Surface mount antenna architecture

Abstract

A surface mount antenna (SMA) is formed as a standalone printed circuit board (PCB). The SMA comprises a first layer, a second layer a plurality of upper layers. The first layer forms a feeding interface configured for conductively coupling to a motherboard PCB. The feeding interface comprises (i) a flat protrusion configured to couple to a microstrip line of the PCB having a predetermined resistance and to receive radio frequency power via the microstrip line, and (ii) a ground pad configured for conductive coupling to a ground of the motherboard PCB. The second layer is configured to receive the input power from the flat protrusion and distribute the input power to an antenna device. The antenna device is included in a top layer of the plurality of upper layers.

Description

SURFACE MOUNT ANTENNA ARCHITECTUREReference to Related Patent Application(s)

[0001] This application claims the benefit of Convention priority from Australian Provisional Patent Application No. 2024904250, the contents of which are incorporated herein by reference in their entirety.Technical Field

[0002] The present invention relates generally to surface mount antenna design and, in particular, to an architecture for a surface mount antenna.Background

[0003] Designing of a high-quality RF (radio frequency) antenna involves consideration of several factors to allow desired performance and reliability. Relevant factors include feeding structure, radiation gain and efficiency, impedance matching, thermal conductivity, polarization profile, mutual coupling and isolation, size and cost. Some networks use millimetre-wave (mm- wave) antennas operating in the 20-40GHz frequency range for applications such as 5G networks, satellite communications, and automotive radar systems. Mm-wave antennas typically have compact size, high resolution and capability for directional beamforming. Design of mm- wave antennas faces further challenges to those outlined above, such as increased propagation loss, requirements for precise manufacturing tolerances to maintain performance, and addressing issues of thermal management due to higher power densities.

[0004] A popular method for building mm-wave antenna systems in the RF industry is a distributed antenna approach within a multilayered PCB (printed circuit board) structure. A benefit of using distributed antennas within a multiplayer PCB is the compactness achieved by embedding the antenna(s) directly into the PCB. The stable manufacturing process of PCBs ensures each antenna meets stringent quality and reliability standards, important for both commercial and industrial applications. Using distributed antennas within a multiplayer PCB simplifies the assembly and integration process, allowing antennas to be directly connected to a device's circuitry, thereby eliminating the need for additional connectors or components, and reducing overall design complexity.47009825_1

[0005] However, there are limitations to using distributed antennas within a multiplayer PCB. One significant challenge is managing the trade-offs between the antenna design and overall circuit design. Since both the antenna and other electronic circuits share the same PCB, they can influence each other's performance. Additionally, the dielectric properties of the PCB material can affect the antenna's impedance matching, bandwidth, and radiation pattern, necessitating careful consideration of properties such as dielectric constant and loss tangent during the design phase. Constraints may also be imposed by the PCB manufacturing process, for example fixed thickness of PCB layers and the spacing between layers can limit the design flexibility and performance optimization of an antenna. Further, advanced electronic systems include multiple components, including processors, memory chips, power management units, and sensors in a PCB. Each component has specific requirements and constraints, complicating the PCB layout and design process. Integrating antennas into the same PCB can be complex, as each antenna's placement and orientation need to be carefully managed to avoid interference and degradation of performance. Integrating antennas into a complex PCB often requires additional design iterations and simulations, increasing overall design time and cost. Further, reworking or redesigning the PCB to accommodate changes in the antenna design or system requirements can also be costly and time-consuming.

[0006] One existing alternative to designing antennas within a multilayer PCB is to design a surface mount antenna. A surface mount antenna can be mounted directly onto the PCB’s surface, effectively decoupling the antenna design from the rest of the circuit design. Removing the antenna(s) from the PCB can allow simplification in design of the PCB.

[0007] However, surface mount antennas also present practical problems. One challenge is dealing with the variability in motherboard PCB properties, such as unknown layer thickness and dielectric constants. Variations in thickness and dielectric constants can impact the antenna's impedance matching, bandwidth, and radiation efficiency. Achieving consistent performance requires careful design and testing to account for these inconsistencies, often necessitating the development of adaptive or tuneable elements within the antenna design to accommodate different PCB stack-ups. Development of adaptive or tunable elements adds complexity to the design process and demands a high level of precision in manufacturing and quality control.

[0008] Another challenge is designing a reliable feeding interface that allows easy installation while maintaining suitable thermal dissipation. The feeding interface should be robust enough to handle variations in the PCB's surface quality and alignment, yet simple enough to allow for easy, tool-free installation. Ensuring good thermal dissipation is particularly relevant for high-47009825_1power applications where poor thermal management can lead to overheating and reduced performance. This requires innovative designs that incorporate materials and structures to enhance thermal conductivity while maintaining electrical performance. The feeding interface preferably also allows for slight misalignments during installation without degrading the antenna's performance, which involves complex geometric considerations and precision engineering.

[0009] Current surface mount antenna solutions also face challenges in terms of isolation and installation. In terms of isolation, electromagnetic interference (EMI) from adjacent components can significantly degrade the antenna's performance, necessitating the use of shielding or special design techniques to minimize interference, presenting challenges on typical densely- packed PCBs. Ensuring isolation between multiple surface mount antennas in proximity requires careful design of the antenna elements and placement to prevent mutual coupling as well as additional simulation and modelling techniques to predict and mitigate potential interference issues. In terms of installation, current surface mount antenna solutions require specialised tools for installation on a PCB and need to account for potential misalignment and effects on performance due to variations in placement. Many existing solutions use Ball Grid Array (BGA), Land Grid Array (LGA) or surface mount connectors which present difficulties in installation and may provide inadequate thermal conductivity at high power levels. Inadequate thermal conductivity may present problems in terms on performance and component lifespan.

[0010] Many current surface mount antenna solutions are not designed for operation in the mm- wave range. Designing surface mount antennas for operation in this range faces significant problems in terms of miniaturization, material properties, and signal integrity.

[0011] Additionally, current surface mount antenna solutions typically function in standalone mode, and are not suitable for integration as phased-array elements. Inability to use as part of a phased array can limit use in many applications.

[0012] Current surface mount antenna solutions often cannot be configured to provide different polarisation profiles such as dual- and circular-polarizations and therefore cannot be used for improving signal quality and reducing interference. A majority of current surface mount antennas are designed for broad-side radiation rather than end-fire radiations, thereby limiting use in some applications.Summary

[0013] It is an object of the present invention to substantially overcome, or at least ameliorate, one or more disadvantages of existing arrangements.47009825_1

[0014] Disclosed are arrangements providing an architecture for surface mount antennas in which the antenna is designed as a self-contained PCB having a feeding interface for receiving input power (feed) in a first layer and a second layer configured for input feed redistribution. The feeding interface includes a flat protrusion and a ground pad configured to be conductively coupled to a motherboard PCB. The arrangements described provide a flexible approach which can operate with simplified design requirements for integration into a PCB and provide a number of advantages and in terms of operation and broader applications than traditional surface mount antenna solutions.

[0015] According to a first aspect of the present disclosure, there is provided a surface mount antenna formed as a standalone printed circuit board (PCB), comprising: a first layer forming a feeding interface configured for conductively coupling to a motherboard PCB, wherein the feeding interface comprises a flat protrusion contact pad configured to couple to a microstrip line of the PCB having a predetermined resistance and to receive radio frequency power via the microstrip line, and a ground pad configured for conductive coupling to a ground of the motherboard PCB; a second layer configured to receive the input power from the flat protrusion contact pad and distribute the input power to an antenna device; and a plurality of upper layers, where in the antenna device is included in a top layer of the plurality of upper layers.

