WO2013060683A1 - Système d'antenne pour dispositif portatif sans fil - Google Patents

Système d'antenne pour dispositif portatif sans fil Download PDF

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Publication number
WO2013060683A1
WO2013060683A1 PCT/EP2012/070976 EP2012070976W WO2013060683A1 WO 2013060683 A1 WO2013060683 A1 WO 2013060683A1 EP 2012070976 W EP2012070976 W EP 2012070976W WO 2013060683 A1 WO2013060683 A1 WO 2013060683A1
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WIPO (PCT)
Prior art keywords
casing part
antenna system
antenna
band
slot
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Ceased
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PCT/EP2012/070976
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English (en)
Inventor
Aleksander Krewski
Werner Schroeder
Jan Vercruysse
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Option NV
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Option NV
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Publication of WO2013060683A1 publication Critical patent/WO2013060683A1/fr
Anticipated expiration legal-status Critical
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/10—Resonant slot antennas
    • H01Q13/103—Resonant slot antennas with variable reactance for tuning the antenna
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/2258—Supports; Mounting means by structural association with other equipment or articles used with computer equipment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
    • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
    • H01Q1/242—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
    • H01Q1/243—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use with built-in antennas

Definitions

  • This invention relates to an antenna system for a wireless device, e.g. a portable wireless device, such as a laptop computer, a PDA a smartphone, a mobile phone, a tablet, and to a portable wireless device incorporating the antenna system.
  • a wireless device e.g. a portable wireless device, such as a laptop computer, a PDA a smartphone, a mobile phone, a tablet, and to a portable wireless device incorporating the antenna system.
  • the design of wireless devices is constrained by a number of design parameters. Users require a device which is lightweight and robust. It is also necessary to provide an antenna system which will support wireless connectivity across one or more frequency bands.
  • One design approach for portable wireless devices is to provide a metal unibody casing, also known as a monocoque.
  • the outer metal casing provides structural rigidity for the device.
  • a laptop computer is formed as two separate unibody casing parts: a first (base) part which accommodates components such as the keyboard, processor, memory and storage; and a second (lid) part which accommodates the screen.
  • the unibody approach can provide robustness combined with low weight, especially when a material such as aluminium is used.
  • a disadvantage of the unibody design is that it can hinder the provision of wireless connectivity.
  • One approach to providing a wireless antenna within a laptop casing is to locate antenna elements at the top of the lid. Where the laptop casing is a unibody part, an opening in the local region of the antenna elements is required. This opening will reduce the strength of the unibody casing. This is a widespread conventional solution.
  • Another approach is to provide an antenna which can fold out, or extend beyond, the unibody casing. This has a disadvantage that the antenna must be manually operated between a storage position and an operational position. Also, the antenna is prone to damage.
  • MIMO Multiple Input-Multiple Output
  • the present invention seeks to provide an antenna system for a wireless device having conductive casing parts.
  • a wireless device such as a portable wireless device, such as a laptop computer, a PDA, a smartphone, a mobile phone, a tablet and a portable wireless device incorporating the antenna system.
  • An aspect of the present invention provides an antenna system according to any of the claims 1 to 44 wherein each dependent claim defines a separate embodiment of the present invention.
  • a further aspect is a terminal or wireless device including the antenna system as defined in any of the claims 1 to 44.
  • the present invention provides a portable wireless device comprising an antenna system as described above.
  • the portable wireless device can be a smartphone, a laptop, a tablet, a PDA, a mobile phone, for example.
  • the casing parts can be unibody or monocoque parts, which are manufactured from a conductive material such as metal (e.g. aluminum) or a conductive plastic material.
  • Casing parts of electronic devices comprises always a layer or coating of conductive material for Electromagnetic Compatibility (EMC) reasons.
  • EMC Electromagnetic Compatibility
  • the parts may be moveable with respect to each other, e.g. hinged as with a conventional laptop, or one can be a sleeve for the other for example.
  • there is a slot (opening) provided inside or between the casing parts.
  • a number of conductive couplers can be placed in the slot connecting both casing parts.
  • circuitry is arranged to provide an in-phase excitation of the characteristic mode and further connection between the feed port with its first and second terminals and one wireless TX/RX (transmit/receive) module.
  • the antenna system couples inductively to the chassis of the portable wireless device, e.g. to the laptop's chassis (inductive coupler). This arrangement can be used in one of the operating frequency bands, such as a low-band frequency range.
  • in-phase and out-of-phase excitation are a way to excite two different superpositions of characteristic modes on the chassis.
  • the general case is to have N couplers and to use N properly chosen superpositions of feed-port signals so as to excite N different superpositions of characteristic modes which will give us N different radiation patterns and thereby a N-port (MIMO) antenna system (or alternatively a multiband system or something in between).
