KR20050053829A - Dual band front end module - Google Patents

Abstract

The present invention is a dual band front end module consisting of a low pass filter, a diplexer, a phase shifter, a saw filter, comprising a capacitor and a plurality of inductors connected in parallel and configured with a matching part that is matched when a power is applied. The insertion loss and harmonic characteristics can be improved by reducing the

Description

Dual Band Front End Module

The present invention relates to a dual band front end module that eliminates the extra inductance inevitably generated by adding a plurality of inductors connected in parallel to the matching portion of the power stage.

With the recent development of mobile communication systems, mobile communication devices such as mobile phones and portable information terminals are rapidly spreading, and the frequencies used in these mobile communication systems are also different from each other in various directions such as 800 MHz-1 GHz and 1.5 GHz-2.0 GHz. A system for transmitting and receiving a signal of a band is provided.

Therefore, from the demand for miniaturization and high performance of these devices, miniaturization and high performance of components used in them are required, and efforts for miniaturization and cost reduction of portable electronic devices are inevitably concerned with the integration of passive elements constituting them. And research is active.

Conventionally, active devices are mostly integrated into high density integrated circuits based on silicon technology, and are implemented as only a few chip components. However, passive devices (resistance, capacitors, inductors, etc.) are hardly integrated. Individual elements were attached to the circuit board by soldering or the like.

Therefore, there is an increasing demand for an integrated technology of passive devices for miniaturizing electronic devices, improving performance and reliability of these passive devices, and an integrated technology using low temperature synchronous ceramics is currently actively being solved. Is being studied.

This LTCC technology is applied to the front-end module of mobile communication devices by implementing various passive devices such as resistors, capacitors, and inductors due to the advantage of using conductive metals that have excellent conductivity such as gold or silver and can be fired in an oxidizing atmosphere. do.

Hereinafter, the front end module will be described with reference to the accompanying drawings.

1 is a view schematically showing the configuration of a conventional front-end module, Figure 2 is a diagram showing a conventional matching unit embedded in the LTCC.

Referring to FIG. 1, the front end module includes a diplexer 100, a first LPF 110a, a second LPF 110b, a first phase shifter 120a, a second phase shifter 120b, and a first saw. The filter 140a, the second saw filter 140b, the diodes 150a, 150b, 150c, and 150d, the capacitors 160a and 160b, and the matching unit 170 are included.

The diplexer 100 is connected to an antenna to separate a first frequency band (GSM) signal and a second frequency band (DCS) signal.

The first LPF 110a removes the high frequency noise of the signal transmitted from the GSM transmitter, and the second LPF 110b removes the high frequency noise of the signal transmitted from the DCS transmitter. In this case, when the first LPF and the second LPF are pie type, the performance of the LPF is determined by a combination of a capacitor and an inductor connected in parallel with each other. The number of the combination of the capacitor and the inductor may be infinite.

The first phase shifter 120a converts a phase of a frequency such that a signal of a first transmission band (GSM) transmission band is not received together with the first reception band (GSM) reception signal received by the diplexer 100. Let's do it.

The second phase shifter 120b converts the phase of the frequency such that the second frequency band DCS signal is not received together with the second frequency band DCS signal received by the diplexer 100.

Here, the received signals of the GSM and DCS are separated by the diplexer 100, but do not affect the signals respectively received by the first phase converter 120a and the second phase converter 120b.

The first saw filter 140a passes only signals in a predetermined range of frequencies desired by the GSM receiver for the signal passing through the first phase converter 120a, and removes signals outside the range, and removes the second saw filter. 140b passes only signals of a frequency band desired in the DCS receiver for a signal passing through the second phase shifter 120b, and removes a signal outside this range.

The diodes 150a, 150b, 150c, and 150d include a first diode 150a, a second diode 150b, a third diode 150c, and a fourth diode 150d.

The first diode 150a and the second diode 150b change the transmission path and the reception path of the first frequency band (GSM) signal, and the third diode 150c and the fourth diode 150d. ) Changes the transmission path and the reception path of the second frequency band (DCS) signal.

That is, in the GSM transmission mode, a voltage is applied to the power supply terminal V1 (V2 is in an off state), and the first diode 150a and the second diode 150b are turned on. In the DCS transmission mode, a voltage is applied to the power supply V2. (V1 is in an off state) The third diode 150c and the fourth diode 150d are turned on.

