Antenna element for wireless communication

Abstract

An antenna element (200) includes a first conductor (220) at a first lateral surface (212) of a substrate (210), the first conductor having a feed line portion (222) and a monopole portion (224), the monopole portion having a neck (226) extending from the feed line portion and a head (228) at a distal end of the neck. The head has a width that is greater than a width of the neck and greater than a width of the feed line portion. The head has a slot (230) to increase a bandwidth of the first conductor to at least a first frequency band and a second frequency band. A second conductor (250) is disposed on the first lateral surface, the second conductor having first and second ground planes (251, 252) and first and second stubs (253, 254). The ground planes are disposed adjacent opposite sides of the feed line portion. The stubs are disposed on opposite sides of the ground planes and extend in a direction substantially perpendicular to the feed line portion. The ground planes and stubs are arranged relative to the first conductor to form a coplanar waveguide.

Description

Technical Field

[0001] The main topic of this article is antenna elements used for wireless communication. Background Technology

[0002] In the field of automotive communications, specific antenna elements are provided for wireless communication. For example, in automotive applications, rooftop antenna assemblies are designed to contain multiple antenna elements for communication with various devices at various frequencies, such as analog and digital radio reception, cellular communication, satellite communication and vehicle-to-everything (V2X) communication, Wi-Fi communication, Bluetooth communication, etc. It is desirable to incorporate various antenna elements into the rooftop antenna assembly. However, placing multiple antenna elements in the same rooftop antenna assembly may negatively impact the functionality of each individual antenna element. The size and positioning of the antenna elements may be constrained to geometrically fit the housing of the rooftop antenna assembly.

[0003] There is still a need for an antenna element that can operate at multiple frequencies for wireless communication across multiple frequency bands. Summary of the Invention

[0004] In one embodiment, an antenna element is provided, comprising a substrate having at least a first lateral surface. A first conductor is disposed on the first lateral surface. The first conductor includes a feed portion and a monopole portion. The monopole portion includes a neck extending from the feed portion and a head at a distal end of the neck. The width of the head is greater than the width of the neck and greater than the width of the feed portion. The head has a slot to increase the bandwidth of the first conductor to at least a first frequency band and a second frequency band. A second conductor is at least partially disposed on the same first lateral surface. The second conductor includes a first ground plane and a first stub extending from the first ground plane. The second conductor includes a second ground plane and a second stub extending from the second ground plane. The first ground plane and the second ground plane are disposed on the first lateral surface adjacent to opposite sides of the feed portion of the first conductor. The first stub and the second stub are disposed on the first lateral surface at opposite sides of the respective first ground plane and second ground plane. The first stub and the second stub extend in a direction substantially parallel to the feed portion of the first conductor. The first ground plane and the second ground plane of the second conductor, as well as the first stub and the second stub, are arranged relative to the first conductor to form a coplanar waveguide. Attached Figure Description

[0005] The invention will now be described by way of example with reference to the accompanying drawings, in which:

[0006] Figure 1 An antenna assembly according to an exemplary embodiment is shown.

[0007] Figure 2 This is a schematic diagram of an antenna element according to an exemplary embodiment.

[0008] Figure 3 This is a front view of an antenna element according to an exemplary embodiment.

[0009] Figure 4 Analysis results of measurements for exemplary antenna elements are provided, such as those according to exemplary embodiments. Figure 2-3 The antenna element shown.

[0010] Figure 5 Analysis results of measurements for exemplary antenna elements are provided, such as those according to exemplary embodiments. Figure 2-3 The antenna element shown.

[0011] Figure 6 Analysis results of measurements for exemplary antenna elements are provided, such as those according to exemplary embodiments. Figure 2-3 The antenna element shown. Detailed Implementation