[0016] Other aspects are also disclosed.Brief Description of the Drawings

[0017] Some aspects of the prior art and at least one embodiment of the present invention will now be described with reference to the drawings, in which:

[0018] Fig. 1 shows a prior art arrangement for a distributed antenna element on a multi-layer PCB;

[0019] Fig. 2 shows a prior art arrangement for a surface mount antenna;

[0020] Figs. 3A, 3B, 3C and 3D show an example arrangement of a surface mount antenna configured for broadside radiation;

[0021] Figs. 4A, 4B and 4C show an example arrangement of a surface mount antenna configured for end-fire radiation;47009825_1

[0022] Figs. 5A and 5B show an example arrangement of a surface mount antenna including detail for operation of a feeding interface;

[0023] Fig. 6 shows an example arrangement of a surface mount antenna of Fig. 5A including detail of PCB layers;

[0024] Fig. 7A shows another example arrangement of a surface mount antenna;

[0025] Fig. 7B shows an equivalent circuit for a portion of the surface mount antenna of Fig. 7A;

[0026] Figs. 8A and 8B show example configurations of contact and ground pads of a feeding interface of a surface mount antenna;

[0027] Fig. 9 shows an example phased array of surface mount antennas;

[0028] Fig. 10 shows an example arrangement of a surface mount antenna configured for dual polarisation;

[0029] Fig. 11 shows an example arrangement of a surface mount antenna configured for circular polarisation;

[0030] Fig. 12 shows example connections for a surface mount antenna using differential excitation;

[0031] Fig. 13 shows an example arrangement of a surface mount antenna having a high impedance surface;

[0032] Fig. 14 shows an example PCB on which a plurality of surface mount antennas are formed; and

[0033] Figs. 15A and 15B show examples of integration of metamaterial structures with surface mount antennas.Detailed Description including Best Mode

[0034] Where reference is made in any one or more of the accompanying drawings to steps and / or features, which have the same reference numerals, those steps and / or features have for47009825_1the purposes of this description the same function(s) or operation(s), unless the contrary intention appears.

[0035] It is to be noted that the discussions contained in the "Background" section and that above relating to prior art arrangements relate to discussions of documents or devices which form public knowledge through their respective publication and / or use. Such should not be interpreted as a representation by the present inventor(s) or the patent applicant that such documents or devices in any way form part of the common general knowledge in the art.

[0036] The arrangements described herein provide an architecture for surface mount antennas in which the antenna is designed as a self-contained PCB having a feeding interface for receiving input power (feed) in a first layer and a second layer configured for input feed redistribution. The arrangements described provide a flexible approach which can operate with simplified design requirements for integration into a PCB and provide a number of advantages and in terms of operation and broader applications than traditional surface mount antenna solutions.

[0037] Fig. 1 shows an example structure 100 of a pre-existing distributed antenna. The structure 100 includes a multi-layered PCB 105 having a distribution network 107. A number of RF integrated circuits 110 are integrated the PCB 105 and connected to provide RF power (also referred to as input feed) to patch radiators 115 via the distribution network 107. An antenna ground 109 is formed with the PCB 105.

[0038] Fig. 2 shows a simple example 200 of pre-existing surface mount antennas (SMAnt) 220 applied to a PCB 205. Each of the surface mount antennas 220 includes a plurality of mounting joints 222, antenna ground 224 and patch radiator 226. Each of the antennas 220 is connected to one of RF integrated circuits 210 via a distribution network 207 to receive input feed. The distribution network 207 may be on a top, bottom or inner layer of the PCB 205. As shown in Fig. 2, the antennas 220 may be connected to a top or a bottom surface of the PCB 205. Preexisting surface mount antennas, such as 220, use a ball grid array (BGA) of land grid array (LGA) connectors as the mounting joints 222 for mounting to the PCB. The connectors typically involve an array of multiple solder balls (BGA) or flat recessed pads (LGA) that align with corresponding pads on the PCB. The traditional mounting techniques present several drawbacks. BGAs and LGAs are complex and costly, requiring precise alignment and sophisticated equipment for installation. Additionally, BGA and LGA joints typically do not provide adequate thermal conductivity, important for dissipating the heat generated when antennas operate at high-power levels (for example, >36dBm).47009825_1

[0039] The arrangements described provide an architecture for a packaged antenna body designed for direct mounting or dismounting onto a motherboard PCB. In the arrangements described, the entire physical body of antenna is accommodated in a multi-layer substrate, which can be produced using traditional laminate etching processes and cut out into a required pitch size. The structure or architecture described supports surface mount antenna designs for two radiation types: broadside and end-fire.

[0040] Figs. 3A and 3B show an example simplified arrangement of a surface mount antenna configured for broadside radiation. Fig 3A shows a side view 300 of a surface mount antenna 310 applied to a motherboard PCB 315 for broadside radiation. The antenna 310 includes 6 layers 310_1 to 310_6. The antenna 310 is attached to the motherboard PCB 315 by the first layer 310_1 , being the bottom layer. Fig. 3A also shows a top view 320 of the antenna 310 applied to the motherboard 315. As shown in the view 320, the antenna 310 lies fully within a top surface of the motherboard 315.

[0041] Fig. 3B shows a simplified partial side view 350 showing more detail of how the antenna 310 is applied to the motherboard PCB 315. As shown in the view 350, a conducting footprint shape 355 (also referred to as a feeding interface) is formed as the layer 310_1. The conducting footprint shape 355 can be formed by a wire bond compound and form a single shape, for example a quadrilateral shape. The feeding interface 355 typically comprises two components, more detail of which is provided in relation to Fig. 3D. The conducting footprint (feeding interface) 355 can be considered similar to a QFN (Quad flat no lead) package used in PCB design. The footprint 355 can be attached to a contact 360 formed on the PC motherboard 315. The contact 360 is also composed of conducting material and typically has a similar shape to the footprint or contact 355. For example, the contact 360 is typically a microstrip line present in most common PCB structures or another transmission line suitable for conducting microwave signals and conductively connecting to an external component. In the examples provided herein a microstrip line is generally described but other such contacts may also be used. The footprint 355 can be conductively coupled to the microstrip line (contact) 360 by soldering or other common means of connection to a PCB.

[0042] Fig. 3C shows an example 370 set of layers used in an example implementation of the surface mount antenna 310 configured for broadside radiation and a corresponding PCB motherboard such as the PCB motherboard 315.

[0043] The antenna 310 includes the layers 310_1 to 310_6 formed using typical PCB manufacturing processes. The example 370 also includes information regarding the layers of47009825_1the surface mount antenna 300. In the example of Fig. 3B, the bottom layer, layer 301_1 is the layer for interfacing with motherboard PCB 315, configured for conducting input RF power received from the motherboard PCB 315. The second layer, 310_2, is referred to as a redistribution layer. The redistribution layer 310_2 operates to accommodate a transmission line or distribution circuit coupling the received power to an antenna device. The next layer up, layer 310_3 provides the antenna ground, for example a ground plane of a cavity-backed patch antenna. The layer 310_3 also provides a shielding of the upper layers (310_4 to 310_6) from the redistribution layer. The next layers, 310_4 and 310_4 are referred to as intermediate layers and are left empty as resonance cavities in the example of Fig. 3C, thereby creating fence structures or barriers and forming shield between the second layer 310_2 and the top layer 310_6. The top layer, 310_6, includes an antenna device. In the example of Fig. 3D, an antenna device 318 is shown, being a patch radiator.

[0044] The layers 310_1 to 310_6 are separated by typical layers used in PCB architecture, being core layers (for example layers 312 between 310_1 and 310_2, 310_3 and 310_4, 310_5 and 310_6) and prepreg layers (for example layers 314 between 310_2 and 310_3, 310_4 and 310_5).

[0045] Fig. 3C also shows example layers of a motherboard PCB, such as the PCB 315 and a solder layer 375 conductively connecting the surface mount antenna 310 to the PCB 315. As shown in the example of Fig. 3C the surface mount antenna 310 can be attached to the motherboard 315 via the solder layer 375. The motherboard PCB 315 can include multiple layers. A top layer MB1 typically includes microstrip lines and associated shields, for example providing the contact 360. Other layers may include a second (lower) layer MB2 providing a ground plane of the microstrip line of MB1 and a third layer MB3 providing Ground. Dielectric layers may be formed between the each of the layers MB1 to MB3.

