Devices with built-in antennas

Abstract

An electronic device has a housing having an inner surface, a circuit board within the housing, an RF circuit attached to the circuit board, and an antenna formed on the housing. A positioning member is formed on the inner surface of the housing, the positioning member engaging and positioning the circuit board. A first RF coupling portion is formed on the positioning member and electrically connected to the antenna, and a second RF coupling portion is formed on the circuit board and electrically connected to the RF circuit. When the circuit board is attached to the positioning member, the second RF coupling portion is aligned with and RF coupled to the first RF coupling portion to provide an RF coupling between the antenna and the RF circuit, the first RF coupling portion being adapted to provide the RF coupling as a feed for an antenna structure.

Description

[Technical field]

[0001] The present invention relates to a device incorporating an antenna. The present invention is of interest for example for lighting devices such as LED lamps. [Background technology]

[0002] Wireless control of devices by providing built-in antennas is becoming increasingly popular.

[0003] Some examples are light sources for both indoor and outdoor applications. Intelligent lighting is becoming more and more prevalent and RF communication is a powerful technology used in remote management of lamps, especially for home and office environments.

[0004] By using wireless control, instead of controlling the power supply to the lamp, the light source can be controlled directly by sending RF control signals to the lighting device.

[0005] LED bulbs are widely used, but the challenge is how to make these bulbs wirelessly connected. Most state-of-the-art wireless bulbs use off-the-shelf RF modules provided by RF companies, which are essentially circuit boards carrying RF circuits and zig-zag RF antennas. The circuit board has an interface to an external driver circuit. To facilitate connection, the RF module is placed inside the bulb housing together with the driver circuit. This configuration suffers significantly from RF fading when the bulb is placed in a luminaire with RF blocking effects around the bulb housing.

[0006] It is therefore interesting to separate the antenna from the RF and driver circuits.

[0007] From an antenna perspective, a wire (e.g., loop) antenna is the most common design due to its ease of fabrication, minimal cosmetic impact, and low cost. However, given the limited space in a bulb, it is not easy to implement a wire antenna inside the bulb. To solve the above problem of shadowing by the bulb end cap, the antenna should ideally be placed on the housing, e.g., near the light output face of the bulb, rather than inside the housing.

[0008] One problem that arises then, especially when the antenna is formed separately from the circuit board carrying the signal processing circuitry, is how to make the electrical connection between the antenna and the feed point of the circuit board. There are various known approaches.

[0009] The first approach is to solder the connection between the feed point and the antenna, which requires, for example, manual labor, increases manufacturing costs, and may be difficult to implement in tight spaces.

[0010] The second approach is to make a spring or pogo pin connection between the circuit board and the antenna. This also requires a connector on the circuit board, which increases the cost, and the connection pads of the antenna need to be tin- or copper-plated. The assembly is also more complicated. The contact pressure needs to be designed correctly, taking into account the stability and aging. Metal printed antennas are fragile, and disassembly or assembly can result in wear of the connection pads. Summary of the Invention [Problem to be solved by the invention]

[0011] To address these issues, the antenna design and the feed coupling to the antenna must be designed.

[0012] GB2498431A discloses an antenna structure with a sleeve balun, in which the distal surface of the sleeve balun has a groove for receiving a conductor area of ​​a circuit board, and the groove and the conductor area are connected by a solder connection such that the sleeve of the antenna is connected to the shield of the transmission line.Furthermore, the feeding of the antenna in this prior art is implemented by a disk-shaped lateral laminate board part with a central slot, which receives a distal feed connection part, and the disk contacts a feed connection node that connects to the antenna element.

[0013] EP 3 772 874 A1 discloses an intelligent lamp with a communication module including an antenna arranged on a light source substrate. [Means for solving the problem]

[0014] The invention is defined by the claims.

[0015] It is an idea of ​​the present invention to provide an electronic device in which a circuit board carrying an RF circuit is provided within a housing. The circuit board is engaged and positioned by a positioning member formed on an inner surface of the housing. A first RF coupling portion is formed on the positioning member, the first RF coupling portion connecting to an antenna formed on the housing. A second RF coupling portion is formed on the circuit board, the second RF coupling portion connecting to the RF circuit. Thus, RF coupling is automatically achieved by engaging the circuit board with the positioning member. The positioning member can provide a firm and stable fixation with the circuit board, thus providing a stable and consistent (i.e., good product-to-product uniformity) RF coupling for the two RF coupling portions, preferably without the need for soldering or spring connections to achieve the required coupling between the RF circuit and the antenna. Most importantly, the RF coupling so formed serves as a feed for the antenna. Thus, the reliability of the feed is increased.