[0012] Figure 1 An antenna assembly 100 according to an exemplary embodiment is shown. In an exemplary embodiment, the antenna assembly 100 is a multi-band roof antenna assembly. For example, the antenna assembly 100 may be mounted on the roof 102 of a vehicle 104. In an exemplary embodiment, the antenna assembly 100 integrates a plurality of antenna elements 106 into a common structure for a multi-band antenna automotive system mounted to the vehicle 104. For example, the antenna assembly 100 may include dedicated short-range communication (DSRC), cellular, and / or satellite antenna elements to provide versatility for communication to the vehicle 104. In an exemplary embodiment, the antenna assembly 100 may communicate on DSRC frequencies for “vehicle-to-everything” communication. For example, one or more of the antenna elements 106 may operate in the Bluetooth band and / or low Wi-Fi band and / or high Wi-Fi band and / or V2X DSRC band. One or more of the antenna elements 106 may operate on one or more cellular frequencies (e.g., 5G, LTE, etc.). One or more of the antenna elements 106 can operate on one or more satellite signals (e.g., Satellite Digital Audio Radio (SDARS), Global Navigation Satellite System (GNSS), etc.). Antenna assembly 100 may include antenna elements that can operate at other frequencies, such as amplitude modulation (AM), frequency modulation (FM), etc.

[0013] Antenna assembly 100 includes an antenna housing 110 that holds antenna element 106. Antenna housing 110 includes a cover or radome 114 that forms an internal housing for receiving antenna element 106. Antenna element 106 is covered by radome 114. Optionally, radome 114 may be aerodynamically designed, for example, having a shark fin shape. In alternative embodiments, radome 114 may have other shapes, such as disc, dish, or shaped as a panel to conform to the exterior of the vehicle. Optionally, antenna assembly 100 may be embedded in roof 102 such that the outer surface of radome 114 is substantially flush with roof 102.

[0014] In an exemplary embodiment, the antenna element 106 of the antenna assembly 100 includes: a first or primary cellular antenna 120 configured to operate on one or more cellular frequencies, a second or secondary cellular antenna 122 configured to operate on one or more cellular frequencies, a first satellite antenna 124 configured to operate on one or more satellite frequencies, a second satellite antenna 126 configured to operate on one or more satellite frequencies, and a V2X antenna 128 configured to operate on a DSRC frequency, such as a Bluetooth frequency, a Wi-Fi frequency, and / or a V2X DSRC frequency. In an exemplary embodiment, the first cellular antenna 120 and the second cellular antenna 122 may be monopole antennas. The first satellite antenna 124 and the second satellite antenna 126 may be patch antennas. The V2X antenna 128 may be a monopole antenna, such as a dual-band monopole antenna.

[0015] In an exemplary embodiment, the first cellular antenna 120 and the second cellular antenna 122 cover a wide frequency range to meet the bandwidth requirements of 5G cellular networks. For example, the first cellular antenna 120 and the second cellular antenna 122 may cover a frequency range from approximately 617 MHz to 5 GHz. In an exemplary embodiment, the first satellite antenna 124 is used for satellite positioning, such as in conjunction with a vehicle's GPS system. For example, the first satellite antenna 124 is configured to operate to receive Global Navigation Satellite System (GNSS) signals. The first satellite antenna 124 may be a dual-band (L1 and L5) antenna element. The first satellite antenna 124 may have a low axial ratio to provide high-precision positioning for assisted driving and autonomous driving. In an exemplary embodiment, the second satellite antenna 126 is used for satellite radio. The second satellite antenna 126 may operate to receive Satellite Digital Audio Radio Service (SDARS) signals (e.g., Sirius XM, Telematics Processing Control Unit (TCU), etc.).

[0016] In an exemplary embodiment, the V2X antenna 128 is used for communication with the surrounding environment, such as vehicle-to-vehicle communication, vehicle-to-infrastructure communication, vehicle-to-pedestrian communication, etc. In an exemplary embodiment, the V2X antenna 128 transmits and / or receives DSRC signals for communication with the surrounding environment or for interaction with other vehicles, pedestrians, road infrastructure, and other networks. In an exemplary embodiment, the V2X antenna 128 is a monopole antenna configured to transmit and receive signals omnidirectionally. The V2X antenna 128 can be operated to receive Bluetooth signals in a 2.4 GHz frequency range. The V2X antenna 128 can be operated to receive Wi-Fi signals, for example, in a 2.5 GHz and / or 5 GHz frequency range. The V2X antenna 128 can be operated to receive V2X DSRC signals, for example, in a 5.9 GHz frequency range.

