TWI399885B - Radio-frequency apparatus with electrostatic protection - Google Patents

Description

Electrostatic protection RF device

The present invention relates to a radio frequency device having electrostatic protection, and more particularly to a radio frequency device that utilizes a circuit structure composed of a capacitor and an inductor to simultaneously achieve electrostatic protection and impedance matching.

The electrostatic discharge (ESD) event is often the main cause of damage to the integrated circuit during the manufacturing process or after the wafer is completed. Therefore, the integrated circuit usually needs the function of static electricity protection to prevent external electrostatic signals from damaging the integrated circuit. For example, today's radio frequency devices (such as wireless transceivers, mobile phones, global positioning systems, etc.) must use the antenna to transmit and receive RF signals, and it must be measured that the transmission path provided by the antenna also causes an electrostatic discharge event.

For the above reasons, the conventional radio frequency device adopts different electrostatic protection measures for different kinds of antennas. For example, when a conventional RF device uses a planar inverted-F antenna as a path for transmitting and receiving an RF signal, since the design of the planar inverted-F antenna itself has a grounding path, when an electrostatic discharge event occurs, Conventional RF devices can utilize the ground path in a planar inverted-F antenna to avoid the effects of external electrostatic signals on the internal RF circuitry. However, the planar inverted-F antenna has a problem that the bandwidth is too narrow in use. In contrast, when a conventional radio frequency device utilizes a planar inverted-F antenna to enhance the electrostatic protection function, the performance of the antenna will be limited by the planar inverted-F antenna and cannot be improved.

In addition, conventional radio frequency devices can also use a monopole antenna to transmit and receive RF signals. At this time, the conventional radio frequency device shields the monopole antenna from the edge of the casing of the radio frequency device by means of a mechanism covering the monopole antenna. As a result, the monopole antenna will not be able to provide a transmission path to the external electrostatic signal, thereby causing the conventional radio frequency device to have an electrostatic protection function. However, with the demand for light and thin consumer electronics, the distance between the monopole antenna and the edge of the casing is forced to be reduced. This method of covering the monopole antenna will prevent the conventional RF device from being miniaturized. purpose.

Another way is to use an ESD suppression component, such as the conventional radio frequency device 100 with electrostatic protection as shown in FIG. 1, which uses the antenna 110 to receive signals. When an electrostatic discharge event occurs, the electrostatic signal will be transmitted to the ground through the ESD suppression component 120, thereby preventing the electrostatic signal from damaging the RF circuit 130. However, electronic components that can be used as the ESD suppression element 120 today, such as a low capacitance varistor or a polymer ESD suppressor, often have an overpriced problem. In addition, the conventional radio frequency device 100 using the conventional ESD suppression element 120 as the static electricity protection cannot pass the test condition of the third level (air discharge +/- 8 kV) in the IEC61000-4-2 test specification. In other words, the conventional radio frequency device 100 using the conventional ESD suppression element 120 has extremely poor electrostatic protection effect.

The invention provides a radio frequency protection device with electrostatic protection, which utilizes a circuit structure composed of a capacitor and an inductor to cause the electrostatic signal to be discharged to the ground end and reduce the loss of the radio frequency signal in the radio frequency device.

The invention provides a radio frequency device with static electricity protection, which prevents the electrostatic signal from entering the radio frequency device through the built-in antenna or the external antenna, thereby impairing the circuit performance of the radio frequency device.

The invention provides a radio frequency device with electrostatic protection, which has the advantages of miniaturization and improving the performance of the radio frequency device, in addition to having good electrostatic protection effect.