  • MIMO N-port
  • the antenna system supports multi-band operation.
  • the present invention allows providing at least a further conventional antenna system comprising an antenna element placed at the top of one of the casing's parts such as a lid.
  • these present conventional antenna solutions are capacitive couplers while in accordance with embodiments of the present invention the primary antenna system is an inductive coupler.
  • the present invention may provide a further complementary second antenna system with similar features but supporting another frequency band other than the primary antenna system.
  • a mixture of first, second and conventional antenna systems will be implemented in future wireless devices.
  • the combined system allow for connectivity when the casing is closed or not sufficiently open.
  • the antenna system can as a way of example support SISO antenna operation in a portion of the operating frequency range (e.g. a low band) and MIMO operation with two independent antenna ports in another portion of the operating frequency range (e.g. mid-band and ISM frequency band).
  • SISO antenna operation in a portion of the operating frequency range (e.g. a low band)
  • MIMO operation with two independent antenna ports in another portion of the operating frequency range e.g. mid-band and ISM frequency band.
  • a single antenna operation in a low frequency band is provided and MIMO operation in a mid-band and in a higher frequency range with two independent antennas.
  • Primary and standard antenna systems can support multi-band operation thus providing at least two independent antennas for MIMO in defined low-band and up to four antennas in defined mid-band and for a higher frequency band.
  • an aspect of the invention relates to an antenna system for a portable wireless device comprising a first casing part, a second casing part which is connected to the first casing part, wherein there is a slot between the first casing part and the second casing part, the first casing part and the second casing part being electrically conductive, at least two interconnecting elements between the first casing part and the second casing part for providing an electrically impedance between the first casing part and the second casing part, a first coupling element in the slot providing a further electrically impedance between the first casing part and the second casing part, a second coupling element in the slot, physically offset from the first coupling element along a longitudinal axis of the slot, providing a further electrically impedance between the first casing part and the second casing part; a first node located on, or adjacent to, the first or second coupling element; a second node located anywhere on the antenna system, and circuitry for connecting the first node and the second node with at least one transmit
  • At least one of said two characteristic modes of the system defined by the first and second casing part is a higher order mode thereof.
  • an antenna system for a portable wireless device comprising a first casing part, a second casing part which is connected to the first casing part, wherein there is a slot between the first casing part and the second casing part, the first casing part and the second casing part being electrically conductive, at least two interconnecting elements between the first casing part and the second casing part for providing an electrically impedance between the first casing part and the second casing part, N>2 coupling elements in the slot providing a further electrically impedance between the first casing part and the second casing part; each of said coupling elements being physically offset from each other along a longitudinal axis of the slot, M, preferably equal to N, nodes, of which at least part are located on, or adjacent to said coupling elements, and the other being located anywhere on the antenna system; circuitry for connecting the nodes with at least one transmit/receive module, wherein preferably the system is being adapted to excite at least N characteristic modes of the system defined by the first
  • Another aspect of the invention relates to method of computer assisted designing an antenna system as described, the method comprising the steps of loading required antenna behavior in a computer system, adapting one or more of the amount of electrical interconnecting and coupling elements, the physical (width) and electrical (impedance) parameters of those electrical elements and their position in the slot, and the location of the first and second node in a computer model of the antenna system; simulating the computer model with the amounts, parameters, positions and locations of the previous step, comparing the obtained behavior and repeating steps 2 or 3 till the required antenna behavior is achieved.
  • Another aspect of the invention relates to the use, in portable wireless device, having a first casing part and a second casing part which is connected to the first casing part, wherein there is a slot between the first casing part and the second casing part, the first casing part and the second casing part being at least partly electrically conductive, of elements within the slot between the first and second casing part, to selectively excite one or more of at least two characteristic modes of the casing parts, by modifying the current paths within the casing parts, preferably at least one of said two characteristic modes of the system defined by the first and second casing part is a higher order mode thereof.
  • a portable wireless device comprising an antenna system according to any one of the embodiments, may comprise of a second antenna system, either a classical one or again one in accordance with one of the embodiments of the invention.
  • Such combined antenna system may support multi-band operation thus providing at least two independent antennas for MEVIO in defined low-band and up to four antennas in defined mid-band and for a higher frequency band.
  • At least one of said conductive coupling element includes a mode matching network.
  • the invention relates to antenna systems, the method of use of those and methods and related software to design such systems and determine suitable ways of us thereof, all those various aspects are characterized in that one or more of the antenna element (such as couplers) are placed in the slot between two casing parts of a (wireless) device (such as a laptop), such placement being selected to enable to excite characteristic modes on the chassis of a laptop.
  • the invention provides for use of any number N of couplers (and related terminals or ports) into the slot in order to selectively excite N different superpositions of characteristic modes, preferably also higher order modes, on the chassis of the device to thereby create an N-port antenna arrangement which in principle allows for N-antenna MIMO transmission, preferably with addition of necessary matching circuitry.