[0017] Figure 2 This is a schematic diagram of antenna element 200 according to an exemplary embodiment. Antenna element 200 can be used as antenna element 106 of antenna assembly 100 (e.g., Figure 1 (As shown). For example, antenna element 200 can represent V2X antenna 128 (as shown). Figure 1 (As shown). In an exemplary embodiment, antenna element 200 is mounted to base 150. In various embodiments, the base may be a circuit board. Base 150 includes a ground plane to provide a ground signal to antenna element 200. Base 150 may include feed circuitry for powering antenna element 200. For example, antenna element 200 may be soldered to circuitry or conductors on base 150, such as connected to the ground plane. Alternatively, in the illustrated embodiment, power to antenna element 200 may be provided by cable 160, such as a coaxial cable. Cable 160 may extend along base 150, such as parallel to antenna element 200. Cable 160 may be connected at other locations, such as to the bottom of base 150, and extend from the bottom of base 150.

[0018] Antenna element 200 includes a substrate 210 as a structural element, with a first conductor 220 and a second conductor 250 disposed on the substrate 210. The substrate 210 includes a first lateral surface 212. The first conductor 220 and the second conductor 250 may be disposed on the first lateral surface 212. Optionally, the first lateral surface may be planar (e.g., flat). In alternative embodiments, the first lateral surface 212 may be non-planar (e.g., curved). In various embodiments, the substrate 210 includes opposing second lateral surfaces 213. In various embodiments, the second lateral surface 213 may be parallel to the first lateral surface 212. The first lateral surface 212 and the second lateral surface 213 may be the front and rear surfaces of the substrate 210. Optionally, the substrate 210 may be oriented such that the first lateral surface 212 is oriented substantially vertically (e.g., the longitudinal axis of the substrate 210 is oriented vertically).

[0019] Substrate 210 is made of a dielectric material to prevent short circuits between the first conductor 220 and the second conductor 250. Substrate 210 may be made of a material that provides low loss in terms of quality factor or dissipation factor for a specific permittivity or dielectric constant at a desired frequency. For example, substrate 210 may be made of an epoxy- or polyamide-based material. Other exemplary materials for substrate 210 may be FR4, PC (polycarbonate), or ABS (acrylonitrile butadiene styrene). Substrate 210 provides structural support and thereby separates the first conductor 220 from the second conductor 250, such that both conductors 220 and 250 are conductive materials with different shapes. In various embodiments, substrate 210 is a circuit board, and conductors 220 and 250 may be circuitry on one or more layers of the circuit board.

[0020] The first conductor 220 includes a feed portion 222 and a monopole portion 224 extending from the feed portion 222. For example, the monopole portion 224 may be located above the feed portion 222. The first conductor 220 is disposed on a first lateral surface 212 of the substrate 210, for example, on the front. In an exemplary embodiment, the antenna element 200 includes a resistor 225 between the feed portion 222 and the second conductor 250. The resistor 225 may be disposed on the substrate 210, for example, on the first lateral surface 212. The difference between the feed portion 222 and the monopole portion 224 of the first conductor 220 is due to their function in conjunction with the second conductor 250, which will be explained in more detail below. The intersection between the feed portion 222 and the monopole portion is called the antenna feed point F.

[0021] In an exemplary embodiment, the monopole portion 224 is non-linear. The monopole portion 224 includes a neck 226 and a head 228 at the distal end of the neck 226. For example, the head 228 is located above the neck 226. The neck 226 extends between the feed portion 222 and the head 228. The neck 226 may be an extension of the feed portion 222 (e.g., having the same width and extending in a common direction). The head 228 is wider than the neck 226. In an exemplary embodiment, the head 228 includes a slot 230 surrounded by a plurality of head segments. The head segments may form a rectangular antenna structure. For example, the head 228 includes a lower segment 232, an upper segment 234, and side segments 236, 238 extending between the lower segment 232 and the upper segment 234. Optionally, the upper segment 232 and the lower segment 234 may be oriented parallel to each other. Optionally, the side segments 236, 238 may be oriented perpendicular to the upper segment 232 and the lower segment 234. More or fewer head segments can be provided to change the shape of the head 228 and the slot 230, for example, to tune the antenna element 200 to a target frequency.

