The present invention relates to a multiband antenna and a method of manufacturing such a multiband antenna.
Increasing numbers of radio protocols and corresponding radio bands required in portable electronic devices, such as mobile terminal devices or handsets, have fostered the need for new ways of creating all of the required frequency bands in an ever decreasing space or volume within the device.
Instead of having a single antenna for a single frequency band, it would be valuable to have more than one radio protocol or frequency band covered by the same antenna.
EP 0 593 185 A1 discloses a compact wideband antenna arrangement where two compact antenna coils are arranged concentrically, one within the other. The first antenna coil is tuned to include a first frequency, and the second coil is tuned to include a second frequency different from the first frequency. One of the antenna coils is used for reception and is tuned to the reception frequency, while the other is used for transmission and is tuned to the transmission frequency.
Additionally, WO 99/14819 discloses a dual-band helix antenna with a parasitic element positioned either inside or outside of the helix antenna and parallel to the major axis of the helix. The parasitic element is positioned so that when radio frequency energy in the higher of two frequency bands is incident on the antenna arrangement, the helix antenna and the parasitic element are capacitively coupled, while when radio frequency energy in the lower of the two frequency bands is incident, the helix antenna is substantially isolated from the parasitic element. Thereby, the antenna arrangement is capable of operating in two or more widely separated frequency bands.
In some embodiments an antenna arrangement comprises:
a first antenna element carried on said outer surface; and
a second antenna element carried on said inner surface or on an outer surface of a second support body which is at least partially inserted inside said first support body.
Furthermore, in some embodiments a portable electronic device has an antenna arrangement which comprises:
Further, in some embodiments an antenna arrangement comprises:
Additionally, in some embodiments a method of manufacturing an antenna arrangement comprises:
Moreover, in some embodiments a method of manufacturing an antenna arrangement comprises:
Accordingly, a multiband antenna construction is enabled by providing a multi-part mechanical structure which allows a first antenna to be carried on the outside surface of a first body, and a second antenna to be carried on the inside surface of the first body, or on the outside surface of a second body which is inserted inside the first body. The first body is completely or partially “hollowed” such that a second body can be inserted therein. The proposed mechanical construction of antenna arrangement makes possible multiband operation by using a floating parasitic antenna or resonator inside a main antenna or resonator. This enables tight packing of multi-resonant antennas into a small space, so that the size of multiband antennas can be reduced. The volume available inside the first support body can be used efficiently, while no galvanic or electric connection is needed for the second antenna.
The proposed manufacturing methods enable use of technologies such as three dimensional (3D) plating of conducting material (e.g. by laser direct structuring (LDS)) for antenna manufacturing.
In another embodiment, the second antenna element may be carried on the inner surface of the first support body and a third antenna element may be carried on the outer surface of the second support body. The third antenna element may for example be electrically connected to at least one of the first and second antenna elements.
Optionally, the second antenna element may not be galvanically connected to the first antenna element, so as to act as a floating parasitic resonator.
At least one of the first and second support bodies may be made of a dielectric material. Then, a dielectric constant of the first support body may differ from a dielectric constant of the second support body. More specifically, the second support body may be made of a material composition which enables a predetermined dielectric load on the first and second antenna elements at their respective operating frequencies.
In a specific exemplary implementation, the first and second antenna elements may be arranged in a helical structure. Thereby, a small helix antenna can be provided, in which multiband operation is made possible by using a coaxial and optionally floating parasitic helical resonator inside the main helical section or antenna.
In yet another specific exemplary implementation, the first antenna element may be a parasitic element and the second antenna element may be the fed or driven element, thereby forming the second antenna element within the parasitic element.
The second antenna element may have a resonance on at least one frequency which differs from a resonance frequency of the first antenna element.
Furthermore, the first and second support bodies may be configured in a substantially rectangular shape. The mounting or attaching of the first and second antenna elements or radiators may comprise metal plating a helical or other structure on the respective surface.
Further advantageous modifications are defined in the dependent claims.