[0016] According to an example according to an aspect of the present invention, a housing having an inner surface; a circuit board within the housing; an RF circuit attached to the circuit board; an antenna structure formed in the housing; a positioning member formed on the inner surface of the housing, the positioning member adapted to engage and position the circuit board; a first RF coupling portion formed on the positioning member and electrically connected to the antenna structure; a second RF coupling portion formed on the circuit board and electrically connected to the RF circuit; An electronic device is provided in which, when the circuit board is engaged and positioned by the positioning member, the second RF coupling portion is aligned with and RF coupled to the first RF coupling portion to provide RF coupling between the antenna structure and the RF circuit, and the first RF coupling portion is adapted to provide the RF coupling as a power feed portion for the antenna structure.

[0017] The antenna structure is, for example, formed on the inner surface of the housing.

[0018] As mentioned above, the device has a coupling between a built-in antenna structure and a circuit board, especially an RF circuit board, and the coupling is implemented by simply attaching the circuit board to a positioning member on the inner surface of the housing. The positioning member achieves the dual function of both firmly positioning the circuit board and providing stable spatial positioning of two RF coupling parts, so that the RF coupling between the circuit board and the antenna can be ensured. In particular, an RF coupling is formed, and the RF coupling preferably does not require a conductive connection (such as a solder connection). Clearly different from the prior art in which the feeding of the antenna is implemented by a complicated structure including a disk as a connector between the board and the antenna, the feeding of the antenna in this application is implemented by the structure defined above. The feeding part in this application is simple without extra loss and is also robust. Prior art GB2498431A only discloses providing a mechanical structure for connecting a shield as a sleeve balun for the antenna, but does not disclose using the mechanical structure to implement the feeding of the antenna.

[0019] The RF coupling may be, for example, a galvanically isolated coupling, for example a capacitive coupling, ie a dielectric coupling, or an inductive coupling.

[0020] The capacitive coupling may also implement, for example, a high-pass filter, which may implement (and replace) the function of, for example, a DC blocking capacitor.

[0021] To form the second RF coupling, only a small sized area of ​​the circuit board, such as a small contact pad, is required, which saves space compared to other components. The same advantage applies to the housing when forming the first RF coupling, and again, no other circuit board coupling components are required, since the first RF coupling may only include a contact pad on the positioning member.

[0022] The device has easy assembly and assembly consistency is easily achieved. The antenna structure can be a low-cost conformal antenna (that fits the shape of the housing) and takes up little or no additional space. The antenna design is highly reliable as there are no oxidation or aging issues and no need to check the quality of the contacts.

[0023] The positioning member may be, for example, made of plastic. The positioning member may be attached to the housing, or preferably, the positioning member may be integral with the plastic housing as a single part.

[0024] The circuit board may for example be snap-fit ​​connected to the housing to secure the connection between the circuit board and the housing, this snap-fit ​​connection being separate from the positioning member, such that the positioning member serves to align the RF coupling portion, whereas the snap-fit ​​connection holds the circuit board in place.

[0025] The RF coupling may, for example, be galvanically isolated, the first RF coupling portion having a first conductive pad electrode, the second RF coupling portion having a second conductive pad electrode, and the RF coupling may include a capacitive coupling between the first conductive pad electrode and the second conductive pad electrode.

[0026] In another aspect of the invention, a housing having an inner surface; a circuit board within the housing; an RF circuit attached to the circuit board; an antenna structure formed in the housing; a positioning member formed on the inner surface of the housing, the positioning member adapted to engage and position the circuit board; a first RF coupling portion formed on the positioning member and electrically connected to the antenna structure; a second RF coupling portion formed on the circuit board and electrically connected to the RF circuit, when the circuit board is engaged and positioned by the positioning member, the second RF coupling portion is aligned with and RF coupled to the first RF coupling portion to provide RF coupling between the antenna structure and the RF circuit; An electronic device is provided, wherein the RF coupling is galvanically isolated, the first RF coupling portion has a first conductive pad electrode, the second RF coupling portion has a second conductive pad electrode, and the RF coupling includes a capacitive coupling between the first conductive pad electrode and the second conductive pad electrode.