[0022] Slot 230 is open (e.g., without conductors) between the upper segment 232 and the lower segment 234, and between the first side segment 236 and the second side segment 238. Slot 230 has a slot height 240 between the upper segment 232 and the lower segment 234, and a slot width 242 between the first side segment 236 and the second side segment 238. The slot height 240 and the slot width 242 can be controlled based on the width and height of the head segment. Slot 230 increases the bandwidth of the first conductor 220 to cover the low-frequency bands of Bluetooth and Wi-Fi. Slot 230 enhances performance in the high-frequency bands of Wi-Fi and the DSRC band.

[0023] The second conductor 250 is at least partially disposed on the first lateral surface 212 of the substrate 210. The second conductor 250 includes a first ground plane 251 and a second ground plane 252 adjacent to the first conductor 220. In an exemplary embodiment, the second conductor 250 includes a first stub 253 extending from the first ground plane and a second stub 254 extending from the second ground plane 252. In an alternative embodiment, the second conductor 250 may include additional stubs. In an exemplary embodiment, the first stub 253 and the second stub 254 are electrically connected to the first link portion 255 and the second link portion 256 via the first ground plane 251 and the second ground plane 252, respectively.

[0024] Ground planes 251 and 252 are disposed on the first lateral surface 212, adjacent to the opposite side of the feed portion 222 of the first conductor 220. For example, the first ground plane 251 is disposed on the right side of the feed portion 222, and the second ground plane 252 is disposed on the left side of the feed portion 222 of the first conductor 220. The terms "left side" and "right side" refer to the orientation of the first conductor 220 with its front face facing upwards. In an exemplary embodiment, ground planes 251 and 252 are disposed equidistantly on the opposite sides of the feed portion 222 of the first conductor 220. In other words, the spacing or distance between the feed portion 222 of the first conductor 220 and the ground planes 251 and 252 of the second conductor 250 is the same on both opposite sides. In an exemplary embodiment, the first ground plane 251 is separated from the feed portion 222 by a first gap, and the second ground plane 252 is separated from the feed portion 222 by a second gap. In an exemplary embodiment, resistor 225 extends across a first inspection extension between feed portion 222 and first ground plane 251; however, resistor 225 may additionally or alternatively extend across a second gap between feed portion 222 and second ground plane 252.

[0025] In an exemplary embodiment, links 255 and 256 extend from the distal ends of ground planes 251 and 252. Thus, stubs 253 and 254 connect to ground planes 251 and 252, near the antenna feed point F, i.e., near the intersection between feed portion 222 and monopole portion 224. In an exemplary embodiment, the first stub 253 and the second stub 254 extend substantially parallel to the first ground plane 251 and the second ground plane 252. Stubs 253 and 254 are located outside ground planes 251 and 252. In an exemplary embodiment, the first stub 253 and the second stub 254 turn downward from the first link 255 and the second link 256 and extend towards the base 150. The first link 255 and the second link 256 extend between stubs 253 and 254 and ground planes 251 and 252 and define the spacing between them. For example, the first link 255 defines a first gap 258 between the first ground plane 251 and the first stub 253, and the second link 256 defines a second gap 259 between the second ground plane 252 and the second stub 254. The first stub 253 and the second stub 254 do not extend into the region near (i.e., adjacent to) the monopole portion 224 of the first conductor 220. Therefore, the arrangement of the antenna element 200 maintains open space between the monopole portions 224 of the first conductor 220. The first stub 253 and the second stub 254 extend in a direction substantially parallel to the feed portion 222 of the first conductor 220. When the monopole portion 224 is aligned with the feed portion 222 of the first conductor 220, the stubs 253 and 254 also extend in a direction substantially parallel to the monopole portion 224.

[0026] Ground planes 251 and 252 and stubs 253 and 254 together form a coplanar waveguide. In the context of this specification, the terms "coplanar" or "plane" should not be limited to planar surfaces (i.e., planes), but should be understood to relate to any surface, including curved surfaces. In this respect, the statement "the ground plane and the stub together form a coplanar waveguide" means that both are located on the same (planar or curved) surface and thus form the waveguide.