 In the GSM reception mode, the power supply terminal V1 is turned off and the first diode 150a and the second diode 150b are turned off. In the DCS reception mode, the power supply V2 is turned off and reception is performed.

The capacitors 160a and 160b include a first capacitor 160a and a second capacitor 160b, and are DC blocking capacitors that prevent the DC signals of the power terminals V1 and V2 from flowing into the antenna.

The matching unit 170 is a capacitor 172 connected to ground and shunt as a device for matching when power is applied from V2 to the fourth diode.

Referring to FIG. 2, the capacitor 172 is embedded in the LTCC by patterning, and in order to connect from the embedded capacitor pattern 172 to the ground, an extra pattern 174 or a via must be inserted. It will have an inductor value.

However, the inductance inevitably generated in the matching part of the conventional front end module generates a band band ripple, which greatly reduces the insertion loss.

Accordingly, it is an object of the present invention to provide a front end module that eliminates extra inductors inevitably occurring in the matching unit, thereby improving insertion loss and reducing harmonic characteristics.

According to an aspect of the present invention to achieve the above object, in a dual band front end module consisting of a low pass filter, a diplexer, a phase converter, a saw filter, the power supply is composed of a capacitor and a plurality of inductors connected in parallel A dual band front end module is provided that includes a matching portion that is matched when applied.

The matching part is installed at the power supply terminal.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view schematically showing the configuration of the front-end module according to an embodiment of the present invention, Figure 4 is a view showing a built-in matching unit in the LTCC according to an embodiment of the present invention.

Referring to FIG. 3, the front end module includes a diplexer 300, a first LPF 310a, a second LPF 310b, a first phase shifter 320a, a second phase shifter 320b, and a first saw. The filter 340a, the second saw filter 340b, the diodes 350a, 350b, 350c, and 350d, the capacitors 360a and 360b, and the matching unit 370 are included.

The diplexer 300 is connected to an antenna to separate a first frequency band (GSM) signal and a second frequency band (DCS) signal.

The first LPF 310a removes the high frequency noise of the signal transmitted from the GSM transmitter, and the second LPF 310b removes the high frequency noise of the signal transmitted from the DCS transmitter. In this case, when the first LPF 310a and the second LPF 310b are pie type, the performance of the LPF is determined by a combination of a capacitor and an inductor connected in parallel with each other. It can be infinite.

The first phase shifter 320a converts a phase of a frequency such that a signal of a first frequency band GSM transmission band is not received together with a first frequency band GSM signal received by the diplexer 300. Let's do it.

The second phase converter 320b converts the phase of the frequency such that the second frequency band DCS signal is not received together with the second frequency band DCS signal received by the diplexer 300.

Here, the received signals of the GSM and DCS are separated by the diplexer 300, but do not affect the signals respectively received by the first phase converter 320a and the second phase converter 320b.

The first saw filter 340a passes only signals in a predetermined range of frequencies desired by the GSM receiver for the signal passing through the first phase converter 320a, and removes signals outside the range, and the second saw filter The signal 340b passes only signals of a predetermined frequency band desired by the DCS receiver for the signal passing through the second phase shifter 320b and removes signals outside the range.

The diodes 350a, 350b, 350c, and 350d include a first diode 350a, a second diode 350b, a third diode 350c, and a fourth diode 350d.

The first diode 350a and the second diode 350b change a transmission path and a reception path of the first frequency band (GSM) signal, and the third diode 350c and the fourth diode 350d. ) Changes the transmission path and the reception path of the second frequency band (DCS) signal.

That is, in the GSM transmission mode, a voltage is applied to the power supply terminal V1 (V2 is in an off state), and the first diode 350a and the second diode 350b are turned on. In the DCS transmission mode, a voltage is applied to the power supply V2. (V1 is in an off state) The third diode 350c and the fourth diode 350d are turned on.

 In the GSM reception mode, the power supply terminal V1 is turned off to turn off the first diode 350a and the second diode 350b. In the DCS reception mode, the power supply V2 is turned off to receive the reception signal.

