KR100614936B1 - Quad band front end module - Google Patents

Abstract

The present invention relates to a quad band front end module, comprising: an RF switch for branching a signal transmitted and received through an antenna according to a control voltage and including first to fourth switch terminals; A diplexer connected to a first switch terminal of the RF switch and sharing a signal input from a first transmitting end and a signal input from a second transmitting end in one path; A matching circuit for splitting a plurality of signals input by one path from the second switch terminal of the RF switch according to the characteristics of the filter; A first band pass filter (BPF) which passes only signals of a predetermined band among the signals input by being divided by the matching circuit; A second band pass filter (BPF) which passes only signals of a predetermined band among the signals input by being divided by the matching circuit; A third band pass filter (BPF) for passing only signals of a predetermined band among signals input from the third switch terminal of the RF switch; And an input / output terminal connected to the fourth switch terminal of the RF switch to input / output a signal, thereby providing a front end module that can accommodate up to four bands as a simple circuit configuration.

Front End Module, SP4T Switch, Quad Band, GSM, PCS, DCS, UMTS

Description

Quad band front end module

1 is a block diagram showing the configuration of a conventional triple band front end module

Fig. 2 is a block diagram showing a quad band front end module as a first embodiment of the present invention.

3 is a block diagram showing a quad band front end module as a second embodiment of the present invention;

<Description of the symbols for the main parts of the drawings>

205: antenna 210: RF switch

215: first switch terminal 220: second switch terminal

225: third switch terminal 230: fourth switch terminal

235: first transmitting party 240: first low pass filter (LPF)

245: second transmitter 250: second low-pass filter

255: diplexer 260: matching circuit

265: first band pass filter (BPF) 270: second band pass filter

275: third band pass filter 280: input / output terminal (UMTS terminal)

285: (GSM) receiver 290: (DCS) receiver

295: (PCS) receiver 305: diode

The present invention relates to a quad band front end module, and more particularly, to a front end module for a mobile communication terminal that can accommodate up to four bands.

Operating systems of mobile terminals, especially mobile phones, include GSM and DCS systems in Europe, and PCS in the United States. Recently, UMTS is expected to be commercialized as Europe's next-generation mobile communication system.

As described above, since various mobile communication systems are operated in different ways around the world, mobile phone users need to continue to use one mobile phone even under different mobile communication systems.

As a result, cellular phones are equipped with multi-band front end modules that can accommodate multiple bands for use under different mobile communication systems.

1 is a block diagram showing the configuration of a conventional triple band front end module.

As shown in FIG. 1, a conventional triple band front end module includes a first low pass filter (LPF) 13a for removing high frequency noise of a signal transmitted from a DCS / PCS transmitter (Tx) and a GSM transmitter. A second low pass filter 13b for removing high frequency noise of the signal, an SP3T GaAs switch 15 for changing a transmission path and a reception path of the DCS / PCS / GSM signal, and the DCS / PCS / GSM transmitter A signal transmitted from the antenna 16 for transmitting the signal to the DCS / PCS / GSM receiving end separated by the SP3T GaAs switch 15 and connected to the frequency band of each system among the signals transmitted from the antenna 16. According to the high frequency band (DCS / PCS) and the low frequency band (GSM), the diplexer 14 to determine which side to connect to, and the GSM receiver in the frequency band separated by the low frequency band by the diplexer 14 ( Desired desired in Rx) The first bandpass filter 11a (BPF) for passing only the signal of the above frequency band (925 to 960MHz) and removing the signal outside this range and the frequency band separated by the diplexer 14 into the high frequency band are similar. The first phase transformer 12a and the second phase transformer 12b for splitting the PCS band and the DCS band, which are the frequency bands, respectively, and the signal of the frequency band (1930 to 1990 MHz) in the desired range is passed through the PCS receiver. A second band pass filter 11b for removing a signal outside the signal; and a third band pass filter 11c for passing a signal in a frequency band (1805-1880 MHz) in a desired range only at the DCS receiver and removing a signal outside this range. It is configured to include.

