FIELD OF THE INVENTION

This present invention relates to the field of antennas, and more particularly to a series collinear antenna for communication of RF signals to lighting devices. BACKGROUND OF THE INVENTION

Intelligent lighting has become widespread, and RF communication is a technology widely used for remote management of lighting devices. Instead of controlling the power (e.g. 230V supply) to the lighting device, the recent trend has moved towards directly controlling the light source or lighting device (i.e. the exchangeable lighting element lighting device) by sending an RF control signal to the lighting device.

For commercial and professional application, the tubular lighting device is the most commonly employed lighting device, and, due to this, a tubular LED (TLED) has been designed to be a retro-fit lighting device which can replace a conventional tubular lighting device without requiring modification to the lighting fixture.

Wireless communication functionality is normally enabled in lighting devices by adding an RF module and associated antenna into the lighting device. For tubular lighting devices, however, the structure (e.g. tubular housing, shape and size) places limitations on the antenna design and thus limits antenna performance (e.g. to having limited wireless control range/direction). This is particularly problematic in view of recent developments in mesh network optimization and/or functionality that require an antenna to support extended wireless control range/direction.

Series collinear antenna segments are well known in the field of antenna design. They consist of a number of alternate radiating elements and inter-element phasing sections resulting in a phased array antenna. Each radiating element is optimally fed in phase so that the radiating elements will radiate in unison. Each individual radiating element is designed to be of a specific physical length in order to provide the most effective radiation of power for a given wavelength. Following each active radiating element is an inter-element phasing section, wherein the radiation from the antenna is suppressed until the next correct phase point on the wavefront is reached, so that the next radiating element is then fed in series.

The ideal theoretical physical length of the radiating element should be 1/2λ (where λ is the design wavelength for the antenna) and the ideal theoretical physical spacing between two radiating elements should be 1/4 λ (as measured from the top of one radiating element to the bottom of the next radiating element). Thus, there are design constraints which make the realization of the theoretical ideal series collinear antenna difficult. Also, this does not address the requirement to support flexible wireless range coverage/direction).

An approach to realizing a theoretical ideal antenna is to use a 1/2 λ wire phasing coil for an inter-element phasing section. Coil-based series collinear antenna segments such as this have 1/2λ phase elements which are separated by the ideal physical spacing of 1/4 λ. However, the capacitance of these coils is high and thus the Q factor (and hence the wavelength sensitivity) is high. This means that phase difference introduced by a coil varies significantly with wavelength. Such coil-based series collinear antenna segment designs therefore suffer from performance degradation in pattern stability (resulting from the variation in the phase difference with wavelength) and are thus unsuitable where flexible wireless range coverage/direction are required. Another significant disadvantage is that the physical structure of the coils must be tightly controlled (especially when designing for short wavelengths) thus adding to the cost of manufacture.

US20080079640A1 discloses a compact multi-element antenna with phase shift. EP1411588A1 discloses a broad band antenna in a radome. WO2016066564A1 discloses a wireless LED tube lamp device.

SUMMARY OF THE INVENTION

It would be advantageous to develop a tubular lighting device that employs an antenna which caters for the tubular structure of the lighting device whilst providing improved wireless radiation characteristics, such as controllable directivity/antenna diversity. It would be particularly advantageous for the antenna design to be convenient and low cost to manufacture when compared with prior art.

A basic idea of proposed embodiments is to employ, in a tubular lamp, a coil- based series collinear antenna design (comprising alternate radiating elements and coil-based inter-element phasing sections) and then use a phase adjustment circuit coupled to the coil of an inter-element phasing section. Using the phase adjustment circuit, the turns (e.g. turn number) of the coil may be changed so as to adjust the phase difference introduced by the coil, thereby providing what may be considered a "phase adjusting element". By way of example, the phase adjustment circuit may comprise a plurality of switches, and the switches may be manipulated so as to either disconnect or connect turns of the coil. Alternatively, the coil arrangement can be replaced by other kind of phase balance arrangement such as track or phase stub that provides a phase delay.