[0027] The first conductor 220 also includes an RF input 260 for feeding an RF signal to be transmitted via a single-pole portion 224 of the first conductor 220. In other words, the RF signal is input via the RF input 260 near the feed portion 222 of the first conductor 220 for radiation by the single-pole portion 224 of the first conductor 220. The RF signal may be provided to the RF input 260 via the center conductor of the coaxial cable 160 or a transmission line of a circuit board such as the base. The second conductor 250 also includes a ground connection 262 for providing a GND signal to a first ground plane 251 and a second ground plane 252 of the second conductor 250. In other words, the GND signal is input via the ground connection 262 near the proximal end of either ground plane 251 or 252 to provide a reference voltage to the first conductor 220. The ground planes 251 and 252 may be electrically connected to each other via the base 150, for example, via vias, traces, etc., which may be on one or more layers of the base 150. The GND signal can be provided via the outer conductor of the coaxial cable 160 or the transmission line of the base 150, such as the ground plane of the circuit board at the base 150.

[0028] Figure 3 This is a front view of antenna element 200 according to an exemplary embodiment, showing its size and shape configured for use in a dual-band configuration at frequencies of approximately 2.4 GHz and 5.9 GHz. Variations in the size and shape of conductors 220 and 250 can configure antenna element 200 for other target frequencies.

[0029] In an exemplary embodiment, the feed portion 222 of the first conductor 220 is rectangular and has a length 300 of approximately 16 mm and a width 302 of approximately 1 mm. In an exemplary embodiment, the feed portion 222 is vertically oriented such that the length 300 defines the height of the feed portion 222.

[0030] In an exemplary embodiment, the unipolar portion 224 of the first conductor 220 includes a rectangular portion. For example, the neck 226 is rectangular, having a length 310 (e.g., height) of about 2 mm and a width 312 of about 1 mm. The width 312 may be the same as the width 302 of the feed portion 222. The head 228 is rectangular, having a length 314 (e.g., height) of about 5 mm and a width 316 of about 12 mm. The length 314 and width 316 are sufficient to accommodate the head segment and the slot 230. For example, the slot width 242 and slot height 244 are smaller than the width 316 and length 314. In the illustrated embodiment, the slot width 242 is about 10 mm and the slot height 244 is about 2 mm. The head segment has a height and width that, together with the height and width of the slot 230, define the length 314 and width 316 of the head 228. The height and width of the individual head segments may be different. In the illustrated embodiment, the upper segment 232 has a height of approximately 1 mm and a width of approximately 12 mm (e.g., spanning the entire width 316 of the head 228). In the illustrated embodiment, the lower segment 234 has a height of approximately 2 mm and a width of approximately 12 mm (e.g., spanning the entire width 316 of the head 228). In the illustrated embodiment, the side segments 236, 238 have a height of approximately 2 mm (e.g., spanning the entire slot height 244) and a width of approximately 1 mm. In alternative embodiments, other heights and widths are possible to vary the size and shape of the monopole portion 224 relative to the second conductor 250, thereby altering antenna characteristics such as target frequency, return loss, antenna gain, etc.

[0031] In an exemplary embodiment, the first ground plane 251 and the second ground plane 252 are similar in size and shape. For example, the first ground plane 251 and the second ground plane 252 may be mirror images of each other on opposite sides of the feed portion 222. The dimensions described herein refer to the first ground plane 251 but may be the same as the second ground plane 252. In an alternative embodiment, the first ground plane 251 and the second ground plane 252 may have different shapes from each other. The first ground plane 251 is rectangular, having a length 330 (e.g., height) of approximately 15 mm and a width 332 of approximately 3 mm. A first gap may have a gap width 334 of approximately 0.5 mm between the first ground plane 251 and the feed portion 222. In the illustrated embodiment, the antenna element 200 may have an outer edge width 336 of approximately 8 mm from the outer edge of the first ground plane 251 to the outer edge of the second ground plane 252.