However, since the conventional technology is composed of a front end module that can accommodate only DCS, PCS, and GSM bands and cannot accommodate UMTS bands, the conventional front end module cannot be applied under a UMTS mobile communication system. There was this.

In addition, since the DCS / PCS transmitter and the GSM transmitter of the conventional front end module occupy separate switch terminals, there is a hassle that separate switching work has to be performed when transmitting the DCS / PCS signal and the GSM signal.

 In addition, in the prior art, the DCS / PCS received signal and the GSM received signal are branched by the diplexer 14 and then sent to each receiving end, in which case the signal is transmitted by the diplexer 14. Loss of signal (about 0.4 dB) occurs when branching, which causes a problem that the reception sensitivity of the signal is lowered.

Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to accommodate four bands, and to be applied to a mobile communication system requiring linearity, and excellent in both transmitting and receiving signals. To provide a front end module.

According to an aspect of the present invention, there is provided a quad-band front end module comprising: an RF switch for branching a signal transmitted and received through an antenna according to a control voltage and including first to fourth switch terminals; A diplexer connected to a first switch terminal of the RF switch and sharing a signal input from a first transmitting end and a signal input from a second transmitting end in one path; A matching circuit for splitting a plurality of signals input by one path from the second switch terminal of the RF switch according to the characteristics of the filter; A first band pass filter (BPF) which passes only signals of a predetermined band among the signals input by being divided by the matching circuit; A second band pass filter (BPF) which passes only signals of a predetermined band among the signals input by being divided by the matching circuit; A third band pass filter (BPF) for passing only signals of a predetermined band among signals input from the third switch terminal of the RF switch; And an input / output terminal connected to the fourth switch terminal of the RF switch to input and output a signal.

Here, the signal input from the first transmitter is a DCS / PCS signal, the signal input from the second transmitter is a GSM signal, the signal passing through the first band pass filter is a DCS signal, the second band pass The signal passing through the filter is a PCS signal, and the signal passing through the third band pass filter is characterized in that the GSM signal.

The input / output terminal may be a UMTS terminal for transmitting and receiving a UMTS signal.

In addition, the RF switch is characterized in that the SP4T Si switch or SP4T GaAs switch.

The quad band front end module may further include a first low pass filter (LPF) connected between the first transmitter and the diplexer and configured to pass a signal of a predetermined band input from the first transmitter. It is characterized by.

The quad-band front end module may further include a second low pass filter (LPF) connected between the second transmitter and the diplexer and configured to pass a signal of a predetermined band input from the second transmitter. It is characterized by.

The quad band front end module may further include a diode connected between the first transmitter and the diplexer and turned on / off according to a control voltage.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings, and a description of overlapping portions will be omitted.

< First embodiment >

Fig. 2 is a block diagram showing a quad band front end module as a first embodiment of the present invention.

As shown in FIG. 2, the quad-band front end module according to the first embodiment of the present invention branches the signals transmitted and received through the antenna 205 according to the control voltages Vc1 and Vc2 and first to fourth. RF switch 210 including switch terminals 215 to 230, a first low pass filter (LPF) 240 for removing high frequency noise of a signal input from the first transmitter 235, and a second transmitter 245. RF switch by the second low pass filter 250 to remove the high-frequency noise of the signal input from the first signal, and the first low pass filter 240 and the second low pass filter (250) A diplexer 255 for transmitting to the first switch terminal 215 of 210 and a plurality of signals input via a single path from the second switch terminal 220 of the RF switch 210 to be described later. A matching circuit 260 for branching according to the characteristics of (265, 270) and the matching circuit 260 A first band pass filter (BPF) 265 for passing only a signal of a predetermined band among the input signals, and a second band pass filter 270 for passing only a signal of a predetermined band among the signals input by being split by the matching circuit 260. ), A third band pass filter 275 for passing only a signal of a predetermined band among signals input from the third switch terminal 225 of the RF switch, and a fourth switch terminal 230 of the RF switch. And an input / output terminal 280 for inputting and outputting a signal.

