KR20040016105A - Module for high frequency switch - Google Patents

Abstract

PURPOSE: A high frequency switch module is provided to divide the signal having two frequency bandwidths by applying a low temperature cofired ceramics(LTCC), thereby reducing the number of elements in a high frequency switching. CONSTITUTION: A high frequency switch module includes a high frequency switch(401), a first surface acoustic waves(SAW) filter(404), a second SAW filter(405), a pair of phase converters(406a,406b), a first low pass filter(LPF)(402) and a second LPF(403). The high frequency switch(401) is connected to the antenna and provided with a first signal transmitter and a second signal receiver and a first signal receiver and a second signal transmitter. The first SAW filter(404) passes the first signal received by the high frequency switch(401) and the second SAW filter(405) passes the second signal received from the high frequency switch. The pair of phase converters(406a,406b) are provided on the front ends of the first SAW filter(404) and the second SAW filter(405) to convert the phases of the input signals. The first low pass filter(LPF)(402) passes the transmission signal by the first signal transmitter and the second LPF(403) passes the transmission signal by the second signal transmitter.

Description

High Frequency Switch Module {MODULE FOR HIGH FREQUENCY SWITCH}

The present invention relates to a high frequency switch module, and in particular, by applying low temperature cofired ceramics (LTCC) in high frequency switching to separate and transmit two frequency band signals, reducing the number of parts to improve the yield The present invention relates to a high frequency switch module using LTCC.

In recent years, with the development of mobile communication systems, mobile communication devices such as mobile phones and portable information terminals are rapidly spreading, and the frequencies used for communication of these mobile communication systems are also 800 MHz to 1 GHz band and 1.5 GHz to 2.0 GHz band. There is provided a system for transmitting and receiving signals of different frequency bands in various fields.

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 related to the directization of passive components constituting them. Interest and research is active.

In the past, active devices are mostly integrated into high density integrated circuits based on silicon technology, and are implemented with only a few chip components, whereas passive devices (resistors, capacitors, inductors, etc.) are almost integrated. The individual elements were attached to the circuit board by soldering, for example.

Therefore, there is an increasing demand for a technology for integrating passive devices to miniaturize electronic devices, improve performance and reliability of these passive devices, and to solve such problems, low temperature cofired ceramics: Directization technology using LTCC is currently being actively researched.

1 is a view schematically showing a direct package of a passive device using a general low temperature synchronous ceramic. As shown in the drawing, low temperature co-fired ceramics (LTCC) are a thick dielectric film (thickness of several tens to hundreds of micrometers) and various circuit elements manufactured by tape casting. As a technique of manufacturing a multi-layer stacked device using a conductive metal paste, various passive devices may be included in such a stacked device, and active devices may be mounted together.

2 is a flowchart illustrating a general LTCC process. As shown in the drawing, first, a low-temperature sintered dielectric thick film having a constant thickness and width supplied in a form wound on a roll is cut, and then sliced to a predetermined size. do. It cuts slightly larger than the blank size using a razor blade to prepare as many sheets as the total number of laminated sheets.

Then, the step of heat-treating the dielectric thick film prepared in the form of a sheet for 20 to 30 minutes in the air at a temperature of 120 ℃. Here, or the sheet may be kept in a dry nitrogen atmosphere for about one day.

A blanking process is performed on the dielectric film that has undergone the pretreatment process to form an orientation mark and a mark indicating a work zone by using a blank die.

Next, a punching or laser is used to form appropriately sized via holes in the sheet. Here, the vias are for electrical connection between the layers, and thermal vias facilitate heat diffusion, tool holes, and patterns for aligning each layer to the correct position in the lamination step. It is used as a register hole for setting a reference point.

Subsequently, filling each via hole formed in the sheet with a conductive paste is performed. Here, a thick film screen printer or an extruded via filter is used, and the paste is filled in the exact position of the via hole using a stencil made of brass or stainless steel sheet. At this time, the conductive paste used should have a good shrinkage ratio after firing with the sheet.

Then, a thick film screen printing machine and circuit elements and patterns of various shapes are formed by a conductor pattern printing method using a conductor paste. The screen used at this time is a thick film screen of a standard emulsion type, and as in the beer filter stage, a vacuum is held between the porous bodies to hold the sheet.

Here, the sheet is controlled and aligned using visual alignment or mechanical registers. The conductive paste used for printing the pattern should have a shrinkage ratio in the X and Y directions with the dielectric thick film after firing.

Subsequently, the conductive paste filling the via hole and the paste having the conductor pattern formed thereon are dried at a temperature of about 120 ° C. for 5 minutes in a box oven.

The via and patterned sheets are then inspected on an illumination desk using an enlarged microscope.