[0032] In an exemplary embodiment, the first stub 253 and the second stub 254 are similar in size and shape. For example, the first stub 253 and the second stub 254 may be mirror images of each other on opposite sides of the feed section 222. The dimensions described herein refer to the first stub 253 but may be the same as the second stub 254. In an alternative embodiment, the first stub 253 and the second stub 254 may have different shapes from each other. The first stub 253 is rectangular, having a length 340 (e.g., height) of approximately 8.5 mm and a width 342 of approximately 1 mm. The first spacing 258 may have a spacing width 344 of approximately 2 mm between the first ground plane 251 and the first stub 253. In the illustrated embodiment, the antenna element 200 may have an outer edge width 346 of approximately 14 mm from the outer edge of the first stub 253 to the outer edge of the second stub 254.

[0033] In an exemplary embodiment, the first link 255 and the second link 256 are similar in size and shape. For example, the first link 255 and the second link 256 may be mirror images of each other on opposite sides of the feed section 222. The dimensions described herein refer to the first link 255 but may be the same as the second link 256. In an alternative embodiment, the first link 255 and the second link 256 may have different shapes from each other. The first link 255 is rectangular, having a length 350 (e.g., height) of about 1 mm and a width 352 of about 2 mm. The width 352 may define a first gap 258 between the first ground plane 251 and the first stub 253. Alternatively, the width 352 of the first link 255 and thus the first gap 258 may correspond to (e.g., approximately equal to) the length 310 (e.g., height) of the neck 226. Thus, the gap 358 between the head 228 and the second conductor 250 may be equal to the gap between the ground plane 251 and the stub 253.

[0034] The transmission operation of the RD signal via antenna element 200 is described in more detail. However, the operation of antenna element 200 is not limited to this. Specifically, antenna element 200 can be similarly used for receiving operations, where the antenna element is excited by an externally radiated signal. An RF signal is input to the RF input 260 of the first conductor 220, and a GND signal is input to the ground connection 262 of the second conductor 250. Due to the ground planes 251 and 252 of the second conductor 250, the feed portion 222 of the first conductor 220 operates as a coplanar transmission line to transmit the RF signal received at the RF input 260 to the antenna feed point F. The voltage generated by the RF signal at the antenna feed point F at the gap between the feed portion 222 of the first conductor 220 and the two ground planes 251 and 252 of the second conductor 250 causes an RF current to flow in the monopole portion 224 of the first conductor 220. The differential current transmitted by the feed portion 222 of the first conductor 220 returns to the RF input 260 along the surfaces of the ground planes 251 and 252 of the second conductor 250 closest to the feed portion 222. The energy radiated by the monopole portion 224 of the first conductor 220 can also induce a common-mode current, which flows out from the antenna feed point F along the surfaces of the two ground planes 251 and 252 of the conductor closest to the feed portion 222. Problems may arise, such as unwanted RF radiation from the two ground planes 251 and 252, because their width and length are limited relative to the operating frequency.

[0035] To eliminate or reduce unwanted RF radiation from the two ground planes 251, 252, stubs 253, 254 are used. Common-mode current may tend to flow to the other side of the two stubs 253, 254 (i.e., to the surface of the stub furthest from the feed section 222) and return to the far ends of the stubs 253, 254. When designing the antenna element, the lengths of the two stubs 253 and 254 can be chosen to prevent common-mode current from flowing back to the RF input 260. This impedance effect can be explained by considering that the two ground planes 251, 252 and the two stubs 253, 254 form a coplanar waveguide (CPW) transmission line. According to this model, the two ground planes 251, 252 form the center conductor of the CPW, and the two stubs 253, 254 form the outer conductor of the CPW. The waveguide is short-circuited at its far ends by connecting sections 255, 256. If the effective length of the CPW is approximately one-quarter wavelength (e.g., at the center frequency of the desired band), the impedance at the open end of the CPW (e.g., near the ends of the two stubs 253, 254) may be almost infinite at the target operating frequency. This impedance prevents common-mode current from flowing back to the source along the two ground planes 251, 252, resulting in the element antenna 200 tending to be more balanced in the sense of reducing or eliminating radiation from the feed section 222 at the target frequency corresponding to the lengths of the stubs 253, 254. In this case, it might be desirable for the monopole section 224 of the first conductor 220 to have an effective length of approximately one-quarter wavelength and to correspond to the frequency at which the stub length is selected. However, the effective lengths of the monopole section 224 and the feed section 222 can be multiples of one-quarter of the wavelength of the desired frequency. In addition to the resonance corresponding to the one-quarter wavelength stub and monopole, additional resonances can be induced by properly selecting the ground plane height relative to the monopole and stub dimensions. Careful sizing allows for dual-frequency operation, where the effects of the stub and ground plane are minimized in the second band. Dual-band operation is enhanced when the second resonant spacing is sufficiently large and the stub size is relatively small relative to the wavelength in the second frequency band (e.g., 2.4 GHz and 5.8 GHz, with the stub length optimized for 5.8 GHz). For example, a quarter-wavelength stub and head portion of a single pole are optimized for the 5.8 GHz high-frequency band. It should be understood that any description of the operation of the antenna elements according to the embodiments is presented herein for illustrative purposes only. It is worth noting that such explanation, in itself, does not represent or impose any limitation on any configurations set forth in the various implementations described above.