Here, when the filtering function of the low pass filter (not shown) constituting the diplexer 255 can be sufficiently utilized, the first low pass filter 240 and the second low pass filter 250 are May be omitted.

The signal passing through the first low pass filter 240 is a DCS / PCS signal, the signal passing through the first band pass filter 265 is a DCS signal, and the second band pass filter 270 is connected to the signal. The signal passed is a PCS signal, and the signal passed through the second low pass filter 250 and the third band pass filter 275 is a GSM signal. In addition, the input / output terminal 280 is a UMTS terminal 280 that transmits and receives a UMTS signal. However, each of the signals is merely an example of a signal that can be preferably applied to the present embodiment, and each of the signals can be sufficiently changed according to a mobile communication system to be developed in the future.

The quad band front end module of the present embodiment configured as described above includes the UMTS terminal 280 which is separate, and the UMTS terminal for transmitting and receiving UMTS signals with the fourth switch terminal 230 of the RF switch 210 ( 280 is connected to each other, unlike the prior art has a structure that can accommodate the signal of the UMTS band.

Here, the UMTS mobile communication system is a system requiring high linearity between an input signal and an output signal, and in order to satisfy such high linearity, the RF switch 210 must have a structure capable of linearly switching input and output signals. The RF switch 210 is preferably an IC type SP4T Si switch or SP4T GaAs switch capable of linearly switching input / output signals.

In particular, the SP4T Si switch or SP4T GaAs switch has a very low insertion loss and excellent isolation between signal bands, thereby improving transmission and reception performance in each signal band.

In addition, the quad-band front-end module of the present embodiment, unlike the prior art, to share the DCS / PCS transmission signal and GSM transmission signal to the diplexer 255 to transmit to the RF switch 210 in one path Because of the structure, it is possible to perform a separate switching operation in the transmitting end. However, the output of the transmission signal may be reduced by about 0.4 dB due to the diplexer 255. However, the reduction of the output signal of such a degree is sufficiently acceptable in the set company employing the front end module. This is not a problem in particular.

In addition, the quad band front end module of the present embodiment is not a structure in which the GSM receive signal and the DCS / PCS receive signal from one switch terminal are divided into a diplexer as in the prior art, but the GSM receive signal and the DCS / PCS Since the reception signal is transmitted from each switch terminal, the phenomenon that the reception signal is attenuated (approximately 0.4 dB) in the diplexer can be prevented as in the prior art. Particularly, in the case of a set company employing a front end module, the attenuation of the reception signal is more strictly applied than the reduction of the output signal of the transmission signal, and according to the present embodiment, the GSM reception signal and the DCS / PCS reception signal are respectively applied. It is very advantageous over the prior art to take the structure of transmitting from the switch terminal of.

Hereinafter, an operation process of the quad band front end module according to the present embodiment will be described in detail with reference to Table 1 below.

A plurality of signals received through the antenna 205 is routed according to control voltages Vc1 and Vc2 corresponding to a band to be received. Here, Vdd is a switch driving voltage for driving the switch.

Table 1 below is a preferred embodiment of the control voltage.

Table 1

Vc1 Vc2 Vdd GSM Receiver (Rx) Low Low on DCS / PCS Receiver High Low on GSM Transmitter (Tx) High High on DCS / PCS Transmitter High High on UMTS OUT Low High on

Referring to Table 1, the operation of the quad band front end module according to the present embodiment will be described. If the GSM signal is to be received by the GSM receiver 285 (Rx), the control voltages Vc1 and Vc2 are both set to Low. In this case, the RF switch 210 is switched to the third switch terminal 225, so that the signal received from the antenna 205 passes through the third switch terminal 225 to pass only signals in the GSM band. Only the GSM signal is filtered through the third band pass filter 275 and then output through the GSM receiver 285.

In addition, if the DCS receiver 290 and the PCS receiver 295 is to receive the DCS signal and PCS signal, the control voltage Vc1 is set to the high state and Vc2 is set to the low state, in this case the RF switch 210 The switch is switched to the second switch terminal 220, and the signal received from the antenna 205 passes through the second switch terminal 220 and is then input to the matching circuit 260.

