KR20060096749A - Front end module - Google Patents

Abstract

The present invention relates to a front end module, in particular a capacitor located inside the gallium arsenide switch to minimize the second harmonic (Harmonic) components generated by the non-linear characteristics of the gallium arsenide (GaAs) switch, and the outside of the switch The present invention relates to a front end module for wire-bonding an inductor to minimize the second harmonic at the final antenna stage.

The front end module according to the present invention, the gallium arsenide switch for controlling the transmission and reception signals; At least one filter connected to the switch to control the received signal; At least one bandpass filter connected to the switch to remove noise of the transmission signal; Characterized in that it comprises a.

Front end module (FEM), gallium arsenide (GaAs) switch, secondary harmonic frequency, capacitors, inductors

Description

Front End Module

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

2a to 2c are views for explaining the resonance (resonance) of the front end module according to the present invention.

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

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

       300: gallium arsenide switch 302: the first saw filter

       304: second saw filter 306: third saw filter

       308: ESD circuit 310: wire bonding pad

       312: first low pass filter 314: second low pass filter

The present invention relates to a front end module (FEM).

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 different from each other in various ways such as 800 MHz to 1 GHz and 1.5 GHz to 2 GHz. A system for transmitting and receiving signals in a frequency band is provided.

Due to 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 the mobile communication device are inevitably miniaturized and various components constituting the communication device and There is a lot of interest in research and integration.

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

Referring to FIG. 1, the front end module includes a diplexer 100, a first low pass filter 102, a second low pass filter 104, a first phase converter 106, and a second phase converter 108. ), A first saw filter 110, a second saw filter 112, a diode 114, and a capacitor 116.

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 low pass filter 102 removes high frequency noise of a signal transmitted from the first frequency band (GSM) transmitting end, and the second low pass filter 104 transmits a second frequency band (DCS) transmitting end. Eliminate high frequency noise in the signal.

In this case, when the first low pass filter 102 and the second low pass filter 104 are pi type, the performance of the low pass filter LPF is determined by a combination of a capacitor and an inductor connected in parallel. However, there may be a plurality of methods of combining the capacitor and the inductor.

On the other hand, the first phase converter 106 is a phase of the frequency so as not to receive a signal of the first frequency band (GSM) transmission band with the first frequency band (GSM) reception signal received by the diplexer 100 To convert

In addition, the second phase shifter 108 converts the phase of the frequency such that the second frequency band (DCS) transmission signal received by the diplexer 100 is not received.

Here, the signals transmitted and received in the second frequency band and the first frequency band are separated by the diplexer 100, but are signals respectively received by the second phase shifter 108 and the first phase shifter 106. Does not affect.

In addition, the first saw filter 110 passes only signals of a predetermined range of frequency bands desired by the first frequency band (GSM) receiver for the signal passing through the first phase shifter 106. Remove it.

In addition, the second saw filter 112 passes only signals in a predetermined range of frequencies desired by the second frequency band (DCS) receiver for the signal passing through the second phase shifter 108 and removes signals outside the range. .

In addition, the diode 114 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4.

The first diode D1 and the second diode D2 change the transmission path and the reception path of the first frequency band signal, and the third diode D3 and the fourth diode D4 are the It serves to change the transmission path and the reception path of the second frequency band signal.

That is, the voltage is applied to the power supply terminal V1 in the first frequency band transmission mode (V2 is off), so that the first diode and the second diode are turned on, and the power is supplied in the second frequency band transmission mode. However, a voltage is applied to V2 (V1 is in an off state), and the third diode and the fourth diode are turned on.

In the first frequency band reception mode, the power supply terminal V1 is turned off, and the first diode and the second diode are turned off. In the second frequency band reception mode, the power supply terminal V2 is turned off to receive the signal. Is done.

In addition, the capacitor 116 includes a first capacitor and a second capacitor, and is a DC blocking capacitor that prevents the DC signals of the power terminals V1 and V2 from flowing into the antenna.

