Radio frequency switch circuit module built by PIN diodes

Abstract

The invention provides a radio frequency switch circuit module built by PIN diodes, and relates to the technical field of electronic communication. Comprising a radio frequency input end arranged on a trunk; the plurality of branch circuits are electrically connected with the main circuit, and a first PIN diode, a first biasing circuit and a matching network are correspondingly arranged on each branch circuit; the anode of the first PIN diode is electrically connected with the main circuit, the cathode of the first PIN diode is electrically connected with the output end of the first biasing circuit and the input end of the matching network, and the output end of the matching network can serve as the output end of the branch circuit; the first bias current is used for biasing or cutting off the first PIN diode; when the first PIN diode is switched on by the first bias circuit of the current branch, the output end of the current branch is in communication connection with the radio frequency input end, the first PIN diode of the corresponding branch is kept cut off by the first bias circuit of the non-current branch, and multi-channel selective communication is realized by selectively switching on the first PIN diode on one branch.

Description

Technical Field

[0001] The present invention relates to the field of electronic communication technology, and in particular to a radio frequency switch circuit module constructed by a PIN diode. Background Art

[0002] RF switches play a vital role in modern wireless communication devices. They are used to switch between different RF signal paths to achieve a variety of functions, such as antenna selection, frequency tuning, etc. Traditional RF switches usually use FET (field effect transistor) or MEMS (microelectromechanical system) technology, but these technologies are expensive, complex in structure, and perform poorly in high-frequency environments. PIN diodes have been widely used in RF and microwave circuits due to their advantages of high withstand voltage, high isolation, and low insertion loss. The unique structure of PIN diodes enables them to perform well in high-frequency applications, and are particularly suitable for the control and switching of high-power RF signals. However, the integration of existing PIN diode-based RF switch circuits is relatively general, and it is difficult to meet the needs of multi-channel, diversified, and highly integrated wireless communications.

[0003] Therefore, it is very necessary to develop an RF switch circuit module constructed with PIN diodes that can perform fast frequency selection switching of different RF paths in order to improve the communication requirements of multi-channel high integration. Summary of the invention

[0004] In view of this, the present invention proposes a radio frequency switch circuit module constructed of PIN diodes with high integration, capable of smoothly switching between different branches, and having good isolation and insertion loss.

[0005] The present invention provides a radio frequency switch circuit module constructed by a PIN diode, comprising a trunk circuit and a plurality of branches, wherein the plurality of branches are all electrically connected to the trunk circuit; and further comprising:

[0006] The radio frequency input terminal is arranged on the trunk line;

[0007] A first PIN diode, a first bias circuit and a matching network are respectively provided on the plurality of branches; the anode of the first PIN diode is electrically connected to the main circuit, the cathode of the first PIN diode is electrically connected to the output end of the first bias circuit and the input end of the matching network respectively, and the output end of the matching network can be used as the output end of the branch; the first bias current is used to bias or cut off the first PIN diode;

[0008] When the first bias circuit of the current branch turns on the first PIN diode, the output end of the current branch is communicatively connected to the RF input end, and the first bias circuit of the non-current branch keeps the first PIN diode of the corresponding branch turned off.

[0009] On the basis of the above technical solution, preferably, the first bias circuit includes a first coil and a first capacitor, one end of the first coil is electrically connected to the first control end and one end of the first capacitor respectively, the other end of the first capacitor is grounded, and the other end of the first coil is electrically connected to the cathode of the first PIN diode; the first control end is used to bias the first PIN diode or cut off the first PIN diode.

[0010] Preferably, when the first control end biases the first PIN diode, the voltage of the bias signal does not exceed 0V; when the first control end cuts off the first PIN diode, the voltage of the bias signal is higher than the turn-on voltage of the first PIN diode.

[0011] Preferably, each branch is also configured with a second bias circuit; the second bias circuit includes a second PIN diode and a second capacitor, the anode of the second PIN diode is electrically connected to the input end of the matching network, the cathode of the second PIN diode is electrically connected to one end of the second capacitor and the second control end respectively, and the other end of the second capacitor is grounded.

[0012] Further preferably, the level signals of the first control end and the second control end located on the same branch are different.

