Low-elevation-angle zero-setting antenna method and system

Abstract

A Global Navigation Satellite System (GNSS) employs a set of geospatially positioned satellites to broadcast precisely synchronized navigation messages, enabling a dedicated GNSS receiver to determine network time and geographic location. However, such GNSS antennas are susceptible to interference in the horizon direction. The susceptibility to interference of the antenna is typically reduced by reducing antenna gain or zeroing it at low elevation angles. However, such designs are only applicable to narrowband situations, while GNSS antennas need to operate under broadband, e.g., in multiple GNSS bands. Thus, a broadband antenna design is provided that reduces gain or zeros it at low elevation angles.

Description

Cross-reference to related applications

[0001] This patent claims priority to U.S. Provisional Patent Application 63 / 499,088, filed April 28, 2023. Technical Field

[0002] This patent application relates to a low elevation angle nulling antenna, a method for implementing a low elevation angle nulling antenna using a four-arm antenna element, assembling a flexible substrate antenna, and a method for assembling a flexible substrate antenna. Background Technology

[0003] Global Navigation Satellite Systems (GNSS) use a set of geospatial satellites to broadcast precisely synchronized navigation messages, enabling dedicated GNSS receivers to determine network time and geographic location. These receivers not only provide a ubiquitous global time reference but also support a wide range of geospatial applications, from consumer navigation devices to global warming monitoring equipment, precision agriculture, and even military applications.

[0004] However, such GNSS antennas are susceptible to interference along the horizon. Therefore, it is beneficial to provide a GNSS antenna capable of reducing or even zeroing gain at low elevation angles, commonly referred to as a Low Elevation Null Antenna (LEANA). However, existing LEANA designs are only suitable for narrowband applications, while GNSS antennas need to operate over a wide range, for example, across multiple GNSS frequency bands.

[0005] Therefore, it would be beneficial to provide a method for LEANA devices and systems that can operate with high efficiency over broadband.

[0006] Other aspects and features of the invention will become apparent to those skilled in the art after reading the following description of specific embodiments of the invention in conjunction with the accompanying drawings. Summary of the Invention

[0007] One object of the present invention is to overcome the limitations of the prior art related to low elevation angle nulling antennas, methods for implementing low elevation angle nulling antennas using quad-arm antenna elements, assembling flexible substrate antennas, and assembly methods of flexible substrate antennas.

[0008] According to an embodiment of the present invention, a method is provided, comprising: An upper antenna element is provided for receiving or transmitting circularly polarized wireless signals within a predetermined frequency range. The upper antenna element is arranged above the lower antenna element along a coaxial line with the lower antenna element, and the upper antenna element includes a first electrical interface coupled to a circuit via an electrical path. A lower antenna element is provided for receiving and transmitting another circularly polarized wireless signal within a predetermined frequency range. The lower antenna element includes a second electrical interface coupled to a circuit via another electrical path; and A phase circuit is provided, located in another electrical path between the lower antenna element and the circuitry; wherein, A circularly polarized wireless signal is 180° out of phase with another circularly polarized wireless signal, which causes the antenna to exhibit maximum gain along the coaxial line and minimum gain in the direction perpendicular to the coaxial line. The phase circuit, combined with another electrical path between the circuit and the lower antenna element, provides a frequency-varying phase at the second electrical interface, which is equal to another frequency-varying phase at the first electrical interface; and The lower antenna element and the upper antenna element are rotated and offset relative to each other. This rotational offset is determined based on the absolute phase difference between the circularly polarized radio signal at the first electrical interface and another circularly polarized radio signal at the second electrical interface.

[0009] According to an embodiment of the present invention, an antenna is provided, comprising: The upper antenna element is used to receive or transmit circularly polarized wireless signals within a predetermined frequency range. The upper antenna element is arranged above the lower antenna element along a coaxial line with the lower antenna element, and the upper antenna element includes a first electrical interface coupled to a circuit through an electrical path. A lower antenna element for receiving and transmitting another circularly polarized wireless signal within a predetermined frequency range, the lower antenna element including a second electrical interface coupled to the circuit via another electrical path; and The phase circuit is located in another electrical path between the lower antenna element and the circuit; wherein, The circularly polarized wireless signal works in conjunction with another circularly polarized wireless signal to make the antenna exhibit maximum gain along the coaxial line and minimum gain in the direction perpendicular to the coaxial line. The phase circuit, combined with another electrical path between the circuit and the lower antenna element, provides a frequency-varying phase at the second electrical interface, which is equal to another frequency-varying phase at the first electrical interface; and The lower antenna element and the upper antenna element are rotated and offset relative to each other. This rotational offset is determined based on the absolute phase difference between the circularly polarized radio signal at the first electrical interface and another circularly polarized radio signal at the second electrical interface.

