Background technology
At mobile phone, personal digital assistant (Personal Digital Assistant, portable electron device today of popularizing such as PDA), its function, appearance and modeling, cost have become the principal focal point of portable terminal market competition, and how lower cost and the volume that reduces each parts become the direction of mobile terminal design.
Along with the volume of portable electron device dwindles gradually, it is more and more limited to make that its inside is used to install the space of each electronic devices and components, and the portable electron device function constantly increases, thus feasible each electronic devices and components miniaturization day by day that is installed in the portable electron device.Antenna is as the critical elements of portable electron device transmitting/receiving wireless signal, and its miniaturization manufacturing technology has significant values.Prior art adopts SMD PIFA antenna usually, see also Fig. 1, existing P IFA antenna 10 is located on the circuit board 14, it comprises an antenna radiator 11, one load point 12, one earth point 13, described antenna radiator 11, load point 12 and earth point 13 are the lamellar body that electric conducting material is made, described load point 12 and earth point 13 1 ends are vertically connected at described radiant body 11, the other end all is vertically connected at described circuit board 14, according to the PIFA antenna characteristics, in order to obtain preferable signal transmitting and receiving effect, described antenna radiator 11 needs to keep certain distance with circuit board 14.Is example with operating frequency for 2.4GHz commonly used, and the distance of described aerial radiation 11 bodies and printed circuit board 14 needs to reach more than the 4mm at least, and this space can not hold other part, otherwise can influence antenna performance.Obviously, this antenna need take bigger installing space, is unfavorable for the miniaturization of portable electron device.
Summary of the invention
In view of this, be necessary to provide a kind of less PIFA antenna of volume that takies.
In addition, also be necessary to provide a kind of portable electron device with described PIFA antenna.
A kind of PIFA antenna comprises a radiant body, a grounding parts and a signal feed-in part, and described radiant body is one to be flat circuit board module, and its part surface is provided with a radiation area; Described grounding parts comprises one first folding part and one second folding part, described first folding part is connected in described radiant body, described second folding part is connected and is parallel to described radiant body setting with first folding part, described signal feed-in part is connected on the described radiant body, and it is in order to receive electromagnetic wave signal.
A kind of portable electron device comprises a circuit main board and a PIFA antenna, described PIFA days vinculum one radiant body, a grounding parts and a signal feed-in part, and described radiant body is one to be flat circuit board module, its part surface is provided with a radiation area; Described radiant body is parallel to described circuit main board setting and electrically connects by described grounding parts and signal feed-in part and described circuit main board; Described grounding parts comprises one first folding part and one second folding part, and described first folding part is connected in described radiant body, and described second folding part is connected with first folding part, and is fixed on the described circuit main board; Described signal feed-in part is connected on the described radiant body, and it is in order to receive electromagnetic wave signal.
Compared to prior art, the present invention utilizes a circuit board module as antenna radiator, utilize a grounding parts, and constitute a PIFA antenna by adding a signal feed-in part, so effectively solved the required problem of antenna installation in the prior art, realized the demand of portable electron device miniaturization than large space.
Embodiment
See also Fig. 2, be depicted as preferred embodiment of the present invention and be arranged at the interior PIFA antenna 80 of portable electron devices such as mobile phone, PDA.Described PIFA antenna 80 is a planar inverted-F antenna, it is parallel is located on the circuit main board 30 of described portable electron device, described PIFA antenna 80 comprises a radiant body 82, a grounding parts 84 and a signal feed-in part 86, one end of described grounding parts 84 and signal feed-in part 86 all is connected in described radiant body 82, and the other end all is connected with described circuit main board 30.
Described circuit main board 30 is existing portable electron device circuit board, and it comprises a top layer (Top Layer) 32 and a bottom (Bottom Layer) (figure do not show) relative with described top layer 32, and some electronic components 33 are set on the described top layer 32.
Described radiant body 82 is one to be flat circuit board module, its main body is printed circuit board (PCB) (the Printed Circuit Board that is located in the described portable electron device, PCB), described radiant body 82 is parallel to described circuit main board 30 and is provided with, and electrically connect with described circuit main board 30 by described grounding parts 84 and signal feed-in part 86, described radiant body 82 have one first plane 822 with one with the second relative plane 824 of 822 positions, described first plane, this first plane 822 and second plane 824 are all parallel with described circuit main board 30, described first plane 822 and described top layer 32 opposing settings, some buttons 825 and some light-emitting diodes (Light-Emitting Diode can be set on it, LED) 826, described second plane 824 is oppositely arranged with described top layer 32, it is an electric connection face, can electrically connect by electronic component and described circuit main board 30.Also be provided with an exposed radiation area 828 that forms by electric conducting material such as copper, silver, electrically conductive ink etc. on the part surface of described radiant body 82, described radiation area 828 plays radiation effects in described PIFA antenna 80, and the impedance matching of described PIFA antenna 80 and the adjustment of working frequency range can be realized in the position that area by changing described radiation area 828 and described signal feed-in part 86 are connected in described radiant body 82.
