KR100918004B1 - Front End Module for WLAN and Method Thereof - Google Patents

Abstract

The present invention discloses a front end module for short-range wireless communication and an implementation method thereof. The present invention relates to a power amplifier for amplifying a predetermined multiple of a transmission signal, and an element interface unit which is a mounting space and a circuit of a switch providing a time division connection path of a transmission or reception signal; A matching circuit unit including an impedance matching circuit for improving the power amplifier characteristics; A low pass filter for removing harmonic components of the power amplifier; A band pass filter for extracting a signal of a desired frequency band from the received signal; A main interface portion for providing the band pass filter output, the power amplifier input, and a control signal interface of the components, wherein the device interface portion, the matching circuit portion, the low pass filter, and the band pass filter are provided in at least one layer. Its features are its implementation.

The present invention implements the RF front end block as a module to facilitate matching with the power amplifier and peripheral circuits, thereby reducing the size of the device, reducing the number of parts, and reducing development time.

Probe Station, Wireless LAN, FEM, Impedance Matching, Front End Module

Description

Front End Module for WLAN and Method Thereof

The present invention relates to a front end module for short-range wireless communication and an implementation method, and more particularly, to a front end module for short-range wireless communication and an implementation method capable of shortening an RF module development time by implementing an RF front end block as one module.

Local area network (LAN) is a communication method for data sharing or data transmission between terminals through coaxial cable in a small or medium-sized network. This is a communication method based on a wired communication network, and thus is limited in mobility. .

In order to overcome these limitations, a local area network (WLAN) technology has emerged, which eliminates line-to-wire connections such as coaxial cables and uses radio frequency (RF) as a communication medium. Local area wireless network is a technology that provides wireless high-speed Internet within a certain distance from where the access point (AP) is installed to ensure mobility. Hereinafter, the RF circuit of the short-range wireless communication apparatus according to the prior art will be described with reference to the accompanying drawings.

1 is a block diagram illustrating an RF block of a short-range wireless communication apparatus according to the prior art. As shown in FIG. 1, the RF block of the short range wireless communication device according to the related art includes an antenna 110, an RF front end block 120, and an RF integrated circuit (RF integrated circuit) 130. Include.

The antenna 110 is installed in a short range wireless communication device and transmits and receives data transmitted on an 2.4 GHz Industrial Scientific and Medical (ISM) frequency band.

The RF integrated circuit 130 is composed of an analog-to-digital converter, a digital-to-analog converter, an up converter, a down converter, a mixer, and the like.

In detail, the RF integrated circuit 130 converts the digital signal transmitted from the baseband stage into an analog signal, mixes it with an intermediate frequency, passes the RF front end block 120 to the RF front end block 120. The received signal is frequency shifted to an intermediate band, converted into a digital signal, and transmitted to the baseband circuit.

The RF front end block 120 includes a switch for providing an interface connected to a transmitting or receiving side in a time division manner, a power amplifier module (PAM) for amplifying a predetermined multiple of a transmission signal, and an input / output impedance for optimizing power amplifier characteristics. The RF integrated circuit 130 includes a matching circuit, a low pass filter (LPF) for filtering harmonic components of the power amplifier output, and a band pass filter (BPF) for extracting a desired band signal from a received signal. ) And a circuit existing between the antenna 110 are generic.

The power amplifier of the RF front end block 120 is very sensitive to printed circuit board (PCB) characteristics, patterns, circuit configurations, and device characteristics. Therefore, power amplifier related impedance matching is a time consuming task in RF circuit design and implementation.

In addition, since the power amplifier impedance matching element is very large, the area occupied by the entire RF front end block 120 is inevitably increased by using a general-purpose component. In particular, the inductor connected to the power stage is so large that it is almost impossible to embed it in the module. Nevertheless, the use of miniaturized and specialized devices for impedance matching raises the overall product cost and is therefore unproductive.

The present invention implements the RF front end block as a single module to facilitate matching with the power amplifier and peripheral circuits, thereby reducing the number of components, reducing the number of parts and development time short-range wireless front end module and implementation method The purpose is to provide.

