Impedance matching circuit and radio frequency switch

Abstract

The utility model relates to radio frequency communication technical field, concretely is a kind of impedance matching circuit and radio frequency switch. Impedance matching circuit is composed of multiple rectangular matching sections connected in turn and a circular matching section located at the end, and the size of each rectangular matching section is:0.93mmx0.33mm, 0.55mmx0.92mm, 0.74mmx0.82mm, 0.76mmx1.1mm and 1mmx0.25mm, and the diameter of circular matching section is 0.7mm, form a kind of novel circuit for impedance matching, apply it in radio frequency switch, can make radio frequency switch have higher bandwidth, break through the limitation that traditional broadband PIN switch can only reach 18GHz, and working frequency range reaches 2GHz-21GHz, standing wave is ≤2.2dB, insertion loss is ≤5dB, isolation is >60dB.

Description

Technical Field

[0001] This utility model relates to the field of radio frequency communication technology, specifically an impedance matching circuit and a radio frequency switch. Background Technology

[0002] By utilizing the impedance characteristics of PIN diodes, which exhibit approximate conduction or disconnection under DC forward and reverse bias, microwave channel switching is controlled. When the PIN diode is forward biased, the equivalent resistance Rs and inductance Ls are equal; when the PIN diode is reverse biased, the equivalent capacitance Cj and inductance Ls are equal. The reverse bias caused by the multi-stage switch combination causes impedance mismatch at the common port due to the capacitance, which limits the operating frequency of the RF switch to 18GHz, thus limiting the broadband frequency and making it unsuitable for practical applications. Utility Model Content

[0003] In view of this, the purpose of this utility model is to provide an impedance matching circuit and a radio frequency switch to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] An impedance matching circuit consists of multiple rectangular matching sections connected in sequence and a circular matching section at the end. The dimensions of the rectangular matching sections are 0.93mm×0.33mm, 0.55mm×0.92mm, 0.74mm×0.82mm, 0.76mm×1.1mm and 1mm×0.25mm, respectively, and the diameter of the circular matching section is 0.7mm.

[0006] Preferably, the substrate corresponding to the impedance matching circuit is made of RT / duroid® 5880 material.

[0007] A radio frequency switch includes an input power supply section and a PIN diode array section, and further includes an impedance matching circuit, wherein the input power supply section is electrically connected to the PIN diode array section through the impedance matching circuit.

[0008] Preferably, the input power supply section includes capacitor C1, capacitor C9, current-limiting resistor R8, and inductor L1;

[0009] One end of the inductor L1 is electrically connected to one end of the capacitor C1 and the impedance matching circuit, respectively.

[0010] The other end of the inductor L1 is electrically connected to one end of the capacitor C9 and one end of the current-limiting resistor R8, respectively; the other end of the capacitor C9 and the other end of the current-limiting resistor R8 are both grounded.

[0011] Preferably, the PIN diode array includes six branch channel structures, each of which includes a first PIN diode, three second PIN diodes, a voltage regulator unit, a first inductor, a first capacitor, and a second capacitor.

[0012] The anode of the first PIN diode is electrically connected to the output terminal of the impedance matching circuit. The cathode of the first PIN diode is electrically connected to the anodes of the three second PIN diodes and the input terminal of the voltage regulator unit. The cathodes of the three second PIN diodes are all grounded. The output terminal of the voltage regulator unit is electrically connected to one end of the first inductor and one end of the second capacitor. The other end of the first inductor is electrically connected to the peripheral drive unit. The first capacitor is connected in series with the other end of the first inductor. The other end of the second capacitor is electrically connected to the peripheral drive unit.

[0013] Preferably, the six first PIN diodes are arranged in a petal-like pattern around the circular matching section and electrically connected to the circular matching section.

[0014] Preferably, the three second PIN diodes in the same branch channel structure are arranged at 3mm intervals.

[0015] Preferably, the voltage regulator unit includes a third PIN diode and a resistor connected in parallel, wherein the positive terminal of the third PIN diode is electrically connected to the negative terminal of the first PIN diode.