[0013] More preferably, the first PIN diode and the second PIN diode located on the same branch have opposite on or off states.

[0014] Further preferably, each branch is further provided with a second inductor, one end of the second inductor is electrically connected to the cathode of the first PIN diode, and the other end of the second inductor is electrically connected to the anode of the second PIN diode.

[0015] More preferably, the inductance of the second inductor is 10nH.

[0016] On the basis of the above technical solution, preferably, an input coupling device is further included, the input coupling device includes a coupling capacitor and a coupling inductor, one end of the coupling capacitor is electrically connected to the RF input end, the other end of the coupling capacitor is electrically connected to one end of the coupling inductor and a common end of several branches, and the other end of the coupling inductor is grounded.

[0017] On the basis of the above technical solution, preferably, the matching network is an output capacitor.

[0018] The radio frequency switch circuit module constructed by a PIN diode provided by the present invention has the following beneficial effects compared with the prior art:

[0019] (1) The present invention realizes the core functional part of the radio frequency switch by using an array of PIN diodes, and realizes the selection of different branches through the series / parallel PIN diodes on the parallel branches, thereby realizing the switch control of radio frequency signals of different channels;

[0020] (2) On a single branch, the first PIN diode is switched between on and off states through the first control terminal, so that the radio frequency signal responds quickly within the frequency range, and low-loss signal transmission is achieved in combination with the input coupling device;

[0021] (3) The second PIN diode and the second capacitor configured on the branch can further improve the isolation of the switch array. However, the insertion loss of the switch array will change with the second bias circuit connected in parallel. The number of second bias circuits configured can be selected according to actual needs.

[0022] (4) Further introducing a second inductor for isolation into the branch circuit can enhance the switch isolation and avoid mutual interference between signals in different paths. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A circuit structure diagram of a radio frequency switch circuit module constructed by a PIN diode of the present invention;

[0025] Figure 2 An improved circuit structure diagram of a radio frequency switch circuit module constructed by a PIN diode of the present invention;

[0026] Figure 3 Another improved circuit structure diagram of a radio frequency switch circuit module constructed by a PIN diode of the present invention;

[0027] Figure 4 A switching indicator of a radio frequency switch circuit module constructed by a PIN diode of the present invention before introducing a second bias circuit and a second inductor;

[0028] Figure 5 The invention discloses a switching index of a radio frequency switch circuit module constructed with a PIN diode after introducing a second bias circuit and a second inductor. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The integration of existing PIN diode-based RF switch circuits is relatively general, and it is difficult to meet the requirements of multi-channel, diversification, and high integration. In view of this, in order to ensure the long-term stable operation of the power module, the present invention provides a PIN diode-built RF switch circuit module, including a trunk and a plurality of branches, the plurality of branches are electrically connected to the trunk; the trunk is the side where RF_IN is located; the plurality of branches are the side where RF-OUT1, RF_OUT2, and RF_OUT3 are located. For the sake of distance description, this embodiment lists the RF switch circuit structure of three branches, but it is not regarded as a limitation of the scheme. The actual number of branches can be greater or less than three, which will not be repeated here.

[0031] The radio frequency input terminal is arranged on the trunk line;

[0032] A first PIN diode, a first bias circuit and a matching network are respectively arranged on a plurality of branches; an anode of the first PIN diode is electrically connected to the main circuit, a cathode of the first PIN diode is electrically connected to an output end of the first bias circuit and an input end of the matching network respectively, and the output end of the matching network can be used as an output end of the branch; a first bias current is used to bias or cut off the first PIN diode; the conduction or cutoff of the first PIN diode determines the opening or closing of the corresponding branch, that is, the gating function of the corresponding branch is realized.

[0033] When the first bias circuit of the current branch turns on the first PIN diode, the output end of the current branch is connected to the RF input end, and the first bias circuit of the non-current branch keeps the first PIN diode of the corresponding branch turned off. It should be noted that when the current branch is biased, the remaining branches will maintain the cut-off state, so as to avoid interference between channels.

