EP3092676A1

EP3092676A1 - Box antenna and method for producing the same

Info

Publication number: EP3092676A1
Application number: EP14878375.6A
Authority: EP
Inventors: Bengt Gustafsson
Original assignee: Cbg Holding AB
Current assignee: CBG HOLDING AB
Priority date: 2014-01-10
Filing date: 2014-01-10
Publication date: 2016-11-16
Also published as: WO2015105442A1; CN105874645A

Abstract

The present invention relates to an antenna box (1) with applications in the radiocommunication market comprising: a number of dipole elements (3), distribution network (4), adaptation circuits (5), a back cover (9), and a front panel (2) wherein: the back cover (9) can function as a reflector (10) and have a shielding function, the dipole elements (3), distribution network (4) and adaptation circuits (5) are integrated in the flat, essentially flat or slightly shaped front panel (2), the back cover (9), and the front panel (2) essentially functions as the supporting structure of the box (1). The present invention also relates to a method for producing the antenna box (1).

Description

BOX ANTENNA AND METHOD FOR PRODUCING THE SAME

FIELD OF THE INVENTION The present invention relates to an antenna box with ap^¬ plication in the radio communication market and a method for producing the same.

The antenna box comprises a front panel with a number of dipole elements and a back cover with a reflector.

BACKGROUND

Background to this patent application is a previously ap- proved patent application, Swedish patent no 530 103 (WO 2008/004970) (Ref 1) . Inventor in Ref 1, same as for this patent, has later found that further advantages can be achieved by making the design differently. The concept presented in told patent Ref 1, for a box an^¬ tenna design with backplane reflector, was that the An^¬ tenna Dipole Elements was integrated with the front of the shaped radom cover, instead of being mounted in the back structure, as has historically been done. Considerable production cost and performance advantages could then be achieved .

Patent description according to prior art, focused on the TV-market, which at that time was of interest due to the ongoing process of change from analogue to digital terres^¬ trial TV-distribution. This market however was found to not to expand as long and as much as expected. The market for TV antennas is not considered in below description. However the presented design can also be used for TV antennas .

Present new invention means that other applications be- comes more interesting to consider, for example base sta^¬ tions antennas for mobile telephony and antennas for Wire less LAN (WLAN) , which are very big markets. These have been, are, and will continue to be interesting markets. Base for concept here described is an antenna function, being mechanically realised in a type of box design.

Most antennas are equipped with a radom, which is a vital function for antennas. The concept of a radom includes some basic functions;

1 . Cover the antenna elements and electronics and

thereby protect them from weather degradation.

2. Be transparent for radio waves in the functional direction for transmit and receive, normally being the same direction.

Historically the radom has been a separate mechanical cover unit, being mounted on to the supporting structure of the antenna. The radom has been shaped to realise the cover function. The supporting structure has generally, as for antenna types here considered, been realised by the backside of the antenna box. The back side, has normally been a flat panel made of metallic or metallised material, having ability to realise a reflector function for the an- tenna assembly. The cover radom was mounted on the back panel . In a box design antenna, e.g. an antenna in a mobile te^¬ lephony base station, the antenna elements has histori^¬ cally, been realised in mechanics, been mounted on the back panel/structure of the antenna. These can now be much more effectively realised.

Small, low performance antennas, not having a proper re^¬ flector, with application on e.g. the TV market, have often been realised on circuit boards, covered by a radom. These are not further considered in discussion below, but can however also be more effectively produced with here presented concept.

PRESENT INVENTION

The front side of an antenna box is defined as the surface being perpendicular to and most far out in the transmit/receive direction. Opposite side is called the back^¬ side .

The new basic change of antenna design in this patent ap^¬ plication is that front side of the antenna becomes a separate unit, being a flat panel. And the sidewalls of the box antenna are integrated with the back side instead of the front side.

Above means that the historical concept of a radom is no longer relevant. The weather protection function of the antenna more becomes a part of the backside structure of the box antenna assembly, instead of being part of a radom having only the radom functions. The radio wave transparency function of the radom becomes a part of the functions in the front panel of the antenna.

Above design means that the front panel can hold more functions. These can now be realised and integrated more effectively. Antenna elements, distribution and adaptation network, active and passive antenna electronics can fa^¬ vourably be integrated in one process, being same or simi^¬ lar to what is used for Printed Circuit boards. This means possibility for a more stable, accurate and cost effective manufacturing process, being possible only since the front part of the antenna is here a flat panel. Historically above has been realised with a lot of mechanical parts and separate circuit boards requiring a lot of manufacturing and assembly of components.

