the capacitance between the dipole and ground are reduced or ideally eliminated. Within an embodiment of the invention the one or more gaps may be a single gap, e.g. a circular metallized region with constant radial gap to the ground element. Within an embodiment of the invention the one or more gaps may be a pair of gaps, e.g. a rectangular metallized region with one gap to the ground element at each end of one axis of the rectangle and another gap to the ground element along another axis of the rectangle.

[0118] The embodiments of the invention described and depicted with respect to Figures 6A to 15B and 17 may, with respect to an alternative description, be viewed as comprising a printed circuit, another printed circuit and a pair of ground elements. The printed circuit comprising a dipole element disposed on an insulating substrate with centrally disposed feed connections where metallization of the dipole element at each distal end of the dipole element from the centrally disposed feed connections extends onto protruding extensions of the printed circuit.

[0119] The another printed circuit having a ground plane disposed parallel to and offset from a longitudinal axis of the dipole element by a predetermined offset. With respect to the pair of ground elements then each ground element has a predetermined length and width and is metallized upon an insulating substrate and is disposed at a distal end of the dipole element. The insulating substrate may be common to the pair of ground elements of they may within another embodiment of the invention be a pair of insulating substrates.

[0120] A first end of each ground element of the pair of ground elements is electrically connected to the ground plane on the another printed circuit. Each ground element of the pair of ground elements comprises by a hole in its insulating substrate which is encircled by a metallized region isolated from the ground element metallizations by one or more defined gaps. Each metallised protruding extension of the printed circuit board at the distal ends of the dipole element is inserted into the hole of a ground element of the pair of ground elements and the metallization of the dipole element at that distal end of the dipole element is directly electrically connected to the metallized region of that ground element of the pair of ground elements. Optionally, the protruding extension of the printed circuit board at the distal ends of the dipole element may project through the hole of the ground element of the pair of ground elements associated with it.

[0121] Accordingly, radiative excitation of each ground element of the pair of ground elements to the metallized region of that ground element of the pair of ground elements via adefined capacitive reactance. The one or more defined gaps between the metallized region of each ground element and the ground element define the characteristic capacitance.

[0122] The inventors established that a dipole antenna as depicted as described comprises a pair of antenna loops, each antenna loop formed between an arm of the dipole, the ground plane and the ground element which extends from the ground plane to a distal end of the arm of the dipole. The antenna loop being sensitive to the variations within the radiative coupling between the distal end of the arm of the dipole and the ground element arising from mechanical tolerances, assembly variations etc. Accordingly, the inventors established that mechanically connecting the circuit board upon which the dipole was formed to the ground element eliminate some of these variations whilst electrically connecting the dipole to metallization upon the ground element removed other variations such that the radiative coupling was consistent between antennas as the capacitive reactance between the dipole arm and the ground element is defined by one or more gaps between the metallization upon the ground element and the ground plane metallization upon the ground element.

[0123] Accordingly, the inventors modify each ground element of the pair of ground elements so that it coupled to a metallised protruding extension of the printed circuit board at a different end of the dipole via the metallized region of the ground element which is isolated from a ground plane metallization of the ground element by the one or more defined gaps. The metallised protruding extension is electrically connected to the metallized region of the ground element. If soldered this electrical connection between the metallised protruding extension and the metallized region of the ground element provides for the mechanical connection as well as electrical connection.

[0124] The embodiments of the invention described and depicted with respect to Figures 6A to 15B and 17 may, with respect to an alternative description, be viewed as comprising a printed circuit board (PCB), a base ground PCB, first and second metallized ground elements and first and second predetermined capacitive reactances. The PCB provides an insulating substrate upon which is disposed a dipole element with disposed feed terminals for connection to a balanced feed network, with metallization of the dipole comprising a first terminal forming part of the feed terminals, a second terminal forming another part of the feed terminals, and at each distal end of the dipole element extending onto a third terminal and a fourth terminal.

[0125] The base ground PCB has a planar geometry with metallization providing a ground plane of the antenna having a dimension along the PCB insulating substrate along a longitudinal axis of the dipole element defined in dependence upon a length of the dipole element along the longitudinal axis, the base ground PCB disposed parallel to and offset fromthe longitudinal axis of the dipole element by a predetermined offset. The first and second metallized ground elements are metallized onto insulating substrates, each said metallized ground element having a first end and a distal second end, each of a predetermined length and width having the first end electrically connected to the base ground PCB at one or more points laterally disposed on the base ground PCB and their second distal end disposed proximate to a distal end of the dipole element.