[0010] According to an embodiment of the present invention, an antenna is provided, comprising: The upper antenna element is used to receive or transmit circularly polarized wireless signals within a predetermined frequency range. The upper antenna element is arranged above the lower antenna element along a coaxial line with the lower antenna element, and the upper antenna element includes a first electrical interface coupled to a circuit through an electrical path. A lower antenna element for receiving and transmitting another circularly polarized wireless signal within a predetermined frequency range, the lower antenna element including a second electrical interface coupled to the circuit via another electrical path; and The phase circuit is located within the electrical path between the upper antenna element and the circuit; wherein, The circularly polarized wireless signal works in conjunction with another circularly polarized wireless signal to make the antenna exhibit maximum gain along the coaxial line and minimum gain in the direction perpendicular to the coaxial line. The phase circuit, combined with the electrical path between the circuit and the upper antenna element, provides a frequency-varying phase at the first electrical interface, which is equal to another frequency-varying phase at the second electrical interface; and The lower antenna element and the upper antenna element are rotated and offset relative to each other. This rotational offset is determined based on the absolute phase difference between the circularly polarized radio signal at the first electrical interface and another circularly polarized radio signal at the second electrical interface.

[0011] According to an embodiment of the present invention, an antenna is provided, comprising: The upper antenna element is used to receive or transmit circularly polarized wireless signals within a predetermined frequency range. The upper antenna element is arranged above the lower antenna element along a coaxial line with the lower antenna element, and the upper antenna element includes a first electrical interface coupled to a circuit through an electrical path. The lower antenna element is used to receive and transmit another circularly polarized wireless signal within a predetermined frequency range. The lower antenna element includes a second electrical interface coupled to the circuit via another electrical path. The first phase circuit is located within the electrical path between the upper antenna element and the circuit; and The second phase circuit is located in another electrical path between the lower antenna element and the circuit; wherein, The circularly polarized wireless signal works in conjunction with another circularly polarized wireless signal to make the antenna exhibit maximum gain along the coaxial line and minimum gain in the direction perpendicular to the coaxial line. The first phase circuit, combined with the electrical path between the circuit and the upper antenna element, provides a frequency-varying phase at the first electrical interface, which is equal to another frequency-varying phase determined at the second electrical interface by the second phase circuit combined with another electrical path; and The lower antenna element and the upper antenna element are rotated and offset relative to each other. This rotational offset is determined based on the absolute phase difference between the circularly polarized radio signal at the first electrical interface and another circularly polarized radio signal at the second electrical interface.

[0012] Other aspects and features of the invention will become apparent to those skilled in the art after reading the following description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0013] Embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 An array pattern consisting of two isotropic elements, fed with a 180° phase difference and arranged at half-wavelength spacing, is shown for implementing a low elevation null antenna (LEANA) device. Figure 2 An exemplary LEANA is shown, which employs a pair of stacked quad-arm helical antenna elements; Figure 3A The LEANA system according to an embodiment of the present invention is shown, including a pair of stacked quad-arm helical antenna elements and a phase compensation circuit; Figure 3B It shows Figure 3A The phase diagram of the system according to an embodiment of the invention is shown to visually represent the rotation applied between a pair of stacked quadruple-arm helical antenna elements; Figure 4 This is a schematic diagram of a three-section π-type network of a transmission line; Figure 5 It shows Figure 4 The three-section π-type network shown is combined with a capacitor to simplify the circuit. Figure 6 It shows that according to Figure 5 The phase-frequency response difference between the upper and lower antenna elements in the LEANA according to an embodiment of the present invention is shown. Figure 7 The diagram shows the orthogonal dipole element and its support carrier of a GNSS antenna according to U.S. patent application US2022 / 0,344,823 in the prior art, but excludes the lower ground plane / support and the flexible substrate antenna lobes. Figure 8 and Figure 9 An assembled antenna according to U.S. patent application US2022 / 0,344,823 in the prior art is shown, illustrating the lower ground plane / support and flexible substrate antenna lobes; Figure 10 An assembled antenna according to an embodiment of the present invention is shown, which employs a mechanical interface to reduce the assembly complexity of the flexible substrate antenna lobes with the support carrier or dipole element; and Figure 11 A partial assembly according to an embodiment of the present invention is shown. Figure 10 The antenna shown illustrates a mechanical interface designed to reduce the assembly complexity of flexible substrate antenna lobes with support carriers or dipole elements. Detailed Implementation

[0014] This invention relates to a low elevation angle nulling antenna, a method for implementing a low elevation angle nulling antenna using a four-arm antenna element, assembling a flexible substrate antenna, and a method for assembling a flexible substrate antenna.