Also the back structure can effectively hold more func^¬ tions then the historical backplane, being used as reflec^¬ tor and mounting structure. Now when the sidewalls are in the same part as the reflector, the sidewalls will also and preferably be conductive for electricity. That means that an effective and cheap antenna side lobe shielding can be realised. This can be of interest in many applica^¬ tions, for example in base station antennas for mobile te- lephony.

Here presented antenna concept has not been seen earlier according to our knowledge, and it means major advantages in cost reduction and improved performance. MARKET ASPECTS

Telecommunication market has become very competitive, re^¬ quiring lower prices, and better performance.

Also environmental issues have become increasingly impor^¬ tant. There is a demand for products with low energy use in production and life cycle, less use of natural re^¬ sources .

The present invention responds to above and other related problems and requirements.

Base Station antennas.

These antennas normally use the some kind of dipole an^¬ tenna elements, often V-Dipoles, mounted on a backplane which acts as reflector and mounting structure.

The frequencies are typically at 900 MHz and 1800 MHz, frequencies are moving upwards, meaning antenna elements get smaller, and they get a higher quantity of dipoles stacked one above the other.

These antennas are normally realised in a box design. The antenna elements, are typically made of metal, mounted on metal and fixed to the metallic backplane of the antenna. The antenna mechanics/electronics is covered by a radom. Pivoting mechanics is realised by turning around a point at upper and/or lower end of the antennas.

This is a costly solution, using a lot of metallic parts for the antenna elements and their fixation, needing environmentally undesirable processes including surface treat- merits. These can now be replaced by a metallic pattern in the existing front surface of the antenna.

Distribution networks needs a lot of costly cables, con- nectors and mounting mechanics, using a lot of processes and material. These can also be replaced by a metallic pattern in the existing front surface of the antenna.

The invention will have positive effects on the antenna including better side lobe performance, lower manufacturing cost and lifecycle costs, lower logistic costs and ad^¬ vantageous environmental aspects

Sectorial W-LAN antennas

W-LAN system are normally used in smaller cells then mobile telephony, for local WiFi systems, used in e.g. pri^¬ vate homes, train stations, a cafeteria, a hotel etc. Nor^¬ mally they operate in the 2.5 or the 5 GHz band.

Antennas for these system are normally realised in a box design. The antenna elements and the active electronics are typically realised on an interior Printed Circuit Board, PCB . Antenna elements can also be realised by dis- crete metallic sheet parts, mounted inside the radom as for the base station antennas. These are costly designs.

Present invention allows for a smaller and a more effec^¬ tive design of these antenna boxes. The antenna functions are realised as a part of the front surface/panel of the antenna, and the interior PCB becomes obsolete. DESCRIPTION OF THE FIGURES

Fig. 1 shows an exploded view of the antenna box according to a preferred embodiment of the present invention, and

Fig. 2 shows a side cross section of the antenna

DETAILED DESCRIPTION

The invention according this document is regarded as an improvement of design in relation to told prior art. Pre- sent invention comprises following basic parts;

a design realisation concept of an antenna box, methods for producing the design concept.

Fig. 1 shows an exploded view of an antenna box 1 accord- ing to a preferred embodiment of the present invention. The antenna box 1 comprises, a number of dipole elements 3, distribution network 4 and adaptation circuits 5 integrated in the flat front panel 2, connector 7, a back cover 9 including the reflector 10 and sidewall shielding 11, and means 12-13 for mounting the box on a wall or similar .

Further in Fig 1 is shown a cable 8 and a connector 7 mounted on the front panel 2 over a bracket 6, and in Fig 2 is shown the cable 8 and connector 7 going through the back cover 9. It is here found that the classical radom as a single part is no longer relevant as described above.

This is a design concept that allows for considerable ad- vantages for the antenna box realisation.

The type of design as here described has not been real^¬ ised, described or discussed elsewhere to inventor knowl^¬ edge .

Present invention enables the design of the box 1 to have a flat or nearly flat surface of the front cover 2. This means major advantages from production and integration aspects. Antenna elements 3, distribution networks 4 and ad- aption circuits 5 can very efficiently be realised as in^¬ tegrated in the front panel 2 in one established proc^¬ esses.