[0046] Fig. 3D shows a more detailed view 380 of the surface mount antenna 310 applied to the motherboard PCB 315. The antenna ground for the device 310 is formed at layer L3 (310_3), while layers L4 and L5 (310_4 and 310_5) are left empty to create a resonance cavity filled with dielectric material. The cavity formed by 310_4 and 310_5 operates to stabilize electromagnetic fields associated with the antenna 310, thereby enhancing the antenna 310's performance. In the example of Fig. 3D, the antenna device 318 (a patch radiator) is positioned on the topmost layer 310_6. To achieve a fractional bandwidth exceeding 20%, parasitic capacitance and inductance can in some implementations be incorporated into the radiator 318. The parasitic capacitance and inductance can be used to fine-tune resonance, allowing the antenna 310 to effectively handle a broader range of frequencies.47009825_1

[0047] The footprint structure of the antenna 310 provides sufficient thermal performance and efficient heat dissipation to enable handling of high-power inputs. Surface mount antennas designed using the structure of the antenna 310 can be positioned in most locations on the motherboard PCB, except in regions very close (less than 1.5 times the wavelength) to the edge, where performance could be compromised due to edge effects. In the example of Fig. 3D, the PCB 315 includes the microstrip line 360 and heat sink vias 385. The heatsink vias 385 are optional but can assist further in thermal performance.

[0048] Fig. 3D also shows an example top-level view 390 of the footprint shape (feed interface) 355 of the antenna layer 310_1 forming the feeing interface 355. A portion of the PCB 315 is included in the view 390 for reference. As shown in Fig. 3D the footprint 355 includes a contact pad 392, also referred to as a flat protrusion. The contact pad 392 is typically in form of a relatively flat protrusion having a geometric shape suitable for soldering to the microstrip line 360 of the PCB 315. The protrusion 392 formed by the contact pad is referred to as a flat protrusion as the geometric shape suitable for soldering to the microstrip line forms a substantially flat surface for contacting the microstrip line 360. The flat protrusion 392 is generally of a conducting material suitable for soldering to a PCB interface, such as copper or another wirebond material for example. The flat protrusion typically has a protrusion height suitable for soldering to a PCB without incurring unnecessary heat dissipation when conducting, for example a height of a typical metal layer of a PCB, and will vary in implementations. Factors affecting height of the flat protrusion 392 include the metal layer thickness of a laminated substrate material and whether suitable for soldering. In this regard, the height in some implementations is typically around 18um or 35um. Other factors which may affect the height of the flat protrusion 392 include material used, expected application frequency and the like.

[0049] The geometric size and shape of the flat protrusion (contact pad) 392 is typically quadrilateral and may be varied based on expected shape of an interface with the PCB 315 or trends in shapes of interface contacts such as microstrip lines. The flat protrusion 392 typically has a larger effective surface contacting the PCB 315 via the interface contact (microstrip line 360) than a BGA or LGA connector. In particular, the geometric size of the contact pad is typically similar in width to a microstrip line (or as described in relation to Figs. 8A and 8B, varied by a predetermined fractional amount compared to the microstrip line 360). The larger effective contact area allows a higher thermal conductivity, and accordingly improved heat dissipation, between the surface mount antenna 310 and the motherboard PCB 315 compared to a traditional LGA or BGA connection. The flat protrusion 392 has a substantially flat shape for connection to the PCB, particularly compared to the substantially curved or frusto-spherical shape of a BGA connector. The flat protrusion 392 is typically more similar in shape to a QFN47009825_1(quad flat no lead) package. On being conductively coupled to the microstrip line 360, the flat protrusion 392 receives input feed from the motherboard PCB 315 for distribution via the redistribution layer L2 (310_2) to radiators of the surface mount antenna 310. The feed interface 355 includes a ground solder pad 394 substantially surrounding, but isolated from, the contact pad 391. The ground pad 394 and the flat protrusion 392 are both suitable for soldering into conductive communication with the PCB 315. The ground pad 394 and the flat protrusion 392 both form part of the feeding interface layer L1 (310_1). The ground pad 394 is typically of the same material and height as the flat protrusion 392. Dimensions of the ground pad 394 (in terms of X and Y axes) may vary based on factors such as an expected application, microstrip line sizes, overall surface mount antenna size and the like.

[0050] The footprint structure of the flat protrusion 392 and the ground pad 394 forming the only conducting contacts with the motherboard PCB allows that only the impedance of the contact point 360 (e.g. microstrip line) need be known. For example, the surface mount antenna specification may require a predetermined impedance of the microstrip line 360, for example 50 ohms. Different surface mount antennas may be designed to require different impedance at the contact point 360. However, in contrast to pre-existing solutions other properties (such as thickness or dielectric constant) of the motherboard PCB need not be known and the surface mount antenna need not be designed around other properties on an individual PCB-by-PCB basis.

[0051] Fig. 4A shows an example simplified arrangement of a surface mount antenna configured for end-fire radiation. Fig 4A shows a side view 400 of a surface mount antenna 410 applied to a motherboard PCB 415 for broadside radiation. The motherboard PCB 415 may have a similar structure to the PCB 315. The antenna 410 includes four layers 410_1 to 410_4. The antenna 410 is attached to the motherboard 415 by the first layer 410_1 , being the bottom layer. Fig. 4A also shows a top view 420 of the antenna 410 applied to the motherboard 415. As shown in the view 420, the antenna 410 does not lie fully within a top surface of the motherboard 415 but rather protrudes partially over an edge of the PCB 415.

[0052] Fig. 4B below shows an example 470 set of layers used in an example implementation of the surface mount antenna 410 configured for broadside radiation.

[0053] The antenna 410 includes the layers 410_1 to 410_4, manufactured using typical PCB processes. The example 470 also includes information regarding the layers of the surface mount antenna 400. In the example of Fig. 4B, the bottom layer, layer 401 _1 is the layer for interface with motherboard PCB 415 and is referred to as a feeding interface, similarly to the47009825_1layer 310_1. The feeding interface layer 410_1 accommodates a footprint (similar to 355) for attachment to the motherboard PCB 415. The second layer, 410_2 is referred to as a redistribution layer, also similarly to the layer 310_2. The redistribution layer 410_2 operates to accommodate a transmission line or distribution circuit providing power received at the antenna 410, for example from a contact of the PCB 415 (similar to 360) via the feeding interface to an antenna device. The next layer up, layer 410_3 provides a transition layer, accommodating a transition from the microstrip line contact of the redistribution layer to a dielectric slab. The layer 410_3 can be used as a waveguide. The top layer 410_4, does not provide functionality in terms of mounting to the PCB 415 but rather provides a top boundary of a waveguide for endfire radiation. The example also shows core layers 412 (similar to the core layers 312) and a prepreg layer 414 (similar to 314) between layers, as common under typical PCB structure.

[0054] Fig. 4C shows a view 480 providing more detail on how the surface mount antenna is typically connected to the motherboard PCB 415 and operational structure of the surface mount antenna 415.

[0055] An antenna device 418 includes a left portion 481 serving as the feeding junction, while a section 482 on the right is the leaky-wave radiator, which uses a periodic-slot waveguide. The antenna 410 is implemented using a 4-layer PCB architecture in which an end-fire radiation mechanism is designed for edge placement, enhancing directional signal propagation along a horizontal plane of the motherboard PCB 415. A feed interface 455 receives input power or feed via a microstrip part 460 of the PCB 415, which is excited by RF device (not shown) located on the PCB 415. The redistribution layer 410_2 receives the input (RF) power and distributes the input power to the feeding junction 481 (typically a microstrip) using a via 484, setting a foundational electromagnetic wave propagation along the antenna 410. From the feed interface 481 , the input power is coupled into an SIW (Substrate Integrated Waveguide) type of transmission line 483. The SIW 483 acts as a medium through which the signal is channelled and controlled within a confined substrate space. The antenna 418 operates to transmit RF signals via the leaky-wave radiator 482.

