Double-frequency inverted F-type antenna
Technical field
The present invention relates to a kind of double-frequency inverted F-type antenna (PIFA antenna), particularly be applied to the antenna on the radio communication product.
Background technology
Fast development along with wireless telecommunications in recent years; on every demand of product, also improve gradually; except the specification of reaching electrical characteristic; reach in appearance on the practical convenience also gradually towards diversification; therefore the built-in antenna of miniaturization becomes the main flow of recent wireless product, and in order to reach the downsizing of size, and on antenna performance, still must keep the characteristic of multiband or wideband; usually can make the design of built-in antenna be tending towards complicated, and be difficult for doing the adjustment on the specification.Therefore how in limited environment and space, utilize effective antenna parameter to reduce the complexity of design and reach required specification of product and DE, become the important pointer of built-in antenna design.
Be applied to mobile communication equipment at present as the built-in antenna of products such as mobile phone, PDA(Personal Digital Assistant), usually adopt reversed F-typed Antenna Design, conventional inverted F shaped antenna design is as United States Patent (USP) the 6th, 727, No. 854 " reversed F-typed plate aerial " (with reference to figure 1), it discloses a kind of built-in antenna that is applied to mobile phone, the main radiation sheet metal part of its antenna, set out by load point 15 and short dot 16 and can roughly be divided into three current paths 10,13,14, utilize this difference path to inspire different resonance frequencys, form double frequency or multi-band operation; No. 2003/0103010 " dual-band antenna position " (with reference to figure 2) of U.S. Patent Publication and for example, it also discloses a kind of built-in antenna that is applied to mobile phone, the main radiation sheet metal of its antenna is set out by load point 25 and short dot 26, also can roughly divide into two current paths 23 and 24, excite two resonance modes to reach dual frequency operation respectively.
Though above-mentioned inverted F shaped antenna design can be reached double frequency or multi-band operation; but since its structure comparatively complexity and path are more; therefore adjust certain current path when finely tuning certain frequency band in reality; regular meeting impacts other current paths; make the frequency of other frequency band also can and then change, cause the adjustment difficulty on antenna performance.Be head it off, we propose a kind of innovative design of double-frequency inverted F-type antenna in the present invention, utilize an inverted T-shape slit to make the main radiation sheet metal of this antenna form a simple folding path, in order to first (low frequency) and second (high frequency) operator scheme that produces this antenna, and the two branch road slits that utilize this inverted T-shape slit can be distinguished independent these two operator schemes of control, and do not influence the frequency of operation of another pattern, therefore antenna of the present invention is under the situation that does not increase the antenna overall complexity, the frequency of operation that can adjust its resonance mode easily is the innovative design that has the industry using value to reach the required bandwidth requirements of system.
Summary of the invention
As mentioned above, the present invention's purpose is to provide a kind of innovative design of double-frequency inverted F-type antenna, can be easy to adjust the frequency of operation of antenna with the required frequency band range of compliance with system.Antenna of the present invention comprises: a radiation sheet metal, this radiation sheet metal has an approximate inverted T-shape slit, one load point and a short dot, wherein this load point and this short dot position are adjacent to each other and be positioned on the edge of this radiation sheet metal, should approximate inverted T-shape slot then be by a central slit, one first branch road slit and one second branch road slit are formed, one end opening of this central slit is positioned at this radiation sheet metal near extending on this edge of this load point and this short dot and within this radiation sheet metal and being connected with this first and second branch road slit, this first branch road slit then extends to this load point and this short dot direction, this second branch road slit is then to extending away from this load point and this short dot direction, should make this radiation sheet metal form a folding path by approximate inverted T-shape slit, in order to first (low frequency) and second (high frequency) operator scheme that produces this antenna, and the initiating terminal in this folding path is with terminal adjacent to each other, and wherein this first branch road slit is used to control this first (low frequency) operator scheme, and this second branch road slit then is used to control this second (high frequency) operator scheme; One ground plane; One feed-in sheet metal, one end are connected to this load point of this radiation sheet metal, and the other end then is connected to system signal feed-in source, in order to the input electrical signal; One short-circuiting jumper, one end are connected to this short dot of this radiation sheet metal, and the other end then is connected to this ground plane; An and medium substrate.
