KR20070110957A - Front end module - Google Patents

Abstract

A front end module is provided to embed an antenna therein, thereby reducing signal loss caused by line distance without separately manufacturing an antenna or cost problems. Plural antenna patterns are formed on a substrate to transceive multi-band signals. An RF(Radio Frequency) switch unit and transmission/reception filters(150,160) are disposed on the substrate. The RF switch unit consists of the first RF switch(141) for distinguishing transmission and reception paths of the multi-band signals, the second RF switch(142) for switching transmission signals of a transmission end to the first RF switch(141), respectively, and the third RF switch(143) for switching reception signals of the first RF switch(141) to a reception end.

Description

Front End Module {Front End Module}

1 is a block diagram showing a conventional front end module.

2 is a block diagram showing a front end module according to an embodiment of the present invention.

3 is a cross-sectional view of a front end module substrate according to an exemplary embodiment of the present invention.

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

100: front end module 110: antenna

111: antenna pattern 120: matching unit

130: ESD protection unit 140: RF switch unit

141 to 143: RF switch 145: decoder

150: transmission filter 151,152: LPF

160: Receive filter 161 to 664: SAW filter

170: substrate

The present invention relates to a front end module of a mobile communication terminal.

BACKGROUND With the recent development of mobile communication systems, mobile communication terminals such as mobile phones and portable information terminals are rapidly spreading, and a system for transmitting and receiving signals in the 800 MHz to 1 GHz and 1.5 GHz to 2.0 GHz bands also used in mobile communication systems. Are being provided.

As mobile communication terminals are developed in a trend of high performance and miniaturization, components embedded in the terminals are also being developed due to integration, miniaturization, and light weight.

In addition, a method for communicating with other methods using a mobile communication terminal has been developed. That is, a multi band front-end module (FEM) in which a single antenna is used to cover multiple bands or a component that integrates a component capable of transmitting and receiving signals of multiple frequency bands into one module Front End Module is being developed.

1 is a block diagram of a conventional dual band front end module.

Referring to FIG. 1, the front end module 20 is connected to an antenna 10, an electro static discharge (ESD) protection unit 21, an RF switch unit 22, and a low pass filter for receiving a multi-band signal. (LPF: Low Pass Filter) 23, 24, and SAW (Surface Acoustic Wave) filters 25, 26 for multi-band signal transmission.

The ESD protection unit 21 protects the RF switch unit 22 from the electrostatic discharge phenomenon input from the antenna 10 input terminal.

The RF switch unit 22 selects only one path of a frequency band such as a digital cellular system (DCS) or a personal communication service (PCS), and transmits / receives an RF signal transmitted / received through the selected path to the antenna 10 or Switch to stage (Tx / Rx).

A first low pass filter (LPF) 23 is connected to a PCS transmitter (PCS Tx), and a second low pass filter 24 is connected to a DCS transmitter (DCS Tx) for the multi-band signal transmission. Connected.

A first surface acoustic wave (SAW) filter 25 is connected to a DCS receiver DCS Rx, and the second SAW filter 26 is connected to a PCS receiver PCS Rx to receive the multi-band signal.

Since the front end module 20 and the antenna 10 are manufactured as separate products, respectively, and electrically coupled within the terminal, there is a problem in that the manufacturing process and the cost are high.

In addition, since the antenna and the front end module are mounted in separate spaces, the line length from the antenna to the front end module is increased, so signal loss due to a line may occur, and there is a difficulty in implementing antenna characteristics.

The present invention provides a front end module.

The present invention provides an antenna built-in front end module.

The front end module according to the present invention includes an RF switch unit and a transmit / receive filter mounted on the substrate.

And a third RF switch configured to switch a received signal of a first RF switch to a receiver, a second RF switch to switch a transmission signal of a first RF switch transmitter to the first RF switch for distinguishing a transmission or reception path of a multi-band signal. It includes a switch.

Hereinafter, with reference to the accompanying drawings as follows.

2 is a block diagram illustrating a front end module according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the front end module 100 is a module for transmitting / receiving signals of two or more frequency bands, and may be implemented as a dual band, a three band, a quad band, and more. That is, among the DCS (Digital Cellular System) method and the PCS (Personal Communication Service) method using the high frequency band, the Global Systems for Mobile communication (GSM) method and the Extended Global Systems for Mobile communication (EGSM) method using the low frequency band It is implemented to transmit / receive signals of two or more frequency bands.

The front end module 100 includes an antenna 110, a matching unit 120, an ESD protection unit 130, an RF switch unit 140, a decoder unit 145, a transmission filter 150, and a reception filter 160. It includes.

The signal received from the antenna 110 is impedance-matched by the matching unit 120 and output. The matching unit 120 is implemented as an element such as an inductor or a capacitor.

The ESD protection unit 130 protects the circuits, devices, etc. inside the module from being damaged by the signal input from the antenna input terminal.

The RF switch unit 140 is switched to select a transmission / reception path of a multi-band signal, and may be implemented as a GaAs switch. The RF switch unit 140 may be composed of one RF switch (SP4T, SP6T), or may be composed of a plurality of RF switches (SP2T, SP4T, etc.).

The RF switch unit 140 of the present invention includes the first to third RF switch (141, 142, 143), the first RF switch 141 is a switching output signal received from the antenna 110 to the third RF switch 143 In addition, the transmission signal input to the second switch (142, 143) is switched to the antenna.

The second RF switch 142 is switched to select a path of a transmission signal input from a specific transmission terminal Tx of a multi band, and the path selected signal is transmitted through the first RF switch 141.