[0056] This SIW 483 is connected to a periodic slot geometry on both the top and bottom sides of the PCB, for example slots 488. The slots 488 are designed to facilitate the emission of radiation in a direction parallel to the traveling wave, required for achieving efficient end-fire radiation. The configuration using slots 488 allows radiation to be directed outward from the edge of the PCB 415. Outward directed radiation is particularly suitable for applications requiring linear array configurations or where space constraints limit traditional antenna deployment.47009825_1

[0057] The surface mount antenna 410 receives input feed from the PCB 415 via a footprint shape or feed interface 455 of the antenna 410. Fig. 4C includes a view 490 showing structure of the feed interface 455, which corresponds to structure of the feed interface 355. A portion of the PCB 415 is included in the view 490 for reference. As shown in Fig. 4C the feeding interface 455 includes a flat protrusion 492 (corresponding to the flat protrusion 392). The flat protrusion 492 is typically a substantially flat contact and has a geometric shape suitable for soldering to the microstrip line 460 of the PCB 415, as described in relation to the flat protrusion 392. The geometric size and shape of the flat protrusion 492 is typically quadrilateral and may be varied based on expected shape of an interface with the PCB 415 or trends in shapes of interface contacts such as microstrip lines. On being conductively coupled to the microstrip line 460, the flat protrusion 492 receives input feed from the motherboard PCB 415 for distribution via the redistribution layer 410_2 to higher layers of the surface mount antenna 410. The feed interface 455 includes a ground solder pad 494 (corresponding to the ground pad 394) substantially surrounding, but isolated from, the flat protrusion 492. The ground pad 494 and the flat protrusion 492 are both suitable for soldering to the PCB 415. The ground pad 494 and the flat protrusion 492 both form part of the feeding interface layer 410_1. As with the feeding interface 355, the feeding interface 455 only requires that the point with which the contact pad is conductively coupled (soldered) to has a predetermined impedance.

[0058] Based on Figs. 3 and 4, the architecture of the surface mount antenna (310 or 410), which can be formed as a standalone printed circuit board (PCB), includes a first layer (310_1 or 410_1 ) . The first layer forms a feeding interface (355 or 455) configured for conductively coupling to a motherboard PCB (315 or 415). The feeding interface comprises a flat protrusion (392 or 492) configured to conductively couple to a microstrip line (such as 360 or 46) of the PCB and a ground pad (394 or 494) configured for conductive coupling to a ground of the motherboard PCB. The microstrip line has a predetermined resistance and the flat protrusion is configured to receive radio frequency power via the microstrip line. The surface mount antenna includes a second layer (310_2 or 410_2) configured to receive the input power from the flat protrusion and distribute the input power to an antenna device (318 or 418). Each antenna configuration includes a plurality of upper layers (for example 310_3 to 310_6 or 410_3 to 410_4), the antenna device being included in a top layer of the plurality of upper layers.

[0059] While the layers 310_1 and 410_1 may be described as ‘lower’ layers and the layers 610_6 and 410_4 as upper layers, this is in relation to proximity to the motherboard PCB (315 or 415). The surface mount antennas 310 and 410 can be mounted to a top or a bottom surface of a motherboard PCB via the corresponding feeding layer (310_1 and 410_1).47009825_1

[0060] Fig. 5A shows a view 500 of a surface mount antenna 510 conductively coupled to a motherboard PCB 515 to receive input power, for example from a microstrip line 560 of the motherboard PCB 515. The PCB 515 is similar to the PCB 315 and includes layers MB1 and MB2. The antenna 510 is similar to the antenna 310 and configured for broadside radiation from an antenna device 518 on an upper surface 532. The surface 532 corresponds to the layer 310_6 of Fig. 3A for example.

[0061] The antenna 510 has a feed interface or footprint 555 for connecting to the motherboard 515 and receiving input feed. The feed interface 555 can connect to a microstrip line 560 feeding input for example.

[0062] In the example of Fig. 5A, a first layer 510_1 (corresponding to 310_1) is attached to the PCB 515 by a layer of solder 507. A redistribution layer 510_2 (corresponding to 310_2) receives the input feed from the layer 510_1 by a via 521. The layer 510_2 connects input feed to the radiators 518, for example connected by a via 524. A ground layer 510_3 (corresponding to 310_3) provides antenna ground, for example using vias 522. The ground layer 510_3 is connected to a ground pad 574 by a via 523.

[0063] As shown in Fig. 5A, architecture of the feed interface 555 can be fed directly by a microstrip (MS) line such as 560 with intrinsic impedance (Z0) on the top layer (MB1) of the motherboard PCB 515. In other implementations, the feedline 560 may be on a top or bottom layer of the PCB 515 and the antenna 510 connected to respectively to the top side or the bottom side of the motherboard PCB 515.

[0064] A view 570 shows an example structure of the feed interface 555. The feed interface 555 has a similar structure to the interfaces 355 and 455. As shown in 570, the feed interface 555 has a flat protrusion 572 (corresponding to the flat protrusion 392) for connecting to the strip 560, and a ground pad 574 (corresponding to the ground pad 394). The feeding structure 555 is configured for soldering to a conductor footprint on the PCB 415 includes the ground (GND) soldering pad 574 as well as the flat protrusion 572.

[0065] Fig. 5B shows a series of cross-sectional views 580, 585 and 590 taken from viewpoints A-A’, B-B’ and C-C’ of Fig. 5A to assist in showing function of the feed interface and the redistribution layer 510_2. The views 580, 585 and 590 demonstrate changing adaptation and use of the layers in different regions of the surface mounted antenna 510. As shown by the view 580, the motherboard PCB 515 includes intrinsic impedance layers MB1 (including 560) and MB2, each of which may be connected as a feedline to the antenna 510.47009825_1

[0066] The feed interface 555 receives incoming signal transmission from 560. The PCB 515 can be conductively connected to the layer 510_1 via soldering, such as by a layer of solder 507, connecting the flat protrusion 572 of the layer 510_1 , as shown in the view 585. The feed input 555 simultaneously conductively connects a transition junction towards the microstrip line 560 (with same intrinsic impedance Z0) on the redistribution layer (510_2) using the via 521 as show in 590 from the C-C’ viewpoint 590. As also shown in the viewpoint 590, the ground pad 574 is connected by solder motherboard PCB 515.

[0067] The feeding configuration 555 and the connections shown in Fig. 5B can provide a reliable impedance matching junction, adapted to the variance of motherboard substrate thickness and dielectric index values.

[0068] Figure 6 shows an example 600 of a connecting structure in a 6-layer PCB stack up. In Fig. 6, an antenna PCB 610 has 6 layers corresponding to 310_1to 310_6 respectively. For ease of viewing only layers 610_1 , 610_2 and 610_6 are labelled in Fig. 6. A microstrip line 660 is provided by a motherboard PCB. The layer 610_1 connects to the microstrip line 660 at a transition area 620. A feed point 630, corresponding to a flat protrusion such as 572, 392 or 492, provides input received at 610_1 to the layer 610_6 via the layer 610_2.

[0069] The structure of the feeding pad 655 provides consistency in performance, irrespective of skill of the person connecting the surface mount antenna to the motherboard PCB. In particular, given the contact pad and ground pad design even if there is excessive soldering on the front side of the surface mount antenna, the excess solder will have very limited impact the signal transmission quality, the limited effect of excess solder allows a relatively robust and reliable connection, allowing suitable high performance to be achieved in varying assembly conditions. The feeding pad structure is suitable for standalone surface mount antenna utilization or phased array antennas with a maximum of two rows.

[0070] The feed interface structure described addresses feed and integration issues with motherboard PCBs in existing solutions, which may have unknown substrate thickness and dielectric index. The feeding pad structure described only requires the microstrip line on the top or bottom side of the motherboard PCB top have a known impedance value (for example 50 ohms or another impedance value), regardless of the width and distance to the ground layer of the microstrip line. Implementations of the invention may therefore be designed for a specific impedance of interface with the motherboard PCB, depending on intended use. A use of implementations of the surface mount antenna described herein can use a motherboard PCB, or motherboard PCB with a microstrip line impedance according to specifications of the47009825_1antenna. Different products requiring different impedance may be implemented to provide a broad range of applications.

