The example and non-limiting embodiments of this invention relate generally to wireless communication systems, methods, devices and computer programs and, more specifically, relate to a radio antenna and related feeding arrangement.
This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
Increasingly, mobile radio handsets incorporate one or multiple radios that operate over different protocols and different frequency bands. This is true over multiple cellular band as with tri and quad-band mobile devices that operate in several cellular systems such as GSM (global system for mobile communications, or 3G), UTRAN (universal mobile telecommunications system terrestrial radio access network, or 3.5G), WCDMA (wideband code division multiple access), and OFDMA (orthogonal frequency division multiple access), to name but a few examples. Additionally, many handsets come equipped with secondary radios such a global positioning system GPS, Bluetooth, wireless local area network WLAN, and/or traditional FM radio that operate alongside the cellular band radios.
Simultaneous with this desire for communication over diverse frequency bands is the continued preference of ever smaller handsets. This creates several technological challenges, not least of which is design and placement of antennas for such varied bands in the small and crowded handset in a manner that generally assures reliable signal transmission and reception without excessive interference with or from other electronics within that same handset housing.
This is a challenging environment for the antenna designer. There are quite strict requirements for several operating bands, and the small antenna volumes available within the handset impose conflicting constraints. Especially cellular bands are very difficult to cover with a single resonance and so require either multiple antennas or tunable antennas. This readily leads to complicated matching topologies, adding to the designer's burden of simultations and difficulty in finding an operable solution.
In a first aspect thereof the exemplary embodiments of this invention provide an apparatus comprising multiband antenna circuitry and feed circuitry. The multiband antenna circuitry comprises: a resonator; a first ground port configured to couple the resonator to a common voltage potential; and at least one reactive component disposed between the resonator and the first ground port. The feed circuitry comprises: a signal feed port configured to couple to a radio; a second ground port configured to couple the feed circuitry to the common voltage potential; and a feeding element disposed between the signal feed port and the second ground port, the feeding element configured to inductively couple the feed circuitry to the antenna circuitry between the resonator and the first ground port.
In a second aspect thereof the exemplary embodiments of this invention provide an apparatus comprising multiband antenna circuitry and feed circuitry. The multiband antenna circuitry comprises: resonating means; first grounding means; and electrical length extending means between the resonating means and the first grounding means. The feed circuitry comprises: radio coupling means; second grounding means; and induction means between the radio coupling means and the second grounding means for inductively passing electrical signals between the feed circuitry and the antenna circuitry between the resonating means and the first grounding means.
In a third aspect thereof the exemplary embodiments of this invention provide a method comprising: transmitting a first signal at a first frequency through an antenna arrangement by driving the signal from a feed port to a resonator via an inductive coupling disposed between a coil and a ground port, in which the first signal passes through the coil prior to transmission from the resonator; and transmitting a second signal at a second frequency through the antenna arrangement by driving the signal from the feed point.
These and other aspects are detailed with greater particularity below.
Each of
At
In some exemplary but non-limiting embodiments, the resonator 102 may be a planar radiating element; and/or the reactive component 104 may be a coil or winding which extends the effective electrical length of the antenna circuitry 100 between the area of inductive coupling and the resonator 102; and/or the variable reactance 108 may be a variable capacitor or a variable inductor or multiple such components. The variable reactance enables the resonator 102 to operate at a tunable resonance, and therefore operate as a multiband antenna.
Further at
In some example embodiments, the feeding element 124 is one or more loops of conductive wire or trace that substantially surround a section 101 of the antenna circuitry between the fixed reactive component or coil 104 and the variable reactance 108. In some example embodiments there may be a plurality of such loops forming a helix, which may run at least partly alongside the coils of the fixed reactive component 104. There may be a gap formed between the section 101 of the antenna circuitry mentioned above and the inductive feeding element 124, this gap may be an air gap or it may be filled with material suitable for efficient electromagnetic coupling between the section 101 of antenna circuitry and the inductive feeding element 124. The gap may therefore have material properties such as dielectric constant and loss tangent which provide the required coupling and minimize any RF losses in the coupling structure. When the gap is filled with a material, the material may additionally provide mechanical support to the coupling structure such that the amount of coupling with respect to frequency may be closely controlled.