The invention provides a radio frequency protection device with electrostatic protection, comprising an antenna, an inductor, a capacitor and a radio frequency circuit. The radio frequency device uses an antenna to receive an RF signal, and the frequency of the RF signal is within a specific range. In addition to the RF signal, an undesired electrostatic signal may enter the RF device through the antenna. At this time, since the capacitor has the function of transmitting the RF signal and blocking the electrostatic signal, the RF circuit will cooperate with the antenna to receive the RF signal. . On the other hand, since the inductor has the function of transmitting an electrostatic signal and blocking the RF signal, when an electrostatic event occurs, the electrostatic signal is transmitted to the ground through the inductor. In addition, the impedance value of the capacitor is maintained within a first range, and the impedance value of the inductor is maintained within a second range, so that the impedance matching circuit composed of the capacitor and the inductor can block the impedance at a specific voltage. Static signal.

In an embodiment of the invention, when the specific voltage is ±8 kV, the first range is that the impedance value of the capacitor is less than or equal to 39 pF, and the second range is that the impedance value of the inductor is less than or equal to 56 nH. In addition, it is worth noting that the above specific range is that the frequency of the RF signal is greater than or equal to the frequency of 750 MHz.

The invention further provides a radio frequency protection device with static electricity protection, comprising a built-in antenna, a radio frequency switch, a first inductor, a capacitor and a radio frequency circuit. The RF switch has a fixed connection end, a preset connection end, and a signal connection end. Here, the preset connection end is used to provide a connection path to an external antenna, and the RF switch is electrically connected to the fixed connection end and the preset connection end according to the connection state of the preset connection end. One. Thereby, the radio frequency device receives an RF signal from the built-in antenna or the external antenna through the connection state of the preset connection end, wherein the frequency of the RF signal is maintained within a specific range.

When the RF signal or the electrostatic signal is transmitted to the signal connection end, if the impedance value of the capacitor is maintained within a first range, and the impedance value of the first inductor is maintained within a second range, the capacitor is used to transmit the RF signal to the RF circuit. It can block the static signal from entering the RF circuit, and the first inductor is used to introduce the electrostatic signal to the ground end and block the RF signal from being introduced into the ground. In addition, the impedance matching circuit formed by the capacitor and the first inductor can block the electrostatic signal at a specific voltage.

In an embodiment of the invention, the radio frequency device further includes a second inductor and an impedance matching circuit. The second inductor is electrically connected between the built-in antenna and the ground end to directly transmit the electrostatic signal from the built-in antenna to the RF device, so that the electrostatic signal cannot enter the RF circuit. The impedance matching circuit is electrically connected between the built-in antenna and the RF switch, so that the impedance of the built-in antenna matches the impedance of the RF switch. In addition, an impedance matching circuit composed of the capacitor and the first inductor is used to cause the impedance of the built-in antenna or the external antenna to match the impedance of the RF circuit.

The invention further provides a radio frequency protection device with static electricity protection, comprising a built-in antenna, a radio frequency switch, a first inductor, a second inductor, a capacitor and a radio frequency circuit. The RF switch has a fixed connection end, a preset connection end, and a signal connection end. Here, the preset connection end is used to provide a connection path to an external antenna, and the RF switch is electrically connected to the fixed connection end and the preset connection end according to the connection state of the preset connection end. One. Therefore, the RF circuit receives an RF signal from the built-in antenna or the external antenna through the connection state of the preset connection terminal, wherein the frequency of the RF signal is maintained within a specific range, and an electrostatic signal may also be used. The built-in antenna or external antenna enters the RF device.

When the RF signal or the electrostatic signal is transmitted to the signal connection end, if the impedance value of the capacitor is maintained within a first range, and the impedance values of the first inductor and the second inductor are both maintained within a second range, the capacitor is used to transmit The RF signal to the RF circuit can block the electrostatic signal from entering the RF circuit, and the first inductor and the second inductor are used to transmit the electrostatic signal to the ground end and can block the RF signal from being introduced into the ground. In addition, an impedance matching circuit composed of a capacitor, a first inductor, and a second inductor can block an electrostatic signal at a specific voltage.