[0071] Figs. 3-5 provide a first embodiment of a surface mount antenna architecture. The first embodiment is for a self-contained multilayer PCB antenna including a first feeding layer configured for attachment by a feeding pad and receiving input from a line having a known or predetermined impedance. The self-contained multilayer PCB antenna includes second layer for distribution of the input feed and a plurality of further layers. The function of the further layers may vary depending on the implementation, for example whether for broadside or end-fire radiation. In the first embodiment, the feeding pad configured in the first layer includes a contact and ground solder pad, the ground solder pad surrounding most side of the contact such that the contact forms at least a partial edge of the feeding interface. The contact provides interface functionality similar to a microstrip line.

[0072] The feed interface structure described for the first embodiment can be considered similar to a QFN pad. In a second embodiment, a “pull-back” structure of the feeding pad may be implemented. In the “pull-back” structure, the contact of the feeding pad does not form an edge but is surrounded by the ground solder pad.

[0073] Fig. 7A shows an arrangement 700 used to illustrate the second embodiment of the feed interface. In the arrangement 700, a surface mount antenna 710 is coupled to a motherboard PCB 715. The antenna 710 has a similar 6-layer structure to the antenna 310 or 510. However, for ease of viewing not all layers are shown in Fig. 7A. A layer of solder 707 attaches the surface mount antenna 710 to the motherboard PCB 715. A feedline 760 provides input feed from the PCT 715 to the antenna 710. In the example of Fig. 7A, the feed 760 does not form a top layer of the PCB 715 but forms a contact with a portion of the top layer of the motherboard PCB 715 and is conductively coupled to a feeding interface 755 of the antenna 710.

[0074] A view 770 of Fig. 7A shows an example structure of the feed interface 755. As shown in 770, the footprint 755 has a flat protrusion 772 (corresponding to 392 or 492) for connecting to the strip 760 and a ground pad 774 (corresponding to ground pads 394 or 494). The feed interface 755 includes the ground (GND) soldering pad 774 as well as the flat protrusion 772. In contrast to the flat protrusion 572 of the feed interface 555, the flat protrusion 772 is fully surrounded by the ground pad 774 and does not form a partial side edge of the footprint 755. The dimensions of the flat protrusion 772 are based on similar factors to the flat protrusion 392. The dimensions of the ground pad 774 are based on similar factors to the ground pad 394.47009825_1

[0075] The flat protrusion 772 receives input feed from microstrip line 760 at a first layer 710_1 (similar to 310_1 ) of the surface mount antenna 710. The input feed is passed to a second, distribution layer 710_2 (similar to 310_2) by a via. The layer 710_2 is configured for providing the input feed to an antenna device such as 730. The antenna ground is connected to ground pad 774 by a via 723.

[0076] The embodiment described in relation to Fig. 7A is configured to allow couple signals from a microstrip line on MB2 to another microstrip line on the redistribution layer (L2). The example of Fig. 7A addresses the need for efficient signal transition between different layers while maintaining impedance matching and minimizing signal loss, providing a reliable signal path. As described above, the “pull-back” style shown in the view 700 allows feed interfacing with lower or inner layers of the PCB 715, such as layer MB2 shown in Figs. 3 to 5.

[0077] To compensate for the capacitance introduced by the oversized footprint pad 755 (compared to 555 for example), a stub-line-based impedance transformer is integrated into the transmission structure, acting as an inductance. An example impedance transformer 745 is shown in Fig. 7A. The impedance transformer 745 is implemented where the redistribution later interfaces with the flat protrusion 772, for example where the via 721 meets the layer 710_2 at a location 740. The impedance transformer 745 operates to transition the signal from the microstrip line 760 on the motherboard PCB 715 to a microstrip line on the redistribution layer 710_2. An enlarged view 750 of interface of the flat protrusion 772 with the layer 710_2 including the impedance transformer 745. The impedance transformer in ins some arrangements formed as an arrangement of line design as part of the antenna structure, or may be formed using other techniques know in the art. In the example of Fig. 7A, a short-circuit transmission line forms the impedance transformer 745. Addition of the transformer 745 allows impedance to remain generally consistent throughout the signal path from interface at the footprint 755 to the layer 710_2, thereby enhancing the overall performance of the antenna 710. An equivalent circuit 790, shown in Fig. 7B demonstrates how the impedance transformer 745 compensates for the capacitance, maintaining a stable impedance.

[0078] The stub-line-based impedance transformer 745 provides a mechanism for maintaining signal integrity. Use of the transformer 745 with structure of the feeding pad 755 mitigates potential mismatches arising from differences in dielectric properties and physical dimensions between the two layers (760 of MB2 and 710_2). By incorporating the transformer 745, the signal path can be optimised in terms of minimising reflection and maximising power transfer, as required for high-frequency applications.47009825_1

[0079] The embodiment described in relation to Fig. 7A is particularly well-suited for applications where the motherboard PCB's distribution network is built in a microstrip line configuration, providing a reliable method for signal transition and performance even in complex circuit environments. Additionally, the arrangements of Fig. 7A are suitable for relatively large- scale planar phased arrays comprising multiple surface mount antennas in a lattice arrangement. The relatively precise impedance matching and effective signal transition capabilities are suitable for phased array applications, where beamforming and directional signal control are typically required.

[0080] The pull-back design shown in 700 also offers flexibility in the placement and orientation of the surface mount antenna 710 on PCB motherboards. The adaptability is especially beneficial in densely packed PCBs, where efficient use of available space is required. Antenna performance may be maintained despite variations in the surrounding circuitry.

[0081] In the embodiments of Figs. 3-7, the flat protrusion and ground pad have a size similar to the microstrip line or associated contact on the motherboard PCB to which they are connected. However, in practice installation of a surface mount antenna can be adversely affected by misalignment in the XY plane, especially when a tool-free approach is used. Misalignment can lead to poor signal transmission and impedance mismatches, degrading the antenna's performance.

[0082] In some implementations, to mitigate misalignment issues, geometric adjustments can be made to the feed interface structure to enhance the antenna's tolerance to placement errors. The geometric adjustments are typically made to the flat protrusion and the ground pad of the footprint such that the geometric size of the contact is different to the corresponding contact point on the motherboard PCB. In a preferred embodiment, the flat protrusion and ground pad of the footprint are designed to be smaller in both the X and Y directions by approximately 15% compared to the corresponding contacts (pads or microstrip lines for example) on the motherboard PCB. The size reduction allows for a more forgiving alignment process. Additionally, the opening width of the footprint on the surface mount antenna is designed to be 15-20% larger than the opening on the motherboard PCB. The increased width further accommodates potential misalignments. In other implementations the size may be decreased by a different amount, for example anywhere in a range of 10-20% or even above, depending on factors such as an expected or factored misalignment tolerance. While the decrease in geometric size in typically implemented equally in both X and Y directions, in some implementations the scale of change of size may be different in X and Y directions, depending on factors such as expected contact pad size on the motherboard PCB and the like.47009825_1

[0083] Figs. 8A and 8B show example geometric adjustments. Fig. 8A shows a feeding interface 800, similar to that of 555. The interface 800 includes a flat protrusion 832 for feed input (similar to 572) and a ground pad 834 (similar to 574). A dotted line 842 shows an example new edge or border of 832 when the size has been decreased by a predetermined amount. A dotted line 844 shows a new edge or border of 834 when the size has been decreased by a predetermined amount.

[0084] Fig. 8B shows a feeding interface 850, similar to that of 770. The interface 850 includes a flat protrusion 862 for feed input (similar to 772) and a ground pad 864 (similar to 774). A dotted line 872 shows an example new edge or border of 862 when the size has been decreased by a predetermined amount. A dotted line 874 shows a new edge or border of 864 when the size has been decreased by a predetermined amount.

[0085] Use of geometric adjustments in size of the contact and ground pads can provide an effect that a misalignment of + / -10- 15% during the installation of the surface mount antenna will not significantly affect the impedance matching or the signal transmission to and from the antenna. Ability to account for misalignment further assists in maintaining the surface mount antenna's performance and reliability despite potential installation inaccuracies. By allowing for misalignment tolerances, the surface mount antenna can be more easily and reliably installed without the need for highly precise placement, making the installation process more robust and user-friendly.