[0015] The following description provides illustrative embodiments only and is not intended to limit the scope, applicability, or configuration of this disclosure. Rather, the following description of embodiments will provide guidance to those skilled in the art on implementing one or more embodiments of the invention. It should be understood that various changes to the function and arrangement of elements may be made without departing from the spirit and scope set forth in the appended claims. Therefore, the embodiments are examples or implementations of the invention, and not the only implementations. The various expressions “one embodiment,” “a kind of embodiment,” or “some embodiments” do not necessarily all refer to the same embodiment. Although various features of the invention may be described in the context of a single embodiment, these features may also be provided individually or in any suitable combination. Conversely, although for clarity, the invention may be described in the context of different embodiments and may be implemented in a single embodiment or any combination of embodiments.

[0016] When the description refers to "an embodiment," "an embodiment," "some embodiments," or "other embodiments," it means that a particular feature, structure, or characteristic described in those embodiments is included in at least one embodiment, but not necessarily in all embodiments. The vocabulary and terminology used herein are for descriptive purposes only and should not be construed as restrictive. It should be understood that when the element "a" or "an" is mentioned in the claims or description, this reference should not be construed as meaning that there is only one such element. It should be understood that when the description refers to a combination, feature, structure, or characteristic as "may," "may," "may," or "can" be included, that component, feature, structure, or characteristic is not necessarily included.

[0017] When this document uses terms such as "left," "right," "up," "down," "front," and "back," it refers to the orientation of a specific feature, structure, or element in the accompanying drawings describing the embodiments. Clearly, these directional terms have no specific meaning relative to the actual use of the device, as one or more users can use the device in multiple orientations.

[0018] When the terms "comprising," "including," "consisting of," and their grammatical variations are used herein, it does not preclude the addition of one or more components, features, steps, or integers, or combinations thereof, and these terms should not be construed as specifying any component, feature, step, or integer. Similarly, when the phrase "substantially constitutes" and its grammatical variations are used herein, it should not be construed as excluding additional components, steps, features, integers, or combinations thereof, provided that such additional features, integers, steps, components, or combinations thereof do not substantially alter the fundamental and novel characteristics of the claimed composition, apparatus, or method. If the specification or claims refer to the element "additional," this does not preclude the existence of multiple additional elements.

[0019] When referring to terms such as “vertical,” “along,” “parallel,” and their grammatical variations, descriptions of alignment and / or direction should not be considered absolute but rather subject to certain tolerances, such that these directions and / or alignments are “substantially” as stated. For example, the permissible range of tolerances for the aforementioned directions and / or alignments can be determined by manufacturing tolerances, performance tolerances, manufacturing costs, etc.

[0020] The term "azimuth" as used in this article refers to the rotation angle relative to a defined direction in the XY plane, centered on the origin.

[0021] The term "elevation angle" or "altitude" as used in this article refers to the angle between the Poynting vector of the incident plane wave and the XY plane (ground). Therefore, a grazing incident wave from the horizon has an elevation angle close to zero degrees, while a vertically incident wave has an elevation angle of 90°.

[0022] The “axial ratio” used in this article refers to the degree to which an antenna can suppress circularly polarized signals that do not require polarization (second rotation direction) relative to the desired polarization (first rotation direction). It is also a measure of the ability to suppress multipath signals, which is a very important parameter for precision antennas.

[0023] The term "phase center offset" as used in this article refers to the concept of a region associated with the antenna. For an ideal antenna, this region tends towards a point from which all signals can be considered to be received or transmitted. This is a virtual spatial region / point, typically located above the midpoint of the physical antenna, and is a limiting measure of the antenna's position in space.

[0024] The term "phase center shift" as used in this article refers to a measure of the apparent phase center shift at all incident angles (i.e., all azimuth and all elevation angles) and at all frequencies within the bandwidth. The phase center shift of an ideal antenna is zero.

[0025] As used herein, "lobe" refers to a metallized antenna structure, which may be independent, frame-supported, patterned on a substrate, or patterned on a frame-supported substrate / carrier, providing a receiving antenna element for a GNSS antenna. For simplicity, in the following mechanical description of a GNSS antenna according to embodiments of the present invention, the term lobe refers to the metallized antenna structure, any substrate or carrier, and auxiliary elements for mechanical connection / fixation, whether alone or in a lobe array with one or more other elements of the GNSS antenna. In the following functional description of a GNSS antenna according to embodiments of the present invention, the term lobe refers to the metallized antenna structure.

[0026] The term "dipole antenna" (commonly referred to as a dipole) used in this article refers to, but is not limited to, any type of antenna that produces a radiation pattern that approximates a basic electric dipole and has a radiation structure that supports a line current, which is excited in such a way that the current has only one node at each end.

[0027] Multi-band low elevation angle nulling antenna design GNSS receivers are widely used in both civilian and military markets. One mainstream configuration for civilian applications is the dual-frequency receiver (formerly Navstar GPS), which uses the L1+L2 bands of the GPS system. Table 1 below lists the operating frequency bands of GPS L1 and GPS L2 compared to those of other major GNSS systems introduced in the 21st century (i.e., BeiDou, Galileo, GLONASS, GPS, and NAVIC).