  • the invented design method allows for co-design of the location of the hinges (having at least an electrical impedance for instance being conductive) and the locations of the feed ports, in particular by placement of further electrical impedances, for example further conductive connections or couplers ("links", "strips") between the base part and lid and by choice of the width of the connections (which determines the impedance such as the inductance).
  • L-shaped stubs can be introduced, to aid in resonance tuning of some frequency bands.
  • the invention provides also for use of the above systems or systems arising from the design method for MIMO applications, especially by providing that in one of the embodiments N ports, which can be used simultaneously in the same frequency band, are introduced.
  • Figure 1 shows a portable wireless device and position of ports of an antenna system
  • Figure 2 shows connections between a lid and a base of the portable wireless device
  • Figure 3 shows return loss for the antenna system when first and second ports are used in-common mode
  • Figure 4 shows modal excitation coefficients for characteristic chassis modes of the portable wireless device
  • Figure 5 shows positioning of additional antenna elements in the slot between the lid and base of the portable wireless device
  • Figure 6 shows a first embodiment of circuitry for connecting antenna ports to wireless transmit/receive modules
  • Figure 7 shows a second embodiment of circuitry for connecting antenna ports to transmit/receive modules
  • Figure 8 shows return loss and isolation for one of the symmetric ports of the antenna system
  • Figure 9 shows return loss when using the circuitry of Figure 6 to provide in- common ⁇ and differential mode ⁇ connections between a wireless MiMo transmit/receive module and the antenna ports;
  • Figure 10 shows return loss and isolation when using one of the symmetric antenna ports in the ISM band
  • Figure 11 shows an example position of element of a second antenna system on the portable wireless device
  • FIG. 12A shows circuitry connecting the antenna systems and transmit/receive modules
  • Figures 12B and 12C show the circuitry of Figure 12A for different operating frequency bands.
  • Figure 13 gives an arrow representation of the surface current density of the strongest characteristic mode at 900 MHz, defined low band.
  • Figure 14 shows the layout for a three port MIMO antenna system
  • Figure 15 shows the return loss and isolation for a three port MEVIO antenna system
  • Figure 16A shows for a single port penta-band antenna system
  • Figure 16B and 16C shows the return loss versus frequency for a single port penta-band antenna system
  • Figure 17 (a) Structure of a simple one-port dual-band antenna, b) Return loss versus frequency.
  • Figure 18 (a) Structure of one-port LTE low-band / mid-band antenna, (b) Return loss versus frequency.
  • Figure 19 (a) Structure of two-port MIMO LTE mid-band antenna system, (b) Return loss and isolation versus frequency.
  • Figure 20 (a) Structure of antenna system with 3 ports, (b) RL and isolation versus frequency.
  • Figure 21 (a) Structure of two-port multi-band MIMO antenna system, (b) Return loss and Isolation versus frequency.
  • Figure 22 (a) Structure of the primary antenna (second antenna not shown), (b) Return loss and isolation of the combined 2-port antenna system.
  • Figure 23 (a) Structure of the primary antenna system (second antenna not shown), (b) Return loss and isolation of the combined 3-port antenna system.
  • Figure 24 (a) Two-port antenna structure under investigation, (b) Modal return loss versus frequency
  • MIMO transmission modes are a feature of many wireless communication systems. They are used in wireless communication standards such as Evolved Universal Terrestrial Radio Access (E-UTRA), Long Term Evolution (LTE), Worldwide Interoperability for Microwave Access (WiMAX) and High-Speed Packet Access (HSPA) and are also used in Wireless Local Area Network (WLAN) communications and in other applications. Explanations of MIMO transmission modes can be found in "Introduction to space-time wireless communications" by Paulraj et.al, ISBN 0 521 82615 2. A summary of MIMO operation will be provided before describing embodiments of the invention.
  • E-UTRA Evolved Universal Terrestrial Radio Access
  • LTE Long Term Evolution
  • WiMAX Worldwide Interoperability for Microwave Access
  • HSPA High-Speed Packet Access
  • WLAN Wireless Local Area Network
  • a wireless device So as to support MIMO transmission modes such as Receive Diversity (RD) and Spatial Multiplexing (SM), it is necessary for a wireless device to be equipped with at least a two port antenna system, and in the general case a multi-port antenna which is designed to receive (or transmit, respectively) signals from different ports independently of each other in the same frequency band.
  • receive mode independently means that the different ports of the multiport antennas are capable of receiving different superpositions of incoming multi-path components which requires that their polarimetric complex radiation patterns are sufficiently distinct.
  • a quantitative measure of this capability is the correlation between signals received at different antenna ports in a given reference propagation scenario.
  • Figures 1 and 2 show a portable wireless device 10 in the form of a portable computer (e.g.