[0036] The size and shape of antenna element 200 are geometrically adapted to a roof-mounted antenna assembly. The construction of antenna element 200 allows for a narrow near end of substrate 210. The regions on either side of the monopole portion 224 of antenna element 200 are left blank, allowing portions without the second conductor 250 (i.e., stubs 253, 254) to be positioned close to the monopole portion 224. Simultaneously, stubs 253, 254 can be implemented with the same length as the monopole portion 224, i.e., λ / 4. Therefore, antenna element 200 can be advantageously incorporated into a roof-mounted antenna assembly. In an exemplary embodiment, antenna element 200 also achieves the advantage of an omnidirectional radiation pattern. Specifically, the construction of antenna element 200, including the monopole portion 224 extending from the second conductor 250, provides the ability to radiate equal power in all directions perpendicular to the reverse direction of the antenna element.

[0037] Figure 4-6 Analysis results for measurements of exemplary antenna elements are provided, such as... Figure 2-3 The antenna element shown. Performance loss is kept at a very low level while providing multi-band functional operation, such as supporting vehicle Bluetooth and / or Wi-Fi and / or V2X DSRC communication. Figures 4 to 6 The analytical results shown are provided for illustrative purposes and not for limiting purposes. Alternative embodiments of the antenna element may be configured differently and have the same characteristics as... Figures 4 to 6 The different operating or performance parameters shown.

[0038] Figure 4 The diagram shows the impedance matching (S11) of antenna element 200 in decibels versus its frequency in gigahertz. The performance of antenna element 200 meets the requirements of automotive antennas, for example, operating below -5 dB in the desired frequency ranges of 2.4–2.6 GHz and 5–6 GHz. For example, the measured reflections 400, 402, 404, and 406 in the Bluetooth (2.4 GHz), low Wi-Fi (2.5 GHz), high Wi-Fi (5.15 GHz), and V2X DSRC (5.85 GHz) frequency ranges are all below -5 dB, and in the illustrated embodiment, even below -10 dB, to meet operational requirements. Antenna element 200 advantageously has sufficient impedance matching across multiple frequency bands. A single antenna element 200 can be used for Bluetooth communication, Wi-Fi communication, and DSRC communication. This allows antenna element 200 to be used in vehicle communication applications, such as vehicle-to-everything (V2X) communication, where wireless communication with various types of devices at various frequencies is important.

[0039] Figure 5This is a graph illustrating the directional radiation pattern of the antenna element 200 according to an exemplary embodiment. The antenna element 200 is omnidirectional and has gain in all directions. The graph shows the realized gain in the horizontal plane at different frequencies, such as Bluetooth frequency (2.4 GHz), low Wi-Fi frequency (2.5 GHz), high Wi-Fi frequency (5.15 GHz), and V2X DSRC (5.85 GHz) frequency. The realized gain is approximately between 5 dB and 7.5 dB in all directions, indicating good performance of the antenna element 200 in all directions. Figure 5 It was revealed that the antenna gain of antenna element 200 in the horizontal plane is similar to the azimuth pattern, producing an omnidirectional pattern in the horizontal direction with a variation of less than approximately 2.5 dB. Antenna element 200 advantageously possesses an omnidirectional radiation pattern in the horizontal plane. This allows antenna element 200 to be used in vehicle-to-vehicle communication applications, where wireless communication in any horizontal direction is important.