In order to achieve the above object, the front end module for short-range wireless communication according to the present invention is a device interface unit which is a mounting space and a circuit of a power amplifier for amplifying a predetermined multiple of a transmission signal and a time division connection path of a transmission or reception signal. ; A matching circuit unit including an impedance matching circuit for improving the power amplifier characteristics; A low pass filter for removing harmonic components of the power amplifier; A band pass filter for extracting a signal of a desired frequency band from the received signal; A main interface portion for providing the band pass filter output, the power amplifier input, and a control signal interface of the components, wherein the device interface portion, the matching circuit portion, the low pass filter, and the band pass filter are provided in at least one layer. Its features are its implementation.

Here, the device interface unit exists in an independent layer, and the device interface unit includes a power amplifier mounting unit in which the power amplifier is mounted; And a switch mounting unit in which the switch is mounted.

In addition, the band pass filter exists in a lower layer of the switch mounting unit containing layer, the low pass filter is a lower layer of the power amplifier mounting unit containing layer, and exists in an upper layer of the matching circuit unit, and the power amplifier The mounting unit does not overlap other components with respect to the neighboring upper and lower layers, and is preferably spaced apart from other components by a predetermined interval within the same layer.

In this case, the device interface unit and the low pass filter; The low pass filter and the band pass filter and the matching circuit portion; And the band pass filter, the matching circuit unit, and the main interface unit are separated into ground layers, respectively.

According to another aspect of the invention, (a) designing a power amplifier impedance matching circuit; (b) measuring the measured impedance with a probe station; (c) designing an impedance matching equivalent circuit with reference to the measured impedance; (d) A method for implementing a front end module for short range wireless communication is provided, the method comprising manufacturing the front end module for short range wireless communication with reference to the designed equivalent circuit.

In this case, the matching circuit in step (a) is designed with a method including a data sheet and a trial and error method of the individual device, step (b) is to measure the impedance of the power amplifier output in the state that the power amplifier is not mounted Steps.

In addition, the step (c) comprises the steps of (c-1) implementing the equivalent circuit form through the simulation with reference to the measured impedance; (c-2) determining an element including an equivalent circuit based on the simulation result.

In addition, the step (d) may include (d-1) manufacturing the front end module in which the determined device is mounted; (d-2) comparing the produced module performance with the expected design performance through a test process, and if the comparison result is less than the expected performance in the step (d-2), analyze the cause of performance degradation and determine the cause After removal, it is desirable to perform a redesign.

The front end module and method for short-range wireless communication according to the present invention implement an RF front end block as one module to facilitate matching with the power amplifier and peripheral circuits, thereby minimizing device size, reducing component parts, and reducing development time. It can be effective.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments are provided to those skilled in the art to fully understand the present invention, can be modified in various forms, the scope of the present invention is limited to the embodiments described below no.

2A and 2B are structural diagrams illustrating a front end module for short range wireless communication according to an embodiment of the present invention. 2A is a perspective view of the front end module for short range wireless communication, and FIG. 2B is a side view of the front end module for short range wireless communication. A description with reference to FIGS. 2A and 2B is as follows.

As shown in Figs. 2A and 2B, the front end module 200 for short-range wireless communication is an element that is a mounting space and a circuit of a power amplifier for amplifying a predetermined multiple of a transmission signal and a time division connection path of a transmission or reception signal. An interface unit 210; A matching circuit unit 232 having an impedance matching circuit for improving power amplifier characteristics; A low pass filter 221 for removing the harmonic component of the power amplifier; A band pass filter 231 for extracting a signal of a desired frequency band from the received signal; And a main interface unit 240 that provides an interface to the output of the band pass filter 231, the input of the power amplifier, and the control signals of the components.

The device interface unit 210 generally exists on an outer layer of the substrate, and provides an interface for mounting a power amplifier and a switch through an SMD process including a mounting pad (PAD) of the device.

The device interface unit 210 may include a power amplifier mounting unit 212 on which a power amplifier IC is mounted; And a switch mounting unit 211 on which the switch IC is mounted.

On the other hand, since the power amplifier is a sensitive device whose characteristics vary depending on the environment of the peripheral device and the substrate, the power amplifier mounting unit 212 is a device related to impedance matching in the same layer for power amplifier characteristics and smooth heat conduction. It is preferable that the other elements are spaced apart from each other by a predetermined interval, and other elements are not embedded in the vertical lower layer.