Thus, there is proposed a concept for controlling the phase delay introduced by a inter-element phasing section of a series collinear antenna. With such phase adjustment, the antenna may support a range of directivities/antenna diversity. Further, such adjustment may be achieved in an automatic and/or controlled manner such that the antenna may provide self- adjustment functionality. For example, by receptions at different directivities and finding the optimized reception, an optimized directivity corresponding to that optimized reception can be determined.

A further idea of the application is implementing this coil-based series collinear antenna in a tubular lighting device.

According to examples in accordance with an aspect of the invention, there is provided a tubular housing that is elongated in a longitudinal direction; light emitting elements within the tubular housing; and a series collinear antenna comprising: first and second radiating elements connected in series and oriented along the longitudinal direction; a phase balance arrangement connected between the first and second radiating elements, the phase balance arrangement being adapted to introduce a phase delay to radiation from the first radiating element before feeding the radiation to the second radiating element; and a phase adjustment circuit coupled to the phase balance arrangement and adapted to modify the phase delay.

There may therefore be provided a series collinear antenna suitable for reliable communication of RF signals across a range of directivities/antenna diversity. The series collinear antenna may be designed with compact dimensions (so as to fit within

predetermined housing dimensions, for example) and may provide an adjustment

functionality wherein the phase delay introduced by an inter-element phasing section of the series collinear antenna may be modified. Embodiments may therefore provide for improved communication abilities of a wider range of wavelengths when compared to conventional series collinear antennae.

A series collinear antenna according to an embodiment may therefore be designed with dimensions that enable use in tubular lighting device. As a result,

embodiments may be suitable for low energy replacement lamps (such as smart TLEDS) which can be remote controlled, e.g. with respect to such as on/off, intensity, color, beam width, and light orientation. By way of example, the lighting device may comprise a tubular LED. Embodiments may thus be applicable to smart TLEDs, although they may also be applicable to other types of smart tubular lighting devices. Such applicability to smart TLEDs may make proposed embodiments useful for a wide range of applications.

In a preferred embodiment, the phase balance arrangement is implemented by coil. Proposed is a concept for altering the suppression of radiation caused by a coil-based inter-element phasing section through the use of a phase adjustment arrangement to alter the effective number of turns in a coil of the inter-element phasing section. By changing an operational number of turns in a coil of the inter-element phasing section, the radiation pattern, more specifically the directivity/antenna diversity, of the antenna can be changed, thereby enabling the antenna to be adjusted. In other words, the phase delay introduced between neighboring radiating elements can be changed by changing the number of turns of a coil connected between the neighboring radiating elements. Simple arrangements may thus be employed, thereby reducing the associated complexity and/or cost of embodiments.

For example, in an embodiment, the phase adjustment circuit may be adapted to modify a number of coil turns of the coil arrangement in response to a control signal. Simply changing the number of effective turns of the coil arrangement may change the amount of suppression of radiation (e.g. phase delay) caused by the coil arrangement. Phase adjustment, and thus wavelength tuning of the antenna, may therefore be achieved using a relatively simple arrangement.

For instance, the phase adjustment circuit may comprise a switch arrangement comprising at least one switch connected in parallel with at least one turn of a coil of the coil arrangement, said switch being adapted to be selectively short circuit said turn of the coil. Cheap components and relatively simple circuitry arrangements may be used, thereby reducing the associated complexity and/or cost of obtaining an improved series collinear antenna.

Further, the coil may comprise steel wire connected between the first and second radiating elements, and wherein a switch is connected between turns of the steel wire. Existing and/or cheap components may thus be used, and simple circuit arrangements may be employed, thereby reducing the associated complexity and/or cost of embodiments.