[0028]

[0029] Table 1: GNSS operating frequencies (closest to 1MHz) Furthermore, an increasing number of satellites are providing navigation signals in the L5 band, leading to a rise in GNSS receivers supporting L1+L5 or L1+L2+L5 signals. The L5 band offers several advantages, including, but not limited to: it is up to twice the frequency of the L2 band; it lies within the band designated by the International Telecommunication Union (ITU) for Aeronautical Radio Navigation Services (ARNS); it is less susceptible to interference from ground-based navigation aids; and it shares the same frequency space as the Galileo E5A signal. Similarly, GNSS receivers compatible with both GPS and Galileo systems offer advantages, such as allowing equipment containing such receivers to be used in areas accessible by one or both GNSS systems.

[0030] Single-band stacked low elevation null antenna The basic design concept of a Low Elevation Null Antenna (LEANA) is a radiating structure with maximum gain at the apex and minimum gain at or near the horizon, and null points existing across the entire azimuth plane around the horizon. This reduces interference from near-horizon radiation sources to GNSS systems coupled with the LEANA.

[0031] like Figure 1 As shown, this can be achieved by applying antenna array theory and stacking a pair of antenna elements one on top of the other along the z-axis (i.e., the antenna apex). When the pair of antenna elements are fed in opposite phase and their spacing is set to half a wavelength, a strong gain is generated at the apex in the resulting superimposed radiation pattern due to constructive interference; while a strong null is formed near the horizon due to destructive interference.

[0032] For example, GNSS antennas are very useful in time applications where continuous and reliable absolute time measurements are required from GNSS information. Therefore, it is beneficial in these applications to improve the reliability of GNSS antennas and prevent the loss of GNSS lock-on by minimizing their sensitivity to ground interference. Thus, a single-band LEANA antenna can be used. The design of a single-band stacked antenna typically begins with selecting a center frequency corresponding to the antenna's resonant frequency. For example, the AJ3000 antenna studied by Houtkul et al., "An Anti-jamming GNSS Antenna for Time Applications" (18th International Symposium on Antenna Technology and Applications Electromagnetism, 2018, pp. 1-3), selects a frequency corresponding to the 1575MHz GPS L1 signal.

[0033] However, a challenge with stacked antenna configurations is feeding the two elements in the array in out-of-phase. Traditionally, coaxial transmission lines (e.g., cables) are used to feed from the bottom antenna to the top antenna. However, the phase response reaching the top antenna via such a coaxial transmission line varies with frequency. While this phase response remains linear, its frequency slope will differ. This limits the antenna to operating in narrowband conditions, typically suitable for the upper band of GNSS covering GPS L1.

[0034] However, as mentioned above, many GNSS antenna applications require wider frequency bands, such as L1+L2 band combinations, L1+L5 band combinations, or L1+L2+L5 band combinations. Therefore, the inventors propose a novel LEANA implementation that uses phase manipulation technology to correct phase response variations between the two antenna elements in a stacked configuration.

[0035] Phase manipulation technology To understand the fundamental concept of phase response varying with frequency, we consider the basic electrical concepts of electromagnetic wave propagation within a transmission line or coaxial cable. Pozar, in *Microwave Engineering* (Willy Press), outlines the telegraph equations derived from Maxwell's equations. These equations are a set of coupled linear partial differential equations describing the variations in voltage and current along an electrical transmission line with distance and time. They are used to calculate the voltage and current of electromagnetic (EM) waves along the cable's length (z-axis), where the electromagnetic waves possess amplitude and, importantly, phase characteristics.

[0036] The electromagnetic (EM) field propagating through a lossy transmission line is taken into consideration. Equation (1) is the partial differential equation defining this EM field. The propagation constant is denoted as . In this case, the electric field propagating along the z-axis in the coaxial cable is determined by... This indicates that the electric field is perpendicular to the z-axis.

[0037] (1) It can be shown that the slope of the propagation constant as a function of frequency depends on the material properties of the transmission line medium, as shown in equation (2), where the angular frequency... for By extracting the propagation constant from equation (1) and substituting it into the angular frequency, we can obtain equation (2).

[0038] (2) Therefore, the slope of the phase response through the transmission line is determined by... Given that any dual-band or tri-band LEANA requires the use of lossy coaxial cable, the phase slope difference between the top and bottom antenna phases is unavoidable and a limitation that cannot be mitigated. Therefore, the inventors propose a two-pronged approach to alleviate this phase slope difference.

[0039] Multi-band implementation methods To design a multi-band antenna with a null point at the horizon based on phased array theory, two independent multi-band antenna elements need to be stacked on their vertex axes, spaced half a wavelength apart. With anti-phase feeding, this stacking will produce constructive interference at the vertex and destructive interference near the horizon, as shown below. Figure 1 As shown.