In this design, first (low frequency) operator scheme that the folding path excited of this radiation sheet metal and second (high frequency) operator scheme are two resonance modes before this antenna, and the initiating terminal in this folding path and the terminal capacity effect that produces adjacent to each other, can be used for adjusting the impedance of this two resonance mode, make it reach good impedance matching, and this two branch roads slit can be distinguished the frequency of operation of independent this two resonance mode of control, and do not influence another resonance mode, via the length of this two branch roads slit of suitable adjustment, can obtain the dual-band antenna of compliance with system demand.
The accompanying drawing summary
Fig. 1 is conventional inverted F shaped antenna one example structure figure;
Fig. 2 is conventional inverted F shaped antenna one example structure figure;
Fig. 3 is double-frequency inverted F-type antenna one embodiment 3 structure charts of the present invention;
Fig. 4 loses experimental result A for returning of embodiment 3;
Fig. 5 loses experimental result B for returning of embodiment 3;
Fig. 6 loses experimental result C for returning of embodiment 3;
Fig. 7 is double-frequency inverted F-type antenna one embodiment 7 routine structure charts of the present invention;
Fig. 8 is double-frequency inverted F-type antenna one embodiment 8 routine structure charts of the present invention.
Execution mode
Figure 3 shows that an embodiment 3 of double-frequency inverted F-type antenna of the present invention, it comprises: a radiation sheet metal 30, this radiation sheet metal 30 place on the medium substrate 36, and this medium substrate 36 can be air or dielectric constant near 1 plastic material.This radiation sheet metal 30 has an approximate inverted T-shape slit 301, one load point 302 and a short dot 303, wherein this load point 302 and this short dot 303 positions are adjacent to each other and be positioned on the edge of this radiation sheet metal 30, should approximate inverted T-shape slot 301 then be by a central slit 304, one first branch road slit 305 and one second branch road slit 306 are formed, one end opening of this central slit 304 is positioned on this radiation sheet metal 30 this edge near this load point 302 and this short dot 303, and within this radiation sheet metal 30, extend and with this first and second branch road slit 305,306 are connected, 305 of this first branch road slits extend to this load point 302 and this short dot 303 directions, this second branch road slit 306 is then to extending away from this load point 302 and this short dot 303 directions, should make this radiation sheet metal 30 form a folding path 307 by approximate inverted T-shape slit 301, in order to first (low frequency) and second (high frequency) operator scheme that produces this antenna, and the initiating terminal in this folding path 307 is with terminal adjacent to each other, by the capacity effect that its spacing produced, can make this two operator scheme obtain good impedance matching, and wherein this first branch road slit 305 can be used for controlling this first (low frequency) operator scheme, and this second branch road slit 306 then is used to control this second (high frequency) operator scheme; Via the length of this first and second branch road slit of suitable adjustment, the resonance frequency that can adjust this two operator scheme easily is to obtain the dual-band antenna of compliance with system demand.
Fig. 4 loses experimental result A for the returning of embodiment 3 of double-frequency inverted F-type antenna of the present invention; Curve 41 is first (low frequency) operator scheme of this antenna among the figure, 42 of curves are second (high frequency) operator scheme of this antenna, these two operator scheme centre frequencies that can be obtained this embodiment by experimental result are respectively 920MHz and 1800MHz, the impedance frequency range is in 3.5: 1VSWR (voltage standing wave ratio) definition down, 80MHz and 240MHz can be reached, the bandwidth requirements of mobile phone GSM900 and DCS1800 system can be satisfied.
Fig. 5 loses experimental result B for the returning of embodiment 3 of double-frequency inverted F-type antenna of the present invention; Wherein the curve of distinct symbols is respectively the loss result that returns that the first branch road slit of this antenna measures when different length, and curve 51 is first (low frequency) operator scheme of this antenna among the figure, 52 of curves are second (high frequency) operator scheme of this antenna, can obtain when changing the first branch road slit length of this antenna by experimental result, the frequency of operation of this first (low frequency) operator scheme 51 can be along with change, and the frequency of operation of this second (high frequency) operator scheme 52 is then unaffected.
