Summary of the invention
In view of the foregoing, it is necessary to which a kind of wireless communication device that can improve double-antenna isolation is provided.
A kind of wireless communication device comprising first antenna, the second antenna, processor, adjustment unit and match circuit, it shouldProcessor and adjustment unit are electrically connected, which is electrically connected by match circuit and first antenna, which usesIn exporting high level or low level according to the received signal strength of the second antenna to change or maintain the circuit parameter of adjustment unit,So that the adjustment unit and match circuit adjust the impedance of first antenna jointly.
A kind of wireless communication device comprising first antenna, the second antenna, processor, adjustment unit and match circuit, it shouldProcessor and adjustment unit are electrically connected, which is electrically connected by match circuit and first antenna, which usesIn the second antenna received signal strength decline when export high level, adjustment unit capacitance under the control of high levelIt increases, to generate offset with the working frequency range of match circuit co- controlling first antenna.
Received signal strength of the above-mentioned wireless communication device using processor according to the second antenna exports high level or lowLevel changes the capacitance of adjustment unit whereby, it is made to adjust the impedance matching of first antenna jointly with match circuit.Therefore,When the second antenna is in use state, which can generate frequency deviation, thus it is not Chong Die with the working frequency range of the second antenna,The problem of isolation between antennas to improve the wireless communication device.
Specific embodiment
Referring to Fig. 1, presently preferred embodiments of the present invention provides a kind of wireless communication device 100, it can be mobile phone, a numberWord assistant (PDA), tablet computer etc..The wireless communication device 100 is operable with different systems, such as gsm system, time-division are sameWalk CDMA (Time Division-Synchronous Code Division Multiple Access, TDSCDMA) systemSystem and cdma system etc..In the present embodiment, it is with the wireless communication device 100 for working at the same time in gsm system and cdma systemExample is introduced.
The wireless communication device 100 includes processor 10, transmitter 20, radio-frequency front-end 30, adjustment unit 40, match circuit50, first antenna 60 and the second antenna 70.In the present embodiment, which is GSM antenna, is set to wireless communicationOne end of device 100, working frequency range are about 880-960MHz；Second antenna 70 is CDMA antenna, is set to wireless communicationThe other end of device 100, working frequency range are about 824-894MHz.
The processor 10 and transmitter 20 are electrically connected, and for demodulating the wireless signal transmitted by transmitter 20, and are used forIt is radiofrequency signal to be sent to transmitter 20 by modulates baseband signals.
In addition, the processor 10 and the second antenna 70 are electrically connected, which further includes that one universal input/output connectsMouthful (General Purpose Input Output, GPIO), the processor 10 are also used to the according to wireless communication device 100Received signal strength (Received Signal Strength Indication, RSSI) the control universal input of two antennas 70/Output interface GPIO exports high level or low level.Specifically, which was stored in advance a reference intensity value, when second dayWhen the received signal strength RSSI of line 70 is lower than the reference intensity value, the universal input/output interface GPIO exports high level；WhenWhen the received signal strength RSSI of second antenna 70 is higher than the reference intensity value, the universal input/output interface GPIO output is lowLevel.
The transmitter 20 is electrically connected between processor 10 and radio-frequency front-end 30, for radiofrequency signal to be sent to radio frequencyFront end 30.The radio-frequency front-end 30 is used to the processing such as be filtered radiofrequency signal, amplify, which also further passes throughMatch circuit 50 and first antenna 60 are electrically connected, to send radiofrequency signal by first antenna 60.
The adjustment unit 40 electrically connects with universal input/output interface GPIO of processor 10 and match circuit 50 simultaneouslyIt connects, which is used under universal input/output interface GPIO output high level or low level control, with matchingCircuit 50 adjusts the impedance of first antenna 60 jointly.In the present embodiment, which is a varactor(Varactor), there is an initial capacitance value, and the initial capacitance value changes with the variation of the voltage of additional direct current.The adjustment unit 40 has a threshold voltage, when the voltage of additional electric signal is higher than threshold voltage, the varactorInitial capacitance value increases；When the voltage of additional electric signal is lower than threshold voltage, the initial capacitance value of the varactor is notBecome.By selecting the circuit parameter of match circuit 50 and the initial capacitance value of adjustment unit 40, first antenna 60 can be made to existNormal transmitting/receiving wireless signal in scheduled frequency range；By the initial capacitance value of change (raising) adjustment unit 40, can makeThe working frequency range of first antenna 60 is suitably toward high frequency offset.
The application method of the wireless communication device 100 is further illustrated below.When wireless communication device 100 is needed usingWhen two antennas 70 (for example, in state is answered), due to the working frequency range of first antenna 60 and the working frequency range of the second antenna 70It partly overlaps, the received signal strength RSSI of the second antenna 70 is caused to reduce.At this point, when the received signal strength of the second antenna 70When RSSI is lower than the reference intensity value that processor 10 prestores, universal input/output interface GPIO of processor 10 exports high level.When the voltage of the high level is higher than the threshold voltage of adjustment unit 40, the initial capacitance value of adjustment unit 40 is increased.At this point, theThe impedance matching of one antenna 60 by adjustment unit 40 change after capacitance and match circuit 50 codetermine.
It should be noted that for when ensuring that the received signal strength RSSI of the second above-mentioned antenna 70 is reduced to a certain extentIt is enough to change the capacitance of adjustment unit 40, reasonable reference intensity value and selection, which is arranged, for processor 10 has suitable thresholdingThe adjustment unit 40 of voltage is very important.
On the other hand, which is radiofrequency signal by modulates baseband signals, which emits radiofrequency signal, shouldRadiofrequency signal enters match circuit 50 after the processing of radio-frequency front-end 30, and launches via first antenna 60.Due at this timeThe initial capacitance value of adjustment unit 40 increases, therefore the impedance matching of first antenna 60 obtains appropriate adjustment, first antenna 60Working frequency range is suitably toward high frequency offset, thus not Chong Die with the working frequency range of the second antenna 70.In this way, being beneficial to improve the nothingThe problem of isolation between antennas of line communication device 100, is convenient for the normal transmitting/receiving wireless signal of the second antenna 70.
When wireless communication device 100 is in standby, the second antenna 70 is temporarily not used by (answers for example, being not inState), processor 10 exports low level, and the initial capacitance value of adjustment unit 40 will not change.At this point, the impedance of first antenna 60Matching is codetermined by the initial capacitance value and match circuit 50 of adjustment unit 40, allows first antenna 60 in preset frequencyNormal transmitting/receiving wireless signal in range.
It is worked at the same time in gsm system and cdma system, also it is appreciated that wireless communication device 100 of the invention does not limit toCan work at the same time in gsm system+TD SDMA TDSCDMA system and gsm system, or work in gsm system+Wideband code division multiple access (Wideband Code Division Multiple Access, WCDMA) system and gsm system.It is corresponding, first antenna 60 and the second antenna 70 are adjusted, to work in corresponding working frequency range.
Wireless communication device 100 of the invention is defeated according to the received signal strength RSSI of the second antenna 70 using processor 10High level or low level out change the capacitance of adjustment unit 40 whereby, it is made to adjust first antenna jointly with match circuit 5060 impedance matching.Therefore, when the second antenna 70 is in use state, which can generate frequency deviation, thus not withThe problem of working frequency range of second antenna 70 is overlapped, isolation between antennas to improve the wireless communication device 100.