[0027] As mentioned above, the capacitive coupling eliminates the need for a galvanic (i.e. ohmic) electrical contact and also provides a capacitor that can be functionally used in a circuit, the capacitive coupling forming part of a transmission line between the RF circuitry and the antenna structure.

[0028] The capacitance of the capacitive coupling is, for example, greater than 1 pF, more preferably greater than 4 pF, which reduces the frequency shift caused by the series capacitance between the RF circuit and the antenna structure.

[0029] The positioning member may, for example, have a retention structure adapted to receive and retain a portion of the circuit board, thereby positioning the circuit board, and the first RF coupling portion may be formed in the retention structure and the second RF coupling portion may be formed in the portion of the circuit board.

[0030] Thus, the function of holding the circuit board also aligns the first and second RF coupling portions.

[0031] The retention structure may, for example, be first and second spaced apart flanges that protrude from the inner surface of the housing and are adapted to clamp the circuit board between the first and second flanges, the flanges having inner walls that clamp around the periphery of the circuit board.

[0032] In that case, the RF coupling is across the first flange. Preferably, the first RF coupling is on a side wall of the first flange. The material of the first flange therefore acts as a dielectric for the capacitive coupling between the first and second RF coupling portions.

[0033] In one example, the antenna structure is a single monopole antenna, which only requires a single RF coupling.

[0034] In another example, the antenna structure includes a first antenna and a second antenna, and the electronic device includes: a third RF coupling on the second flange, the third RF coupling electrically connected to the second antenna; a fourth RF coupling portion formed on the circuit board on a side of the circuit board facing the third RF coupling portion and connected to the RF circuit; When the circuit board is engaged and positioned by the positioning member, the third RF coupling portion is aligned with and RF coupled to the fourth RF coupling portion to provide further RF coupling between the second antenna and the RF circuit.

[0035] Thus, each of these two flanges has its own RF coupling for connecting to the circuit board (particularly on both sides of the circuit board), thus forming two RF couplings for these two antennas.

[0036] For example, the second coupling portion and the fourth coupling portion do not overlap on opposite sides of the circuit board. In another example, the second coupling portion and the fourth coupling portion at least partially overlap on the circuit board, and the distance between the second coupling portion and the first coupling portion and the distance between the fourth coupling portion and the third coupling portion are smaller than the distance between the second coupling portion and the fourth coupling portion. In other words, the thickness of the circuit board needs to be larger than the thickness of the flange.

[0037] This prevents a decrease in the transmission efficiency of the antenna from occurring. In case of overlap, the distances defined above are used to ensure that the outer RF couplings (i.e., the RF couplings between the first coupling portion and the second coupling portion, and between the third coupling portion and the fourth coupling portion) dominate the inner couplings (i.e., the couplings between the second coupling portion and the fourth coupling portion).

[0038] In the case of two antennas, the RF coupling may be a signal coupling and the further RF coupling may be a ground coupling. In another example, the RF coupling and the further RF coupling may both be signal couplings providing a differential / balanced RF signal. This essentially implements a dipole antenna.

[0039] A balanced transmission line may be provided between a) the first and third RF couplings and b) the antenna structure. This defines a feed line to the antenna. It may be a parallel wire transmission line or any other two-conductor transmission model. The transmission line can be used to adjust the input impedance of the antenna by designing its characteristic impedance and electrical length.

[0040] The desired insertion loss of the transmission line between the RF circuit and the antenna, and the desired resonant frequency of the antenna can be designed by appropriate design of the transmission line.

[0041] The circuit board may, for example, comprise a microstrip parallel transmission line that couples between the RF circuitry and the second and fourth RF couplings, which is designed to provide low insertion loss to prevent power radiation into the air in front of the antenna.

[0042] The first antenna and the second antenna may be adapted to form a symmetric dipole antenna.