The invention adopts a circuit structure composed of an inductor and a capacitor, so that the radio frequency device has the function of electrostatic protection, and does not need to intentionally maintain the distance between the monopole antenna and the casing. In addition, since the circuit structure composed of the inductor and the capacitor also has the function of impedance matching, the present invention has the advantages of miniaturization and improving the performance of the radio frequency device, in addition to the good electrostatic protection effect, compared with the prior art. Advantage.

The above described features and advantages of the present invention will be more apparent from the following description.

2 is a schematic structural view of a radio frequency device with static electricity protection according to an embodiment of the invention. Referring to FIG. 2, the radio frequency device 200 includes an antenna 210, an inductor L21, a capacitor C21, and a radio frequency circuit 220. The inductor L21 is electrically connected between the antenna 210 and the ground, and the capacitor C21 is electrically connected between the antenna 210 and the radio frequency circuit 220.

In overall operation, the radio frequency device 200 receives the radio frequency signal through the path provided by the antenna 210, wherein the frequency of the radio frequency signal is maintained within a specific range. When the RF signal enters the RF device 200, since the capacitor C21 is a low impedance to the RF signal, the inductor L21 is a high impedance to the RF signal, so the capacitor C21 has the function of transmitting the RF signal, and the inductor L21 has the barrier. The function of the RF signal. In other words, at this time, the capacitor C21 transmits the RF signal received by the antenna 210 to the RF circuit 220, and the inductor L21 can prevent the RF signal from leaking to the ground when being transmitted to the RF circuit 220. In this way, the RF circuit 220 can be configured to receive the RF signal correspondingly to the antenna 210.

On the other hand, when an electrostatic discharge event occurs, an external electrostatic signal will enter the radio frequency device 200 through the path provided by the antenna 210. At this time, the capacitor C21 is a high impedance to the electrostatic signal, and the inductor L21 is a low impedance to the electrostatic signal. Therefore, the inductor L21 has the function of transmitting an electrostatic signal, and the capacitor C21 has the function of blocking the electrostatic signal. Thereby, the inductor L21 can directly conduct the electrostatic signal to the ground end in the path between the antenna 210 and the RF circuit 220, and the capacitor C21 disposed in the path between the antenna 210 and the RF circuit 220 can block the electrostatic signal from passing through the antenna. 210 invades the RF circuit 220.

For the above reasons, when the RF device 200 receives the RF signal through the antenna 210, the static signal may enter the RF device through the antenna, and the RF circuit 220 will pass through the inductor L21 and the capacitor C21, respectively, to suppress the electrostatic signal and receive the RF signal. In turn, the effect of electrostatic protection is achieved. On the other hand, the inductor L21 and the capacitor C21 form an impedance matching circuit 230 with respect to the antenna 210 and the radio frequency circuit 220 to reduce the loss of the radio frequency signal in the radio frequency device 200. Wherein, when the impedance value of the inductor L21 is maintained within a first range, and the impedance value of the capacitor C21 is maintained within a second range, the impedance matching circuit 230 formed by the inductor L21 and the capacitor C21 can block a specific voltage. The static signal underneath. It is worth mentioning that the above specific range is the frequency of the RF signal is greater than or equal to 750MHz, so for Global System for Mobile Communications (GSM), Global Positioning System (GPS), British Telecom BT, Japan Telecom KDDI, and various communication standards such as The frequency band specified by CDMA, WCDMA, Bluetooth (Blue Tooth), WiFi, WiMax, DVB-H, and the radio frequency device 200 are all applicable. In addition, when the specific voltage of the electrostatic signal is ±8 kV, the first range is that the impedance value of the capacitor C21 is less than or equal to 39 pF, and the second range is that the impedance value of the inductor L21 is less than or equal to 56 nH. In other words, the electrostatic protection effect of the radio frequency device 200 at this time can at least pass the test condition of the third level (air discharge +/- 8 kv) in the IEC61000-4-2 test specification. If the impedance value of the inductor L21 and the capacitor C21 is further reduced, the radio frequency device 200 can pass the fourth level of the IEC61000-4-2 test specification (air discharge +/- 15 kv). On the other hand, the antenna 210 described above may be a monopole antenna or a wideband antenna.