  • the portable wireless device can be a laptop, smartphone, mobile phone, PDA, tablet etc.
  • One part of the portable wireless device may be a lid or cover, e.g. a sleeve.
  • the two parts of the portable wireless device will be described as a lid and a base, but it will be understood that these relates to first and second parts of the portable wireless device.
  • the lid 1 and base 2 are physically interconnected by hinges 11, 12 but the present invention is not limited thereto.
  • the lid 1 can be moved between a storage configuration in which the lid 1 lies parallel to the base 2, against the base 2, and an operational configuration in which the lid 1 lies at an angle to the base, such as an angle in the range between 50° and 150°. Relative movement of the two parts is not necessary, provided a slot is provided between the two parts as described below.
  • Figure 1 shows the device in an operational configuration.
  • Figure 2 shows the device in plan view, with the lid fully opened, to clearly show the connections between the lid 1 and base 2.
  • the casing parts 1, 2 are unibody parts formed from metal (e.g. aluminum).
  • a unibody is also known as a monocoque. It is a casing with a shell that is the principal source of its structural strength, which is designed and constructed to serve that purpose.
  • a unibody can be a frame made from a single block of aluminum but other material, such as polycarbonate, can be used.
  • a "unibody laptop” can be considered as an electrically uniform frame contrary to its mechanical construction for which three or more separate pieces can be distinguished. Electrically uniform means that surface currents can move freely.
  • the casing can be a conductive plastic casing or a non-conductive material (e.g. plastic) with a conductive layer which is formed on, or as part of, the plastic casing, thus creating a casing which has a conductive layer.
  • the base 2 typically accommodates components such as the keyboard, track pad, processor, memory and storage and the lid 1 typically accommodates the screen.
  • the lid 1 and base 2 are separated by a slot 18. The width of the slot is defined by the hinges 11, 12.
  • the portable wireless device 10 can comprise a primary antenna system.
  • the primary antenna system can comprise two aspects:
  • N an inductive coupler, which can excite at least one strong characteristic mode in the casing parts 1, 2; or alternatively, N > 1 inductive couplers are placed, which can excite N different superpositions of characteristic modes. If the N feed ports of the N couplers do not have yet orthogonal patterns we can achieve orthogonality by a mode matching network (MMN) constructed by a modal matching criterion, e.g. TMRL.
  • MNN mode matching network
  • one or two parasitic elements are mounted in the slot 18 between the casing parts 1, 2.
  • this can comprise one, or a pair of, parasitic elements positioned at locations 21, 22 in the slot 18.
  • the elements can be L-shaped stubs.
  • the primary antenna system can provide a sufficiently wide bandwidth to cover the whole low-band frequency range in a Single Input - Single Output (SISO) configuration without using any switching. Also, the whole mid-band frequency range can be covered in a Multiple Input - Multiple Output (MEVIO) configuration (with switching). If the two additional parasitic element(s) are mounted in the slot 18, these can be used to expand the coverage to the 2.4GHz ISM band, used for WLAN, in a MEVIO configuration.
  • the LTE low band is defined from 704MHz up to 960MHz, which is from the 3GPP band number- 17 to band number- 8.
  • the LTE mid frequency band is defined and ranged from 1710 MHz up to 2170 MHz. It is from 3GPP band number-3 to band number- 1.
  • the portable wireless device 10 can comprise a conventional antenna system.
  • the conventional antenna system can comprise an antenna element positioned, for example, at the top of the lid 1.
  • the conventional antenna system can couple capacitively to the chassis. If the conventional antenna system is mounted within a metallic unibody casing part, the unibody shell will require an opening in the local region of the second antenna system.
  • the primary antenna system uses the casing parts 1, 2 themselves as part of its radiating structure.
  • Each feed port has two terminals.
  • a first feed port 15 has its terminals connected to parts 1 and 2 at a first position along the longitudinal axis of the slot 18. .
  • the feed port 15 connects to its first terminal where the second terminal connects the same feed port by means of a conductive link 13.
  • a second feed port 16 has its terminals connected to parts 1 and 2 by means of a conductive link 14 at a second, different, position along the longitudinal axis of the slot 18 compared to that of the first port 15..
  • Figure 2 shows the ports 15, 16 on the base 2 side of the slot 18. Through each feed port 15, 16 the lid 1 and base 2 of the device 10 are electrically connected in a well-defined lid-base location area, along the longitudinal axis of the slot.
  • the conductive links, for example 13, 14 can be carried out as a complex impedance. These complex impedances construct the mode matching circuit.
  • excitation occurs on the terminals of the ports. With both terminals excited in-phase, higher than 7 dB return loss can be achieved in the complete defined low- band frequency range. A superposition of the primary few characteristic modes with low radiation quality factors is excited giving, as a result, around 30% relative bandwidth.