More extensive passive and active electronic functions like amplifier, can thereby also be realised integrated in the front panel 2 using surface mounted components. The front panel can be regarded as a single sided printed cir^¬ cuit board, PCB, and similar processes and functions as for PCB' s can be applied.

Low cost processes, existing and developed, can be used unifying requirements for antenna elements and for elec^¬ tronic circuitry. In mobile telephony base stations, the antenna elements, adaptation circuits and distribution cable network are normally mounted on the backplane. All the mechanics needed for this purpose can now be deleted, replaced by metallic patterns in the front panel 2. The front side of an antenna which is needed anyway is now used to hold all the antenna functions, except for reflector and shielding function, which are being realised in the back cover. The interior components of the antenna become obsolete.

Mounting mechanics for the antenna elements and cabling can be deleted. Mechanical antenna elements and cables can be deleted, replaced by a pattern in the front panel.

Previous extensive assembly operations decrease dramati^¬ cally, which means lower costs.

Assembly production costs are lowered. Front panel can be mounted by a quick and easy snap function.

Weight and dimensions are lowered. This means secondary positive effects on environment and logistics including storage and transport.

Cooling of active electronics is generally a problem. Pre^¬ vious designs are creating a greenhouse effect for the heat dissipating active electronics being covered/housed in a radom containing air standing still. Cooling of ac- tive electronics now becomes more effective, since they are mounted on an outer wall.

The total quantity of needed and handled components will decrease dramatically lowering component and logistic costs.

Less components, materials and substances decrease the cost and use of energy. Antennas in masts often need additional top mounted elec^¬ tronics, such as filters and amplifiers. These can now be integrated with the antenna element circuits on the front panel.

The fact that front panel 2 becomes close to flat, includ^¬ ing antenna electromechanical functions and components, makes logistics in manufacturing easier/cheaper for this vital and sensitive part of the design..

The distance from the antenna elements to the reflector is defined by the frequency. Since reflector 10 is integrated in the back cover 9 and antenna elements 3 in front panel 2, the required depth of the antenna is minimised, lower^¬ ing outer dimensions, lowering production costs and logistics of finalised antenna.

Smaller dimensions and lower weight means also after sales savings in transportation and storage. Another important aspect is load on end use mountings. Lower wind load from smaller dimensions, and lower weight decreases load on mount and supporting structures, such as masts. Sideway radio wave shielding is often of interest for an^¬ tennas. Since sidewalls 11 and the reflector 10 in the in^¬ vention now is in the same part, the back cover 9 and sideway radio wave shielding can more effectively be real^¬ ised in the same process step as for the reflector. They will naturally in the process have the same metallic or metallised character. Sidewall radio wave shielding would have been more compli^¬ cated and expensive in previous design according to prior art . If reflector function and/or radio wave shielding, is not wanted, the back cover can be made of plastic material, meaning depth of antenna can be decreased to a very slim design . Well known effective processes forming metallic/metallised back cover 9, can be used realising above functions for back cover in one step.

Invention include means 12-13, for pivotically mounting and fix the antenna to a wall.

The invention covers mounting a cable feed through connec^¬ tor 7 on the flat front panel using a bracket. This com^¬ pleted unit then includes all the sensitive electrical an- tenna components.

Advantage compared to prior art, is the fact that this sensitive completed antenna unit becomes fairly flat, mak^¬ ing it much easier/cheaper and quality safe to handle/store in production.

The invention includes mounting of a feed through connec^¬ tor 7 being mounted on a bracket 6.

The invention also includes that mounting of cable 8, can done more effectively by avoiding use of intermediate feed through connector 7, and instead letting the cable 8 pass the back cover 9, and have an outer end connector on the loose cable to connect to the external cable. Positive ef- fects are lower production costs; no brackets 6 needed cheaper connector and mounting. Another advantage is ability for easy check and replacement of connector. Connec^¬ tors are many times a reason for problems eg due to corro- sion degradation.

The invention describes methods for producing the antenna that becomes available and favourable for the design of the invention.

Back cover 9 can be made of metallic or plastic material to be metallised or made conductive by other means.

If reflector function and/or radio wave shielding, wholly or partly, is not wanted, the back cover can be made of non metallised plastic wholly or partly.