[0040] However, as mentioned above and as Figure 2As shown, the top antenna 220 and the bottom antenna 230 are coupled to the external GNSS circuit 210 via coaxial cables, or the top antenna 220 is fed by the bottom antenna 230. In either case, one or more lossy cables will cause the phase response of the LEANA to become uncontrollable. This will produce a phase slope difference, so the required anti-phase feed will only be effective in a narrow band. This means that dual-band or tri-band antennas cannot be implemented in this configuration unless the phase slope of the bottom antenna can be controlled to match the phase slope entering the top antenna.

[0041] Therefore, as Figure 3A As shown, controllable phase between the top antenna 220 and the bottom antenna 230 can be achieved by using discrete component transmission lines as feed lines to the bottom antenna element. Therefore, as shown, the GNSS circuit 210 is directly coupled to the top antenna 220 and coupled to the bottom antenna 230 via the phase circuit 310. However, it is obvious that the phase circuit 310 can also be arranged on the path from the GNSS circuit 210 to the top antenna 220, while the bottom antenna 230 is directly coupled to the GNSS circuit 210. Alternatively, two different phase circuits can be arranged on each path from the GNSS circuit 210 to the top antenna 220 and the bottom antenna 230, respectively.

[0042] The transmission line can be approximated by a series inductor L and its parasitic resistance R, and a parallel capacitor C and its parasitic transconductance G. Its propagation constant is given by equation (3). For the purpose of discussion, and to simplify mathematical calculations, it is assumed that lossless discrete components are used (i.e., R and G are zero), then equation (3) can be simplified to equation (4), and the phase slope of the transmission line is given by equation (5).

[0043] (3) (4) (5) (6) Therefore, by using an N-segment discrete transmission line network of series inductors and parallel capacitors, the phase slope of the bottom antenna can be adjusted according to equation (6) to match the phase slope of the top antenna. Thus, the left side of equation (6) is a constant whose value depends on the coaxial cable used; while the right side is controllable, determined by the L and C elements of each transmission line segment. Through analysis, the inventors confirmed that using more than three segments of discrete transmission lines has significant advantages, each segment being a π (Pi) type network. Figure 4 The diagram below shows a three-segment Pi-type network.

[0044] By combining internal capacitor pairs. Figure 4 The circuit shown can be simplified to Figure 5The circuit is shown. Therefore, by measuring the phase response of the coaxial cable used inside the stacked antenna pair, the values ​​of the discrete components can be determined, for example, by using an electronic simulator, so that the phase response in the circuit has the same slope as the cable.

[0045] A typical constraint of a transmission line is that its characteristic impedance should be 50Ω to match the impedance of the input / output components / circuits at its two ends. However, it is obvious that other impedance values ​​can be used without departing from the scope of this invention. Therefore, L and C elements are chosen to meet the target impedance requirement.

[0046] Since the phase circuit can only compensate for phase slope differences, it is necessary to feed the top antenna element (e.g., Figure 3A The top antenna 220 and the feed to the bottom antenna element (e.g., Figure 3A There will be an additional phase difference between the bottom antenna 230 and the antenna 230. This is because the compensation circuit introduces an additional phase shift, such as Figure 3A Phase circuit 310 and Figure 5 This is one implementation shown. This means that neither antenna element is driven in an inverted manner.

[0047] However, this can be achieved by making Figure 3A The top antenna 220 relative to Figure 3A The bottom antenna 230 is rotated (as shown by rotation arrow 300A) to compensate for this phase difference, namely the phase shift between the top antenna 220 and the bottom antenna 230, thereby achieving a 180° phase difference between the top and bottom elements across the entire antenna band, for example, dual-band or tri-band coverage. Alternatively, the same compensation for this phase difference can be achieved by rotating the bottom antenna 230 relative to the top antenna 220 (as shown by rotation arrow 300B). Clearly, whether rotating the top antenna 220 or the bottom antenna 230, the direction of rotation may be opposite to that shown in the figure. Regardless of the direction of rotation, the magnitude depends on... Figure 3B The phase angle offset of the wireless signals of the top antenna 220 and bottom antenna 230 is described and shown in the diagram. Alternatively, both the top antenna 220 and the bottom antenna 230 can be rotated simultaneously, rather than just one of them.

[0048] refer to Figure 3B , showed Figure 3A The phase diagram of the system according to an embodiment of the invention is shown to visually represent the phase rotation applied between a pair of stacked quadruple-arm helical antenna elements. Therefore, the first indicator 320, at an angle of α°, represents the electrical path from GNSS circuit 210 through the electrical path between GNSS circuit 210 and the top antenna 220 to... Figure 3AThe phase angle of the wireless signal from the top antenna 220. The second indicator 330, with an angle of (α+180)°, represents the expected phase angle of the wireless signal from the GNSS circuit 210 through another electrical path to the bottom antenna 230, such that the radiated wireless signals are 180° out of phase. Figure 1 The above describes the method to enable the LEANA, which includes a top antenna 220 and a bottom antenna 230 (physically spaced at half a wavelength), to be zeroed at low elevation angles.