In the conventional front end module as described above, the gallium arsenide switch portion is composed of a plurality of PIN diodes. However, since the front end module is space-limited for miniaturization and multifunction, the front end module is no longer generated by using a PIN diode. There is a problem that the second harmonic component cannot be minimized.

According to an embodiment of the present invention, a capacitor located inside the gallium arsenide switch and a inductor outside the switch are wire-bonded to minimize a second harmonic component generated by the nonlinear characteristic of the gallium arsenide (GaAs) switch. It is to provide a front end module to minimize the second harmonic in the final antenna stage.

The front end module according to the present invention, the gallium arsenide switch for controlling the transmission and reception signals; At least one filter connected to the switch to control the received signal; At least one bandpass filter connected to the switch to remove noise of the transmission signal; Characterized in that it comprises a.

In addition, the gallium arsenide (GaAs) switch is characterized in that a capacitor is included.

In addition, the capacitor and the inductor connected to the capacitor is provided on the outside of the switch, it characterized in that the line length between the inductor is changed, it is adjusted to the inductance value that resonance occurs at the harmonic frequency.

In addition, the filter may be operated according to a first SAW filter operated according to a received signal of a first frequency band, a second saw filter operated according to a received signal of a second frequency band, and a received signal of a third frequency band. The band pass filter unit includes a first low pass filter for removing noise in a first frequency band and a second low pass filter for removing noise in a second or third frequency band. It features.

As the mobile terminal becomes smaller and more versatile, the front-end module must be smaller and more versatile, so a switch that uses a plurality of PIN diodes in a limited space can no longer be multifunctional.

Herein, the switch may be a switch using various materials for convenience. Hereinafter, a gallium arsenide (GaAs) switch will be described as an example.

The gallium arsenide (GaAs) switch is used for the multifunction, but the gallium arsenide (GaAs) switch has the same nonlinear characteristics as the PIN diode switch, so the second harmonic component and many It is accompanied by noise.

The harmonic refers to a frequency component that is twice or an integer multiple of the use frequency. Therefore, the harmonic is inevitably a noise component because it is a frequency component other than the use frequency. In general, a mobile terminal supports multiple bands such as 800 MHz and 1800 MHz. In particular, since a harmonic component of 800 MHz directly affects 1800 MHz, the second order of the 800 MHz band of the front end module is used. It is important to remove harmonics.

Conventional front end modules rely on the second harmonic rejection only for the low pass filter, but the present invention minimizes the second harmonic component generated in the gallium arsenide switch while maintaining the second harmonic rejection characteristic of the low pass filter. Finally, the second harmonic component is not output from the antenna end of the front end module.

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

2A to 2C are diagrams for describing resonance of the front end module according to the present invention. Numerical values in the drawings are merely examples for explaining resonance phenomena, and may be modified.

FIG. 2A is a graph showing decibels (dB) according to a frequency change of only an inductor connected to a capacitor located inside the gallium arsenide switch outside the gallium arsenide switch. Referring to FIG. 2A, it can be seen that the inductor has a characteristic of better passage as the frequency is lower.

Figure 2b is a graph showing the decibel (dB) according to the frequency change of only the capacitor located inside the gallium arsenide switch. Referring to FIG. 2B, it can be seen that the capacitor passes well at higher frequencies as opposed to the inductor.

2C is a diagram illustrating a case in which an inductor having the characteristics of FIG. 2A and a capacitor having the characteristics of FIG. 2B are connected in series according to the present invention.

Referring to FIG. 2C, the inductor prevents flow by creating and solving a magnetic field as the frequency increases, and the property of the capacitor combines the property of a capacitor to allow a good current to flow through a rapid electric field change as the frequency increases. It can be seen that the resonance phenomenon of passing only the frequency 200 at a specific point forming an equilibrium.