[0086] Ability to tolerate misalignment can also be beneficial in high-volume manufacturing environments where slight variations in placement can occur. Addition of misalignment tolerance can reduce the need for rework and increase the overall yield of the manufacturing process.

[0087] The surface mount antennas described in relation to Figs. 1-8 are primarily designed to operate as standalone radiation units, rather than implemented as an antenna unit within a phased array configuration. Employing surface mount antennas as 'embedded types' within a phased array, requires adapting to a distinct impedance environment compared to standalone configurations. During the design phase of embedded type surface mount antennas, specific configurations such as a master-slave boundary condition and an active S-parameter optimizer are implemented within the simulation environment. The specific configurations are tailored to the array type, whether rectangular or triangular lattice, aiming to optimize array element performance across all beamforming angles. Table 1 shows design approached used for each type of surface mount antenna.47009825_1Table 1

[0088] Furthermore, in scenarios where a phased array requires a broad angular range of beam steering, a specialized type of parasitic surface mount antenna, known as the 'dummy element,' can be strategically placed around the perimeter of the phased array to minimize edge effects. The dummy type of surface mount antenna shares the same structural design as the embedded types within the phased array but differs in that the contact pad of the feeding interface is subjected to a "short circuit," meaning the flat protrusion of the feeding interface is not actively connected to any signal line on the PCB. For example, in Fig. 3D or 4C, the contact pads 392 and 492 are correspondingly short circuited rather than connected to the microstrip line 360 or 460. This inclusion of dummy elements helps preserve the array's integrity and performance by stabilizing the outermost elements.

[0089] For example, Fig. 9 shows an example 900 of a PCB 915. The PCB has active surface mount antennas (such as 910) coupled thereto in a rectangular configuration. The active surface mount antennas are surrounded by dummy surface mount antennas 320. The active surface mount antennas have an architecture similar to the antenna 310 are connected to receive input from the PCB 915 via the flat protrusion (392) being soldered to a microstrip line similar to 360. The dummy 520 surface mount antennas have an architecture similar to the antenna 310 have the flat protrusion (392) short circuited and so do receive input from the PCB 915.

[0090] In practice, when constructing linear or planar phased arrays using the surface mount antennas described the embedded type is typically used over the standalone type. The inclusion of dummy types of surface mount antennas serves as a beneficial enhancement whenever needed. To allow mechanical stability and prevent squeezing, the overall bottom area dimension (in terms of X and Y axes) of each embedded or dummy surface mount antennas47009825_1can be designed to be smaller than the pitch size of the array. For example, the overall bottom area dimension may be in a region of 5% smaller. Use of a smaller overall bottom area dimension creates a small air gap between adjacent surface mount antennas, allowing for slight physical separation and reducing mechanical stress.

[0091] Use of a smaller overall bottom area not only enhances the functionality and versatility of phased arrays but can also improves the phased array's overall performance by allowing each element, whether active or dummy, to be better integrated and contribute more effectively to the system's objectives. Improved integration of the phased arrays can enable more precise and flexible control over beamforming capabilities, allowing improvement in performance even under diverse operational conditions.

[0092] The surface mount antenna structure described herein, as described above, can be configured for broadside radiation, end-fire radiation, receiving input feed from multiple layers, improved misalignment tolerance and phase array use. The arrangements described can also be extended to allow dual-polarisation and circular polarisation radiation from a surface mount antenna.

[0093] Fig. 10 shows an example 1000 configured for dual polarisation. In Fig. 10, a surface mount antenna 1010 is conductively attached to a motherboard PCB 1015. The motherboard PCB 1015 has a similar structure to the PCB 315 for example. The surface mount antenna 1010 has a similar structure to the antenna 310 in terms of a feed interface 1055 comprising a flat protrusion 1092 and ground pad 1094 (similar to 392 and 394 of 355 respectively). The feed interface forms part of a first, feeding layer 1010_1 (similar to 310_1 ) and a second redistribution layer 1010_2 (similar to 310_2). The flat protrusion 1092 is conductively attached by soldering to a feed line 1060 of the motherboard PCB 1015. In contrast to the antenna 310, the antenna 1010 has a dual-polarised antenna device 1018 (compared to single polarisation on 318). Dual polarisation in enabled in the example of Fig. 10 as the redistribution layer 1010_2 distributes the energy received by the flat protrusion of the feeding line 1010_1 to two different locations, along one of each of two different vias (1022a and 1022b), compared to a single location in the antenna 310. Ground is also provided to the top layer of the surface mount antenna 1010 by two vias, 1024a and 1024b. Ability to provide input feed to more than one radiation location in the antenna 1010 allows dual polarisation to be achieved.

[0094] Fig. 10 also shows a schematic top level view 1080 of the dual-polarised radiator 1018, illustrating connections. The dual-polarised radiator 1018 receives input feed at a first location 1082 from the layer 1010_2 through the via 1022a. The dual-polarised radiator 1018 receives input feed at a second location 1084 from the layer 1010_2 through the via 1022b.47009825_1

[0095] Ability to provide multiple feed points (for example through the vias 1022a and 1022b) to radiating elements via the redistribution layer 1010_2 allows for the implementation of Horizontal / Vertical (H / V) or + / -45-degree slant dual-polarizations. By implementing multiple feed points and manipulating the phase and amplitude of the signals, the surface mount antenna architecture described herein can efficiently support diverse polarization modes. Ability to support different polarisation modes is important for applications requiring robust signal reception and transmission in varied environmental conditions and under different signal orientations. Configuration for dual polarisation, such as the example in Fig. 10, allows surface mount antennas to handle signals from different polarizations simultaneously, increasing the antenna versatility and performance in complex multi-path environments.

[0096] The antenna architecture described can also be extended to support circular polarisation. Fig. 11 shows an example 1100 configured for circular polarisation. In Fig. 11, a surface mount antenna 1110 is conductively attached to a motherboard PCB 1115. The motherboard PCB 1115 has a similar structure to the PCB 315 for example. The surface mount antenna 1110 has a similar structure to the antenna 310 in terms of a feed interface 1155 comprising a flat protrusion 1192 and ground pad 1194 (similar to 392 and 394 of 355). In contrast to the antenna 310, the antenna 1110 has a second flat protrusion 1193. The flat protrusion 1193 typically has a same size and design as the flat protrusion 1192. The flat protrusion 1192 and 1193 and the ground pad 1194 form a bottom, feeding layer 1110_1 similar to the layer 310_1. In the example of Fig. 11, two different input feed lines 1160 and 1161 (for example microstrip lines), are provided on the motherboard 1115 to allow for circular radiation. The flat protrusions 11920 and 1193 are each conductively coupled, typically by soldering, to one of the feedlines. For example, in Fig. 11, the flat protrusion 1192 is soldered to the input line 1160 to provide LHCP (left hand circular polarisation) and the flat protrusion 1193 is soldered to the input line 1161 to provide RHCP (right hand circular polarisation).

[0097] The surface mount antenna 1110 also includes a second layer for feed redistribution, somewhat similar to the layer 310_2. In contrast to the layer 310_2 and the layer 1010_2, the layer 1110_2 includes a planar passive RF component 1140 such as a coupler, a balun, a filter or any other component that split the input feed from the motherboard PCB 1115 into two orthogonal components with a 90-degree phase shift. The component 1140 receives input energy via the flat protrusions 1192 and 1193. The component 1140, for example a 90-degree hybrid coupler, allows circular-polarised radiation to be achieved. By introducing the device 1140, both Left-Hand Circular Polarization (LHCP) and Right-Hand Circular Polarization (RHCP) can be effectively generated by a single surface mount antenna unit. The coupler 1140 splits the incoming signal into two orthogonal components with a 90-degree phase shift, which are47009825_1then fed into separate antenna elements or locations designed to radiate the respective LHCP and RHCP signals.