[0049] However, as indicated by the third indicator 340, the angle β° represents the phase angle of the wireless signal from the GNSS circuit 210 to the bottom antenna 230 and the phase circuit 310, which is another electrical path between the GNSS circuit 210 and the bottom antenna 230. Therefore, the angle β° of the wireless signal coupled to the bottom antenna 230 is not (α+180)°, thus failing to achieve the zeroing effect required by LEANA. However, by rotating the top antenna 220 (as indicated by the first arrow 350), the angle α° is adjusted, thereby creating a 180° phase difference between the wireless signals. Alternatively, by rotating the bottom antenna 230 (as indicated by the second arrow 360), the angle β° is adjusted, thereby creating a 180° phase difference between the wireless signals. Alternatively, both the top antenna 220 and the bottom antenna 230 can be rotated simultaneously, rather than just one of them. Therefore, the present invention can eliminate the phase shift caused by the electrical path, the other electrical path, and the phase circuit 310.

[0050] In the above description, rotation is performed by one or more antenna elements relative to the radiated or received radio signal to achieve the desired zeroing effect. The function of the phase circuit 310 is to make the radio signal traveling back and forth between the bottom antenna 230 and the GNSS circuit 210 identical in phase and frequency with the radio signal traveling back and forth between the top antenna 220 and the GNSS circuit 210, thereby enabling rotational alignment across the entire broadband rather than a narrowband range to achieve zeroing.

[0051] Exemplary results of the phase shift circuit according to embodiments of the present invention are as follows: Figure 6 As shown, the phase shifts of the top and bottom antenna elements are illustrated using a phase circuit. Clearly, the phase shift between the two elements remains constant within one, two, or three frequency bands of interest.

[0052] Although the above embodiments of the invention have been described in conjunction with coaxial cables, it will be apparent that other electrical connection methods, such as radio frequency (RF) traces disposed on a substrate between two antenna elements, may also be used without departing from the scope of the invention.

[0053] While in embodiments of the invention the antenna elements are depicted as collinear, enabling omnidirectional zeroing (radial symmetry) at low elevation angles, it is apparent that in other embodiments of the invention, although the axes of the pair of antenna elements may be parallel to a coaxial line, they may be offset relative to each other. This offset results in a zeroing effect that is no longer radially symmetrical, which can be beneficial in some cases because it essentially zeros only on one side of the antenna.

[0054] Improved flexible antenna assembly The inventors have described GNSS antenna designs utilizing flexible carriers to realize thin-film antenna elements in other patents, see, for example, patent number PCT / CA2020 / 051188 "GNSS Antenna System, Components and Methods" and patent number PCT / CA2022 / 051674 "Broadband Low-profile Antenna Device and Method". See also Figure 8 The image shows a top perspective view of a GNSS antenna according to patent number PCT / CA2020 / 051188, wherein an array of lobes 810 is inserted into slots in a printed circuit board (PCB) 820, thereby being mounted on the PCB 820.

[0055] The lobes 810 array is formed on a flexible substrate, such as, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), liquid crystal polymers (LCPs), paper, and polydimethylsiloxane (PDMS). The lobes 810 are metallization traces on the flexible substrate, such as, for example, copper (Cu). Optionally, the lobes 810 can be independent metallization elements. Although Figure 8 The design shown includes eight (8) lobes 810, but it is obvious that the number of lobes 810 can be other numbers: N lobes 810, where N is an integer, usually an even number.

[0056] See now Figure 7 This image shows a partially exploded view of the interior of a GNSS antenna according to patent number PCT / CA2020 / 051188. The partially exploded view was created within a flexible substrate, including... Figure 8 The shown is an 810-lobe array. (Example) Figure 7As shown, a first dipole A 720, a second dipole B 730, first to fourth supports 710A to 710D, and a mounting block 740 are illustrated. Slots for inserting the first dipole A 720 and the second dipole B 730 are clearly visible on the mounting block 740. Also clearly visible are slots for engaging the lower inner portions of the first to fourth supports 710A to 710D, respectively. In addition to providing mechanical alignment for the first dipole A 720 and the second dipole B 730, the mounting block 740 also provides beneficial effects in the microwave / RF domain for the performance of the GNSS antenna according to embodiments of the present invention. Both the first dipole A 720 and the second dipole B 730 are substrates, such as polytetrafluoroethylene (PTFE), composite materials consisting of a woven glass fiber surface and a paper core (e.g., CEM-1), glass mat and glass cloth composite substrates (e.g., CEM-3), glass fiber reinforced epoxy resin laminates (e.g., FR-4), etc., with a metallization layer (e.g., Cu) provided thereon to provide the RF dipoles. During assembly, the two dipoles are orthogonal. The first to fourth supports 710A to 710D can, for example, be non-metallized substrates (e.g., PTFE, CEM-1, CEM-2, CEM-3, FR4, FR-2, FR-3, FR-5, FR-6, G-10, CEM-4, and CEM-5).