Subsequently, registration is performed using a precise lamination frame. Here, the dielectric thick film sheets separated from the frame holding the respective sheets are stacked one by one in the correct positions in order.

Then, a lamination step of bonding the laminated sheets to each other using heat and pressure is performed. In this case, a uniaxial press or an isostatic press is used. When the uniaxial pressure is used, it is pressurized for about 5 minutes using a plate heated to about 70 ° C., and rotated by 180 ° again in the same manner. Pressurized to ensure a uniform pressure delivery throughout. On the other hand, when using hydrostatic pressure, the laminated sheets are put in a plastic bag and vacuum-packed, and hydrostatic pressure is applied using heated water.

Here, the pressurization time and temperature is the same as the uniaxial pressure, but the process of pressurizing by rotating 180 ° again after 5 minutes of pressurization is not necessary.

After the lamination is finished, it is put on a flat setter tile and fired in a furnace. If it is maintained for about 1 hour or more in the temperature range of about 200 to 500 ° C., it is possible to burn off organic materials such as the provider included in the dielectric thick film film and paste, and then it is continuously heated to be baked in the temperature range of 850 to 900 ° C. .

After the firing process is completed, a thick film resistor, a dielectric, a conductor, or the like is formed or other special ceramic process is performed.

Subsequently, after the firing and the post-firing process is completed, whether or not an electrical short is performed for all products. After cutting using various methods, the cut parts are finally inspected.

In other words, the LTCC technology of the above process is excellent in conductivity, such as gold or silver, and because of the advantage of using a conductive metal that can be fired in an oxidizing atmosphere, by implementing a variety of passive devices such as resistors, capacitors, inductors, the mobile communication Applies to the front-end module of the device.

3 is a view schematically showing a configuration of a high frequency switching module according to the related art. As shown here, a digital cellular system (DCS) connected to an antenna using a 1.8 GHz band and a digital cellular system using a 1.8 GHz band and a transmitter Tx of a global mobile communication system (GSM) using a 900 MHz: A high frequency switch 301 for switching between a DCS) and a receiver Rx of a global mobile communication system (GSM) using 900 MHz; A first diplexer (302) for separating the signal received by the high frequency switch (301) into signals of DCS and GSM; A first SAW filter (304) for passing the DCS signal according to the band of the signal separated by the first diplexer (302); A second SAW filter 305 for passing the GSM signal by the band of the signal separated by the first diplexer 303; A first LPF 306 for passing the DCS transmission signal by the transmission unit Tx and a second LPF 307 for passing the transmission signal of GSM; And a second diplexer 303 for separating the transmission signal passing through the first LPF 306 and the second LPF 307.

Here, phase shifters 308a and 308b are provided between the first SAW filter 304 and the second SAW filter 305 and the first diplexer 302 so that signals of different frequency bands are not received. do.

Therefore, the high frequency switching module configured as described above has a somewhat large number of parts used, and the operation mode is also complicated, which affects the miniaturization of the parts.

The present invention has been made to improve the above problems, by applying Low Temperature Cofired Ceramics (LTCC) in the high-frequency switching to separate and transmit two frequency band signals, reducing the number of parts The purpose is to provide a high-frequency switch module using LTCC that can improve the yield.

1 is a schematic view showing a direct package of a passive device using a common low temperature synchronous ceramic.

2 is a flowchart illustrating a process of a general LTCC.

3 is a view schematically showing the configuration of a high frequency switching module according to the prior art.

4 is a view schematically showing the configuration of a high frequency switch module according to the present invention.

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

301, 401 --- high frequency switch 302 --- first diplexer

303 --- 2nd diplexer 304, 404 --- 1st SAW filter

305, 405 --- Second SAW Filter 306, 402 --- First LPF

307, 403 --- 2nd LPF 308a, 308b, 406a, 406b --- phase shifter

High frequency switch module according to the present invention to achieve the above object,

A high frequency switch connected to the antenna to switch between a first signal transmitter and a second signal receiver, and a first signal receiver and a second signal transmitter;

A first SAW filter for passing a first signal received by the high frequency switch;

A second SAW filter for passing a second signal received by the high frequency switch;

A phase converter provided in front of the first SAW filter and the second SAW filter to convert a phase of an input signal;

A first LPF for passing the transmission signal by the first signal transmitter;

It is characterized in that it comprises a second LPF for passing the transmission signal by the second signal transmitter.

Particularly, the first signal transmitter and the second signal receiver are arranged in parallel, and the first signal receiver and the second signal transmitter are arranged in parallel so as to be switched by the high frequency switch.

According to the present invention, by applying Low Temperature Cofired Ceramics (LTCC) in the high-frequency switching to separate and transmit two frequency band signals, it is possible to further improve the yield by reducing the number of parts.