It should be understood by those skilled in the art that when the radio frequency device 200 operates in different frequency bands, that is, when receiving radio frequency signals of different frequencies, the radio frequency device 200 only needs to adjust a specific range for limiting the impedance values of the inductor L21 and the capacitor C21. It can achieve the effect of electrostatic protection and impedance matching at the same time. Therefore, the above numerical values are only one embodiment of the present invention, and the present invention should not be limited thereto. In addition, since the type of the antenna is constantly changing with the rapid development of technology, the type of antenna used as the antenna 210 should not be limited to the above-mentioned examples.

3 is a schematic structural view of a radio frequency device with static electricity protection according to another embodiment of the present invention. Referring to FIG. 3, the radio frequency device 300 includes a built-in antenna 310, an impedance matching circuit 320, a radio frequency switch 330, an inductor L31, a capacitor C31, and a radio frequency circuit 340. The impedance matching circuit 320 is electrically connected between the built-in antenna 310 and the fixed connection end 331 of the RF switch 330. The inductor L31 is electrically connected between the signal connection end 333 of the RF switch 330 and the ground. The capacitor C31 is electrically connected between the signal connection end 333 of the RF switch 330 and the RF circuit 340.

Here, the impedance matching circuit 320 is configured to cause the impedance of the built-in antenna 310 to match the impedance of the RF switch 330 to reduce the loss of the RF signal in the RF device 300. The preset connection end 332 of the RF switch 330 is used to provide a connection path to an external antenna (not shown). When the external antenna is electrically connected to the preset connection end 332, the signal connection end 333 of the RF switch 330 is electrically connected to the preset connection end 332. Otherwise, the signal connection end 333 is electrically connected to the fixed connection end 331. . In other words, the RF switch 330 can cause the RF signal received by the built-in antenna 310 or the external antenna to be transmitted to the signal connection terminal 333 according to the connection state of the preset connection terminal 332, wherein the frequency of the RF signal is maintained at Within a certain range, the electrostatic signal may also enter the radio frequency device through the built-in antenna 310 or an external antenna.

After the capacitor C31 has the function of transmitting the RF signal and blocking the electrostatic signal, the capacitor C31 disposed in the path between the RF switch 330 and the RF circuit 340 can transmit the RF signal received by the built-in antenna 310 or the external antenna to The RF circuit 340 blocks the static signal from entering the RF circuit 340, so that the RF circuit 340 can cooperate with the built-in antenna 310 or an external antenna to receive the RF signal correspondingly. On the other hand, since the inductor L31 has a function of transmitting an electrostatic signal and blocking the RF signal, when an electrostatic discharge event occurs, the inductor L31 can directly introduce the electrostatic signal into the ground on the path between the RF switch 330 and the RF circuit 340. The electrostatic signal is prevented from entering the RF circuit 340, thereby achieving the effect of electrostatic protection, and the RF signal can still be transmitted to the RF circuit 340. It should be noted that the inductor L31 and the capacitor C31 form an impedance matching circuit 350 between the built-in antenna 310 and the RF circuit 340 to reduce the loss of the RF signal in the RF device 300. When the impedance value of the inductor L31 is maintained within a first range, and the impedance value of the capacitor C31 is maintained within a second range, the impedance matching circuit 350 formed by the inductor L31 and the capacitor C31 can block a specific voltage. Static signal.