The phase adjustment circuit may be adapted to modify the phase delay so as to modify an angle between the longitudinal direction and the radiation pattern of the collinear antenna. This may enable adjustment and control of the radiation pattern, thereby facilitating optimization of the antenna.

In an embodiment, each of the first and second radiating elements may comprise line radiators. Elongated radiators that are able to fit inside lighting devices with compact cross-sections may thus be employed by embodiments. For example, the use of line radiators may enable embodiments to fit inside the tubular housing of a tubular lighting device. Other forms of radiators may also be employed. For example, the line radiator can be replaced by patterned antenna like a meandered antenna.

In some embodiments, the first and second radiating elements may be provided on an elongated substrate that is curved about a longitudinal axis extending in the longitudinal direction. Also, the first and second radiating elements may be printed on the substrate, and electrical contacts may be provided at the ends of the radiating elements. In this way, an antenna according to an embodiment may be provided in a form which enables it to be inserted in housing of compact cross-section, such as tubular housing. After insertion, the contacts may enable connection of the coil arrangement in a simple manner, assisting the manufacture process of a device (such as a smart lighting device for example)

In an embodiment, the tubular housing may comprise a housing portion formed from an elongated substrate that is curved about the longitudinal axis, and the first and second radiating elements may be provided on the housing portion. The first and second radiating elements may thus be provided on the curved housing portion, and this curved housing portion may form at least part of the upper or lower part of the tubular lighting device. For example, the first and second radiating elements may be provided on the inner surface of the lens part of a TLED. In this way, components of the antenna may be integrated with the lighting device so as to maximize use of the available space within the device.

Also, the first and second radiating elements may be printed on the substrate, and electrical contacts may be provided at the ends of the radiating elements. In this way, established printing techniques (including 3D printing) may be employed during

manufacture. This may reduce the cost and/or complexity of manufacture whilst also providing for accurate control of the design and implementation of the radiating elements.

The phase adjustment circuit may be provided on a Printed Circuit Board

(PCB) that is positioned within the tubular housing. Cheap components and relatively simple circuitry arrangements may be used, thereby reducing the associated complexity and/or cost of embodiments. The coil arrangement may comprise a coil having a plurality of turns with a diameter substantially equal to that of the tubular housing. In this way, the coil arrangement may make maximum possible use of the available space in the tubular housing. Such proposed embodiment may be designed and optimized for use in tubular lighting devices.

In an alternative embodiment, said phase balance arrangement comprises a track with a total length, and the phase adjustment circuit comprises at least one switch placed aside the track and adapted to short circuit a portion of the track thereby tuning an effective length of the meandered track between the first and second radiating elements.

This embodiment provides another implementation for the phase delay element. The track and switch are easily assembled together, like in a PCB, and the assembly tolerance is low.

In a further embodiment, the track comprises a half closed phasing stub or a completely closed phasing stub.

Embodiments may be employed in conjunction with new or existing lamps. For example, an embodiment may be retro-fitted to a conventional lamp, whereas another embodiment may be integrated into a new lamp at time of manufacture. Accordingly, an aspect of the invention may provide a lamp comprising a lighting device according to an embodiment.

Embodiments may be employed in the field of building lighting, stadium lighting, home/residential lighting, temporary lighting, and other fields/applications where remotely controllable lighting is desirable.

Embodiments may be employed in conjunction with a remote control unit for wireless RF control of a lighting device. Accordingly, an aspect of the invention may provide a lighting system comprising: a tubular lighting device according to a proposed embodiment; and a remote control unit adapted to communicate, with the series collinear antenna of the tubular lighting device, an RF signal for controlling of at least one parameter of the tubular lighting device.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention will now be described in detail with reference to the accompanying drawings, in which: Fig. 1 is a schematic drawing of a series collinear antenna according to an embodiment;

Fig. 2A illustrates simulation results for the embodiment of Figure 1 employed in a TLED having a total length of 60cm;

Fig. 2B and 2C show the different coverage of the antenna with a selected directivity.