The matching circuit 260 is configured such that the impedance of the transmission line on the side of the second band pass filter 270 is almost opened when the signal input to the matching circuit 260 is a DCS signal. When the signal input to the signal 260 is a PCS signal, the impedance of the transmission line on the side of the first band pass filter 265 is almost opened.

Accordingly, signals other than the PCS signal among the signals input to the matching circuit 260 are branched from the matching circuit 260 to the first band pass filter 265, and the divided signals are first band pass filter. After filtering by the DCS signal only through 265 is output through the DCS receiving end 290.

In the same manner, signals other than the DCS signal among the signals input to the matching circuit 260 are branched from the matching circuit 260 to the second band pass filter 270, and the divided signals are divided into the second band. The filter is filtered by the PCS signal only through the pass filter 270 and then output through the PCS receiver 295.

In addition, if the DCS / PCS signal and / or the GSM signal are to be transmitted, both the control voltages Vc1 and Vc2 are set to a high state, in which case the RF switch 210 is switched to the first switch terminal 215. .

At this time, the DCS / PCS transmission signal passing through the first transmitter 235 and the first low pass filter 240 and / or the GSM transmission passed through the second transmitter 245 and the second low pass filter 250. The signal is applied to the first switch terminal 215 via the diplexer 255 and output through the antenna 205.

In addition, if the UMTS signal is to be transmitted and received, the control voltage Vc1 is set to the low state, Vc2 is set to the high state, in this case, the RF switch 210 is switched to the fourth switch terminal 230, the antenna 205 The signal received from) is applied to the UMTS terminal through the fourth switch terminal 230. At this time, the UMTS terminal transmits and receives a UMTS signal and a UMTS block (not shown) installed outside the front end module.

The quad band front end module according to the present embodiment can accommodate all four bands through the above-described operation.

In particular, the quad-band front end module according to the present embodiment, by using the IC type SP4T Si switch or SP4T GaAs switch as the RF switch 210, a next generation mobile communication system such as a UMTS mobile communication system requiring high linearity Also has applicable features.

< Second embodiment >

3 is a block diagram showing a quad band front end module as a second embodiment of the present invention.

As shown in Fig. 3, the configuration of the quad band front end module according to the present embodiment includes the diode 305 and the diode 305 provided between the first low pass filter 240 and the diplexer 255. Except for the control voltage Vc3 which controls the operation, it is the same as the first embodiment described above.

However, the diode 305 according to the type of the signal passing through the first low pass filter 240 and the second low pass filter 250 (for example, the frequency passing through the second low pass filter is For example, a DCS / PCS signal) may be provided between the second low pass filter 240 and the diplexer 255.

Hereinafter, an operation process of the quad band front end module according to the present embodiment will be described in detail with reference to Table 2 below.

A plurality of signals received through the antenna 205 is routed according to control voltages Vc1 and Vc2 corresponding to the bands to be received. Here, Vdd is a switch driving voltage for driving the switch, Vc3 is a control voltage for controlling the operation of the diode 305.

Table 2 below is a preferred embodiment of the control voltage.

TABLE 2

Vc1 Vc2 Vc3 Vdd GSM Receiver (Rx) Low Low Low on DCS / PCS Receiver High Low Low on GSM Transmitter (Tx) High High Low on DCS / PCS Transmitter High High High on UMTS OUT Low High Low on

Referring to Table 2, the operation of the quad-band front-end module according to the present embodiment will be described first. If the GSM signal is to be transmitted first, the control voltages Vc1 and Vc2 are set to a high state and Vc3 is set to a low state. In this case, the RF switch 210 is switched to the first switch terminal 215, and the diode 305 is turned off to open the line.

At this time, even if there is a DCS / PCS transmission signal passing through the first transmitter 235 and the first low pass filter 240, the DCS / PCS transmission signal is blocked in the line opened by the diode in the OFF state. This prevents input to the diplexer 255.