[0126] The first predetermined capacitive reactance is connected between the third terminal of the dipole element and the second distal end of the first metallized ground element whilst the second predetermined capacitive reactance is connected between the fourth terminal of the dipole element and the second distal end of the second metallized ground element. The balanced feed network provides identical, antipodal feed signals at the first terminal and the second terminal wherein the antenna configuration is effective to provide a miniaturized antenna with an improved, wide bandwidth impedance at said first terminal and second terminal.

[0127] Within an embodiment of the invention the first metallized ground element comprises a first metallization isolated from a second metallization extending from the first end towards the second distal end and the second metallized ground element comprises a third metallization isolated from a fourth metallization extending from the first end towards the second distal end. In this embodiment the third terminal of the dipole element is directly connected electrically to the first metallization, the fourth terminal of the dipole element is directly connected electrically to the second metallization, the third terminal is mechanically connected to the first metallized ground element and the fourth terminal is mechanically connected to the second metallized ground element. Accordingly, the first predetermined capacitive reactance is defined in dependence upon a geometry of a gap between the first metallization and the second metallization and the second predetermined capacitive reactance is defined in dependence upon a geometry of a gap between the third metallization and the fourth metallization.

[0128] Whilst the mechanical projections on the dipole carriers and electrical connections between the metallization upon these to the metallization upon the FLEX 610 provides improved reproducibility of the electrical capacitance from a dipole element to ground the mechanical offsets of the two dipole elements relative to one another result in different electrical capacitances between the facing elements of the two dipoles as depicted in Figure 16. First Image 1600A depicts a perspective of a pair of orthogonal dipoles. One comprising first and second Dipole Elements 1610 and 1620 respectively and the other third and fourth DipoleElements 1630 and 1640 respectively. Typically disposed on the other side of each carrier of a dipole is a ground plane.

[0129] Second Image 1600B depicts the capacitances between the dipole elements radially. Accordingly there is a first capacitance Cl between the first Dipole Element 1610 to the third Dipole Element 1630, a second capacitance C2 between the third Dipole Element 1630 to the second Dipole Element 1620, a third capacitance C3 between the second Dipole Element 1620 to the fourth Dipole Element 1640, and a fourth capacitance C4 between the fourth Dipole Element 1640 to the first Dipole Element 1610. When the first and second Dipole Elements 1610 and 1620 are disposed equally either side of a central vertical axis of the crossing dipoles and the third and fourth Dipole Elements 1630 and 1640 similarly equally disposed either side of this central vertical axis with the same separation as the first and second Dipole Elements 1610 and 1640 then the first to fourth capacitances Cl to C4 would be equal. However, as discussed above manufacturing tolerances result in offsets of dipole elements such that the first to fourth capacitances Cl to C4 are not all equal resulting in artifacts within the frequency response of the antenna which can be within the frequency response of the operating band of the antenna.

[0130] These resulting variations in the four capacitances result in some electromagnetic cross-coupling between the orthogonal dipoles which manifests itself within the antenna response. Accordingly, the inventors established that providing an increased dielectric constant material between the dipoles allowed these artifacts within the antenna response to be shifted out of the operating band of the antenna. Accordingly, the mechanical support of the Mounting 640 at the lower portion was augmented with the vertical central section.

[0131] Within third Image 1600C a Tuning Block 1650 has been disposed filling part of the region between the pairs of dipoles. Accordingly, due to the material employed (i.e. its dielectric constant), the radius of the Tuning Block 1650 and the distance vertically the Tuning Block 1650 covers the first to fourth capacitances Cl to C4 are now adjusted to fifth to eighth capacitances C5 to C8 respectively. Additionally, the Tuning Block 1650 adds loss to the microwave feeds from the bottom of the carriers to the dipole elements. In this manner the artifacts within the frequency response of the antenna can be shifted to outside the frequency response of the operating band of the antenna. Within an embodiment of the invention the Tuning Block 1650 may be Mounting 640 in Figure 6 and as depicted in Figure 10.

[0132] Alternatively, within other designs the mounting of the dipole carriers may be an element disposed close to the base, e.g. Base 650, with one or more Tuning Block(s) 1650attached to the base pr mounting. As depicted in Figures 15A and 15B different vertical heights provide for adjustment of the capacitances and hence microwave performance of the antenna.