In an example of the radio frequency device 200, the specific range of the radio frequency signal is a frequency greater than or equal to 750 MHz, and when the specific voltage of the electrostatic signal is ±8 kV, the first range is that the impedance value of the capacitor C31 is less than or equal to 39 pF. And the second range is that the impedance value of the inductor L31 is less than or equal to 56 nH. Therefore, according to the above settings, the radio frequency device 300 is applicable to Global System for Mobile Communications (GSM), Global Positioning System (GPS), British Telecom BT, Japan Telecom KDDI, and various communication standards such as CDMA, WCDMA, Bluetooth (Blue Tooth), WiFi. The frequency bands specified by WiMax and DVB-H, and their static protection can pass at least the test condition of the third level (air discharge +/- 8kv) in the IEC61000-4-2 test specification. On the other hand, the built-in antenna 310 described above may be a monopole antenna or a wideband antenna.

It should be understood by those skilled in the art that when the radio frequency device 300 operates in different frequency bands, that is, when receiving radio frequency signals of different frequencies, the radio frequency device 300 only needs to adjust a specific range for limiting the impedance values of the inductor L31 and the capacitor C31. It can achieve the effect of electrostatic protection and impedance matching at the same time. Therefore, the above numerical values are only one embodiment of the present invention, and the present invention should not be limited thereto. In addition, since the type of the antenna is constantly changing with the rapid development of technology, the type of antenna used as the built-in antenna 310 should not be limited to the above-mentioned examples.

Further, FIG. 4 is a schematic structural view of the impedance matching circuit for illustrating the embodiment shown in FIG. 3. Referring to FIG. 4, the impedance matching circuit 320 includes capacitors C41 to C44 and an inductor L41. The capacitor C41 is electrically connected to the built-in antenna 310. The inductor L41 is electrically connected between the capacitor C41 and the RF switch 320. In addition, the two ends of the capacitor C42 are electrically connected to the first end and the ground end of the inductor L41, respectively. The two ends of the capacitors C43 and C44 are electrically connected to the second end of the inductor L41 and the ground end, respectively. Here, the impedance matching circuit 320 can adjust the impedance of the capacitors C41 ～ C44 and the inductor L41 to match the impedance of the built-in antenna 310 to the impedance of the RF switch 330, thereby reducing the loss of the RF signal in the RF device 300.

FIG. 5 is a schematic structural view of a radio frequency device with static electricity protection according to still another embodiment of the present invention. Referring to FIG. 5, the radio frequency device 500 includes a built-in antenna 510, an impedance matching circuit 520, a radio frequency switch 530, inductors L51 and L52, a capacitor C51, and a radio frequency circuit 540. The electrical connection mode and working principle of the radio frequency device 500 are similar to those of the radio frequency device 300. The impedance matching circuit 520 is mainly used to cause the impedance of the built-in antenna 510 to match the impedance of the RF switch 530. The RF switch 532 is electrically connected to the external connection end 531 and the preset connection end 532 according to whether the preset connection end 532 is electrically connected to an external antenna (not shown). One. As a result, the RF device 500 can receive an RF signal through the built-in antenna 510 or an external antenna, wherein the frequency of the RF signal is maintained within a specific range, and at this time, there may be an electrostatic signal through the built-in antenna 510 or The external antenna enters the RF device.

When the RF signal or the electrostatic signal is transmitted to the signal connection terminal 533, if the impedance value of the capacitor C51 is maintained within a first range, and the impedance value of the inductor L52 is maintained within a second range, since the capacitor C51 has a radio frequency signal and Blocking the function of the electrostatic signal, the capacitor C51 disposed in the path between the RF switch 530 and the RF circuit 540 can transmit the RF signal received by the built-in antenna 510 or the external antenna to the RF circuit 540, and can block the intrusion of the electrostatic signal. In the RF circuit 540, the RF circuit 540 can be configured to receive the RF signal correspondingly with the built-in antenna 510 or an external antenna. In contrast, since the inductor L52 has the function of transmitting an electrostatic signal and blocking the RF signal, when an electrostatic discharge event occurs, the inductor L52 can directly introduce the electrostatic signal into the ground between the RF switch 530 and the RF circuit 540. And the RF signal can still be transmitted to the RF circuit 540. In addition, the inductor L51 and the capacitor C51 form an impedance matching circuit 550 with respect to the built-in antenna 510 and the radio frequency circuit 540, which can block the electrostatic signal at a specific voltage.