Figs. 3A-3E show, in more detail, the simulation results for the embodiment of Fig. 1 employed in a TLED having a total length of 60cm;

Fig. 4 shows simulation results for a collinear antenna according to an embodiment when employed in a TLED having a total length of 120cm;

Figs. 5A and 5B show collinear antennas according to alternative embodiments having a total length of 60cm and 120cm, respectively; and

Fig. 6 shows an exploded view of a tubular lighting device comprising an antenna according to an embodiment;

Fig. 7 shows a collinear antenna according to another embodiment to be integrated in a tubular lamp;

Fig. 8 shows a collinear antenna according to yet another embodiment to be integrated in a tubular lamp.

DETAILED DESCRIPTION

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 indicate the same or similar parts.

Proposed is a design of a collinear antenna that may be used inside a compact housing, such as a plastic or glass tubular housing of a tubular lighting device for example.

The proposed antenna includes two sets of components: radiation elements; and phase balancing elements, alternately arranged in series with each other. The radiation elements may output a wireless signal at required frequency, and the phase balancing elements may be designed so as to ensure that the phase of input signal at each radiation element will be the same value. Such an arrangement may provide maximum directivity of the antenna.

Also proposed is the provision of an adjustment functionality wherein the phase delay introduced by the phase balance elements may be modified using one or more phase adjusting elements. With such phase adjusting element(s), the antenna may be self- adjusting.

In particular, embodiments are proposed wherein the antenna employs coil- based phase balancing elements, and wherein a phase adjustment arrangement is used to alter the effective number of turns in a coil of a phase balancing element. By changing an effective/operational number of turns in a coil of a phase balancing element, the radiation pattern, more specifically the directivity/antenna diversity, of the antenna can be changed, thereby enabling the antenna to be adjusted. In other words, it is proposed to change the phase delay introduced between neighboring radiating elements by changing the number of turns of a coil connected between the neighboring radiation elements.

The term vertical, as used herein, means substantially orthogonal to the surface of a substrate. The terms lateral or horizontal, as used herein, means substantially parallel to the surface of a substrate. Also, terms describing positioning or locations (such as above, below, top, bottom, etc.) are to be construed in conjunction with the orientation of the structures illustrated in the diagrams.

Referring to Figure 1 , there is depicted a schematic drawing of a series collinear antenna 10 according to an embodiment. The series collinear antenna 10 comprises: first 12 to fourth 18 radiating elements connected in series and oriented along a longitudinal direction L. Here, each radiating element comprises a line radiator of length 86.5mm. The line radiators are elongated and thus able to fit inside lighting devices with compact cross- sections, such as tubular lighting devices. Of course, other forms of radiating element (or 'radiators') may also be employed.

Between each pair of adjacent radiating elements is connected a coil arrangement 20. In particular, a first coil arrangement 20 A is connected between the first 12 and second 14 radiating elements, a second coil arrangement 20B is connected between the second 14 and third 16 radiating elements, and a third coil arrangement 20C is connected between the third 16 and fourth 18 radiating elements.

Each coil arrangement is adapted to introduce a phase delay to radiation from an immediately preceding connected radiating element before feeding the radiation to the immediately following connected radiating element.

Also, a phase adjustment circuit is coupled to each of the coil arrangements and adapted to modify the phase delay introduced by the coil arrangements.

By way of example, an enlarged view of the second coil arrangement 20B is provided in Figure 1 (as indicated by the dashed circle). From the enlarged view, it will be seen that the second coil arrangement 20B comprises a single coil 24 of steel wire connected between the second 14 and third 16 radiating elements. Here, the spiral length of the coil 24 is 11.5mm and the spiral diameter is 25mm (which is substantially equal to the diameter of a TLED that the antenna 10 is designed for). Also, the phase adjustment circuit comprises a switch arrangement having a switch 26 connected between each turn of the coil 24. In this way, each switch 26 is adapted to selectively short circuit a respective turn of the coil 24 (for example, in response to a control signal).