[0133] Accordingly, the concepts disclosed above address reproducibility in antenna performance by mitigating manufacturing tolerances and variations.

[0134] Within the embodiments of the invention described above with respect to Figures 1 to XX the structure has been described primarily from the viewpoint or perspective of a receiver of microwave or radio frequency (RF) signals. However, it would be evident to one of skill in the art that the antenna structures described and depicted according to embodiments of the invention may be employed with a transmitter of microwave or RF signals as well as a transceiver for micro wave or RF signals.

[0135] Within the embodiments of the invention a former, i.e. a carrier or PCB, for either a dipole or a pair of cross dipoles or three of more dipoles arranged radially may be designed and formed evenly distribute around the periphery of a surface and form the antennas across this surface. Within embodiments of the invention with a pair of dipoles orthogonally disposed for circularly polarized microwave signals the former may be designed and formed to provide the pair of parasitic elements distributed around and across its surface. Within the embodiments presented the surface may be quasi-rectangular or quasi-hemispherical. However, within other embodiments of the invention the surface may be a frusto-conical surface, an ellipsoidal surface or another surface either by a regular polygon, irregular polygon or one or more mathematical functions, etc. Within other embodiments of the invention the former may be designed and formed to provide N dipole antennas, where N is a positive integer, evenly distributed around the periphery of a polygonal surface and form the antennas across this polygonal surface.

[0136] Such a polygonal surface may have 2N sides or other numbers although typically more sides yield lower angular transitions and hence reduced induced stress and / or fatigue in the former. In a similar manner a former for the parasitic element or parasitic elements may be designed in a similar manner as that described above for the dipoles.

[0137] It would be evident to one of skill in the art that the filar elements are electrical conductors (conductors) formed from a suitable conductive material or combination of conductive materials in alloy and / or layered form. Such conductive materials may include, but not be limited to, copper, gold, silver, aluminum, titanium, tungsten, platinum, palladium, and zinc.

[0138] Specific details are given in the above description to provide a thorough understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details. For example, circuits may be shown in block diagramsin order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.

[0139] The foregoing disclosure of the exemplary embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.

[0140] Further, in describing representative embodiments of the present invention, the specification may have presented the method and / or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be constmed as limitations on the claims. In addition, the claims directed to the method and / or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention.

Claims

CLAIMSWhat is claimed is:

1. An antenna comprising a printed circuit comprising a dipole element disposed on an insulating substrate with centrally disposed feed connections where metallization of the dipole element at each distal end of the dipole element from the centrally disposed feed connections extends onto protruding extensions of the printed circuit; another printed circuit having a ground plane disposed parallel to and offset from a longitudinal axis of the dipole element by a predetermined offset, and a pair of ground elements, each ground element having a predetermined length and width and metallized upon an insulating substrate and disposed at a distal end of the dipole element; wherein: a first end of each ground element of the pair of ground elements is electrically connected to the ground plane on the another printed circuit; each ground element of the pair of ground elements comprises by a hole in its insulating substrate which is encircled by a metallized region isolated from the ground element metallizations by one or more defined gaps; each metallised protruding extension of the printed circuit board at the distal ends of the dipole element is inserted into the hole of a ground element of the pair of ground elements and the metallization of dipole element at that distal end of the dipole element is directly electrically connected to the metallized region of that ground element of the pair of ground elements; and radiative excitation of each ground element of the pair of ground elements to the metallized region of that ground element of the pair of ground elements via a defined capacitive reactance.

2. The antenna according to claim 1, wherein the one or more defined gaps between the metallized region of each ground element and the ground element define the characteristic capacitance.

3. An antenna comprising: a dipole upon a printed circuit; and a pair of ground elements; whereineach ground element of the pair of ground elements is radiatively coupled to a different end of the dipole via a defined capacitive reactance and mechanically connected to the printed circuit.

4. The antenna according to claim 3, wherein each ground element of the pair of ground elements is coupled to a metallised protruding extension of the printed circuit board at a different end of the dipole via a metallized region of the ground element isolated from a ground plane metallization of the ground element by one or more defined gaps; the metallised protruding extension is electrically connected to the metallized region of the ground element; and the defined capacitive reactance is established in dependence upon the one or more defined gaps.

