KR100613580B1 - Apparatus for improving isolation of dual antenna - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a dual antenna device with improved separation.

2. The technical problem to be solved by the invention

An object of the present invention is to provide a dual antenna device having improved separation to prevent mutual interference by improving separation of signals between two antennas by using a separation unit in a device having dual antennas for selecting an antenna through a switch. In this.

3. Summary of the Solution of the Invention

The present invention provides a dual antenna device comprising switching means for switching a high frequency signal by selecting one of a first antenna and a second antenna according to an antenna selection control signal, wherein the switching means and the first antenna are selected according to a first control signal. First separating means for transmitting or interrupting a high frequency signal between the one antenna; Second separating means for transmitting or cutting off a high frequency signal between the switching means and the second antenna according to a second control signal; And control means for generating and transmitting an antenna selection control signal to the switching means, and generating a first control signal and a second control signal and transmitting the first control signal and the second control signal to the first separating means and the second separating means.

4. Important uses of the invention

The present invention is used in a wireless communication terminal.

Pin Diode, Dual Antenna, Isolation, Wireless Communication Terminal

Description

Apparatus for improving isolation of dual antenna             

1 is a configuration diagram of an embodiment of a conventional dual antenna device;

2 is a configuration diagram of an embodiment of a dual antenna device with improved separation according to the present invention.

* Explanation of symbols on the main parts of the drawing

21: first separator 22: second separator

201: first capacitor 202: RF switch

203: second capacitor 204: first inductor (RF choke)

205: first pin diode 206: first resistor

207: third capacitor 208: first antenna

209: fourth capacitor 210: second inductor (RF choke)

211: second pin diode 212: second resistor

213: fifth capacitor 214: second antenna

The present invention relates to a dual antenna device with improved separation, and more particularly, to prevent mutual interference by improving the separation of signals between two antennas by using a separation unit in a device having a dual antenna for selecting an antenna through a switch. The present invention relates to a dual antenna device with improved separation.

In the following example, a wireless communication terminal having a dual antenna device with improved separation will be described as an example.

In the present invention, the dual antenna device, a dual band terminal (for example, a wireless communication terminal that can be used in both the Pan-European standard mobile phone system (GSM) or the code division multiple access method (CDMA)), overcomes the difference in reception sensitivity according to opening and closing of folders An apparatus for communicating using two antennas for a method for diversity or a method for diversity implementation, and the like.

In the present invention, a wireless communication terminal is a mobile communication terminal, a personal digital communication terminal (PCS), a personal digital terminal (PDA), a smart phone, a next generation mobile communication terminal (IMT-2000), wireless communication while being carried by an individual such as a wireless LAN terminal. Say this is possible terminal.

In general, a diode is a semiconductor component that flows current in only one direction. Diodes are widely used in rectifiers, such as rectifiers that convert alternating currents into direct currents in power supplies, for detecting signals at high frequencies, and for switching on and off currents. . Among them, the pin diode A diode with a special structure of a V-junction is used as a switch of a high frequency circuit because it exhibits a high speed switching characteristic.

Isolation, on the other hand, is generally a concept used when trying to isolate two signals. For example, a duplexer needs to isolate or separate the two signals as much as possible because both transmit and receive frequency signals pass through the same device. In this way, when multiple signals use a system or circuit at the same time, the degree of separation between each signal is called isolation. There are many examples of using the term isolation, which can be understood as a measure of the separation of signals, how much less they interfere with each other. In the case of hybrid couplers, one port is designed to carry no power at all, which is also called an isolation port. In practice, however, a small amount of power is leaked to some extent, so that unnecessary reflection is usually prevented by consuming power by connecting a resistor.

1 is a configuration of an embodiment of a conventional dual antenna device.

As shown in FIG. 1, the conventional dual antenna device cuts DC power between a high frequency input terminal and an RF switch 102 and transmits a first high frequency signal to the RF switch 102. ), An RF switch 102 for switching a high frequency signal by selecting a path according to an antenna selection control signal from a controller, and cutting off DC power between the RF switch 102 and the first antenna 104 and A second capacitor 103 for passing a high frequency signal between the 102 and the first antenna 104, a first antenna for radiating a high frequency signal received from the RF switch 102 and receiving a high frequency signal from the outside ( 104, a third capacitor 105 for cutting off the DC power between the RF switch 102 and the second antenna 106 and passing a high frequency signal between the RF switch 102 and the second antenna 106, The RF A control unit for generating a second antenna 106 and an antenna selection control signal for radiating the high frequency signal received from the position 102 and receiving the high frequency signal from the outside and transmitting the generated signal to the RF switch 102 (not shown in the drawing). Not included).