Thus, the suppression of radiation caused by the second coil arrangement 20B can be altered through the use of a phase adjustment arrangement to alter the effective number of turns of the coil 24. By changing the operational number of turns of the coil 24, the phase delay caused by the coil 24, and in turn the radiation pattern, and more specifically the directivity/antenna diversity, of the antenna 10 can be changed. In other words, the phase delay introduced between the second 14 and third 16 radiating elements can be changed by changing the number of turns of the coil 24 connected between the second 14 and third 16 radiating elements. In this embodiment, simple switches 26 are employed, although other suitable arrangements for altering the phase delay introduced by the coil arrangements may be employed.

Referring now to Figure 2A, there are depicted simulation results for the embodiment of Figure 1 employed in a TLED.

As has been detailed above, a phase adjustment arrangement can modify the phase delay introduced by a coil arrangement, thereby modifying an angle between the longitudinal direction L and the radiation pattern of the collinear antenna 10.

The simulation results shown in Figure 2A demonstrate how the angle between the longitudinal direction L and the radiation pattern of the collinear antenna 10 can be changed based on the number of turns of a coil. As can be seen from Figure 2A, the radiation pattern changes based on the number of turns, and the value changed is the angle between radiation pattern and longitudinal axis L of the TLED (and the antenna). These differing angles will result in differing directions of wireless coverage for the antenna 10. More specifically, if there is only one turn (other turns are shorted), the antenna pattern shows that the main direction is near 20 degrees and 60 degrees. If there are two turns (other turns are shorted), the antenna pattern noted by the dashed line shows that the main directions are near 0 and 180 degrees. If there are three turns, the antenna pattern noted by the dotted line shows the main direction deviates from those of two turns, and is at 45 degrees and 135 degrees. If there are four turns, the antenna pattern noted by the dashed-dotted line shows the main direction at 15 degrees, 165 degrees, and 90 degrees. If there are five turns, the antenna pattern noted by the heavy solid line shows the main directions at 0 degrees, 60 degrees, 120 degrees and 180 degrees.

Figure 2B and Figure 2C shows the different coverage of an antenna according to an embodiment with a selected directivity. The dark spot 50 is the antenna's position, and the dashed line 55 depicts its associated coverage. In fig. 2B, the coverage 55 is a long oval shape intended to cover more distance in the horizontal direction; while in fig. 2C, the coverage 55 is a rectangular shape intended to cover both the horizontal and the vertical directions.

By way of further example and explanation, Figures 3A-3D show, in more detail, the simulation results for the embodiment of Figure 1 employed in a TLED of length 60cm. By way of example, a simplified diagram of an exemplary collinear antenna having a length of 60cm is also depicted in Figure 5A

Figure 3A shows the simulation results for when the coils are arranged to have on turn (i.e. when the switch arrangement is controlled to create one effective/operational turn in each coil arrangement).

Figure 3B shows the simulation results for when the coils are arranged to have two turns (i.e. when the switch arrangement is controlled to create two effective/operational turns in each coil arrangement).

Figure 3C shows the simulation results for when the coils are arranged to have three turns (i.e. when the switch arrangement is controlled to create three

effective/operational turns in each coil arrangement).

Figure 3D shows the simulation results for when the coils are arranged to have four turns (i.e. when the switch arrangement is controlled to create four effective/operational turns in each coil arrangement).

Figure 3E shows the simulation results for when the coils are arranged to have five turns (i.e. when the switch arrangement is controlled to create five effective/operational turns in each coil arrangement).

Referring now to Figure 4, there are shown simulation results for a collinear antenna according to an embodiment when employed in a TLED of length 120cm. By way of example, a simplified diagram of an exemplary collinear antenna having a length of 120cm is also depicted in Figure 5B.