  • the operation of the primary antenna system will be described for reception of an incoming electromagnetic wave.
  • the casing parts 1, 2 serve as part of an antenna, with the slot 18 being part of the antenna structure.
  • the hinges 11, 12 serve as interconnecting elements which provide an electrically conductive path between the casing parts 1, 2.
  • An incoming electromagnetic wave induces a current density on the casing parts 1, 2 of the device 10 that can be decomposed into characteristic chassis modes. Part of the induced current is passing through the hinges. By providing conductive links 13, 14 which contain resp. the feed ports' 15, 16 terminals in proper positions, which are obtained from the analysis of the characteristic modes, the remaining part of the induced current is diverted through the conductive links and feed ports.
  • the current gives rise to a surrounding magnetic field. Due to the induced magnetic flux enclosed by the loop comprising the hinges 11, 12, links 13, 14 and parts 1, 2, a voltage is induced on the feed ports' 15, 16 both terminals. Several characteristic modes are usually induced simultaneously. How the superposition as a linear function of characteristic modes is composed depends on the position of the links 13 and 14 along the longitudinal axis. Due to its inductive functionality, the principle of the described arrangement is referred to as an inductive coupler.
  • the conducting link 13, 14 can comprise a single wire, the shield of a coaxial cable, or a strip line for example. Transmission of an electromagnetic wave is achieved by a reversal of the steps just described.
  • one of the characteristic modes shown in Figure 4 is particularly strongly excited (characteristic mode 3, high modal excitation coefficient in the frequency range 850MHz - 960MHz.
  • characteristic mode 3 high modal excitation coefficient in the frequency range 850MHz - 960MHz.
  • the primary antenna system or arrangement will result in two or more independent, uncorrelated ports.
  • the two ports 15, 16 can be driven in a common mode to produce a SISO antenna system.
  • additional L-shaped stubs are used, MIMO operation is possible in the WLAN band.
  • these parasitic elements aid in tuning to the frequency band of interest for the primary antenna system.
  • Table 1 Design arrangement for primary, not operational for lid closed, & conventional antenna system.
  • the "lid open” state is defined as an angle between the lid and base of between 50° and 150° degrees. In the “lid closed” configuration the primary antenna system is not operational and only the conventional antenna system can be used.
  • the electrical connections between the lid 1 and base 2 of device 10 can be realized by individual conductive strips, such as the shield of coaxes or multiconductor lines, or by a flexible carrier, such as a flexible printed circuit board (PCB) which is connected to the lid 1 and base 2.
  • a flexible carrier such as a flexible printed circuit board (PCB) which is connected to the lid 1 and base 2.
  • the PCB is thin and formed from low permittivity, low-loss, thin flexible PCB laminate.
  • the PCB can carry the links 13, 14 which interconnect the lid 1 and base 2.
  • the optimum location of the links 13, 14 along with the resp. feed ports 15, 16 for the defined low-band antenna can be identified from surface current distribution of the strongest characteristic mode at the frequency of interest, here in the lower band at 750MHz.
  • Figure 13 gives an arrow representation of the surface current density of the strongest characteristic mode at 900 MHz, defined low-band.
  • links 13, 14 along with ports 15, 16 are placed along the longitudinal axis where the surface current density is a maximum.
  • the PCB does not have to fill the whole Open air' slot 18.
  • the PCB can carry the L-shaped stubs at positions 21, 22. In the closed position, the flexible PCB or conductive strips are slightly bent or are folded between the lid 1 and the base 2.
  • the additional parasitic element 21 is electrically connected to one of the terminals of port 15.
  • the additional parasitic element 22 is electrically connected to one of the terminals of port 16.
  • the primary antenna system can be operated across multiple bands. Three bands are considered. There is a low band, a higher band, or a lower band and higher band such as a mid-band and a high band:
  • a low-band 700 MHz up to 1 GHz, e.g. LTE low band
  • a mid-band (1 GHz up to 2.2 GHz, e.g. LTE mid band);
  • WLAN band e.g. IEEE 802.11 implementing a wireless local area network (WLAN) computer communication in the 2.4, 3.6 or 5 GHz frequency bands.
  • WLAN wireless local area network
  • parasitic elements 21, 22 provide additional antenna resonance at the WLAN frequency range and connect to the feed ports 15, 16.
  • the antenna system can therefore be matched at the 2.4 GHz ISM band.
  • Parasitic elements 21, 22 are shown as L-shaped strips or stubs.
  • For the defined low-band frequency range only a common mode impedance is matched.
  • In the defined mid-band frequency range the common and differential mode impedances are matched using series capacitance.
  • a matching criterion of a TMRL of 7dB over the whole bandwidth of the frequency range can be used.
  • symmetric matched and uncorrelated ports are produced. ).