On the other hand, capacitors (capacitors) have different interpretations and expressions of terms depending on the use. For example, when entering a power supply circuit, it is called a smoothing capacitor to remove ripple, and a capacitor connected to a power supply (VDD) or ground is called a noise removing capacitor. The capacitors (101, 103, 105) (DC Blocking Capacitor) is for removing a direct current (DC) component.

Since the capacitor's impedance (Xc) is '1 / 2πf _c ', the higher the frequency, the lower the impedance (resistance), and the lower the frequency, the higher the impedance. However, since DC (direct current) has a frequency of 0, the impedance of the capacitor becomes infinite. In other words, the capacitor blocks without passing the direct current.

That is, the capacitors 101, 103, and 105 are used to prevent the DC power between the RF switch 102 and the antennas 104 and 106 from passing through.

However, since the conventional dual antenna device separates high frequency signals transmitted and received by each antenna only by the RF switch 102, the separation degree is not so high, there is a problem that mutual interference between antennas occurs.

The present invention has been proposed to solve the above problems, and in order to prevent mutual interference by improving the separation of signals between two antennas using a separation unit in a device having a dual antenna for selecting an antenna through a switch. It is an object of the present invention to provide a dual antenna device with improved separation.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

According to an aspect of the present invention, there is provided a dual antenna device comprising switching means for switching a high frequency signal by selecting one of a first antenna and a second antenna according to an antenna selection control signal. First separating means for transmitting or cutting off a high frequency signal between the switching means and the first antenna according to a control signal; Second separating means for transmitting or cutting off a high frequency signal between the switching means and the second antenna according to a second control signal; And control means for generating and transmitting an antenna selection control signal to the switching means, and generating and transmitting a first control signal and a second control signal to the first separating means and the second separating means.

In addition, the apparatus of the present invention, the first capacitor for cutting off the DC power between the high frequency signal input terminal and the switching means; A second capacitor for cutting off a DC power supply between the switching means and the first separating means; A third capacitor for cutting off DC power between the first separating means and the first antenna; A fourth capacitor for cutting off a DC power source between the switching means and the second separating means; And a fifth capacitor for cutting off a DC power supply between the second separating means and the second antenna.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a configuration diagram of an embodiment of a dual antenna device with improved separation according to the present invention.

As shown in FIG. 2, the dual antenna device having improved separation according to the present invention cuts off DC power between the high frequency input terminal and the RF switch 202 and transmits the received high frequency signal to the RF switch 202. A first capacitor 201 for switching, an RF switch 202 for switching a high frequency signal by selecting a path according to an antenna selection control signal from a controller, and a direct current between the RF switch 202 and the first pin diode 205. High frequency signals from the second capacitor 203, the second capacitor 203 and the third capacitor 207 to cut off power and pass high frequency signals between the RF switch 202 and the first pin diode 205. The high-frequency signal passing through the second capacitor 203 according to the first inductor (RF choke) 204 and the first pin diode control signal (DC power ON) to block the transmission of the power to the power stage. 1 antenna (208) Or a first pin to block a path to the first antenna 208 and to transmit a high frequency signal received from the first antenna 208 to the RF switch 202 or to block a path to the RF switch 202. DC power between the first pin diode 205 and the first antenna 208, the first resistor 206 for making a current flow by making the impedance of the diode 205, the output terminal of the first pin diode 205 It emits a high frequency signal transmitted through the third capacitor 207, the third capacitor 207 for blocking and passing the high frequency signal between the first pin diode 205 and the first antenna 208 and the high frequency from the outside A high frequency signal between the RF switch 202 and the second pin diode 211 is cut off and the DC power is disconnected between the first antenna 208 and the RF switch 202 and the second pin diode 211 for receiving a signal. Passing A second inductor (RF choke) 210 and a second pin to block a high frequency signal from the fourth capacitor 209, the fourth capacitor 209, and the fifth capacitor 213 from being transmitted to the power supply terminal. The high frequency signal passing through the fourth capacitor 209 is transmitted to the second antenna 214 or the path to the second antenna 214 is blocked in accordance with the diode control signal (DC power ON). Impedance of the second pin diode 211 and the output of the second pin diode 211 for transmitting the high frequency signal received from the antenna 214 to the RF switch 202 or blocking the path to the RF switch 202. To cut off the DC power between the second resistor 212 and the second pin diode 211 and the second antenna 214 to flow the current, and the second pin diode 211 and the second antenna 214 A fifth capacitor 213 for passing a high frequency signal in the liver, The second antenna 214 and the antenna selection control signal for radiating the high frequency signal received through the fifth capacitor 213 and receiving the high frequency signal from the outside are generated and transmitted to the RF switch 202, and the first And a control unit (not shown) for generating a pin diode control signal and a second pin diode control signal and transmitting the generated pin diode control signal and the second pin diode control signal to the first pin diode 205 and the second pin diode 211.