[0043] It should be noted that the above-mentioned monopole antenna and dipole antenna are merely examples. Those skilled in the art will understand that other types of antennas can also be used in devices such as light bulbs, and the same configurations as above can be used to provide RF coupling between the antenna and the RF circuit. Therefore, the scope of the present invention should not be limited as a monopole antenna or a dipole antenna.

[0044] For all possible antenna configurations, the antenna structure may be formed as one or more strip antennas.

[0045] The or each coupling formed on the antenna structure and on the positioning member comprises: a conductive material printed on the housing; or a metal sheet overmolded onto the housing; or It may have a flexible PCB secured to the housing.

[0046] Therefore, there are various ways to implement the required conductors.

[0047] The electronic device may comprise a lighting device, the electronic device comprising: A light source; and a driver circuit for driving the light source, the driver circuit being disposed within the housing and the driver circuit also being disposed on the circuit board.

[0048] The invention may be applied in this manner to lighting devices such as light bulbs.

[0049] The electronic device may, for example, comprise an LED lighting device, the housing having a base part and a light output surface towards which the output of the light source is directed, the base part having a rim, the rim connecting to the light output surface, and the antenna formed adjacent to a portion of the rim.

[0050] In that case, the housing has, for example, a cup shape, the positioning member is, for example, at the waist of this cup, and the transmission line connection is made to the rim where the antenna is formed, This structure has the advantage of better RF radiation, since the antenna is no longer contained within the cup, but level-shifted to the outward rim of the cup where it is less obstructed by the luminaire in which the bulb is mounted.

[0051] These and other aspects of the invention will be elucidated and elucidated with reference to the following embodiments. [Brief description of the drawings]

[0052] For a better understanding of the present invention, and to show more clearly how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which: [Figure 1] Shown is an LED light bulb. [Diagram 2] Shows the LED bulb housing with the circuit board removed. [Diagram 3] 1 shows a first side of the circuit board. [Figure 4] 2 shows the second side of the circuit board. [Diagram 5] 1 shows another view of the interior of the housing. [Figure 6] 12 more clearly shows the positioning member with the circuit board in place. [Figure 7] The circuit board is shown in place and the electric field lines are shown. [Figure 8] Examples of S11 and S12 coupling parameters are shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] The present invention will be described with reference to the drawings.

[0054] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the devices, systems and methods, are for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects and advantages of the devices, systems and methods of the present invention will become better understood from the following description, appended claims and accompanying drawings. It should be understood that the figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the figures to denote the same or similar parts.

[0055] The present invention provides an electronic device having a housing having an inner surface, a circuit board within the housing, an RF circuit attached to the circuit board, and an antenna formed on the housing. A positioning member is formed on the inner surface of the housing, the positioning member engages with the circuit board and positions the circuit board. A first RF coupling portion is formed on the positioning member and electrically connects to the antenna, and a second RF coupling portion is formed on the circuit board and electrically connects to the RF circuit. When the circuit board is attached to the positioning member, the second RF coupling portion is aligned with and RF coupled to the first RF coupling portion to provide an RF coupling between the antenna and the RF circuit. Here, RF coupled means that the RF signal can be transferred in either an electrical (non-galvanically isolated) manner or a galvanically isolated manner, although the following embodiments will describe galvanically isolated RF coupling in more detail.

[0056] The present invention relates generally to any electronic device having a circuit board within a housing that is separate from the circuit board and that must be connected to an antenna formed in the housing among other things. The invention will be described with reference to an LED lighting device, in particular an LED light bulb, having an antenna for receiving wireless control commands to allow wireless remote control of the light bulb. The antenna may also (or instead) be used to transmit signals to a remote unit, for example to transmit sensor data.

[0057] Figure 1 shows an LED light bulb 10. The light bulb 10 has a housing 12 that defines the outer shape of the bulb. The housing 12 has a base 14 and a top that defines a light output surface. In Figure 1, the light output surface is not visible, so the internal components of the bulb can be seen.

[0058] The LED device is provided on the light output surface, e.g. beneath a glass or plastic light output window. The LED device is mounted, for example, on a separate printed circuit board covering the top end of the housing facing the light output direction. The separate printed circuit board with the LED device is not shown.