However, the maximum difference between the radio frequency device 500 and the radio frequency device 300 is that the inductance device L51 is further disposed in the radio frequency device 500. Since the inductor L51 has the function of transmitting an electrostatic signal and blocking the RF signal, the inductor L51 can directly introduce the electrostatic signal entering the RF device through the built-in antenna 510 into the ground between the built-in antenna 510 and the RF switch 530. On the other hand, the RF signal received by the built-in antenna 510 is not affected, and can also enter the RF switch 530 through the impedance matching circuit 520, which helps to improve the electrostatic protection effect of the RF device 500. The other details of this embodiment are included in the above various embodiments, and are not described here.

6 is a schematic structural view of a radio frequency device with static electricity protection according to still another embodiment of the present invention. Referring to FIG. 6, the radio frequency device 600 includes a built-in antenna 610, an impedance matching circuit 620, a radio frequency switch 630, inductors L61 and L62, a capacitor C61, and a radio frequency circuit 640. The impedance matching circuit 620 is electrically connected between the built-in antenna 610 and the fixed connection end 631 of the RF switch 630. The two ends of the capacitor C61 are electrically connected between the signal connection end 633 of the RF switch 630 and the RF circuit 640. The inductor L61 is electrically connected between the first end of the capacitor C61 and the ground, and the inductor L62 is electrically connected between the second end of the capacitor C61 and the ground.

Further, the action flow of the radio frequency device 600 is observed. The impedance of the built-in antenna 610 and the impedance of the RF switch 630 are matched to each other through the impedance matching circuit 620. In addition, the preset connection end 632 of the RF switch 630 provides a connection path to an external antenna (not shown), and the RF switch 630 causes the signal connection according to whether the preset connection end 632 is electrically connected to the external antenna. The end 633 is electrically connected to the fixed connection end 631 or the preset connection end 632. Therefore, the RF device 600 can transmit an RF signal received by the built-in antenna 610 or the external antenna to the signal connection end 633 according to the connection state of the preset connection end 632, and the frequency of the RF signal is maintained within a specific range. However, there may also be an electrostatic signal entering the radio frequency device through the built-in antenna 610 or an external antenna.

After that, if the impedance value of the capacitor C61 is maintained within a first range, and the impedance values of the inductors L61 and L62 are maintained within a second range, since the capacitor C61 has the function of transmitting an RF signal and blocking the electrostatic signal, it is set at the radio frequency. The capacitor C61 in the path between the switch 630 and the RF circuit 640 can transmit the RF signal received by the built-in antenna 610 or the external antenna to the RF circuit 640, and block the static signal from entering the RF circuit 640, so that the RF circuit 640 can be matched. The antenna 610 or the external antenna is configured to receive the RF signal correspondingly. In addition, since the inductors L61 and L62 have the function of transmitting the electrostatic signal and blocking the RF signal, when the electrostatic discharge event occurs, the inductors L61 and L62 can be in the RF switch 630 and the RF. The path between the circuits 640 directs the electrostatic signals directly to the ground, and the RF signals can still be transmitted to the RF circuit 640. It should be noted that the capacitor C61 and the inductors L61 and L62 form an impedance matching circuit 650 with respect to the RF switch 630 and the RF circuit 640, so as to block the electrostatic signal at a specific voltage.

In addition, the specific range is that the frequency of the RF signal is greater than or equal to 750 MHz, and when the specific voltage of the electrostatic signal is ±8 kV, the first range is that the impedance of the capacitor C61 is less than or equal to 39 pF, and the second range is the inductance. The impedance values of L61 and L62 are less than or equal to 56nH. Therefore, according to the above settings, the radio frequency device 600 is applicable to the global mobile communication system, the global positioning system, the British Telecom BT, the Japanese telecommunications KDDI, and various communication standards such as CDMA, WCDMA, Bluetooth (Blue Tooth), WiFi, WiMax, DVB-H. The specified frequency band and its static protection can pass at least the test condition of level 3 (air discharge +/- 8kv) in the IEC61000-4-2 test specification. Other details of this embodiment are included in the above various embodiments, and thus are not described herein.