Here, the first separator 21 includes a first inductor 204, a first pin diode 205, and a first resistor 206, and the second separator 22 includes a second inductor 210, A second pin diode 211 and a second resistor 212 are included.

Here, the RF chokes 204 and 210 refer to circuit elements and structures that prevent external leakage of DC power or block high frequency signals from flowing to the DC power supply. In general, at the radio frequency (RF), the ends are often shown as open by using 1/4 λ microstrip, similar to the effect of connecting an inductor in series. Meanwhile, a method of bypassing a high frequency signal by connecting a parallel capacitor to a bias line end is also used. In conclusion, RF choke is a structure that blocks the RF signal at the DC bias stage.

Here, the capacitors 201, 203, 207, 209, and 213 are additional components in the present invention, and serve to cut off DC power between the elements.

Next, an operation method of the dual antenna device with improved separation will be described.

First, when the RF switch 202 selects a path to the first antenna 208, the first pin diode control signal is turned ON and the first pin diode 205 is shorted to generate an RF path. do. At this time, the second pin diode control signal is turned off, and the separation of the signal between the first antenna 208 and the second antenna 214 is improved by about 15 to 20 dB.

In contrast, when the RF switch 202 selects a path to the second antenna 214, the second pin diode control signal is turned ON and the second pin diode 211 is shorted to generate an RF path. do. At this time, the first pin diode control signal is turned off and the separation of the signal between the first antenna 208 and the second antenna 214 is improved by about 15 to 20 dB.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

As described above, the present invention improves the separation of signals between two antennas by using a separation unit in a device having a dual antenna for selecting an antenna through a switch, thereby preventing mutual interference.

Claims (4)

A dual antenna device comprising switching means for switching a high frequency signal by selecting one of a first antenna and a second antenna according to an antenna selection control signal, First separating means for transmitting or blocking a high frequency signal between the switching means and the first antenna according to a first control signal; Second separating means for transmitting or cutting off a high frequency signal between the switching means and the second antenna according to a second control signal; And control means for generating and transmitting an antenna selection control signal to the switching means, and generating a first control signal and a second control signal and transmitting the first control signal and the second control signal to the first separating means and the second separating means. Dual antenna device to improve the separation including a. The method of claim 1, A first capacitor for cutting off DC power between the high frequency signal input terminal and the switching means; A second capacitor for cutting off a DC power supply between the switching means and the first separating means; A third capacitor for cutting off DC power between the first separating means and the first antenna; A fourth capacitor for cutting off a DC power source between the switching means and the second separating means; And A fifth capacitor for cutting off DC power between the second separating means and the second antenna Dual antenna device to further improve the separation comprising a. The method according to claim 1 or 2, The first separating means, First high frequency blocking means for preventing the high frequency signal from the switching means from being transmitted to the power supply means; A first pin diode for generating or blocking a path between the switching means and the first antenna according to a first control signal from the control means; And A first resistor for flowing an electric current by making an impedance at an output terminal of the first pin diode Dual antenna device to improve the separation including a. The method of claim 3, wherein The second separating means, Second high frequency blocking means for preventing the high frequency signal from the switching means from being transmitted to the power supply means; A second pin diode for generating or blocking a path between the switching means and the second antenna according to a second control signal from the control means; And A second resistor for flowing current by making an impedance at an output terminal of the second pin diode Dual antenna device to improve the separation including a.

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