The matching circuit unit 232 includes an impedance matching device and a matching circuit for improving power amplifier input / output characteristics. In the present invention, the matching circuit unit 232 is embedded in the module, thereby miniaturizing and shortening the implementation period.

The band pass filter 231 is a filter that passes only signals of a predetermined band to remove harmonic components included in a transmission signal which is a power amplifier output signal.

The low pass filter 221 is a filter for transmitting only a signal of a predetermined frequency band and is a filter for wirelessly extracting only a desired signal from a received signal detected by an antenna.

The main interface unit 240 includes a connector, a socket, and the like, exchanges input and output signals with the RF integrated circuit 130 and the RF integrated circuit 130 that exchange input and output signals with the front end module 200 for short-range wireless communication, Provides an interface with a baseband circuit (not shown) that provides a control signal for the front end module 200 for near field communication.

As illustrated in FIG. 2B, the front end module 200 for short range wireless communication may include a first TOP layer 250, a device interface unit 210, a second GND layer 260, a low pass filter 221, The third GND layer 270, the band pass filter and the matching circuit unit 232, the fourth GND layer 280, the main interface unit 240, and the fifth BOTTOM layer 290 are configured.

The first TOP layer 250 is disposed on the uppermost part of the PCB and includes the device interface 210 to provide a pattern and a pad for device mounting.

The device interface unit 210 may exist at the bottom of the first TOP layer 250 and may be divided and managed as a separate layer.

The second GND layer 260 prevents interference and noise generation through the RF shield function between the device interface 210 and the low pass filter 221.

The low pass filter 221 is present between the second GND layer 260 and the third GND layer, and may be divided and managed as a separate layer.

The third GND layer 270 prevents interference and noise generation through an RF shield function between the low pass filter 221, the band pass filter 231, and the matching circuit unit 232.

The band pass filter 231 and the matching circuit unit 232 are present between the third GND layer 270 and the fourth GND layer 280, and may be divided and managed as separate layers.

The fourth GND layer 280 prevents interference and noise generation through the RF shield function between the band pass filter 231 and the matching circuit unit 232 and the main interface unit 240.

The main interface unit 240 is present between the fourth GND layer 280 and the fifth BOTTOM layer 290, and may be divided and managed as a separate layer.

The fifth BOTTOM layer 290 provides an interface with a main circuit that exchanges input and output signals with the front end module 200 for short-range wireless communication through a SMD mounting space (including pads) and a PC of the connector and socket at the outside of the PCB. do.

In the present invention, the second GND layer 260, the third GND layer 270, and the fourth GND layer 280 are added between layers that actually mount the device to prevent interference between RF transmission and reception signals.

3 and 4 are flowcharts illustrating a method for implementing a front end module for short range wireless communication according to an embodiment of the present invention. A description with reference to FIG. 3 is as follows.

FIG. 3 is a photograph showing implementation steps and step-by-step pictures for short-range wireless communication in chronological order, and FIG. 4 is a photograph showing overall steps.

First, a basic impedance matching circuit of a PCB-mounted power amplifier is designed by referring to data sheets of devices such as a power amplifier and a switch (S310).

Here, it is preferable to determine the optimal value among the inferred values through a method such as theoretical value and trial and error indicated on the data sheet.

Subsequently, the measured impedance with respect to the power amplifier output pad is measured using the probe station without mounting the power amplifier in the PC (S320).

The impedance matching element to be mounted in the front end module 200 for short range wireless communication is determined with reference to the measured impedance (S330).

Here, it is preferable that the user configures an equivalent circuit using the measured impedance using a simulator and then determines detailed device values.

Next, the front end module for short range wireless communication is manufactured by embedding the impedance matching device of the determined standard (S340).

In this case, the user may program the front end module manufacturing environment using the automation system, and may also manufacture the front end module in which the device determined through the automation system is mounted.

Then, the manufactured module is subjected to a comparison process with the expected performance at the time of designing through a predetermined test process.

If the comparison result is less than the predetermined performance, the cause of performance degradation is analyzed, the cause is eliminated, and the redesign is started.

5A and 5B are equivalent circuit diagrams of a front end module power amplifier and a matching circuit according to an embodiment of the present invention. At this time, FIG. 5A is before the specialized, 4B is the equivalent circuit after specialized according to the present invention.