5. An antenna comprising a printed circuit comprising a dipole element disposed on an insulating substrate with centrally disposed feed connections where metallization of the dipole element at each distal end of the dipole element from the centrally disposed feed connections extends onto protruding extensions of the printed circuit; another printed circuit having a ground plane disposed parallel to and offset from a longitudinal axis of the dipole element by a predetermined offset, and a pair of ground elements, each ground element having a predetermined length and width and metallized upon an insulating substrate and disposed at a distal end of the dipole element; wherein: a first end of each ground element of the pair of ground elements is electrically connected to the ground plane on the another printed circuit; each ground element of the pair of ground elements comprises by a hole in its insulating substrate which is encircled by a metallized region isolated from the ground element metallizations by one or more defined gaps; and each metallised protruding extension of the printed circuit board at the distal ends of the dipole element is inserted into the hole of a ground element of the pair of ground elements and the metallization of dipole element at that distal end of the dipole element is directly electrically connected to the metallized region of that ground element of the pair of ground elements.

6. The antenna according to claim 5, wherein the one or more defined gaps between the metallized region of each ground element and the ground element defines a characteristic capacitance.

7. A method of providing an antenna comprising providing a printed circuit comprising a dipole element disposed on an insulating substrate with centrally disposed feed connections where metallization of the dipole element at each distal end of the dipole element from the centrally disposed feed connections extends onto protruding extensions of the printed circuit; providing another printed circuit having a ground plane disposed parallel to and offset from a longitudinal axis of the dipole element by a predetermined offset, and providing a pair of ground elements, each ground element having a predetermined length and width and metallized upon an insulating substrate and disposed at a distal end of the dipole element; wherein: a first end of each ground element of the pair of ground elements is electrically connected to the ground plane on the another printed circuit; each ground element of the pair of ground elements comprises by a hole in its insulating substrate which is encircled by a metallized region isolated from the ground element metallizations by one or more defined gaps; and each metallised protruding extension of the printed circuit board at the distal ends of the dipole element is inserted into the hole of a ground element of the pair of ground elements and the metallization of dipole element at that distal end of the dipole element is directly electrically connected to the metallized region of that ground element of the pair of ground elements.

8. The method according to claim 7, wherein the one or more defined gaps between the metallized region of each ground element and the ground element defines a characteristic capacitance.

9. An antenna comprising: a base; a dipole element extending upon a carrier where the dipole element is disposed at a defined distance above the base and extends in a plane horizontal to the base;a ground plane having a portion extending above the dipole element at a defined distance; wherein the dipole element extends along a projection of the carrier; the projection extends through an opening within the ground plane such that the dipole element also extends through the opening; a portion of the dipole element extending through the opening is electrically connected to metallization around the opening; and the metallization around the opening is electrically isolated from the ground plane by a region absent metallization of defined geometry and defined dimensions.

10. The antenna according to claim 9, wherein a capacitance between the dipole element and the ground plane is established in dependence upon the defined geometry and defined dimensions of the region absent metallization between the metallization around the opening and the ground plane.

11. The antenna according to claim 9, wherein the ground plane has another portion extending to the base and electrically connected to another ground plane forming part of the base.

12. An antenna comprising: a base; a pair of dipole elements extending upon a carrier radially from an axis perpendicular to the base where the pair of dipole elements are disposed at a defined distance above the base and extending in a plane horizontal to the base from an end towards the axis to a distal end; a ground plane having a first portion extending over a distal end of a dipole element of the pair of dipole elements at a defined distance and a second portion over a distal end of the other dipole element of the pair of dipole elements at the defined distance; wherein the dipole element of the pair of dipole elements extends along a first projection of the carrier and the other dipole element of the pair of dipole elements extends along a second projection of the carrier; the first projection extends through an opening within the first portion of the ground plane such that the dipole element of the pair of dipole elements extends through the opening;the second projection extends through an other opening within the second portion of the ground plane such that the other dipole element of the pair of dipole elements extends through the other opening; a portion of the dipole element of the pair of dipole elements extending through the opening is electrically connected to metallization around the opening; a portion of the other dipole element of the pair of dipole elements extending through the other opening is electrically connected to metallization around the other opening; the metallization around the opening is electrically isolated from the first portion of the ground plane by a region absent metallization of defined geometry and defined dimensions; and the metallization around the other opening is electrically isolated from the second portion of the ground plane by another region absent metallization of other defined geometry and defined dimensions.

13. The antenna according to claim 12, wherein a capacitance between the dipole element of the pair of dipole elements and the first portion of the ground plane is established in dependence upon the defined geometry and defined dimensions of the region absent metallization between the metallization around the opening and the first portion of the ground plane; and another capacitance between the other dipole element of the pair of dipole elements and the second portion of the ground plane is established in dependence upon the other defined geometry and defined dimensions of the region absent metallization between the metallization around the other opening and the second portion of the ground plane.