[0057] However, see Figure 9 , it is Figure 8 The image shows a lower perspective view of the GNSS antenna, where the protrusions 930 on the lower edge of each lobe 810 are clearly visible through PCB 820. Figure 9 In the illustrated embodiment, each lobe 810 has a pair of tabs 930. However, as Figure 10 and Figure 11 Other embodiments shown may have only a single tab. It is obvious that a different number of tabs can be used on each lobe, or the number of tabs can be associated with multiple tabs, so that the number of tabs on each lobe can be an integer or a non-integer.

[0058] See Figure 10 This shows a GNSS antenna 1000A, which employs the same... Figures 7 to 9 The GNSS antenna shown follows the same design principle, featuring four lobes, each pair of opposing lobes associated with a dipole of the GNSS antenna 1000A. Second and third images 1000B and 1000C show views of the GNSS antenna 1000A, illustrating the substrate 1030, lobes 1010, and support element 1020. The support element 1020 is mechanically engaged with a groove at the lower outer edge of the substrate 1030.

[0059] Figure 11The first and second images 1100A and 1100B are shown respectively. Figure 10 The GNSS antenna 1000A is partially assembled. Therefore, the substrate 1030, the flap 1010, and the support element 1020 are shown in the figure. Also clearly visible is the tab 1110 inserted into the slot 1140 on the PCB 1150 of the GNSS antenna. The recess 1160 is clearly visible in the second image 1100B. The dimensions of the recess 1160 and the support element 1020 are designed such that when pressure is applied to the support element 1020 to engage it in the recess 1160, a mechanical interference fit or snap-fit ​​is formed between them. In this way, the flexible substrate on which the flap 1010 is formed is secured in place. This allows the flexible substrate to be held in place independently without additional subsequent assembly steps, or to be more easily manipulated in subsequent assembly steps (such as soldering the tab 1110 to the metallization layer under the PCB 1150).

[0060] Specific details have been set forth in the foregoing description in order to provide a thorough understanding of embodiments of the invention. However, it should be understood that these embodiments can be practiced without these specific details.

[0061] The foregoing disclosure of exemplary embodiments of the present invention is for illustrative and descriptive purposes only and 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 those skilled in the art based on the foregoing disclosure. The scope of the invention is defined only by the appended claims and their equivalents.

Claims

1. A method comprising: providing an upper antenna element for receiving or transmitting a circularly polarized wireless signal in a predetermined frequency range, the upper antenna element being disposed above a lower antenna element along a co-axial line with the lower antenna element, and the upper antenna element including a first electrical interface coupled to an electrical circuit through an electrical path; providing the lower antenna element for receiving and transmitting another circularly polarized wireless signal in the predetermined frequency range, the lower antenna element including a second electrical interface coupled to the electrical circuit through another electrical path; and providing a phase circuit within the other electrical path between the lower antenna element and the electrical circuit; wherein, the circularly polarized wireless signal and the other circularly polarized wireless signal are 180° out of phase such that the antenna exhibits a maximum gain along the co-axial line and a minimum gain in a direction perpendicular to the co-axial line; the phase circuit in combination with the other electrical path between the electrical circuit and the lower antenna element provides a phase at the second electrical interface that varies with frequency equal to another phase that varies with frequency at the first electrical interface; and the lower antenna element and the upper antenna element are rotationally offset from each other, the rotational offset being determined according to an absolute phase difference between the circularly polarized wireless signal at the first electrical interface and the other circularly polarized wireless signal at the second electrical interface.

2. The method of claim 1, wherein, the phase circuit includes N series-connected π networks; and N is an integer greater than or equal to 1.

3. The method of claim 1, wherein, the upper antenna element is a helical antenna; and the lower antenna element is a helical antenna.

4. The method of claim 1, wherein, the upper antenna element is a four-arm helical antenna; and the lower antenna element is a four-arm helical antenna.

5. The method of claim 1, wherein, an axis of the upper antenna element is aligned with the co-axial line; and an axis of the lower antenna element is aligned with the co-axial line.