In the following, the present invention will be described on the basis of embodiments with reference to the accompanying drawings in which:
Embodiments will now be described on the basis of a multiband antenna arrangement with rectangular multi-part construction. It is apparent that the present invention is not intended to be limited to such a shape and that other shapes of the bodies and antenna elements are possible and feasible.
The antenna arrangement, construction or assembly of
Thereby, a mechanical construction for a multiband antenna is provided in which multiband operation is made possible by using a floating or non-floating parasitic resonator inside the main antenna or resonator. Furthermore, the proposed mechanical construction enables antenna manufacturing by simply plating or depositing a metallic or conductive structure for the antenna elements or patterns on the respective surfaces in a three-dimensional manner. This arranging or mounting of the antenna patterns or elements on the inner and/or outer surfaces of the main and sister bodies may be achieved for example by LDS technology which is extremely flexible and requires only three process steps (molding, laser structuring, metallization) without any chemical surface activation (no acid), photoresist, or etching. Of course any other technologies for arranging metallic or other conductive antenna patterns on body surfaces can be used, for example, Molded Interconnect Device (MID) 3D molding technology.
This proposed mechanical antenna structure makes it possible to reduce the size of multiband antennas. It utilizes effectively the volume available inside the main body 20. In case of a floating parasitic resonator, no galvanic or electric connection is need for the inner second radiator.
As already mentioned, the proposed multiband antenna construction provides a multi-part mechanical component which allows the first antenna element to be carried on the outside surface 22 of the first or main body 20. The second antenna element may be carried on the outside surface 12 of the second or sister body 10 which is inserted inside the main body 20. The main body 20 is to be completely or partially “hollowed” such that a second body maybe inserted therein. This mechanical construction allows at least two antenna elements to be closely coupled utilizing at least two surfaces of a 3-dimensional component or components.
In a second embodiment the second antenna element may be carried on the inside surface 24 of the main body 20, while the sister body 10 may still be inserted into the main body 20. In other words, in the second embodiment the sister body 10 may have no conductive traces or patterns carried on its own surfaces.
The second antenna element may be a parasitic helical element or any other pattern. The sister body 10 may provide only a dielectric load to the main body 20 (which may have one or more antenna elements). The main body 20 may also provide some dielectric loading.
According to a third embodiment the main body 20 may carry a first antenna element on the outside surface 22 and a second antenna element on the inside surface 24, while the second antenna element may or may not be connected to the first antenna element. However, the first antenna element may be coupled to a third antenna element deposed on an outer surface of the sister body 10 inserted within the main body 20. In the third embodiment the third antenna element can be in circuit (e.g. galvanically or electrically coupled) with the second antenna element and may also be in circuit (e.g. galvanically or electrically coupled) with the first antenna element. The third antenna element is disposed on the sister body 10 which may have a substantially different dielectric constant compared to the main body 20.
Helical antenna elements can be configured to awake several resonances by changing the pitch of the helix or using another coaxial helix or whip connected to the same feed point.
The multiband helix antenna shown in
Arranging or mounting or disposing of the antenna patterns or elements (e.g. helical antenna sections of
Based on the above embodiments, at least two manufacturing procedures or methods can be distinguished for the proposed antenna arrangement.
When the antenna arrangement of the above third embodiment is manufactured, a combination of the above first and second options may be used to mount or dispose the proposed three antenna elements.
As can be gathered from
In summary, a compact multiband antenna arrangement and method of manufacturing such an arrangement have been described, wherein a first support body is provided, which is at least partially hollow and which has an outer surface and an inner surface. A first antenna element is carried on the outer surface, and a second antenna element is carried on the inner surface or on an outer surface of a second support body which is at least partially inserted inside the first support body.
It is to be noted that the present invention is not restricted to the above preferred embodiment but can be implemented in connection with any at least partially hollow body of any shape having outer and inner surfaces. Any kind and pattern of antenna elements may be carried on at least some portions of the inner and outer surfaces of the two support bodies. It is even possible to insert more than one sister body with or without antenna element into the main body. The antenna elements or patterns or structures need not be arranged in a concentric manner. They can be arranged at different surface portions, with different patterns and/or pattern orientations. The preferred embodiment may thus vary within the scope of the attached claims.