[0059] The base 14 has a waist between its upper and lower ends. An electrical connector 15 is at the lower end and a wide lip 16 that defines the shape of the light output surface is at the upper end. The housing thus has a cup shape. In this example, the diameter of the housing gradually increases from the lower end to the upper end. It is also possible that the diameter is constant from the lower end to the upper end, such as in the shape of a track light.

[0060] A circuit board 20 is mounted within the housing 12. RF circuitry is mounted on the circuit board to enable wireless communication. Among other things, wireless control commands can be received by the bulb and / or wireless reporting data can be transmitted by the bulb. A lighting driver is also provided on the circuit board.

[0061] An antenna 22 is formed on the housing, in this example on the inner surface 18 of the housing. The antenna is directly below the edge 16 so that, among other things, the antenna is as far away as possible from the bulb connector 15 and the components on the circuit board 20, thereby minimizing interference.

[0062] The antenna may be a single-ended or differential antenna, or a dipole antenna arrangement (two radiating antenna parts). For example, a microstrip parallel transmission line structure is provided on the circuit board to achieve low insertion loss. The circuit board may also include an RF balun for the single-ended antenna, or a circuit for balanced signal transformation, depending on the needs of the application.

[0063] Preferably, there is also a balanced transmission line integrated with the antenna, which can be designed to match the impedance of the antenna by designing its characteristic impedance and length. The antenna (and the transmission line leading to the antenna) can be formed by metal printing, or by overmolding a metal sheet onto the housing, or by fixing a flexible PCB to the housing.

[0064] Instead of a microstrip parallel transmission line, another two-conductor transmission model may be used.

[0065] The circuit board 20 is held in place by a locating member 24 formed on the inside surface of the housing. The locating member 24 engages and positions the circuit board. Preferably, the locating member 24 is in the waist region of the housing, and thus near the center or near the bottom end of the bulb.

[0066] The positioning member is, for example, plastic. The positioning member may be an integral part of the plastic housing or may be attached to a housing of a different material, such as glass. The positioning member is, for example, in the form of a substrate fixing buckle.

[0067] The positioning member 24 also functions to effect an RF connection between the circuit board 20 and the antenna 24. To this end, there is a first RF coupling 30, such as a conductive pad, formed on the positioning member 24, which coupling 30 electrically connects to the antenna. There is a second RF coupling, such as a conductive pad, formed on the circuit board, which electrically connects to an RF circuit carried by the circuit board 20. The second RF coupling is not visible in FIG.

[0068] By mounting the circuit board 20 on the positioning member 24, the second RF coupling portion of the RF circuit is aligned with and RF-coupled to the first RF coupling portion 30 so as to provide an RF coupling between the antenna and the RF circuit. There may be an additional coupling between the circuit board and the housing, for example at the bottom of the circuit board, for example a snap fit to hold the circuit board in a fixed position relative to the housing. This snap fit ensures the vertical position of the board with a tolerance of, for example, 0.1 mm. Thus, the RF coupling portion on the circuit board and the RF coupling portion on the positioning member can be aligned with a very small tolerance. The positioning member is, for example, a passive positioning without active holding of the circuit board.

[0069] A transmission line connection is made from the positioning member to edge 16 where antenna 22 is formed.

[0070] Preferably, the RF coupling is an inductive coupling, so that there is a capacitive or inductive coupling between the RF coupling parts, rather than a low resistance electrical coupling. There is therefore a galvanically isolated coupling between the RF coupling parts. This means that no soldering or mechanical spring contacts are required. The RF coupling is achieved by simply attaching the circuit board 20 to the positioning members 24 on the inner surface of the housing. Non-galvanically isolated couplings, for example low resistance electrical couplings, are also possible.

[0071] The capacitive RF coupling may also perform, for example, a high-pass filter, said capacitive RF coupling performing (and replacing) the function of, for example, a DC blocking capacitor. The capacitance formed by the RF coupling may, for example, be greater than 1 pF, more preferably greater than 4 pF.

[0072] The RF coupling can be done with small contact pads, thus taking up little space. The antenna 22 can be a low-cost conformal antenna (that fits the shape of the housing) and takes up little additional space. This antenna design is highly reliable since there are no oxidation or aging issues and there is no need to check the quality of the contact.

[0073] The bulb can be easily assembled, with assembly consistency being easily achieved.