3 is a view showing the configuration of a front end module according to the present invention. Referring to FIG. 3, the front end module includes a gallium arsenide switch 300, a first SAW filter 302, a second saw filter 304, and a third saw filter 306. ), An electrostatic discharge (ESD) circuit 308, a wire bonding pad 310, a first low pass filter 312, and a second low pass filter 314.

The gallium arsenide switch 300 replaces the conventional PIN diode, the first or second frequency band (GSM, DCS, PCS) transmission signal by the given power combination connected to the antenna, the first or second frequency band (GSM, DCS, PCS) It separates the received signal.

The first saw filter 302 passes only signals in a predetermined range of frequencies desired by the GSM receiver for the signal passing through the GSM reception path of the gallium arsenide switch 300 and removes the signal out of this range.

In addition, the second saw filter 304 passes only signals in a frequency band of the desired predetermined range from the DCS receiving end of the gallium arsenide switch 300 and removes signals outside the range, and the third saw filter 306 uses the gallium The PCS receiving end of the arsenic switch 300 passes only signals in a desired frequency range and removes signals outside this range.

In addition, the ESD circuit 308 is a circuit connected to the antenna to protect the terminal from static electricity and strong noise that may be introduced from outside the mobile communication terminal, and is generally composed of a capacitor and an inductor.

In addition, the first low pass filter 312 removes the high frequency noise of the signal transmitted from the GSM transmitter, and the second low pass filter 314 removes the high frequency noise of the signal transmitted from the DCS or PCS transmitter. That is, the low pass filter determines the second harmonic component removal characteristic of the front end module.

In addition to the second harmonic component removal characteristic, in order to minimize the second harmonic component generated by the non-linear gallium arsenide switch 300, resonance is caused in the capacitor component inside the antenna output terminal connected to the gallium arsenide switch 300 and the outside. When wire bonding of a predetermined length may occur, resonance occurs with each other at the second harmonic frequency.

Then, the second harmonic component generated by the final gallium arsenide switch 300 can be minimized.

In other words, in order to minimize the second harmonic component, a capacitance component capable of adjusting the second harmonic component must be built in the gallium arsenide switch 300 and wire bonding can be connected in series with the gallium arsenide switch 300. A pad should be inside the gallium arsenide switch 300.

In addition, if the length of the wire bonding is adjusted so that the capacitance component and the wire bonded inductance component generate resonance at the second harmonic frequency of 800 MHz or 1800 MHz, a problem other than the second harmonic frequency cancellation characteristic of the front end module may occur. Second harmonic frequency generation characteristic is improved.

In conclusion, the front end module according to the present invention uses a non-linear gallium arsenide switch 300, and by connecting an inductor to a capacitor located inside the gallium arsenide switch 300 to ground, when resonating at the second harmonic frequency, Unnecessary harmonics are pulled out by the ground, thereby minimizing the second harmonic frequency generation characteristic and do not have to rely only on low pass filters.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible.

Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

According to an embodiment of the present invention, a capacitor located inside the gallium arsenide switch and a inductor outside the switch are wire-bonded to minimize a second harmonic component generated by the nonlinear characteristic of the gallium arsenide (GaAs) switch. The second harmonic component may be minimized at the final antenna stage.

Claims (4)

A gallium arsenide switch for controlling transmission and reception signals; At least one filter connected to the switch to control the received signal; At least one bandpass filter connected to the switch to remove noise of the transmission signal; Front end module comprising a. The method of claim 1, The front end module, characterized in that the gallium arsenide (GaAs) switch includes a capacitor. The method of claim 2, And a capacitor and an inductor connected to the capacitor are provided outside the switch, and the line length between the inductors is changed to adjust the inductance value at which resonance occurs at a harmonic frequency. The method of claim 1, The filter may include a first SAW filter operated according to a received signal of a first frequency band, a second saw filter operated according to a received signal of a second frequency band, and a second saw filter operated according to a received signal of a third frequency band. A third saw filter, wherein the bandpass filter unit includes a first lowpass filter for removing noise in a first frequency band and a second lowpass filter for removing noise in a second or third frequency band Front end module.

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