  • the primary antenna system provides a 2-port MEVIO operation for the defined mid-band or WLAN.
  • Two embodiments of matching and connecting circuitry are shown in Figures 6 and 7.
  • Figure 6 shows matching circuitry and provides switching between all three frequency bands (the defined low-band, the defined mid-band and WLAN). 1. When the switches are in position 1, the diodes are in the conducting state and the common mode output is connected to the defined low-band Rx/Tx. A graph of return loss in this position is shown in Figure 3.
  • the first state (switches in position 1) is for both the defined low-band and WLAN.
  • the second state (switches in position 2) is for the defined mid-band.
  • the first state uses a dual-band 180° "rat-race" coupler.
  • the defined low-band is covered by the common mode output port from the dual band 180° coupler with similar response to that shown in Figure 3.
  • connecting a coupler to the output of the defined mid-band matching network in position 2) the frequency response on ⁇ and ⁇ ports is given in Figure 9, without the 180° coupler, the response on one of the symmetric ports in Figure 8.
  • a 180° coupler in both figures is optional and depends on the relation between modal bandwidths (or maximum achievable bandwidth in the sense of TMRL bandwidth), which both depends on the size of a device, and bandwidth requirements/isolation requirements.
  • the 180° coupler makes the ports of the antenna system asymmetrical, but the performance criteria in the lower part (Tx portion) of the frequency band, is met more relaxed on the ⁇ -port.
  • the trade-off is that MEVIO operation is only possible for the DL LTE mid-band (e.g. 3GPP band numbers-3 and - 4).
  • a conventional antenna system can be provided in addition to the primary antenna system, known as inductive coupler.
  • the conventional antenna system couples capacitively to the chassis of the device 10, the capacitive coupler. This ensures that both sets of the superposition of the characteristic modes are orthogonal. Cables (e.g. coaxes) connect matching/mode decomposition circuitry to the conventional antenna system 40.
  • Figure 11 shows an example placement of such an antenna system 40 on the top edge of lid 1.
  • the conventional antenna system 40 is mounted on the outer face of the lid 1 so that this antenna system can be used when the lid 1 is closed.
  • FIG 12A shows apparatus provided in the portable wireless device 10.
  • a primary antenna system 5 has feed ports 15, 16.
  • Matching and switching circuitry 31, 32 connects the ports 15, 16 to TX/RX modules 33, 34.
  • Two TX/RX modules are shown, for 2 port MIMO operation.
  • a conventional antenna system 40 has feed ports 45, 46.
  • Matching (and switching) circuitry 41 connects the antenna ports 45, 46 to TX/RX modules 43, 44.
  • Two TX/RX modules are shown, for 2-port MIMO operation. For SISO operation, only one TX/RX module is used.
  • Figures 12B and 12C show the apparatus of Figure 12A for different operating frequency bands.
  • Figure 12B shows defined low-band operation.
  • single antenna operation is supported by the primary antenna system 5, using TX/RX module 33 and (optionally) single antenna operation is supported by the conventional antenna system 40, using TX/RX module 43.
  • the wireless device 10 supports 2-port MIMO operation: one port via the inductive coupler 5 and one port via the capacitive coupler 40. Ports 15 and 16 are connected in common mode to TX/RX module 33.
  • FIG. 12C shows defined mid-band or WLAN band operation.
  • 2-port MIMO operation is supported by the inductive coupler 5, using TX/RX modules 33, 34, and (optionally) 2-port MIMO operation is supported by the capacitive coupler 40, using TX/RX modules 43, 44.
  • the wireless device 10 supports 4-port MIMO operation.
  • Ports 15 and 16 are each connected to a respective TX/RX module 33, 34. Both ports 15, 16 operate at the same frequency band as one another, but provide independent transmit/receive paths as the inductive coupler induces/excites orthogonal characteristic modes to the casing parts.
  • Single Port Multi-band antenna design
  • FIG. 16A A single port antenna system optimized for the DL defined LTE low-band and complete LTE mid-band (UL and DL) is shown in Fig. 16A with the return loss vs. frequency in Fig. 16B and Fig. 16C.
  • Fig. 16A shows the top view of the PCB located between lid and base part and connections between them. This antenna system is designed by removing the second feed port (16, Fig. 5) but, keeping the second conducting strip, and by further optimization of the strip lines.
  • FIG. 14 A 3-port antenna system optimized for the defined mid-band (UL and DL) is shown in Fig. 14. Feed port 2 is added in the middle of the slot. A proper matching network designed using the TMRL matching algorithm will make all ports "truly" independent which results in a 3-port MIMO antenna system. S-parameters of the matched 3-port antenna are presented in Fig. 15. Isolation is better than 10 dB and return loss is better than 7 dB in the whole LTE mid-band frequency range.
  • a one-port dual-band antenna is provided.