[0074] FIG. 2 shows an enlarged view of the housing with the circuit board removed to more clearly show the positioning member 24.

[0075] The locating member 24 has first and second flanges 40, 42 spaced apart from one another and projecting inwardly from the inner surface of the housing, with an edge of the circuit board being received in the space between the flanges. Thus, the flanges are one possible example of a retention structure for clamping the circuit board. It should be noted that other locating structures, such as snap fit connections, are also possible and within the scope of the present invention.

[0076] In this particular example, the flanges 40, 42 have an inner surface that clamps the circuit board. The first RF coupling portion 30 is provided on the opposite outer surface of the first flange 40. The insulating material of the first flange thus acts as a dielectric between the first RF coupling portion 30 and the corresponding second RF coupling portion of the circuit board. Thus, the function of holding the circuit board also aligns the first and second RF coupling portions.

[0077] The thickness and material of the flange determine the coupling capacity, which is designed to achieve a desired tradeoff between coupling capacity and structural strength.

[0078] The antenna may, for example, be a dipole antenna, which may be considered to have a first antenna 22a and a second antenna 22b mounted on the housing, in which case two RF couplings are provided between the RF circuitry and the second antenna.

[0079] For this purpose, a third RF coupling is provided on the second flange 42 and is electrically connected to the second antenna 22b and to a fourth RF coupling formed on the circuit board, which is then on the opposite side of the circuit board to the third RF coupling but is also connected to the RF circuitry. When the circuit board is engaged and positioned by the positioning members, an RF coupling is provided across both flanges 40, 42. The third RF coupling is aligned with and RF coupled to the fourth RF coupling so as to provide a second RF coupling between the further antenna and the RF circuitry.

[0080] For example, the first / third RF coupling may be for an RF signal and the second / fourth RF coupling may be for a ground connection. The first and third couplings (of the positioning member) terminate a parallel wire transmission line that is integrally formed with the antenna.

[0081] The couplings on the positioning member (and the metal parts on the housing) can be positioned with a tolerance of, for example, + / - 0.1 mm, whereas metal lines on the circuit board have a tolerance of, for example, + / - 0.05 mm. The first and second RF couplings preferably have the same size and shape, and the third and fourth RF couplings preferably also have the same size and shape.

[0082] For example, the second coupling portion and the fourth coupling portion do not overlap on the circuit board, i.e., they are at different spatial positions on the opposite side of the circuit board. This reduces signal interference and thus prevents the occurrence of a decrease in transmission efficiency. However, it means that a larger positioning member is required, since contact pads at different spatial positions on the flange are required.

[0083] In another example, the second and fourth couplings may at least partially overlap on opposite sides of the circuit board. This reduces the required size of the positioning member. However, the distance between the second and first couplings and the distance between the fourth and third couplings are smaller than the distance between the second and fourth couplings. Thus, there is better alignment between the contact pads that should be RF coupled to each other than the alignment between the pads on both sides of the circuit board. This ensures that the outer RF coupling (i.e., between the first and second couplings and between the third and fourth couplings) dominates the inner coupling (i.e., between the second and fourth couplings).

[0084] For example, in the case of a monopole antenna, the RF coupling may be a signal coupling and the further RF coupling may be a ground coupling, in another example, the RF coupling and the further RF coupling may both be signal couplings coupled to a differential / balanced RF signal.

[0085] In fact, this design can be applied to any desired antenna structure.

[0086] FIG. 3 shows the first side of the circuit board 20, showing a second RF coupling 32 for an RF signal.

[0087] FIG. 4 shows the second side of the circuit board 20, showing a fourth RF coupling 36, which in one example is for a ground signal.

[0088] The fourth RF bond 36 and the second RF bond 32 may be on the same side / layer of the circuit board so that a low-cost single layer PCB can be used, or they may be on opposite sides or different layers of the circuit board. If the two bonds at least partially overlap, then they must be on opposite sides or different layers of the circuit board.

[0089] Couplings 32 and 36 may be part of a transmission line to prevent power from radiating into the air, thus providing a transmission line from the RF circuit to the antenna.

[0090] FIG. 5 shows another view of the interior of the housing.