The capacitors 360a and 360b include a first capacitor 360a and a second capacitor 360b, and are DC blocking capacitors that prevent DC signals from power terminals V1 and V2 from flowing into the antenna.

The matching unit 370 is an element that matches when the power is applied from the V2 to the fourth diode. The matching unit 370 includes inductors 374 and 376 added in parallel with the capacitor 372 connected to ground and shunt.

The inductors 374 and 376 are added in parallel to remove extra inductors that inevitably occur from the patterned capacitors. There may be a plurality of inductors 374 and 376 added in parallel.

Referring to FIG. 4, when the inductors 374 and 376 are connected in parallel, the impedance value is decreased, the ripple of the band band is eliminated, and the insertion loss is improved.

That is, impedance is composed of inductive reactance and capacitive reactance, and the dual inductor is related to inductive reactance. When the inductive reactance is connected in parallel, the impedance value is reduced. Therefore, when the inductors 374 and 376 are connected in parallel, the impedance value is reduced.

According to another exemplary embodiment of the present invention, the matching unit 370 may be configured to match when power is applied from V1 to the second diode to drive the GSM transmitter.

Hereinafter, the operation of the dual band front end module configured as described above will be described.

The dual band front end module operates by separating transmission and reception signals of a digital cellular system (DCS) using a 1.8 GHz band and a global mobile communication system (GSM) using a 900 MHz.

First, when the power of V1 is turned on and the power of V2 is turned off, the GSM is converted to a transmission mode, and the GSM signal transmitted by the transmitter passes only the low frequency signal through the first LPF 310a. The antenna 350 propagates to the outside through the antenna 350a.

When the power of V1 is off and the power of V2 is on, the DCS is converted to a transmission mode, and the DCS signal transmitted by the transmitter passes only the low frequency signal through the second LPF 310b and the third diode. It propagates to the outside through the antenna 350c.

In addition, when the powers of both V1 and V2 are off, both the GSM and DCS are converted to a reception mode, and the GSM and DCS signals received by the diplexer 300 are separated. In this case, when the GSM signal is received, the diplexer 300 separates and receives the signal into the GSM receiver.

However, in order to prevent the GSM transmission signal transmitted from the GSM transmitter is transmitted to the GSM receiver, the phase of the frequency is converted by the first phase converter 320a.

The first phase converter 320a serves to prevent the GSM transmission signal from being transmitted to the GSM receiver by bringing the impedance of the first saw filter 340a to the GSM transmission signal indefinitely.

On the other hand, when the DCS signal is received, the diplexer 300 separates and transmits the signal to the DCS receiver. The DCS signal received and transmitted by the diplexer 300 passes through the second saw filter 340b to attenuate a high frequency signal outside a predetermined frequency of the received signal.

5 is a diagram illustrating a pass characteristic of a DCS transmission band according to an embodiment of the present invention.

Referring to FIG. 5, it can be seen that the ripple of the band band disappears and insertion loss is greatly improved. It can also be seen that the harmonic properties are attenuated.

The present invention is not limited to the above embodiments, and many variations are possible by those skilled in the art within the spirit of the present invention.

As described above, according to the present invention, by adding a plurality of inductors in parallel to the matching portion of the dual band front end module, it is possible to provide a dual band front end module that can reduce the inductance and improve insertion loss and harmonic characteristics. .

1 is a view schematically showing the configuration of a conventional front-end module.

2 is a view showing a conventional matching unit embedded in the LTCC.

3 is a view schematically showing the configuration of a front-end module according to an embodiment of the present invention.

4 is a view showing a built-in matching unit in the LTCC according to an embodiment of the present invention.

5 is a diagram showing pass characteristics of a DCS transmission band according to an embodiment of the present invention.

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

100, 300: Diplexer 110, 310: LPF

120, 320: phase shifter 140, 340: saw filter

150, 350: diodes 160, 172, 360, 372: capacitors

174, 374, 376: inductor 170, 370: matching part

Claims (2)

A dual band front end module consisting of a low pass filter, a diplexer, a phase shifter and a saw filter, A dual band front end module comprising a capacitor and a plurality of inductors connected in parallel, the matching unit being matched when the power is applied. The method of claim 1, Dual-band front end module, characterized in that the matching unit is installed in the power stage.