Due to the extra length of the TLED, the collinear antenna comprises more radiating elements than the embodiment of Figure 1. In particular, the simulation employed a collinear antenna similar to that depicted in Figure 1 , but comprising nine line radiators connected in series and oriented along the longitudinal length of the TLED. As with the embodiment of Figure 1, a coil arrangement is connected between each pair of adjacent line radiators. Also, a phase adjustment circuit is employed to modify the phase delay introduced by the coil arrangements. More specifically, the phase adjustment circuit is adapted to modify the effective number of turns in each of the coil arrangements.

From a comparison of the simulation results of Figures 3A-3E (for a TLED of 60cm in length) with the simulation results of Figure 4, it can be seen that the increased number of radiation elements provides higher directivity.

With regard to the number of coil turns in each phase adjusting element, it is noted that the number of turns for each phase adjusting element need not be limited to being the same number. Put another way, different phase adjusting elements (e.g. coils) of the same collinear antenna may have differing numbers of coil turns. For example, for a real antenna, there may be a manufacturing error and, in real applications, there may be a specific requirement for phase adjusting. Thus, even though the simulation results have been provided for the same number of turns in each phase adjusting element of a collinear antenna, the number of turns in the different phase adjusting elements of an antenna may be different (and may, for example, depend on manufacturing error and/or real application requirements).

Also, it is noted that, although the radiation elements of the embodiments detailed above have been detailed as comprising line radiators, embodiments are not limited to employing line radiators. For example, an antenna according to another embodiment can be a Planar Inverted F Antenna (PIFA) (comprising of a rectangular planar element located above a ground plane, a short circuiting plate or pin, and a feeding mechanism for the planar element).

From the above-described embodiments, it will be understood that

embodiments may provide a series collinear antenna suitable for reliable communication of RF signals across a range of directivities/antenna diversity. The series collinear antenna may be designed with compact dimensions (so as to fit within predetermined housing dimensions, for example) and may provide an adjustment functionality wherein the phase delay introduced by a coil-based inter-element phasing section of the series collinear antenna may be modified.

For example, a series collinear antenna according to an embodiment can be designed with dimensions that enable its use within a tubular lighting device, such as a smart TLED which can be remote controlled, e.g. with respect to such as on/off, intensity, color, beam width, and light orientation.

By way of example, Figure 6 depicts an exploded view of a tubular lighting device 100 comprising an antenna according to an embodiment. The tubular lighting device 100 comprises: a tubular housing 102 that is elongated in a longitudinal direction L. Light emitting elements 104 are mounted on a printed circuit board (PCB) 106 within the tubular housing 102. A driver module 108 is also provided in the tubular housing 102 and electrically connected to the PCB 106 for providing control signals to the PCB 106 (for controlling the light emitting elements 104. A Radio Frequency (RF) control module 110 is also provide din the tubular housing 102 and electrically connected to the driver module 108 for

communicating control signals to/from the driver module 108. The RF control module 110 is electrically connected to a series collinear antenna 112 according to an embodiment, the series collinear antenna 112 thus providing for the communication of RF signals to/from the RF control module 110.

In the embodiment of Figure 6, the antenna 112 comprises first 114 to third

118 radiation elements that are printed on the inside surface of the (upper portion of the tubular housing 102. Connected between the first 114 and second 116 radiation elements is a first phase adjusting coil 120 having a diameter that is substantially equal to that of the tubular housing 102. Similarly, connected between the second 116 and third 118 radiation elements is a second phase adjusting coil 122 having a diameter that is substantially equal to that of the tubular housing 102. An output port of the RF control module 110 is connected to the first radiation element 114.

Each coil 120,122 is made from high hardness metal so they can be positioned and fixed in the housing 102 and welded to their respective radiation elements.