Since back cover 9 efficiently can be realised in extruded plastics for bigger quantities. It allows for implementa- tion of snap fitting when mounting the front panel 2 to the back cover 9. Mounting bolts 12, 13 can be moulded into the back cover 9. This means lower production costs and increased quality in mounting means. This will de^¬ crease production cost.

Vacuum forming is a cost effective process for small se^¬ ries, having low start cost in tooling.

Many existing types of antennas can effectively be changed into design of invention, with considerable possibilities in production savings, smaller dimensions and less mate^¬ rial/energy used. In W-LAN antennas the antenna functions are realised in internal electronics/mechanics, covered by a radom. With the invention the antenna element and electronic functions can effectively be realised on the front panel 2. Reflec- tor function can effectively be realised on back cover 9. Existing internal circuit boards and mechanics within the radom can be deleted. Also here outer dimensions related to antenna performance are decreased.

Claims

C115 P3PCT LG/AHT

CLAIMS 1.

Antenna box (1) with applications in the radio communica^¬ tion market comprising; a number of dipole elements (3), distribution network (4), adaptation circuits (5), a back cover (9), and a front panel (2) , characterized in that ; the back cover (9) is designed to function as weather protection together with the front panel (2), the dipole elements (3), distribution network (4) and adaptation circuits (5) are attached to / integrated in the es^¬ sentially flat front panel (2), the back cover (9), and the front panel (2) essentially functions as the support^¬ ing structure of the antenna box (1) .

2.

Antenna box (1) according to claim 1, characterized in that, the dipole elements (3) and/or the distribution net^¬ work (4) and/or the adaptation circuits (5) are integrated with the front cover (9) in the same production step.

3.

Antenna box (1) according to any of the claims 1-2, characterized in that, a reflector is included in the antenna box, and the reflector (10) is integrated in the back cover ( 9 ) .

4.

Antenna box (1) according to any of the claims 1-3, characterized in that, the dipole elements (3) and/or distri^¬ bution network (4) are attached to the inside surface of said front panel, by use of glue, tape or some sort of ad^¬ hesive .

5.

Antenna box (1) according to any of the claims 1-3, characterized in that, the dipole elements (3) and/or distri^¬ bution network (4) are moulded, pressed or vacuum formed into the front cover (9) .

6.

Antenna box (1) according to any of the claims 1-3, characterized in that, the dipole elements (3) and/or distri^¬ bution network (4) are printed, screen pressed, etched or similar like for example processes for Printed Circuit Boards, in to the front panel (9) .

7.

Antenna box (1) according to any of the previous claims, characterized in that, mounting a feed through connector (7) to the front cover, for example using a bracket at^¬ tached to the front cover.

8.

Antenna box (1) according to any of the claims 1-7, char- acterized in that, a cable (8) with an end connector passes through the back cover without use of the feed through connector (7) .

9.

Antenna box (1) according to any of the previous claims, characterized in that, the back cover (9), is equipped with function for sideway radio wave shielding.

10.

Antenna box (1) according to any of the previous claims, characterized in that, antenna box is provided with means (12,13) for pivotically attaching the antenna box (1) to a wall or similar.

11.

Antenna box (1) according to any of the previous claims, characterized in that, mounting bolts (12) and (13) are moulded/extruded into a plastic back cover (9) .

12.

Antenna box (1) according to any of the previous claims characterized in that, the side walls of the back cover (9) are metallised, i.e. made electrically conductive in the same process as for the reflector (10) .

13.

Antenna box (1) according to any of the previous claims characterized in that, all or any of the sides of the back cover (9) are not metallic, but has radio wave transpar^¬ ency .

14.

A method for producing an antenna box (1) with applica^¬ tions in the radio communication market comprising; a number of dipole elements (3), distribution network (4), adaptation circuits (5), a back cover (9), and a front panel (2) according to any of the previous claims, charac- terized in that, it comprises following manufacturing steps : integrating the dipole elements (3) and/or the distribution network (4) and/or the adaptation circuits (5) in the front panel (2) and

- forming that back cover in metallic or plastic material and

- fitting the back cover (9) to the front panel (2) .

15.

A method for producing an antenna box (1) according to claim 14,

characterized in that, similar processes as for a printed circuit boards (PCB) are applied on the front panel (2), and preferably additional, active or passive, electronic functions are integrated in front panel (9) .