[0040] Figure 6 It is a graph showing the gain of the antenna element 200 in the far field at varying elevation angles according to an exemplary embodiment, with fixed azimuth angles (0° and 90°). Figure 6 The antenna gain in the vertical plane is shown. Figure 6 This indicates that antenna element 200 has sufficient antenna gain at the relevant vertical angle. For example, antenna element 200 maintains sufficient power between 30° and 90°. More importantly, between 60° and 90°, antenna element 200 has positive realized gain at both the Bluetooth (2.4GHz) and V2X DSRC (5.85GHz) frequencies.

Claims

1. An antenna element (200), comprising: The substrate (210) has at least a first lateral surface (212). A first conductor (220) is disposed on the first transverse surface. The first conductor includes a feed portion (222) and a monopole portion (224). The monopole portion includes a neck (226) extending from the feed portion and a head (228) at a distal end of the neck. The width of the head is greater than the width of the neck and greater than the width of the feed portion. The head has a slot (230) to increase the bandwidth of the first conductor to at least a first frequency band and a second frequency band. The second conductor (250) is at least partially disposed on the same first lateral surface, wherein the second conductor includes at least a first ground plane (251) and a first stub (253) extending from the first ground plane, the second conductor includes a second ground plane (252) and a second stub (254) extending from the second ground plane, the first ground plane and the second ground plane are disposed on the first lateral surface adjacent to opposite sides of the feed portion of the first conductor, the first stub and the second stub are disposed on opposite sides of the respective first ground plane and the second ground plane, the first stub and the second stub extend in a direction substantially parallel to the feed portion of the first conductor, the first ground plane and the second ground plane of the second conductor and the first stub and the second stub are arranged relative to the first conductor to form a coplanar waveguide.

2. The antenna element (200) as claimed in claim 1, wherein, The head (228) includes a head segment surrounding the groove (230), the groove width (242) being greater than the groove height (244).

3. The antenna element (200) as claimed in claim 1, wherein, The head (228) includes a head segment surrounding the slot (230), the head segment and the slot (230) being shaped to enhance operation in the Bluetooth band, low WIFI band, high WIFI band and V2X Dedicated Short Range Communication (DSRC) band.

4. The antenna element (200) as claimed in claim 1, wherein, The feed line portion (222), the first ground plane (251), and the second ground plane (252) extend generally vertically, and the head (228) is located vertically above the feed line portion, the first ground plane, and the second ground plane.

5. The antenna element (200) as claimed in claim 1, wherein, The first ground plane (251) has a first width (332), and the second ground plane (252) has a second width approximately equal to the first width, and the feeder portion (222) has a third width less than the first width and the second width.

6. The antenna element (200) as claimed in claim 1, wherein, The head (228) of the monopole portion (224) includes a lower segment (232) below the slot (230), an upper segment (234) above the slot, and a side segment (236, 238) on the opposite side of the slot between the lower segment and the upper segment. The width of the head is defined between the side segments and is approximately equal to the width of the second conductor (250) defining the space between the first stub (253) and the second stub (254).

7. The antenna element (200) as claimed in claim 6, wherein, The height of the upper segment (234) is greater than the height of the lower segment (232).

8. The antenna element (200) as claimed in claim 1, wherein, The first stub (253) includes a first arm and a first link (255) between the first arm and the first ground plane (251), and wherein the second stub (254) includes a second arm and a second link (256) between the second arm and the second ground plane (252).

9. The antenna element (200) as claimed in claim 8, wherein, The neck (226) has a neck height (310) that is approximately equal to the first link width (352) of the first link (255) and the second link width of the second link (256), such that the head (228) spacing between the head and the second conductor (250) is approximately equal to the first arm spacing between the first arm and the first ground plane (251) and the second arm spacing between the second arm and the second ground plane (252).

10. The antenna element (200) as claimed in claim 1, wherein, The first ground plane (251) is separated from the feed line portion (222) by a first gap, and the second ground plane (252) is separated from the feed line portion by a second gap. The antenna element also includes a resistor between the feed line portion and at least one of the first ground plane and the second ground plane.

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