In the case of using a non-specialized general purpose device as shown in FIG. 5A, not only is the circuit complicated due to the PC ratio, but also most of the devices, in particular, a power stage inductor such as L1 is large and difficult to embed.

On the other hand, the equivalent circuit of FIG. 5B has a small number of devices and is productive because an optimum device value suitable for embedding through the probe station and simulation process of FIGS. 3 and 4 is applied.

The configuration of the present invention has been described above through the preferred embodiments and the accompanying drawings. However, these are only examples and are not used to limit the scope of the present invention. Those skilled in the art will understand from this that various modifications and equivalent other embodiments are possible. The true scope of protection of the present invention should be defined by the technical spirit of the appended claims.

1 is a block diagram illustrating an RF block of a short range wireless communication device according to the prior art.

2A and 2B are structural diagrams illustrating a front end module for short range wireless communication according to the present invention;

3 and 4 are flowcharts illustrating a method for implementing a front end module for short range wireless communication according to the present invention;

5A and 5B are equivalent circuit diagrams of a front end module power amplifier and matching circuit in accordance with the present invention.

<Description of main parts of drawing>

210: device interface unit 211: switch mounting unit

212: power amplifier mounting section 221: low pass filter

231: band pass filter 232: matching circuit portion

240: main interface unit

Claims (13)

An element interface unit which is a mounting space and a circuit of a power amplifier for amplifying a predetermined multiple of a transmission signal and a time division connection path of a transmission or reception signal; A matching circuit unit including an impedance matching circuit for improving the power amplifier characteristics; A low pass filter for removing harmonic components of the power amplifier; A band pass filter for extracting a signal of a desired frequency band from the received signal; A main interface unit providing the band pass filter output, the power amplifier input, and a control signal interface of the components; And the device interface unit, the matching circuit unit, the low pass filter, and the band pass filter in at least one layer. The method of claim 1, wherein the device interface unit, A front end module for short range wireless communication, wherein the front end module exists in an independent layer. The method of claim 1, wherein the device interface unit, A power amplifier mounting unit on which the power amplifier is mounted; Switch mounting unit in which the switch is mounted Short-range wireless communication front-end module comprising a. The method of claim 3, wherein the band pass filter, The front end module for short-range wireless communication, wherein the front end module exists in a lower layer of the layer including the switch mounting unit. The method of claim 3, wherein the low pass filter, And a lower layer of the layer including the power amplifier mounting unit and present in an upper layer of the matching circuit unit. The method of claim 3, wherein the power amplifier mounting unit, The front end module for short-range wireless communication, which does not overlap another component with respect to neighboring upper and lower layers, and is spaced apart from other components by a predetermined interval within the same layer. The method of claim 1, The device interface and the low pass filter; The low pass filter and the band pass filter and the matching circuit portion; And The band pass filter, the matching circuit unit and the main interface unit, A front end module for short range wireless communication, wherein the front end module is divided into ground layers. (a) designing a power amplifier impedance matching circuit; (b) measuring the measured impedance with a probe station; (c) designing an impedance matching equivalent circuit with reference to the measured impedance; (d) manufacturing a front end module for short range wireless communication by referring to the designed equivalent circuit; Method for implementing a front end module for short-range wireless communication comprising a. The method of claim 8, wherein the matching circuit in the step (a), A method of implementing a front end module for short-range wireless communication, which is designed by a method including a data sheet and a trial and error method of an individual device. According to claim 8, wherein step (b) is, Measuring an impedance of the power amplifier output when the power amplifier is not mounted; Method for implementing a front end module for short-range wireless communication comprising a. The method of claim 8, wherein step (c) comprises: (c-1) implementing a form of an equivalent circuit through simulation with reference to the measured impedance; (c-2) determining an element to be included in the equivalent circuit as a result of the simulation Method for implementing a front end module for short-range wireless communication comprising a. The method of claim 11, wherein step (d) (d-1) manufacturing the front end module in which the device is mounted; (d-2) comparing the produced module performance with the expected design performance through a test procedure Method for implementing a front end module for short-range wireless communication comprising a. The method of claim 12, wherein in step (d-2), If the comparison result is less than the expected performance, the cause of the performance degradation is analyzed, and the cause is eliminated, and then redesign is carried out.

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