Certain elements of
Note particularly the electrical arrangement of the resonator 102 with respect to the first ground port 106 in relation to the inductive feeding element 124. It is at this feeding element 124 that the radio signal, originating from a radio transmitter coupled at the feed port 122, is passed from the feed circuitry 120 to the resonator 102 for transmission. In the opposite signal direction a signal received at the resonator 102 is passed from the antenna circuitry 100 to the feed circuitry 120 at the inductive feeding element 124, and thereafter output at the feed port 122 to a radio receiver. This arrangement is an electrically shorted antenna; in other words there is a ground coupling at the first ground port 106 separate from the signal feed to the resonator 102 which is provided inductively at the feeding element 124. All embodiments shown at
For the illustrations at
The
The example embodiment of
The example embodiment of
In the above example embodiments any one or more of the resonators 102, 202, 210, 302, 310402, 412, 502, 512, 602, 610, 612, 702, 710 and 712 may be considered as example embodiments of resonating means; any one or more of the ground ports 106, 126 and 128 may be considered as example embodiments of grounding means; and the various implementations (coil, helix, loop) of the reactive component 104 may be considered example embodiments of electrical length extending means. The exemplary variable capacitor(s) and variable inductor(s) are embodiments of variable reactance means, which enables a tunable resonance for one or more of the resonating means.
Further, the feed port 122 may be considered as an example embodiment of radio coupling means; and the feeding element may be considered as example embodiments of induction means for inductively passing electrical signals between the feed circuitry and the antenna circuitry.
In operation, the antenna radiator or resonator 102, 202, 302, 402, 502, 602, 702 which may be planar or non-planar, is electrically short with respect to a resonant wavelength and is inductively fed via the feeding element 124. This radiator or resonator is also electrically loaded by the reactive component 104, which is functionally an electrical lengthening reactive component or antenna loading reactance (that may be embodied as a coil or helix to name a few non-limiting examples) between the antenna and the feed location at the feeding element 124. The feeding element 124 is configured to electromagnetically couple to a radio circuit (which couples in at the feed port 124) and is located between the first ground port 106 and the antenna resonator 102. Since the antenna is shorted, the variable reactive element 108 is coupled to a ground plane of the antenna. Due to its physical location in the illustrated examples, the inductive feed element 124 also operates as an antenna loading element. Note that in the illustrated example tunable embodiments the variable capacitance or inductance 108 lies on the antenna side of the inductive feed arrangement, in other words the variable reactance 108 is galvanically isolated from the feed port 122.
Additionally, in all illustrated example embodiments the secondary coil 104 serves the dual function of shortening the electrical length of the antenna and also serving as a part of the feed arrangement. Note that the location of the feed point, at which a signal is transferred between the feed circuitry 120 and the antenna circuitry 100, may be disposed anywhere between the variable reactance 108 and the resonator 102. In some exemplary embodiments the coil 104 extends the entire length between those two elements 102, 108 and so the feeding element 124 may be co-axial about the coil 104 itself. In other exemplary embodiments there is a non-coil segment of wire between the coil 104 and the variable reactance 108 (or between the coil 104 and the resonator 102) in which case the feeding element 124 may be co-axial about that non-coil segment of the wire or co-axial about the coil 104 or co-axial about a combination of the two.
In some example embodiments the technical effect of the invention is a smaller antenna volume, good antenna radio frequency radiation efficiency performance, and in some example tunable embodiments the ability to easily tune antenna across a wide bandwidth.
A multiband antenna 100 according to the example embodiments may be disposed in a mobile station 10 such as the one shown at
There are several computer readable memories 14, 43, 45, 47, 48 illustrated there, which may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The digital processor 12 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multicore processor architecture, as non-limiting examples.