Described grounding parts 84 is flexible printed wiring board (the Flexible PrintedCircuit Board that is located at described portable electron device edge, FPCB), it comprises one first folding part 842 and one second folding part 844, described first folding part 842 be one roughly bending be down the lamellar body of L shaped shape, it is provided with perpendicular to described radiant body 82, the short end of described first folding part 842 is connected in second plane 824 of described radiant body 82 abreast and electrically connects with described second plane 824, and its long end extends to described circuit main board 30 along the direction vertical with this short end.Described second folding part 844 is a horizontal lamellar body, is fixed on the bottom of described circuit main board 30 abreast and electrically connects with circuit main board 30, and the long end of described first folding part 842 vertically is connected 844 outsides, second folding part and electrically connects with its foundation.Described second folding part 844 comprises an earth point 848, and described earth point 848 electrically connects with described circuit main board 30, and plays the ground connection effect in described PIFA antenna 80.
Described signal feed-in part 86 is plates, the one end is vertically connected at second plane 824 of described radiant body 82 and with described second plane 824 and electrically connects, the other end vertically is fixed on the top layer 32 of described circuit main board 30 and with described circuit main board 30 and electrically connects, and described signal feed-in part 86 is parallel to the short end of first folding part 842 of described grounding parts 84, and the length of described signal feed-in part 86 is about 4.9mm.
In actual applications, when described PIFA antenna 80 is installed in described portable electron device, described radiant body 82 reliable accessible portable electronic apparatus housing one inner surface settings, button 825 that is provided with on its first plane 822 and LED826 can expose outside the portable electronic device shell and play a role.Described grounding parts 84 can be located at the edge of portable electron device one side, and described first folding part 842 length can with the portable electron device consistency of thickness, can be provided with around the portable electron device outer rim, can save the installing space by this, help the miniaturization of portable electron device.
When described PIFA antenna 80 is worked, signal is after signal feeding portion 86 enters, radiant body 82 transmission along described PIFA antenna 80, at this moment, 828 radiation effects of described radiation area, the earth point 848 of described second folding part 844 provides ground connection for described PIFA antenna 80, thereby makes described PIFA antenna 80 be satisfied with the requirement of carrying out work under the 2.4GHz frequency.
Antenna gain is meant under the condition that input power equates, the ratio of the power density of the signal that actual antennas and desirable radiating element produce in same point place, space.It describes the degree that a sky bundle of lines input power is concentrated radiation quantitatively.When the position that the area and the described signal feed-in part 86 of the described radiation area 828 of appropriate change is connected in described radiant body 82, can obtain different operating frequencies, see also table, record the situation of the gain of the PIFA antenna 80 shown in the preferred embodiment of the present invention along with the operating frequency variation by experiment, when operating frequency was 2.4GHz, the gain of described PIFA antenna 80 was-3.346dB; When operating frequency was 2.45GHz, the gain of described PIFA antenna 80 was-2.057dB; When operating frequency was 2.5GHz, the gain of described PIFA antenna 80 was-2.902dB.
The gain of the PIFA antenna 80 shown in table one present embodiment is with the variation of operating frequency
See also Fig. 3, be depicted as preferred embodiment of the present invention and carry out voltage standing wave ratio (Voltage Standing Wave Ratio, VSWR) results of test figure.Generally speaking, promptly to be considered as receptance below 2dB good for voltage standing wave ratio.As shown in Figure 3, experiment records when described PIFA antenna 80 operating frequencies are 2.4GHz, and voltage standing wave ratio is 1.2dB; When described PIFA antenna 80 operating frequencies were 2.45GHz, voltage standing wave ratio was 1.15dB; When described PIFA antenna 80 operating frequencies were 2.5GHz, voltage standing wave ratio was 1.4dB, so described PIFA antenna 80 is desirable planar inverted-F antenna.
In addition, those skilled in the art also can make various modifications, interpolation and the replacement on other forms and the details in claim of the present invention scope of disclosure and spirit.Certainly, these all should be included within the present invention's scope required for protection according to the variations such as various modifications, interpolation and replacement that spirit of the present invention is made.