[0098] Similarly to the antenna 1010, the antenna 1110 include a dual polarisation antenna device 1118 and provides energy inputs to two different locations on the dual polarisation radiator 1118 using separate vias 1122L and 1122R to provide LHCP and RHCP input respectively.

[0099] Ground is also provided to the top layer of the surface mount antenna 1110 by two vias, 1124_a and 1124_b. Ability to provide input feed to more than one radiation location via the passive component 1140 in the antenna 1110 allows circular polarisation to be achieved. Fig.11 also shows a schematic top level view 1180 of the dual-polarised radiator 1118, illustrating connections. The dual-polarised radiator 1118 receives input feed at a first location (element) 1182 from the layer 1010_2 through the via 1022L. The dual-polarised radiator 1018 receives input feed at a second location (element) 1184 from the layer 1010_2 through the via 1022R.

[0100] As described in relation to the examples of Fig. 10 and Fig. 11, the antenna architecture described herein can simplify antenna design by consolidating multiple polarization capabilities into a single antenna structure. The arrangements described can also operate to enhance in antenna system design as ability to switch between different polarization modes without requiring multiple distinct antennas reduces space requirements and component complexity.

[0101] As described in relation to Fig. 11 , integration of the passive RF device 1140 into the redistribution layer 1110_2 surface mount antenna enhances functionality. For example, a wideband balun, specifically a 180-degree power splitter, can be used as the device 1140. Use of a 180-degree power splitter provides a specific implementation that facilitates differential feeding of the patch antenna (1138 for example), as particularly useful in applications demanding broad operational bandwidths. Differential feeding involves the antenna being powered through two distinct but electrically inverse signal paths, effectively doubling the operational bandwidth compared to singular feed methods.

[0102] In contrast to the antenna 1010, the feed interface on the bottom layer (1110_1) of the antenna 1110 includes two flat protrusions 1192 and 1193, each configured to conductively couple to a motherboard PCB and receive input power from the motherboard PCB in a similar manner to the flat protrusions 392, 492, 572, 772 and the like. In some implementations, if more than two antenna feed inputs are required, a corresponding number of flat protrusions may be47009825_1implemented, each configured to receive input power and connect the input power via a redistribution layer (such as 310_2) to an antenna device (such as 1118).

[0103] The introduction of a wideband balun as the RF device 1140 enables the antenna 1110 to support a large fractional bandwidth, typically greater than 40%, making the surface mount antenna highly suitable for advanced communication systems that require wide bandwidth for high data rate transmission. The balun 1140 not only splits the input signal into two phases, 180 degrees apart, but also matches the impedance between the source (1160 or 1161) and the antenna. The impedance matching can minimise signal reflection at the antenna feed point (for example 1180 or 1184), improve power delivery, and enhance the overall efficiency of the assembled antenna system.

[0104] Fig. 12 shows an example 1200 of input to an antenna unit 1210 of horizontal positive and negative (+H and -H) from a V port (for example via the contact 1192) and vertical positive and negative (+V and -V) from a V port (for example from the contact 1193). A 180-degree power splitter as 1140 achieves the signals required.

[0105] Implementing differential excitation via a wideband balun can reduce the antenna's sensitivity to external noise and signal interference. By feeding the antenna differentially, the design inherently provides improved balance and symmetry in the signal paths, which helps in cancelling out unwanted electromagnetic interference and noise that can often degrade performance in single-ended feed configurations. This is particularly advantageous in dense electronic environments or in applications where signal integrity is paramount.

[0106] Fig. 13 shows a view 1300 of a surface mount antenna 1310 conductively coupled to a motherboard PCB 1315. The example of Fig. 13 is similar to the example of Fig. 5A. The PCB 1315 is similar to the PCB 515 but only a single feeding layer 1360 on the motherboard 1315 is shown. The antenna 1310 is similar to the antenna 1310 and configured for broadside radiation from radiators 1330 on an upper surface 1332. The surface 1332 may corresponds to layer 6 (310_6) of Fig. 3A for example.

[0107] The antenna 1310 has a feed interface or footprint 1355 for connecting to the motherboard 1315 and receiving input feed. The feed interface 1355 can connect to the microstrip line 1360 feeding input for example.

[0108] In the example of Fig. 13, a first layer 1310_1 (corresponding to 510_1) is attached to the PCB 1315 via a feeding interface 1355, which is the same as the interface 355. In contrast47009825_1to the surface mount antenna 510 of Fig. 5A, the surface mount antenna 1310 of Fig. 13 also comprises a corrugated structure 1350 on the outer side of the surface mount antenna package, as depicted in both a side profile in Fig. 13. The corrugated structure 1350 includes a plurality of struts 1351, each being a quarter-wavelength of the targeted radiation in depth. The corrugated structure 1350 forms a High Impedance Surface (HIS) adjacent to the patch radiator 1330. The HIS configuration 1350 provides two primary functions in terms of antenna operation.

[0109] Firstly, the corrugated HIS 1350 provides effective electromagnetic isolation for the antenna's radiator 1330 from surrounding components on the motherboard PCB. Isolation from surrounding components can mitigate unwanted interference from nearby electronic components. By acting as a barrier, the HIS structure 1350 can assist in preventing the spread of surface waves and radiated energy from the antenna 1310 into adjacent electronic circuits, helping that the antenna 1310’s radiation pattern remain clean and unobstructed.

[0110] Further, the HIS 1350 assists in maintaining stable radiation beamwidth when the surface mount antenna 1310 is installed close to a PCB edge, for example an edge of the PCB 1315. Effects of ground interactions, commonly referred to as the ground effect, can be reduced. Reduction of ground effect is especially important for maintaining consistent antenna performance, as proximity to the PCB edge can often lead to variations in the antenna’s radiation pattern due to reflections and interactions with the ground plane. The quarterwavelength corrugated structure 1350 effectively modifies the electromagnetic boundary conditions at the antenna’s edge, creating a scenario where the edge behaves more like free space, thus reducing the boundary-induced distortions in the radiation pattern.

[0111] In addition to assisting with radiation characteristics of the surface mount antenna 1310 itself, the HIS 1350 can also simplify integration of the antenna 1310 into densely packed electronic environments. Simplification of integration is particularly beneficial in complex applications where space is at a premium and antenna performance cannot be compromised by proximity to other components. Incorporating a corrugated HIS such as 1350, improves ability to position the antenna 1310 in different locations on a motherboard PCB without reduced risk of performance degradation due to undesirable electromagnetic interactions.

[0112] The surface mount antenna architecture described can also be used to integrate RF metamaterials into the antenna structure, such as negative index metamaterials, chiral metamaterials, plasmonic metamaterials, photonic metamaterials. RF metamaterials are tailored to refine and control specific antenna characteristics such as radiation pattern, beamwidth, and electromagnetic isolation. The incorporation of metamaterials into motherboard PCBs for use with the surface mount antenna structure described can improve the operational capabilities of47009825_1the surface mountable antennas by directly influencing how the antennas interact with their environment and with each other on the same motherboard PCB.

[0113] On example is surface mountable Electromagnetic Band Gap (EBG) structures and metamaterials. EBG structures specifically designed for particular frequency bands to enhance antenna performance by suppressing surface wave propagation across the motherboard PCB, thereby improving the antenna's radiation efficiency and reducing mutual coupling between adjacent antennas. The EBG structures act as high-impedance surfaces, creating an effective filter that blocks unwanted frequencies and enhances the desired signal's purity and strength.

[0114] On the other hand, metamaterial structures can be used for unique electromagnetic properties, which are not typically found in natural materials. The relevant electromagnetic properties include negative permittivity and permeability, which enable the metamaterials to manipulate electromagnetic waves in unusual ways. For example, metamaterials can be engineered to provide functions like Frequency Selective Surfaces (FSS) or to create high- impedance surfaces that alter the antenna's near-field and far-field properties. Ability to alter properties allows for more precise control over the antenna's radiation pattern and beamwidth, and for optimizing the antenna's performance for specific applications.