6. An antenna comprising: an upper antenna element for receiving or transmitting a circularly polarized wireless signal in a predetermined frequency range, the upper antenna element being disposed above a lower antenna element along a co-axial line with the lower antenna element, and the upper antenna element including a first electrical interface coupled to an electrical circuit through an electrical path; the lower antenna element for receiving and transmitting another circularly polarized wireless signal in the predetermined frequency range, the lower antenna element including a second electrical interface coupled to the electrical circuit through another electrical path; and a phase circuit within the other electrical path between the lower antenna element and the electrical circuit; wherein, the circularly polarized wireless signal and the other circularly polarized wireless signal collectively cause the antenna to exhibit a maximum gain along the co-axial line and a minimum gain in a direction perpendicular to the co-axial line; the phase circuit in combination with the other electrical path between the electrical circuit and the lower antenna element provides a phase at the second electrical interface that varies with frequency equal to another phase that varies with frequency at the first electrical interface; and the lower antenna element and the upper antenna element are rotationally offset from each other, the rotational offset being determined according to an absolute phase difference between the circularly polarized wireless signal at the first electrical interface and the other circularly polarized wireless signal at the second electrical interface. ​ The lower antenna element and the upper antenna element are rotationally offset from each other, the rotational offset being determined according to an absolute phase difference between the circularly polarized wireless signal at the first electrical interface and the other circularly polarized wireless signal at the second electrical interface.

7. The antenna of claim 6, wherein: The phase circuit includes N series-connected pi networks; and N is an integer greater than or equal to 1.

8. The antenna of claim 6, wherein: The upper antenna element is a helical antenna; and The lower antenna element is a helical antenna.

9. The antenna of claim 6, wherein: The upper antenna element is a four-arm helical antenna; and The lower antenna element is a four-arm helical antenna.

10. The antenna of claim 6, wherein: An axis of the upper antenna element is aligned with the common axis; and An axis of the lower antenna element is aligned with the common axis.

11. An antenna, comprising: An upper antenna element for receiving or transmitting a circularly polarized wireless signal in a predetermined frequency range, the upper antenna element being disposed above a lower antenna element along a common axis with the lower antenna element, and the upper antenna element including a first electrical interface coupled with an electrical circuit by an electrical path; The lower antenna element for receiving and transmitting another circularly polarized wireless signal in the predetermined frequency range, the lower antenna element including a second electrical interface coupled with the electrical circuit by another electrical path; and A phase circuit within the electrical path between the upper antenna element and the electrical circuit; wherein: The circularly polarized wireless signal and the other circularly polarized wireless signal collectively cause the antenna to exhibit a maximum gain along the common axis and a minimum gain in a direction perpendicular to the common axis; The phase circuit in combination with the electrical path between the electrical circuit and the upper antenna element provides a frequency-varying phase at the first electrical interface, the phase being equal to a frequency-varying other phase at the second electrical interface; and The lower antenna element and the upper antenna element are rotationally offset from each other, the rotational offset being determined according to an absolute phase difference between the circularly polarized wireless signal at the first electrical interface and the other circularly polarized wireless signal at the second electrical interface.

12. The antenna of claim 11, wherein: The phase circuit includes N series-connected pi networks; and N is an integer greater than or equal to 1.

13. The antenna of claim 11, wherein: The upper antenna element is a helical antenna; and The lower antenna element is a helical antenna.

14. The antenna of claim 11, wherein: The upper antenna element is a four-arm helical antenna; and The lower antenna element is a four-arm helical antenna.

15. The antenna of claim 11, wherein: An axis of the upper antenna element is aligned with the common axis; and An axis of the lower antenna element is aligned with the common axis.

16. An antenna, comprising: an upper antenna element for receiving or transmitting a circularly polarized wireless signal in a predetermined frequency range, the upper antenna element being disposed above the lower antenna element along a co-axial line with the lower antenna element, and the upper antenna element including a first electrical interface coupled to an electrical circuit by an electrical path; the lower antenna element for receiving and transmitting another circularly polarized wireless signal in the predetermined frequency range, the lower antenna element including a second electrical interface coupled to the electrical circuit by another electrical path; and a first phase circuit within the electrical path between the upper antenna element and the electrical circuit; and a second phase circuit within the other electrical path between the lower antenna element and the electrical circuit; wherein the circularly polarized wireless signal and the other circularly polarized wireless signal collectively cause the antenna to exhibit a maximum gain along the co-axial line and a minimum gain in a direction perpendicular to the co-axial line; the first phase circuit in combination with the electrical path between the electrical circuit and the upper antenna element provides a frequency-dependent phase at the first electrical interface that is equal to another frequency-dependent phase determined at the second electrical interface by the second phase circuit in combination with the other electrical path; and the lower antenna element and the upper antenna element are rotationally offset from each other, the rotational offset being determined according to an absolute phase difference between the circularly polarized wireless signal at the first electrical interface and the other circularly polarized wireless signal at the second electrical interface.

17. The antenna of claim 16, wherein: the phase circuit includes N series-connected pi networks; and N is an integer greater than or equal to 1.

18. The antenna of claim 16, wherein: the upper antenna element is a helical antenna; and the lower antenna element is a helical antenna.

19. The antenna of claim 16, wherein: the upper antenna element is a four-arm helical antenna; and the lower antenna element is a four-arm helical antenna.

20. The antenna of claim 16, wherein: an axis of the upper antenna element is aligned with the co-axial line; and an axis of the lower antenna element is aligned with the co-axial line. ​

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