14. The antenna according to claim 12, wherein the first portion of the ground plane has another portion extending to the base and electrically connected to another ground plane forming part of the base; and the second portion of the ground plane has a further portion extending to the base and electrically connected to another ground plane forming part of the base.

15. The antenna according to claim 12, wherein the first portion of the ground plane has another portion extending to the base and electrically connected to another ground plane forming part of the base; andthe second portion of the ground plane has a further portion extending to the base and electrically connected to another ground plane forming part of the base; wherein the another portion of the ground plane is further radially from the axis perpendicular to the base than the dipole element of the pair of dipole elements and the further portion of the ground plane is further radially from the axis perpendicular to the base than the other dipole element of the pair of dipole elements.

16. An antenna comprising: a base; a first dipole comprising a pair of dipole elements extending upon a first carrier radially from an axis perpendicular to the base where the pair of dipole elements are disposed at a defined distance above the base and extending in a plane horizontal to the base from an end towards the axis to a distal end; a second dipole comprising an other pair of dipole elements extending upon a second carrier radially from the axis perpendicular to the base where the other pair of dipole elements are disposed at a defined distance above the base and extending in a plane horizontal to the base from an end towards the axis to a distal end; and a mounting element upon the base comprising: a portion upon which the first carrier and second carrier are mounted orthogonally to one another; and a series of other portions, each other portion extending vertically away from the portion such that it is disposed between a predetermined portion of the first carrier and the second carrier.

17. The antenna according to claim 16, wherein a characteristic feature of the frequency response of the antenna within a frequency band of operation of the antenna occurs outside of the frequency band of operation of the antenna when the first dipole and second dipole are mounted upon the mounting element and inside the frequency band of operation of the antenna when the first dipole and second dipole are employed without the series of other portions.

18. The antenna according to claim 16, wherein a frequency of a characteristic feature of the frequency response of the antenna within a frequency band of operation of the antenna is shifted relative to its frequency when the first dipole and second dipole are employed without the series of other portions; and the shift in the frequency of the characteristic feature of the frequency response of the antenna varies according to the vertical extent of the series of other portions.

19. An antenna comprising: a dipole element, on a printed circuit board (PCB) insulating substrate, with centrally disposed feed terminals for connection to a balanced feed network, with metallization of the dipole comprising a first terminal forming part of the feed terminals, a second terminal forming another part of the feed terminals, and at each distal end of the dipole element extending onto a third terminal and a fourth terminal; a base ground PCB with planar geometry with metallization providing a ground plane of the antenna having a dimension along the PCB insulating substrate along a longitudinal axis of the dipole element defined in dependence upon a length of the dipole element along the longitudinal axis, the base ground PCB disposed parallel to and offset from the longitudinal axis of the dipole element by a predetermined offset, first and second metallized ground elements metallized on insulating substrates, each said metallized ground element having a first end and a distal second end, each of a predetermined length and width having the first end electrically connected to the base ground PCB at one or more points laterally disposed on the base ground PCB and their second distal end disposed proximate to a distal end of the dipole element; a first predetermined capacitive reactance connected between the third terminal of the dipole element and the second distal end of the first metallized ground element; and a second predetermined capacitive reactance connected between the fourth terminal of the dipole element and the second distal end of the second metallized ground element; wherein the balanced feed network provides identical, antipodal feed signals at the first terminal and the second terminal; and said antenna configuration is effective to provide a miniaturized antenna with an improved, wide bandwidth impedance at said first terminal and second terminal.

20. The antenna according to claim 19, wherein the first metallized ground element comprises a first metallization isolated from a second metallization extending from the first end towards the second distal end; the second metallized ground element comprises a third metallization isolated from a fourth metallization extending from the first end towards the second distal end; the third terminal of the dipole element is directly connected electrically to the first metallization; the fourth terminal of the dipole element is directly connected electrically to the second metallization; the third terminal is mechanically connected to the first metallized ground element; the fourth terminal is mechanically connected to the second metallized ground element; the first predetermined capacitive reactance is defined in dependence upon a geometry of a gap between the first metallization and the second metallization; and the second predetermined capacitive reactance is defined in dependence upon a geometry of a gap between the third metallization and the fourth metallization.

Images