[0115] The integration of these metamaterials into the antenna design addresses several challenges in antenna technology, particularly in densely populated electronic environments where interference and signal integrity can be significant issues. By enhancing isolation between surface mount antennas located on the same side of the motherboard PCB, some metamaterials can mitigate cross-talk and other interference effects, enabling cleaner signal transmission and reception pathways. This is particularly important in applications such as multiantenna systems where multiple transmitting and receiving units must coexist without degrading each other's performance.

[0116] Figs. 15A and 15B show examples of integration of metamaterial structures with surface mount antennas. Fig. 15A shows a view 1500 of a motherboard PCB 1515 (similar to 315) to which two surface mount antennas 1510_rx and 1510_tx have been attached. The surface mount antennas 1510_rx and 1510_tx have a similar architecture (and feeding interface) as the antenna 310 and are configured for receiving and transmitting respectively. An array of surface mountable Electromagnetic Band Gap (EBG) structures 1520 are provided between the antennas 1510_rx and 1510_tx.

[0117] Fig. 15B shows a view 1550 of the motherboard PCB 1515 to which one surface mount antenna 1510 has been attached. The surface mount antenna 1510 has a similar architecture (and feeding interface) as the antenna 310. An array of metamaterial structures 1565 are provided surrounding the antenna 1510.47009825_1

[0118] As described in relation to Figs 3-13, the arrangements described allow for improvements in terms surface mount antenna performance and ease of integration into a motherboard PCB. Additionally, the feed interface and layer structure described provide advantages in terms of manufacturing surface mount antennas.

[0119] The antenna architecture described for the feeding interface and redistribution layers allows a straightforward approach for the mass production of surface mount antenna components involves printing a grid array of multiple surface mount antenna structures on the same piece of laminated substrate, as shown in Figure 14.

[0120] The printing process begins with the design and layout of numerous surface mount antenna units on a single large substrate, such that each antenna is precisely positioned and aligned. Once the array is printed and fabricated, the large substrate is then V-cut into individual surface mount antenna pieces, each ready for direct mounting or dismounting onto the motherboard PCB. In practice, the break joint edge on each side of the surface mount antenna typically will not influence the RF performance. Fig. 14 shows a PCB 1400 having multiple surface mount antennas (for example a surface mount antenna 1410) etched or formed within. Each surface mount antenna can be cut from the PCB 1400 and have an antenna device 1430 on a top surface 1430_6 (for example a sixth layer of corresponding to the antenna 310 and one or more feeding interfaces 1455 (corresponding to 355 for example) in a bottom layer 1410_1 corresponding to 310_1.

[0121] The arrangements described are particularly suitable for antennas that operate at mm- Wave frequency bands. The physical dimensions of antenna components operating a mm-wave are Typically in the region of 4mm by 4mm to 8mm by 8mm. The miniaturization associated with mm-wave components allows for a significant number of surface mount antenna units to be produced from a single substrate. For example, a standard 24”x18” PCB board can accommodate approximately 75x100=7500 individual surface mount antenna components that operate at 28GHz. This reactively high yield per substrate not only optimizes the use of materials but also enhances the efficiency and cost-effectiveness of the production process. The method of creating a grid array on a single laminated substrate simplifies the production workflow and minimizes manufacturing time. By leveraging existing PCB manufacturing technologies, the arrangements described allow for each surface mount antenna to be produced with relatively high precision and consistency, meeting required quality and performance standards. Additionally, the mass production technique supports scalability, allowing manufacturers to meet large volume demands without compromising on the quality of each antenna unit.47009825_1

[0122] In the example described the antenna device included in the top layer of the surface mount antenna can be a patch radiator antenna (for example 318), a leaky radiator (for example 418) and a dual polarised radiator (for example 1018 or 1118). Other antenna devices may also be used.Industrial Applicability

[0123] The arrangements described are applicable to the RF industries and particularly for the cellular transmission and mm-wave transmission industries.

[0124] The combination of the feeding interface in first layer and redistribution in second layer in the arrangement described provide a number of benefits. The feeding interface architecture described both facilitates ease of integration of a surface mount antenna into a motherboard PCB and facilitates attachment (soldering) to a motherboard PCB that does not require specialised equipment, unlike typical BGA and LGA solutions. The architecture can be adapted for both broadside and end-fire radiation. The architecture allows that only the impedance of the microstrip line contact with the motherboard PCB needs to be predetermined. Values of other parameters of the motherboard PCB need not be known or accounted for in antenna design. The feeding interface architecture also provides thermal properties suitable for use in the mm-wave industries. The architecture provided can be adapted for use as an embedded antenna in a phase array, for dual polarisation and for circular polarisation. The architecture described also allows for mass production with relatively low cost and for integration of metamaterial structures on and around the antenna body.

[0125] The foregoing describes only some embodiments of the present invention, and modifications and / or changes can be made thereto without departing from the scope and spirit of the invention, the embodiments being illustrative and not restrictive.

[0126] (Australia Only) In the context of this specification, the word “comprising” means “including principally but not necessarily solely” or “having” or “including”, and not “consisting only of”. Variations of the word "comprising", such as “comprise” and “comprises” have correspondingly varied meanings.47009825_1

Claims

CLAIMS:

1. A surface mount antenna formed as a standalone printed circuit board (PCB), comprising: a first layer forming a feeding interface configured for conductively coupling to a motherboard PCB, wherein the feeding interface comprises a flat protrusion configured to couple to a microstrip line of the PCB having a predetermined resistance and to receive radio frequency power via the microstrip line, and a ground pad configured for conductive coupling to a ground of the motherboard PCB; a second layer configured to receive the input power from the flat protrusion and distribute the input power to an antenna device; and a plurality of upper layers, where in the antenna device is included in a top layer of the plurality of upper layers.

2. The surface mount antenna according to claim 1, wherein the surface mount antenna is configured for broadside radiation and the plurality of upper layers comprise: a layer forming an antenna ground, configured for conductive communication with the ground pad; at least one intermediate layer forming a shield between the second layer and the top layer; and wherein the antenna device included in the top surface is patch radiator antenna.

3. The surface mount antenna according to claim 1, wherein the surface mount antenna is configured for end-fire radiation and the plurality of upper layers comprise a transition layer forming a waveguide and the top layer; and wherein the top layer includes a substrate integrated waveguide (SIW) transition line, the SIW transition line connected to a periodic slot geometry on both top and bottom sides of the surface mount antenna, and the antenna device is a leaky-wave antenna device.

4. The surface mount antenna according to claim 1, wherein the predetermined resistance is 50 ohms.

5. The surface mount antenna according to claim 1, wherein the flat protrusion forms at least a partial edge of the feeding interface and is substantially surrounded, but isolated from, the ground pad.47009825_16. The surface mount antenna according to claim 1, wherein the flat protrusion is fully surrounded by, but isolated from, the ground pad; and wherein the second layer further comprises an impedance transformer.

7. The surface mount antenna according to 1 wherein dimensions of a geometric shape of each of the flat protrusion and the ground pad are reduced by a predetermined amount relative to a size of the microstrip line and the ground of the motherboard PCB.

8. The surface mount antenna according to claim 8, wherein the predetermined amount is from 10% to 15%.

9. The surface mount antenna according to claim 1, wherein the surface mount antenna is configured with a free radiation boundary and for passive S parameter optimisation.

10. The surface mount antenna according to claim 1, wherein the surface mount antenna is configured with a mater / slave boundary and for active S-parameter optimisation for phased array implementation.

11. The surface mount antenna according to claim 10, wherein the flat protrusion is not connected to the second layer.

12. The surface mount antenna according to claim 1, wherein the antenna device is a dual polarised radiator and the second layer connect the input power to two locations on the dual polarised radiator.

13. The surface mount antenna according to claim 12, wherein the second layer further comprises a planar passive RF component to split the input power into two orthogonal components, each of the orthogonal components provided to one of the two locations on the dual polarised radiator.

14. The surface mount antenna according to claim 13, further comprising providing differential inputs to the antenna device.The surface mount antenna according to claim 1, further comprising a high impedance surface (HIS) adjacent the antenna device, the HIS having a quarter wavelength corrugation depth.47009825_1

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