  • Fig. 17a shows the structure of a simple one-port antenna which can be used in LTE low-band and shows some potential also for use in mid-band.
  • the sketch in Fig. 17a represents the slot region (between base and lid of the laptop).
  • the wide strips may be identified with conductive hinges.
  • the narrow strips are added to achieve the desired behavior.
  • the left narrow strip is connected at its upper end to the lid. Its lower end serves as one of the two terminals of the feed port.
  • the other terminal of the feed port is directly at the base part.
  • the dot indicates the location of either a source or a load (connected to the two terminals of the port).
  • the right narrow strip is just a shunt connection.
  • the two narrow strips may e.g. be realized using flexible PCB material.
  • the interpretation of the wide strips as conductive hinges is not mandatory. Of relevance is only the presence of the conductive connection.
  • a further improved one-port dual antenna is disclosed.
  • Fig. 18a shows the structure of a one-port, dual-band antenna which has been optimized for use in LTE low-band and mid-band. The return loss is shown in Fig. 18b.
  • This antenna is derived from the previous example (Fig. 17a) by placing a parasitic element close to either of the narrow strips.
  • the parasitic element is a L- shaped strip which is connected with one of its end to the base part of the laptop. The other end is open.
  • the parasitic element enhances operation of the antenna in mid-band because it exposes a quarter-wave resonance there.
  • the L-shape strip is connected to the base part of the laptop but NOT connected to the strips between base and lid. Note that base and lid may in principle be exchanged in Fig. 18a.
  • the L- shaped strip is an optional feature of the invention for matching at frequencies above ⁇ 1GHz. Other methods may exist.
  • a two-port (MIMO) mid-band antenna is provided.
  • Fig. 19a shows a two-port mid-band antenna. This antenna supports MEVIO operation in mid band.
  • the two narrow strips connect the lid to the feed ports.
  • the return loss (note the symmetry with respect to the two ports) and isolation are given in Fig. 19b. Note the excellent isolation between the two ports.
  • a two-port (MIMO) low-band and one-port mid-band antenna is presented.
  • Fig. 20a shows an antenna system with 3 ports which qualifies as two-port (MIMO) system in low-band and one-port mid-band antenna but also supports 3-port Downlink (DLJ-MIMO operation in E-UTRA band number 1 and DL-MIMO in band number 4 (AWS).
  • the antenna was optimized for MIMO LTE in low-band using ports 1 and 3 and a single antenna operation in LTE mid-band using port 2.
  • Return loss and isolation are shown in Fig. 20b. Isolation between all ports is better than 24 dB in the intended frequency ranges. Note that the symmetry of the antenna system implies that the return loss seen at ports 1 and 3 is the same.
  • FIG. 21a shows a two-port (MIMO) multi-band antenna system optimized for LTE low-band, mid-band and the 2:4 GHz ISM band.
  • the two wide strips in the center may be identified with conductive hinges but may also be purposely introduced strips. Non-conductive hinges may be present anywhere.
  • the narrow strips connect to the feed ports as before.
  • the L-shaped quarter-wave stubs support operation in the ISM band (WLAN, Bluetooth). The arrangement allows for excitation of common and differential modes in all bands. Isolation between ports is better than 20 dB return loss within the 7dB matching criterion for all bands of interest (Fig. 21b).
  • Yet another embodiment relates to a two-port (MIMO) dual-band solution by combination with conventional antenna.
  • Any of the antenna systems according to the present invention can be combined with an additional conventional laptop antenna system.
  • the one-port, dual-band antenna system after Fig. 18a, which is shown again in Fig. 22a is combined with a conventional antenna system (not shown) at the top of the lid.
  • the second antenna system which has been assumed for the simulation in Fig. 22b is a prior-art system.
  • the combination of both antennas amounts to a two-port (MIMO), dual-band antenna system optimized for LTE low- band and mid-band as shown in Fig. 22b.
  • the return loss is better than 6 dB and isolation is higher than 25 dB.
  • FIG. 23b shows simulation results for another combination of an antenna system according to the present invention (primary antenna system, Fig. 23a) and a conventional antenna placed at the top of the lid of the laptop (second antenna).
  • the second antenna is a prior art design.
  • the combination of the first antenna system with the second antenna amounts to a 3-port (MIMO) antenna system which supports 3-port MIMO operation in LTE low-band and mid-band and in addition 2-port MIMO operation in the 2:4 GHz ISM band.
  • the current densities which are excited on the chassis by feeding the 3 different ports are mutually orthogonal as can be seen from the high isolation between all 3 ports. Isolation between the ports of the first antenna system is better than 22 dB and isolation against the second antenna better than 25 dB. Return loss is within the 7 dB specification for all bands of interest for the first antenna system and within 6 dB for the second antenna.