Meanwhile, the GSM signal passing through the second transmitter 245 and the second low pass filter 250 is applied to the first switch terminal 215 via the diplex 255 and output through the antenna 205. .

If the diode 305 is not present, the signal may be defective by causing interference between the DCS / PCS signals in the 1800 MHz to 1900 MHz band, which is the harmonic frequency 2f ₀ of the GSM signal f ₀ in the 900 MHz band. However, in the DCS advance so via the diode 305 blocks the DCS / PCS-side signal and the GSM signal (f ₀₎ and the harmonic frequency (2f ₀₎ of the GSM signal (f ₀₎ as in the embodiment The possibility of causing interference between the / PCS signals can be excluded in advance, thus reducing the defect of the signal.

On the other hand, if the DCS / PCS signal is to be transmitted, the control voltages Vc1, Vc2 and Vc3 are all set to a high state, in which case the RF switch 210 is switched to the first switch terminal 215, the diode ( 305 is turned ON, and the line is short-circuited.

At this time, the DCS / PCS transmission signal passing through the first transmitter 235 and the first low pass filter 240 is applied to the first switch terminal 215 via the diplexer 255 to the antenna ( 205).

Here, even if there is a GSM transmission signal passing through the second transmitter 245 and the second low pass filter 250, the GSM transmission signal does not significantly affect the DCS / PCS transmission signal. The reason is that the GSM transmission signal is not the harmonic frequency of the DCS / PCS transmission signal.

On the other hand, the other operation process is the same as the first embodiment described above.

The present invention is not limited to the above-described embodiments, but can be variously modified and changed by those skilled in the art, which should be regarded as included in the spirit and scope of the present invention as defined in the appended claims. something to do.

As described in detail above, the quad band front end module according to the present invention can provide a front end module that can accommodate up to four bands as a simple circuit configuration.

In addition, by using an IC type SP4T switch having excellent linearity as an RF switch, there is an advantage that it can be applied to a system requiring high linearity such as UMTS.

When a plurality of transmission signals are sent through one diplexer, a diode switch is provided between the diplexer and the low pass filter, thereby preventing interference of signals due to harmonic frequency relationships between the plurality of transmission signals. To prevent it.

Claims (7)

An RF switch branching a signal transmitted and received through an antenna according to a control voltage and including first to fourth switch terminals; A diplexer connected to a first switch terminal of the RF switch and sharing a signal input from a first transmitting end and a signal input from a second transmitting end in one path; A matching circuit for splitting a plurality of signals input by one path from the second switch terminal of the RF switch according to the characteristics of the filter; A first band pass filter (BPF) for passing only signals of a predetermined band among the signals input by being divided by the matching circuit; A second band pass filter (BPF) which passes only signals of a predetermined band among the signals input by being divided by the matching circuit; A third band pass filter (BPF) for passing only signals of a predetermined band among signals input from the third switch terminal of the RF switch; And Quad band front end module comprising an input and output terminal for inputting and outputting a signal connected to the fourth switch terminal of the RF switch. The method of claim 1, The signal input from the first transmitter is a DCS / PCS signal, the signal input from the second transmitter is a GSM signal, the signal passing through the first band pass filter is a DCS signal, and the second band pass filter Wherein the signal passed is a PCS signal and the signal passed through the third bandpass filter is a GSM signal. The method of claim 1, The input / output terminal is a quad band front end module, characterized in that the UMTS terminal for transmitting and receiving the UMTS signal. The method of claim 1, The RF switch is a quad-band front end module, characterized in that the SP4T Si switch or SP4T GaAs switch. The method of claim 1, And a first low pass filter (LPF) connected between the first transmitter and the diplexer and configured to pass a signal of a predetermined band input from the first transmitter. The method of claim 1, A quad band front end module connected between the second transmitter and the diplexer and further including a second low pass filter (LPF) through which a signal of a predetermined band input from the second transmitter is passed. . The method according to claim 1 or 2, And a diode connected between the first transmitter or the second transmitter and the diplexer, the diode being ON / OFF according to a control voltage.

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