However, it is worth noting that the RF device 600 can also be provided with an inductor between the built-in antenna 610 and the ground. As in the inductor L51 in FIG. 5, the inductor can be built into the antenna 610 and the RF switch 630. In the inter-path, the static signal that enters the RF device through the built-in antenna 610 is directly introduced into the ground, and the RF signal received by the built-in antenna 610 is not affected, and can also be transmitted to the impedance matching circuit. 620. Thereby, the electrostatic protection effect of the radio frequency device 600 is enhanced by electrically connecting the built-in antenna 610 and the ground through the inductor.

In summary, the present invention utilizes a circuit structure consisting of an inductor and a capacitor to direct the discharge of the electrostatic signal to the ground end, thereby avoiding damage to the radio frequency device caused by the electrostatic discharge event. In addition, the circuit structure consisting of inductors and capacitors also has the function of impedance matching, which can effectively reduce the loss of RF signals in the RF device. Compared with the conventional radio frequency device, the present invention only adopts a circuit structure composed of a capacitive inductor, and at the same time achieves the effects of electrostatic protection and impedance matching, and does not have to intentionally maintain the distance between the antenna and the casing in order to avoid electrostatic discharge. Therefore, in addition to having good electrostatic protection effect, the present invention has the advantages of miniaturization and improved performance of the radio frequency device.

Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100. . . Traditional radio frequency device

110, 210. . . antenna

120. . . ESD suppression component

130. . . Radio frequency circuit

200, 300, 500, 600. . . Radio frequency device

310, 510, 610. . . Built-in antenna

220, 340, 540, 640. . . Radio frequency circuit

230, 320, 350, 520, 550, 620, 650. . . Impedance matching circuit

330, 530, 630. . . RF switch

331, 531, 631. . . Fixed connection

332, 532, 632. . . Preset connector

333, 533, 633. . . Signal connection

L21, L31, L41, L51~L52, L61~L62. . . inductance

C21, C31, C41~C44, C51, C61. . . capacitance

FIG. 1 illustrates a conventional radio frequency device having an electrostatic protection function.

2 is a schematic structural view of a radio frequency device with static electricity protection according to an embodiment of the invention.

3 is a schematic structural view of a radio frequency device with static electricity protection according to another embodiment of the present invention.

4 is a schematic structural view of an impedance matching circuit for explaining the embodiment of FIG. 3.

FIG. 5 is a schematic structural view of a radio frequency device with static electricity protection according to still another embodiment of the present invention.

6 is a schematic structural view of a radio frequency device with static electricity protection according to still another embodiment of the present invention.

200. . . Radio frequency device

210. . . antenna

220. . . Radio frequency circuit

230. . . Impedance matching circuit

L21. . . inductance

C21. . . capacitance

Claims (15)