In addition, the third RF switch 143 switches the signal input from the first RF switch 141 to output the specific reception path Rx of the multi-band.

In the present invention, the RF switch unit 140 switches to one of the transmission or reception paths using the first RF switch 141, and uses the second RF switch 142 to switch the path of the transmission signal and the third RF switch. Using 143, the path of the received signal is switched.

The switching operation of the first to third switches 141 to 143 of the RF switch unit 140 is controlled by the decoder unit 145. The decoder 145 controls the switching operation of the multi-band transmission / reception path using the switch driving voltage Vcc and the control signals V1, V2, and V3.

Transmitting and receiving filters 150 and 160 are coupled to the rear end of the RF switch unit 140. The transmission filter 150 is coupled to the rear end of the second RF switch 142, and the reception filter 160 is coupled to the rear end of the third RF switch 143.

The transmission filter 150 includes a first LPF 151 and a second LPF 152 and removes high frequency noise from a signal input from a specific transmitter Tx. The first LPF 151 filters the signal of the GSM / EGSM transmitter Tx, and the second LPF 152 filters the signal of the DCS / PCS transmitter Tx.

The reception filter 160 includes first to fourth saw filters 161, 162, 163, and 164 and passes only a band necessary for a signal received from the third RF switch 143. The first saw filter 161 filters the received signal of the GSM receiver Rx, the second saw filter 162 filters the received signal of the EGSM receiver Rx, and the third saw filter 163 of the DCS The received signal of the receiver Rx is filtered, and the fourth saw filter 164 filters the received signal of the PCS receiver.

 The front end module 100 according to the present invention is implemented on a substrate. 3 is a cross-sectional view illustrating an example in which a front end module is mounted on a substrate (or an FEM substrate) according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the FEM substrate 170 is a low temperature co-fired ceramic (LTCC) substrate and has a multilayer structure. Here, the LTCC substrate may use a conductive metal having excellent conductivity such as gold or silver and firing in an oxidizing atmosphere, and may implement various passive devices such as resistors, capacitors, and inductors.

An antenna pattern 111 of a conductive material is formed on the dielectric region of the substrate top layer 175, and the antenna pattern 111 is formed of a material having a high dielectric constant (eg, ceramic) on the surface of the substrate top layer 175. A plurality of them are formed in a pattern of a predetermined shape by using the same. A plurality of antenna patterns 111 may be spaced apart at predetermined intervals, bent one or more times, and all may have the same shape.

The antenna 110 transmits and receives through interference or direct inflow of signals due to coupling between the antenna patterns 111. In addition, the center frequency can be determined by the coupling between the antenna patterns, and the characteristics for covering the signal of the multi band can be set by the height (or thickness) of the antenna pattern.

In addition, a plurality of saw filters 161 to 164 which are reception filters 160 are mounted in the other region of the top layer 175 of the substrate 170. A transmission filter 150 including a matching unit 120, an ESD protection unit 130, a decoder unit 145, and a plurality of LPFs 151 and 152 is mounted in an inner region of the substrate 170. Herein, the above-described elements configured on the substrate surface or the inner region are electrically connected, and the arrangement may be made in consideration of the electrical signal characteristics.

In addition, RF switches 141, 142, and 143 of the RF switch unit 140 are installed on the substrate bottom layer. The RF switch 140 is mounted in the etched region 148 under the substrate by a multi-function process, and each RF switch 141, 142, 143 is bonded to the electrode lead 145 as a GaAs switch chip, respectively (eg, a wire). Bonding).

The substrate 170 has a circuit pattern for electrically connecting the components of the front end module in each layer, and a via hole 171, etc. for electrically connecting the other layers.

In addition, the components of the front end module including the chip antenna are distributed and mounted on the inner layer and the outer layer of the substrate by using the multilayer structure of the substrate, thereby solving the interference problem between the components. In addition, by forming a pattern of the chip antenna on the top layer and configuring other components therein, it is possible to solve the interference problem caused by the chip antenna pattern.

When the antenna built-in front end module is applied to a mobile communication terminal, the size of the terminal can be reduced.

The present invention has been described above with reference to preferred embodiments thereof, which are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications are not possible that are not illustrated above. For example, each component shown in detail in the embodiment of the present invention may be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

According to the front end module according to the present invention, by embedding the antenna in the front end module, it is possible to reduce the signal loss according to the line distance.

In addition, by incorporating the antenna into the front end module, it is possible to solve the process or cost problems that must be manufactured separately.

In addition, by applying an antenna with a front end module to a terminal, it is possible to reduce the space occupied by wireless communication components.

Claims (7)

Multiple antenna patterns formed on the substrate for multiband signal transmission and reception And an RF switch unit and a transmit / receive filter mounted on the substrate. The method of claim 1, The RF switch unit is a third RF switch for switching the reception signal of the first RF switch to the receiving end of the second RF switch for switching the transmission signal of the first RF switch transmitting end for the transmission or reception path of the multi-band signal to the first RF switch, respectively Front end module including a. The method of claim 1, The substrate includes a matching part for impedance matching of an antenna input terminal and an electrostatic discharge (ESD) protection part for protecting an internal circuit from electrostatic discharge. The method of claim 1, The reception filter is a front-end module, characterized in that it comprises a multi-band SAW filter. The method of claim 1, And the transmission filter is a low pass filter for each frequency band. The method of claim 1, The substrate is a front end module, characterized in that the multi-layer substrate made of Low Temperature Co-fired Ceramic (LTCC). The method of claim 1, And the antenna pattern and the RF switch unit are formed on the substrate top layer and the bottom layer, respectively.

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