Provided with each coil 120,122 is a respective switching arrangement

124,126. Each switching arrangement 124,126 comprises a plurality of switches adapted to modify a number of turns of the respective coil 120,122. For instance, the first switching arrangement 124 is provided for the first phase adjusting coil 120, wherein the first switching arrangement 124 comprises a plurality of switches adapted to selectively short circuit turns of the first phase adjusting coil 120 so as to alter the effective number of turns of the first phase adjusting coil 120. Similarly, the second switching arrangement 126 is provided for the second phase adjusting coil 122, wherein the second switching arrangement 126 comprises a plurality of switches adapted to selectively short circuit turns of the second phase adjusting coil 122 so as to alter the effective number of turns of the second phase adjusting coil 122. In this example, the switches are fixed and welded to the respective phase adjusting coils 120,122 underneath the PCB 106, thereby minimizing any influence on the antenna's performance. Also, this arrangement enables a control line to be easily connected to the phase adjusting switches from the PCB 106.

It its noted that, after assembling the device (e.g. by closing the housing 102 and attaching end caps 130), some fmalization steps may preferably be undertaken. For instance, the TLED may be placed in anechoic chamber, and the phasing adjusting switches controlled by high and low voltage level. With different voltage level configurations, all possible radiation patterns may then be measured and made to corresponded to configuration words. Then, during use, a required radiation pattern may be achieved by using the associated configuration word. Also, improved adaptation to a real-world environment, the phase configuration words may be implemented and, for each configuration word, the coverage point will receive the wireless signal until it receives a maximum signal level.

From the above-described example of Figure 6, it will be understood that embodiments may be applicable to smart TLEDS. However, embodiments may also be applicable to other types of smart lighting devices. Such applicability to smart lighting devices may make proposed embodiments useful for a wide range of applications.

For applicability to devices with tubular housing, the radiating elements may be provided on an elongated substrate that is curved about a longitudinal axis extending in the longitudinal direction. Also, the first and second radiating elements may be printed on the substrate (using established printing techniques, including 3D printing for example), and electrical contacts may be provided at the ends of the radiating elements. In this way, an antenna according to an embodiment may be provided in a form which enables it to be inserted in housing of compact cross-section, such as tubular housing. After insertion, the contacts may enable connection of the coil arrangement in a simple manner, assisting the manufacture process of a device (such as a smart lighting device for example)

In an alternative embodiment, the tubular housing may comprise a housing portion formed from an elongated substrate that is curved about the longitudinal axis, and the radiating elements may be provided on the housing portion. The radiating elements may thus be provided on the curved housing portion, and this curved housing portion may form at least part of the upper or lower part of the tubular lighting device. For example, the radiating elements may be provided on the inner surface of the lens part of a TLED. In this way, components of the antenna may be integrated with the lighting device so as to maximize use of the available space within the device. Fig. 7 shows another embodiment of the collinear antenna by using a different implementation of the phase balance arrangement. The phase balance arrangement is implemented by tracks. The phase adjustment circuit comprises at least one switch placed aside the track and adapted to short circuit a portion of the track thereby tuning an effective length of the meandered track between the radiating elements. This track can also be called as a phase stub in the field of RF.

In the embodiment of Fig. 7, the track is a half closed meandered track.

Alternatively, the track is a completely closed track, as shown in fig. 8.

This antenna with radiating element and the phase balance tracks could be manufactured only on level 2 PCB of TLED, as printed wires. All the switches are easier to be welded and assembled on the level 2 PCB. And there will be no need to use second assembling and 3D printing technology to manufacture the antenna and phase adjusting element, as discussed in the above embodiment in figure 6.

Embodiments may thus be employed in conjunction with new or existing lamps. For example, an embodiment may be retro-fitted to a conventional lamp, whereas another embodiment may be integrated into a new lamp at time of manufacture. Accordingly, an aspect of the invention may provide a lamp comprising a lighting device according to an embodiment.

Embodiments may be employed in the field of building lighting, stadium lighting, home/residential lighting, temporary lighting, and other fields/applications where remotely controllable lighting is desirable.