An RF-protected RF device includes: a built-in antenna; an RF switch having a fixed connection end, a predetermined connection end, and a signal connection end, wherein the fixed connection end is electrically connected to the built-in antenna, The preset connection end is configured to provide a connection path to an external antenna, and the RF switch transmits an RF signal received by the built-in antenna or the external antenna to the external connection according to the connection state of the preset connection end. a signal connection terminal, wherein the frequency of the RF signal is maintained within a specific range; an RF circuit is configured to receive the RF signal correspondingly with the built-in antenna or the external antenna; a capacitor is electrically connected to the signal connection Between the terminal and the RF circuit, the RF signal is transmitted to the RF circuit; a first inductor is electrically connected between the signal connection end and a ground end to block the RF signal from entering the ground end. And a second inductor electrically connected between the built-in antenna and the ground to block the RF signal from being introduced into the ground and capable of guiding an electrostatic signal The ground end, wherein the impedance value of the capacitor is maintained within a first range, and the impedance value of the first inductor is maintained within a second range, such that when the electrostatic signal having a specific voltage is introduced by the antenna The capacitor can block the electrostatic signal from entering the RF circuit, and the first inductor can introduce the electrostatic signal to the ground end. Radio frequency protection as described in item 1 of the patent application The device, wherein the specific range is that the frequency of the radio frequency signal is greater than or equal to 750 MHz. The radio frequency protection device according to claim 1, wherein when the specific voltage is ±8 kV, the first range is that the impedance value of the capacitance is less than or equal to 39 pF, and the second range is the first The impedance of an inductor is less than or equal to 56nH. The radio frequency protection device according to claim 1, wherein the built-in antenna is a monopole antenna or a broadband antenna. The radio frequency protection device according to claim 1, wherein the impedance of the second inductor is less than or equal to 56 nH. The radio frequency protection device according to claim 1, wherein the impedance matching circuit formed by the capacitor and the first inductor can match the impedance of the built-in antenna to the impedance of the radio frequency circuit. The radio frequency protection device as claimed in claim 1, further comprising: an impedance matching circuit electrically connected between the built-in antenna and the radio frequency switch to cause impedance of the built-in antenna The impedance of the RF switch matches each other. An RF-protected RF device includes: a built-in antenna; an RF switch having a fixed connection end, a predetermined connection end, and a signal connection end, wherein the fixed connection end is electrically connected to the built-in antenna, The preset connection end is configured to provide a connection path to an external antenna, and the RF switch is caused by the connection state of the preset connection end, thereby causing the built-in connection An RF signal received by the antenna or the external antenna is transmitted to the signal connection end, wherein the frequency of the RF signal is maintained within a specific range; and an RF circuit is configured to cooperate with the built-in antenna or the external antenna to correspondingly Receiving the RF signal; a capacitor electrically connected to the first end of the signal connection end, and electrically connected to the second end of the RF circuit, and the capacitor is used to transmit the RF signal to the RF a first inductor electrically connected between the first end and the ground of the capacitor to block the RF signal from being introduced into the ground; and a second inductor electrically connected to the capacitor Between the two ends and the ground end, the RF signal is blocked from being introduced into the ground end, wherein the impedance value of the capacitor is maintained in a first range, and the impedance values of the first inductor and the second inductor are maintained. In a second range, when an electrostatic signal having a specific voltage is introduced through the built-in antenna or the external antenna, the capacitor can block the electrostatic signal from entering the RF circuit, and the first inductor and The second inductor electrostatic signal can be introduced into the ground. The radio frequency protection device as claimed in claim 8 , wherein the specific range is that the frequency of the radio frequency signal is greater than or equal to 750 MHz. The radio frequency protection device as claimed in claim 8 , wherein when the specific voltage is ±8 kV, the first range is that the impedance of the capacitor is less than 39 pF, and the second range is the first inductor. The impedance value with the second inductor is less than 56 nH. The radio frequency protection device as claimed in claim 8 , wherein the built-in antenna is a monopole antenna or a broadband antenna. The radio frequency protection device as claimed in claim 8 further comprising: a third inductor electrically connected between the built-in antenna and the ground end for blocking the introduction of the RF signal into the ground And the electrostatic signal can be introduced to the ground. The radio frequency protection device of claim 12, wherein the third inductance has an impedance value less than or equal to 56 nH. The anti-static protection radio frequency device according to claim 8, wherein the impedance matching circuit formed by the capacitor, the first inductor and the second inductor can make the impedance of the built-in antenna and the impedance of the radio frequency circuit Match each other. The radio frequency protection device as claimed in claim 8 further includes: an impedance matching circuit electrically connected between the built-in antenna and the radio frequency switch to cause impedance of the built-in antenna The impedance of the RF switch matches each other.