  • the present invention further relates to a design approach, now illustrated as the design procedure and optimization of the response considering the common mode as an example in the design of Figure 24, but equally applicable to other modes.
  • Two design parameters are considered.
  • the first parameter is the distance d of the feed ports from the geometrical center of the slot (horizontal distance).
  • the second parameter is the height h of the slot between the lid and the base part of the laptop.
  • Figs. 25 and 26 The results of corresponding parameter sweeps are shown in Figs. 25 and 26. It can be seen from Fig. 25 that the frequency range over which the common mode is matched in low-band can be adjusted by choice of d, which is the horizontal distance from the center of the slot. Colors of the graphs correspond to d £ ⁇ 10,30,50,70,90 ⁇ mm.
  • the invention provides for an antenna system for devices like laptops realized by at least a first impedance connecting the conductive shell of the base part and the lid part, respectively, and at least one further connection between the base and the lid part containing an impedance and the two terminals of a feed port.
  • Either of the impedances may be just a conductive strip.
  • the locations of the connections containing only an impedance and the location of the connections containing an impedance and a feed port are adjusted so as to achieve match of the antenna in some frequency band(s).
  • the values of the impedances are adjusted so as to achieve match of the antenna in some frequency band(s).
  • the width and thickness of conductive strips are adjusted so as to obtain the desired impedances of the connections.
  • any of the systems designed with the above one or more steps of the procedure either alone or combination with classical antenna system are part of the invention, in particular those with N > 1, preferably N>2 connections containing feed port terminals and any number of connections without feed ports, where locations and impedances of the connections are chosen so as to excite different superpositions of characteristic modes on the conductive parts of the laptop when feeding different ports, again preferably the system is so designed so that the different superpositions of characteristic modes (corresponding to different ports) are mutually (nearly) orthogonal, i.e. that isolation between feed ports is high over some desired frequency band(s).
  • At least two of the different feed ports expose high return loss and high mutual isolation in some desired frequency band(s) allowing for MEVIO operation in these frequency bands, hence the systems might have N feed ports and allowing for N-port MIMO operation in some desired frequency band(s).
  • Further elements can be additional parasitic elements, e.g. L-shaped quarter-wave stubs connected to either the lid or the base part of a laptop, for the purpose of improving match of the antenna system in one or more frequency bands.
  • the invention also provides for a combined antenna system for laptops consisting of a first antenna system with N ports following the present invention and having in addition a second antenna system with M ports placed in a different location on the laptop's chassis both designed and located so as to achieve excitation of K > max(M,N) different radiation patterns in some desired frequency band(s), allowing for K-port MIMO operation in these band(s), wherein preferably the K radiation patterns are orthogonal radiation modes.

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Abstract

L'invention concerne un système d'antenne pour un dispositif comprenant : une première partie de boîtier ; une seconde partie de boîtier qui est connectée à la première partie de boîtier, une fente existant entre la première partie de boîtier et la seconde partie de boîtier et la première partie de boîtier et la seconde partie de boîtier étant électroconductrices ; des éléments d'interconnexion électrique entre la première partie de boîtier et la seconde partie de boîtier pour constituer une boucle électroconductrice entre la première partie de boîtier et la seconde partie de boîtier ; un premier élément de couplage entre la première partie de boîtier et la seconde partie de boîtier ; un second élément de couplage, décalé physiquement du premier élément de couplage dans la direction d'un axe longitudinal de la fente ; un premier nœud situé sur le premier élément de couplage ou adjacent à celui-ci ; des circuits pour la connexion du premier nœud avec au moins un module d'émission/réception.
PCT/EP2012/070976 2011-10-23 2012-10-23 Système d'antenne pour dispositif portatif sans fil Ceased WO2013060683A1 (fr)

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US9902826B2 (en) 2014-04-02 2018-02-27 Daicel Corporation Transparent layered film, process for producing same, and electrode for touch panel
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CN110308161A (zh) * 2018-03-20 2019-10-08 佳能株式会社 放射线照相装置和放射线照相系统
CN113097693A (zh) * 2017-04-01 2021-07-09 苹果公司 包含到设备铰链中的天线及方法
US11163338B2 (en) 2017-04-18 2021-11-02 Hewlett-Packard Development Company, L.P. Flexible conductive member within hinge of computing device to selectively make conductive contact with antenna
CN120233294A (zh) * 2025-05-30 2025-07-01 山东大学 一种阻抗/导纳理论误差的评估方法及系统

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US9902826B2 (en) 2014-04-02 2018-02-27 Daicel Corporation Transparent layered film, process for producing same, and electrode for touch panel
US9742055B2 (en) 2014-06-11 2017-08-22 Xiaomi Inc. Antenna and electronic equipment using same
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CN120233294A (zh) * 2025-05-30 2025-07-01 山东大学 一种阻抗/导纳理论误差的评估方法及系统

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