For completeness further detail of an example UE is shown in both plan view (left) and sectional view (right) at
Also shown is an image or video processor 44, a separate audio processor 46, and speakers 34. The graphical display interface 20 is refreshed from a frame memory 48 as controlled by a user interface chip 50 which may process signals to and from the display interface 20 and/or additionally process user inputs from the user interface 22 and elsewhere.
Within the sectional view of
The operable ground plane to which is coupled the ground ports 106, 126, 128 is shown by shading as spanning the entire space enclosed by the UE housing though in some example embodiments the ground plane may be limited to a smaller area or a combination of areas and/or a combination of components, modules, mechanical parts, as not limiting examples, which may form the overall RF ground plane. The ground plane for the multiband antenna according to these teachings may be common with the ground plane used for additional prior art antennas disposed within the UE 10. The ground plane may be disposed on one or more layers of one or more printed wiring boards within the UE 10, and/or alternatively or additionally the ground plane may be formed from a solid conductive material such as a shield or protective case or it may be formed from printed, etched, moulded, or any other method of providing a conductive sheet in two or three dimensions. The signals received at the resonators are amplified by the power chip 38 and output to the RF chip 40 which demodulates and downconverts the various signals for baseband processing. The baseband (BB) chip 42 detects the signal which is then converted to a bit-stream and finally decoded. Similar processing occurs in reverse for signals generated in the apparatus 10 and transmitted from it.
There may be one or more secondary radios (Bluetooth or WLAN shown together as 42 but which may be RFID, GPS, and/or FM in other embodiments) which may or may not use embodiments of the invention. That is, a single host device such as the UE 10 may include multiple instances of the multiband antenna according to these teachings. Specific separate antennas for those secondary radios are not individually shown at
Throughout the apparatus are various memories such as random access memory RAM 43, read only memory ROM 45, and in some example embodiments removable memory such as the illustrated memory card 47 on which various programs of computer readable instructions are stored. Such stored software programs may for example set the capacitance or inductance of the variable reactance 108 for those embodiments in which the resonance of the resonator changes in correspondence with the variable reactance setting, and in correspondence with transmit and/or receive schedules of the relevant radios. All of these components within the UE 10 are normally powered by a portable power supply such as a battery 49.
The aforesaid processors 38, 40, 42, 44, 46, 50, if embodied as separate entities in a UE 10, may operate in a slave relationship to the main processor 12, which may then be in a master relationship to them. Any or all of these various processors of
Note that the various chips (e.g., 38, 40, 42, etc.) that were described above may be combined into a fewer number than described and, in a most compact case, may all be embodied physically within a single chip.
Blocks 906 and 908 of
At block 908 any tunable capability of the resonator is not used and so reference numbers refer to
The various blocks shown in
In general, the various example embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the example embodiments of this invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as nonlimiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.
It should thus be appreciated that at least some aspects of the example embodiments of the inventions may be practiced in various components such as integrated circuit chips and modules, and that the example embodiments of this invention may be realized in an apparatus that is embodied as an integrated circuit. The integrated circuit, or circuits, may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or data processors, a digital signal processor or processors, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the example embodiments of this invention.
Various modifications and adaptations to the foregoing example embodiments of this invention may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-limiting and example embodiments of this invention.
It should be noted that the terms “connected,” “coupled,” or any variant thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are “connected” or “coupled” together. The coupling or connection between the elements can be physical, logical, or a combination thereof. As employed herein two elements may be considered to be “connected” or “coupled” together by the use of one or more wires, cables and/or printed electrical connections. Where coupling is not physical as in inductive coupling, such is so stated herein.
Furthermore, some of the features of the various non-limiting and example embodiments of this invention may be used to advantage without the corresponding use of other features. As such, the foregoing description should be considered as merely illustrative of the principles, teachings and example embodiments of this invention, and not in limitation thereof.