[0091] FIG. 6 more clearly shows the positioning member 24 with a circuit board disposed between the flanges 40,42.

[0092] 6 also shows a balanced transmission line 60 provided between the first and third RF coupling portions (on the positioning member 24) and the antenna 22 (which comprises two antenna portions). This example shows a parallel wire transmission line as the coupling to the antenna, which provides power to the antenna.

[0093] This makes the design metric very simple. By using the S21 insertion loss metric, S-parameters can be used to evaluate the performance. The transmission line 60 does not affect the original parameters of the antenna, and the feed efficiency is only affected if the transmission line 60 is considered as part of the antenna's feed. As a result, the antenna gain is affected. However, the natural frequency and directivity pattern of the antenna are not affected.

[0094] The S21 insertion loss is, for example, less than 1.5 dB.

[0095] The size of the RF coupling can affect the S11 return loss parameter of the transmission line structure. The resonant frequency of the transmission line from the circuit board to the antenna will shift (e.g., when the source impedance is 50 ohms) as will the LC impedance matching network. This affects the minimum reflected feed frequency, but not the resonant frequency of the antenna.

[0096] Any change in the size of the pads (due to positioning errors) will result in a parasitic effect as a result of the change in the series capacitance. The frequency shift caused by this effect can be neglected as long as this capacitance is larger than a threshold such as 1 pF (as also mentioned above), or more preferably 4 pF. However, since the space for coupling is limited, 1 pF to 4 pF is acceptable since the impedance can be adjusted by a matching network by keeping the pad size large (e.g. corresponding to 8 pF or more).

[0097] The pad size, clearance area, and width of the parallel transmission line 60 are the main design parameters that affect the input impedance and resonant frequency. To estimate the effect of capacitance, a simple parallel plate capacitor model can be used.

[0098] The dielectric constant of the capacitance depends on the material of the positioning member, the area depends on the size of the RF coupling, and the distance depends on the thickness of the flange. The characteristics of the RF coupling on the circuit board (e.g., copper pads on the circuit board), such as the size of the pad and the clearance between the pad and ground, also affect the impedance and resonant frequency. Similarly, the characteristics of the RF coupling on the positioning member (e.g., metal printed or molded on the positioning member) also affect the impedance and resonant frequency.

[0099] FIG. 7 shows the circuit board 20 between the flanges 40, 42 and shows the electric field lines between the first RF coupling 30 and the second RF coupling 32, and the third RF coupling 34 and the fourth RF coupling 36. The orientation in FIG. 7 is the same as in FIGS. 3 and 4, with the second RF coupling 32 at the top of the circuit board and the fourth RF coupling 36 at the bottom of the circuit board. It shows the first and third RF couplings in a non-overlapping orientation. The electric field is primarily in the coupling region and the transmission line structure 60.

[0100] Figure 8 shows an example of S11 and S12 coupling parameters. The insertion loss is low and the return loss is good. The resonant frequency shifts as a result of the series capacitance, but this can be easily compensated for by matching.

[0101] Those skilled in the art can understand and effect variations to the disclosed embodiments in the practice of the claimed invention, from a study of the drawings, the specification and the appended claims. In the claims, the word "comprises" does not exclude other elements or steps, and the singular form "a" does not exclude a plurality.

[0102] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0103] Please note that when the term "adapted to" is used in the claims or specification, the term "adapted to" is intended to be equivalent to the term "configured to."

[0104] Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. a housing having an inner surface, the housing having a cup shape with a bottom end, a top end including a light output surface, and a waist portion between the bottom end and the top end; a circuit board within the housing; an RF circuit attached to the circuit board; an antenna structure formed in the housing; a positioning member formed on the inner surface of the housing at the waist of the cup shape, the positioning member adapted to engage with and position the circuit board; a first RF coupling portion formed on the positioning member and electrically connected to the antenna structure; a second RF coupling portion formed on the circuit board and electrically connected to the RF circuit, When the circuit board is engaged and positioned by the positioning member, the second RF coupling portion is aligned with and RF coupled to the first RF coupling portion to provide RF coupling between the antenna structure and the RF circuit, and the first RF coupling portion is adapted to provide the RF coupling as a power feed portion for the antenna structure.