[0034] like Figure 1 As shown, the first bias circuit includes a first coil and a first capacitor, one end of the first coil is electrically connected to the first control end and one end of the first capacitor respectively, the other end of the first capacitor is grounded, and the other end of the first coil is electrically connected to the cathode of the first PIN diode; the first control end is used to bias the first PIN diode or cut off the first PIN diode. Figure 1 In the uppermost branch, the first bias circuit includes a coil L1 and a capacitor C1, which are used to provide a bias or cutoff signal for the first PIN diode D1; similarly, Figure 1 In the middle branch, the first bias circuit includes a coil L2 and a capacitor C3, which are used to provide a bias or cutoff signal for the first PIN diode D2; Figure 1 In the lowermost branch, the first bias circuit includes a coil L3 and a capacitor C3, which are used to provide a bias or cutoff signal for the first PIN diode D3.

[0035] The matching network is an output capacitor, namely, capacitors C2, C4 and C6 arranged at the end of each branch, for meeting the working requirements of the output mode.

[0036] As a further improvement of this embodiment, the chip signal or cut-off signal provided by the first control terminal should consider the magnitude of the conduction voltage and reverse breakdown voltage of the first PIN diode to ensure the stability and reliability of the circuit. The conduction strategy of this embodiment is: when the first control terminal biases the first PIN diode, the voltage of the bias signal does not exceed 0V; when the first control terminal cuts off the first PIN diode, the voltage of the bias signal is higher than the conduction voltage of the first PIN diode. That is, the low level of the first control terminal turns on the first PIN diode, and the high level of the first control terminal turns off the first PIN diode. In the conduction state, the bias voltage of the first PIN diode should be higher than the conduction voltage and remain stable; in the cut-off state, the bias voltage of the first PIN diode should be close to zero or a negative value, so as to reliably turn off the first PIN diode and avoid leakage of RF signals.

[0037] like Figure 2 As shown, as a preferred embodiment, in some special applications, in order to avoid mutual interference between different signals, the present invention further configures a second bias circuit on each branch. The second bias circuit includes a second PIN diode and a second capacitor, the anode of the second PIN diode is electrically connected to the input end of the matching network, the cathode of the second PIN diode is electrically connected to one end of the second capacitor and the second control end, respectively, and the other end of the second capacitor is grounded. Figure 2 The second bias circuit in the uppermost branch includes a second PIN diode D4 and a capacitor C7; Figure 2 The second bias circuit of the middle branch includes a second PIN diode D5 and a capacitor C8; Figure 2The second bias circuit in the bottom branch includes a second PIN diode D6 and a capacitor C9. By configuring the second bias circuit on each branch, the isolation of the switch circuit can be effectively enhanced to avoid mutual interference of signals on different paths. The control logic of the second bias circuit is the same as the logic of the first control end, but the control level is exactly opposite, that is, the level signals of the first control end and the second control end on the same branch are different. On the same branch, when the low level of the first control end turns on the first PIN diode, the second control end outputs a high level to turn off the second PIN diode. The on or off state of the first PIN diode and the second PIN diode on the same branch are opposite, and the first PIN diode and the output capacitor constitute an output path. On the contrary, when other branches are turned on, the first control end of the current branch outputs a high level to turn off the first PIN diode, and the second control end outputs a low level to turn on the second PIN diode, which can effectively eliminate mutual interference.

[0038] Although higher isolation can be obtained by adding a second bias circuit to the RF path, as the number of second bias circuits connected in parallel increases, the isolation of the RF switch circuit module becomes better, but the insertion loss of the RF switch circuit module becomes larger.

[0039] like Figure 3 As shown, in Figure 2 Based on the embodiment of the present invention, each branch is further provided with a second inductor, one end of the second inductor is electrically connected to the cathode of the first PIN diode, and the other end is electrically connected to the anode of the second PIN diode. Figure 3 The inductors L4, L5 and L6 in different branches.

[0040] The inductance of the second inductor is 10nH. By configuring the second inductor, the insertion loss and reflection coefficient caused by the introduction of the second bias circuit can be effectively improved. Considering that the RF switch circuit module is a high-power device, the second inductor is wound with enameled wire with a wire diameter of 0.4mm, which is suitable for applications below 100W RF power. If there is a higher power requirement, an inductor wound with enameled wire with a larger wire diameter can be used.