Fig. 6 loses experimental result C for the returning of embodiment 3 of double-frequency inverted F-type antenna of the present invention; Wherein the curve of distinct symbols is respectively the loss result that returns that the second branch road slit of this antenna measures when different length, and curve 61 is first (low frequency) operator scheme of this antenna among the figure, 62 of curves are second (high frequency) operator scheme of this antenna, can obtain when changing the second branch road slit length of this antenna by experimental result, the frequency of operation of this second (high frequency) operator scheme 62 can be along with change, and the frequency of operation of this first (low frequency) operator scheme 61 does not then change.
Figure 7 shows that another embodiment 7 of double-frequency inverted F-type antenna of the present invention, it comprises: a radiation sheet metal 70, this radiation sheet metal 70 has an approximate inverted T-shape slit 701, one load point 702 and a short dot 703, wherein this load point 702 and this short dot 703 positions are adjacent to each other and are positioned on the edge of this radiation sheet metal, should approximate inverted T-shape slot 701 then be by a central slit 704, one first branch road slit 705 and one second branch road slit 706 are formed, one end opening of this central slit 704 is positioned at this radiation sheet metal 70 near being connected on this edge of this load point 702 and this short dot 703 and to the extension of the inside of this radiation sheet metal 70 and with this first and second branch road slit, 705 of this first branch road slits extend to this load point 702 and this short dot 703 directions, this second branch road slit 706 is then to extending away from this load point 702 and this short dot 703 directions, should make this radiation sheet metal 70 form a folding path 707 by approximate inverted T-shape slit 701, in order to first (low frequency) and second (high frequency) operator scheme that produces this antenna, and the initiating terminal in this folding path 707 is with terminal adjacent to each other, by the capacity effect that its spacing produced, can make this two operator scheme obtain good impedance matching, and wherein this first branch road slit 705 can be used for controlling this first (low frequency) operator scheme, and this second branch road slit 706 then is used to control this second (high frequency) operator scheme; Via the length of this first and second branch road slit of suitable adjustment, the resonance frequency that can adjust this two operator scheme easily is to obtain the dual-band antenna of compliance with system demand.Present embodiment 7 difference from Example 3 are the shape difference in radiation sheet metal 70 and folding path 707.
Be illustrated in figure 8 as the another embodiment 8 of double-frequency inverted F-type antenna of the present invention, it comprises: a radiation sheet metal 80, this radiation sheet metal 80 has an approximate inverted T-shape slit 801, one load point 802 and a short dot 803, wherein this load point 802 and this short dot 803 positions are adjacent to each other and be positioned on the edge of this radiation sheet metal, should approximate inverted T-shape slit 801 then be by a central slit 804, one first branch road slit 805 and one second branch road slit 806 are formed, one end opening of this central slit 804 is positioned on this radiation sheet metal 80 this edge near this load point 802 and this short dot 803, and be connected to the extension of the inside of this radiation sheet metal 80 and with this first and second branch road slit, 805 of this first branch road slits extend to this load point 802 and this short dot 803 directions, this second branch road slit 806 is then to extending away from this load point 802 and this short dot 803 directions, should make this radiation sheet metal 80 form a folding path 807 by approximate inverted T-shape slit 801, in order to first (low frequency) and second (high frequency) operator scheme that produces this antenna, and the initiating terminal in this folding path 807 is with terminal adjacent to each other, by the capacity effect that its spacing produced, can make this two operator scheme obtain good impedance matching, and wherein this first branch road slit 805 can be used for controlling this first (low frequency) operator scheme, and this second branch road slit 806 then is used to control this second (high frequency) operator scheme; Via the length of this first and second branch road slit of suitable adjustment, the resonance frequency that can adjust this two operator scheme easily is to obtain the dual-band antenna of compliance with system demand.Present embodiment 8 difference from Example 3 are the length difference of the first branch road slit 805.
Only be explanation principle of the present invention and effect thereof at the embodiment described in the present invention's explanation, and unrestricted the present invention.Therefore, those skilled in the art can make amendment to the foregoing description without prejudice to spirit of the present invention and change.Interest field of the present invention claims as described later is listed.