2. 2. The electronic device of claim 1, wherein the RF coupling is galvanically isolated, the first RF coupling portion has a first conductive pad electrode, the second RF coupling portion has a second conductive pad electrode, and the RF coupling includes a capacitive coupling between the first conductive pad electrode and the second conductive pad electrode, and preferably the capacitance of the capacitive coupling is greater than 1 pF, more preferably greater than 4 pF.

3. a housing having an interior surface; a circuit board within the housing; an RF circuit attached to the circuit board; an antenna structure formed in the housing; a positioning member formed on the inner surface of the housing, the positioning member adapted to engage with and position the circuit board; a first RF coupling portion formed on the positioning member and electrically connected to the antenna structure; a second RF coupling portion formed on the circuit board and electrically connected to the RF circuit, when the circuit board is engaged and positioned by the positioning member, the second RF coupling portion is aligned with and RF coupled to the first RF coupling portion to provide RF coupling between the antenna structure and the RF circuit; An electronic device, wherein the RF coupling is galvanically isolated, the first RF coupling portion has a first conductive pad electrode, the second RF coupling portion has a second conductive pad electrode, and the RF coupling includes capacitive coupling between the first conductive pad electrode and the second conductive pad electrode.

4. 4. The electronic device of claim 1, wherein the positioning member has a retention structure adapted to receive and retain a portion of the circuit board, thereby positioning the circuit board, the first RF coupling portion being formed on the retention structure, and the second RF coupling portion being formed on the portion.

5. 5. The electronic device of claim 4, wherein the retention structure comprises first and second flanges spaced apart, the first and second flanges protruding from the inner surface of the housing, the first and second flanges adapted to clamp the circuit board between the first and second flanges.

6. 6. The electronic device of claim 5, wherein the RF coupling traverses the first flange, preferably the first RF coupling is on a sidewall of the first flange.

7. the antenna structure is a single monopole antenna; or the antenna structure includes a first antenna and a second antenna formed on the housing, and the electronic device includes: a third RF coupling on the second flange, the third RF coupling electrically connected to the second antenna; a fourth RF coupling portion formed on the circuit board on a side of the circuit board facing the third RF coupling portion and connected to the RF circuit; 7. The electronic device of claim 6, wherein when the circuit board is engaged and positioned by the positioning member, the third RF coupling portion is aligned with and RF coupled to the fourth RF coupling portion to provide further RF coupling between the second antenna and the RF circuit.

8. the RF coupling portion and the further RF coupling portion are on opposite sides of the circuit board; and The second coupling portion and the fourth coupling portion do not overlap on the circuit board; or 8. The electronic device of claim 7, wherein the second coupling portion and the fourth coupling portion at least partially overlap on the circuit board, and the distance between the second coupling portion and the first coupling portion and the distance between the fourth coupling portion and the third coupling portion are smaller than the distance between the second coupling portion and the fourth coupling portion.

9. the RF coupling is a signal coupling and the further RF coupling is a ground coupling; or 8. The electronic device of claim 7, wherein the RF coupling and the further RF coupling are both signal couplings coupled to a differential / balanced RF signal.

10. The electronic device of claim 7 , further comprising a balanced transmission line between a) the first RF coupling portion and the third RF coupling portion and b) the antenna structure.

11. 8. The electronic device of claim 7, wherein the circuit board comprises a microstrip parallel transmission line.

12. The electronic device of claim 7 , wherein the first antenna and the second antenna are adapted to form a symmetric dipole antenna.

13. 4. The electronic device according to claim 1, wherein the antenna structure comprises a strip antenna structure.

14. the or each coupling formed on the antenna structure and the positioning member, a conductive material printed on the housing; or a metal sheet overmolded onto the housing; or 4. The electronic device of claim 1, further comprising a flexible PCB fixed to the housing.

15. a lighting device, the lighting device comprising: A light source and 4. The electronic device of claim 1, further comprising a driver circuit for driving the light source, the driver circuit being disposed within the housing and the driver circuit also being disposed on the circuit board.

16. 15. The electronic device of claim 14, wherein the light source comprises an LED, the housing has a bottom end and a top end including a light output surface toward which the output of the light source is directed, the top end having an opening forming the light output surface, the opening having a rim, and the antenna structure formed adjacent a portion of the rim.

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