[0041] The following is a comparison of the insertion loss and reflection coefficient indicators of the switch before and after optimization. Figure 4 and Figure 5 As shown, it can be seen that the indicators of the RF switch circuit module have been greatly improved after optimization. In the bandwidth range of 150-850MHz, the insertion loss of the RF switch circuit module has changed from -1.1dB to -0.18dB, and the reflection coefficient has changed from -8.8dB to -15.3dB. The indicators have been effectively improved within the bandwidth range of the RF switch circuit module, and the switching performance has been improved.

[0042] like Figure 1-Figure 3 As shown, as a preferred embodiment of the present invention, the present invention also includes an input coupling device, the input coupling device includes a coupling capacitor C0 and a coupling inductor L0, one end of the coupling capacitor C0 is electrically connected to the RF input end, the other end of the coupling capacitor C0 is electrically connected to one end of the coupling inductor L0 and the common end of several branches, and the other end of the coupling inductor L0 is grounded. The input coupling device is used to meet the input requirements of the RF switch circuit module.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A radio frequency switch circuit module constructed by a PIN diode, comprising a trunk circuit and a plurality of branches, wherein the plurality of branches are electrically connected to the trunk circuit; characterized in that: Also includes: The radio frequency input terminal is set on the trunk line; A first PIN diode, a first bias circuit and a matching network are respectively arranged on the plurality of branches; The anode of the first PIN diode is electrically connected to the main circuit, the cathode of the first PIN diode is electrically connected to the output end of the first bias circuit and the input end of the matching network respectively, and the output end of the matching network can be used as the output end of the branch circuit; The first bias current is used to bias or cut off the first PIN diode; When the first bias circuit of the current branch turns on the first PIN diode, the output end of the current branch is communicatively connected to the RF input end, and the first bias circuit of the non-current branch keeps the first PIN diode of the corresponding branch turned off.

2. The radio frequency switch circuit module constructed by a PIN diode according to claim 1, characterized in that: The first bias circuit includes a first coil and a first capacitor, one end of the first coil is electrically connected to the first control end and one end of the first capacitor respectively, the other end of the first capacitor is grounded, and the other end of the first coil is electrically connected to the cathode of the first PIN diode; the first control end is used to bias the first PIN diode or cut off the first PIN diode.

3. The radio frequency switch circuit module constructed by a PIN diode according to claim 2, characterized in that: When the first control end biases the first PIN diode, the voltage of the bias signal does not exceed 0V; when the first control end cuts off the first PIN diode, the voltage of the bias signal is higher than the conduction voltage of the first PIN diode.

4. The radio frequency switch circuit module constructed by a PIN diode according to claim 2, characterized in that: Each branch is also provided with a second bias circuit; the second bias circuit includes a second PIN diode and a second capacitor, the anode of the second PIN diode is electrically connected to the input end of the matching network, the cathode of the second PIN diode is electrically connected to one end of the second capacitor and the second control end respectively, and the other end of the second capacitor is grounded.

5. The radio frequency switch circuit module constructed by a PIN diode according to claim 4, characterized in that: The level signals of the first control terminal and the second control terminal located on the same branch are different.

6. The radio frequency switch circuit module constructed by a PIN diode according to claim 5, characterized in that: The first PIN diode and the second PIN diode located on the same branch have opposite conduction or cutoff states.

7. The radio frequency switch circuit module constructed by a PIN diode according to claim 4, characterized in that: Each branch is also provided with a second inductor, one end of the second inductor is electrically connected to the cathode of the first PIN diode, and the other end of the second inductor is electrically connected to the anode of the second PIN diode.

8. The radio frequency switch circuit module constructed by a PIN diode according to claim 7, characterized in that: The inductance of the second inductor is 10nH.

9. The radio frequency switch circuit module constructed by a PIN diode according to claim 1, characterized in that: It also includes an input coupling device, which includes a coupling capacitor and a coupling inductor. One end of the coupling capacitor is electrically connected to the RF input end, the other end of the coupling capacitor is electrically connected to one end of the coupling inductor and the common end of several branches, and the other end of the coupling inductor is grounded.

10. The radio frequency switch circuit module constructed by a PIN diode according to claim 1, characterized in that: The matching network is an output capacitor.

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