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

4 is a view schematically showing the configuration of a high frequency switch module according to the present invention. As shown therein, the antenna is connected to the switching unit between the receiver Rx of the DCS (: first signal) transmitter Tx and the GSM (: second signal) and the DCS receiver Rx and the transmitter Tx of the GSM. A high frequency switch 401; A first SAW filter (404) for passing the DCS signal received by the high frequency switch (401); A second SAW filter (405) for passing the GSM signal received by the high frequency switch (401); A first LPF 402 for passing the transmission signal by the DCS transmitter; And a second LPF 403 for passing the transmission signal by the GSM transmitter Tx.

Further, phase shifters 406a and 406b are further provided in front of the first SAW filter 404 and the second SAW filter 405.

Here, the high-frequency module configured as described above is provided with a front-end by the LTCC, the loss of the characteristic value of each component due to the integration of the respective passive elements, the reliability of each component is increased.

First, the operation of the digital cellular system (DCS) using the 1.8 GHz band will be described. When transmitting, the high frequency switch 401 switches ON to the transmitter Tx in order to transmit a transmission signal transmitted from the transmitter Tx and passed through the first LPF 402 to the outside. Transmit to the outside through an antenna.

The DCS transmitter Tx and GSM receiver Rx are arranged in parallel, and the DCS receiver Rx and GSM transmitter Tx are arranged in parallel.

Upon reception, the received signal received by the antenna is switched ON by the high frequency switch on the DCS receiver Rx side and passes through the first SAW filter 404 via the phase shifter.

Here, the phase shifters 406a and 406b are defined by a lumped constant element obtained by combining an inductor and a capacitor. When the DCS is received, the input impedance of the first SAW filter 404 is opened in the frequency band of the DCS. The inductor and capacitor values are infinite (∞).

On the other hand, the first SAW filter 404 attenuates harmonics of the received signal by passing the received signal of the DCS.

In particular, SAW filters are commonly used as band pass filters in communication devices and other electronic devices, and horizontal SAW filters having two interdigital transducers (IDTs) arranged at a predetermined distance on a piezoelectric substrate. There is a filter and a SAW resonator filter constituting a resonator on a piezoelectric substrate.

As the SAW resonator filter, a sectional reflection type SAW resonator filter using a shear horizontal surface acoustic wave such as a love wave, a Bleustein-Gulyaev-Shimuzu (BGS) wave, and other similar waves is known.

Recently, a duplexer is manufactured and used as a chip so as to be used to filter and transmit only a predetermined band frequency of a signal when transmitting and receiving a signal in a communication device.

On the other hand, in the case of a global mobile communication system (GSM) using 900 MHz, the high frequency switch (HSM) may be used to transmit a transmission signal transmitted from the transmission unit Tx and passed through the second LPF 402 to the outside during transmission. The 401 transmits to the outside through an antenna when switching to the transmitting unit (Tx) ON.

Upon reception, the received signal received by the antenna is switched ON by the high frequency switch 401 to the GSM receiver Rx side to pass the second SAW filter 405 via the phase shifters 406a and 406b. Will pass through. Here, the second SAW filter 405 attenuates harmonics of the received signal by passing the received signal of GSM.

Here, the phase converters 406a and 406b are defined by a lumped constant element obtained by combining an inductor and a capacitor. In the GSM reception, the inductor and the inductor and the inductor are connected so that the input impedance of the second SAW filter is open to the GSM frequency band. The capacitor value is 50 mW.

Therefore, the high frequency switching module configured as described above can transmit / receive dual bands without a diplexer, can be miniaturized due to the reduction of parts, and the yield is improved.

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.

As described above, the high frequency switch module device using the LTCC according to the present invention, by applying a low temperature cofired ceramics (LTCC) in the high frequency switching to separate and transmit two frequency band signals, more components The yield can be improved by reducing the number.

Claims (3)

A high frequency switch connected to the antenna to switch between a first signal transmitter and a second signal receiver, and a first signal receiver and a second signal transmitter; A first SAW filter for passing a first signal received by the high frequency switch; A second SAW filter for passing a second signal received by the high frequency switch; A phase converter provided in front of the first SAW filter and the second SAW filter to convert a phase of an input signal; A first LPF for passing the transmission signal by the first signal transmitter; And a second LPF for passing the transmission signal by the second signal transmitter. The method of claim 1, And the first signal transmitter and the second signal receiver are arranged in parallel, and the first signal receiver and the second signal transmitter are arranged in parallel so as to be switched by the high frequency switch. The method according to claim 1 or 2, The high frequency switch module is a high frequency switch module, characterized in that using the LTCC.