[0016] The beneficial effects of this utility model are:

[0017] This utility model provides an impedance matching circuit and an RF switch. The impedance matching circuit consists of multiple rectangular matching sections connected in sequence and a circular matching section at the end. The dimensions of the rectangular matching sections are 0.93mm×0.33mm, 0.55mm×0.92mm, 0.74mm×0.82mm, 0.76mm×1.1mm, and 1mm×0.25mm, respectively. The diameter of the circular matching section is 0.7mm. This forms a novel circuit for impedance matching. When applied to an RF switch, it enables the RF switch to have a higher bandwidth, breaking through the limitation of traditional broadband PIN switches that can only reach 18GHz. The operating frequency range reaches 2GHz-21GHz, with a VSWR ≤2.2dB, insertion loss ≤5dB, and isolation >60dB. Attached Figure Description

[0018] Figure 1 This is a circuit connection diagram of a radio frequency switch according to the present invention;

[0019] Figure 2 This is a schematic diagram of the internal structure of the shielding box of this utility model;

[0020] Figure 3 yes Figure 2 A partial enlarged view of the impedance matching circuit section;

[0021] Explanation of icon numbers:

[0022] 1. Shielding box; 2. Input terminal; 3. Output terminal; 4. Impedance matching circuit; 5. Input power supply section; 6. PIN diode array section. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0024] See Figures 1 to 3 The present invention provides an impedance matching circuit, which consists of multiple rectangular matching sections connected in sequence and a circular matching section at the end. The dimensions of the rectangular matching sections are 0.93mm×0.33mm, 0.55mm×0.92mm, 0.74mm×0.82mm, 0.76mm×1.1mm and 1mm×0.25mm respectively, and the diameter of the circular matching section is 0.7mm.

[0025] The beneficial effects of this utility model are:

[0026] The present invention provides an impedance matching circuit, which consists of multiple rectangular matching sections connected in sequence and a circular matching section at the end. The dimensions of the rectangular matching sections are 0.93mm×0.33mm, 0.55mm×0.92mm, 0.74mm×0.82mm, 0.76mm×1.1mm and 1mm×0.25mm respectively, and the diameter of the circular matching section is 0.7mm, forming a novel circuit for impedance matching.

[0027] Preferably, the substrate corresponding to the impedance matching circuit is made of RT / duroid® 5880 material.

[0028] As described above, Rogers RT / duroid® 5880 high-frequency circuit board is made of polytetrafluoroethylene (PTFE) glass fiber reinforced material. These microfibers are randomly distributed within the material, providing maximum strength reinforcement for circuit applications and manufacturing processes. RT / duroid® 5880 has the lowest dielectric constant compared to similar materials currently on the market, measuring 2.20 ± 0.02 under the 10GHz IPC-TM 2.5.5.5 standard. Simultaneously, the dielectric loss of this board, measured under the same standard, is only 0.0009. This extremely low dielectric loss makes it ideal for high-frequency and wideband applications requiring minimal dispersion and loss, supporting frequencies up to the Ku band and even higher.

[0029] See Figures 1 to 3 The present invention provides a radio frequency switch, including an input power supply section and a PIN diode array section, and also includes an impedance matching circuit. The input power supply section is electrically connected to the PIN diode array section through the impedance matching circuit.

[0030] The beneficial effects of this utility model are:

[0031] The present invention provides an RF switch that applies the above-mentioned impedance matching circuit to the RF switch, enabling the RF switch to have a higher bandwidth. It breaks through the limitation of traditional broadband PIN switches that can only reach 18GHz, with an operating frequency range of 2GHz-21GHz, VSWR ≤2.2dB, insertion loss ≤5dB, and isolation >60dB.

[0032] Preferably, the input power supply section includes capacitor C1, capacitor C9, current-limiting resistor R8, and inductor L1;

[0033] One end of the inductor L1 is electrically connected to one end of the capacitor C1 and the impedance matching circuit, respectively.

[0034] The other end of the inductor L1 is electrically connected to one end of the capacitor C9 and one end of the current-limiting resistor R8, respectively; the other end of the capacitor C9 and the other end of the current-limiting resistor R8 are both grounded.

[0035] As can be seen from the above description, the input power supply section is formed through the specific circuit design described above.

[0036] Preferably, the PIN diode array includes six branch channel structures, each of which includes a first PIN diode, three second PIN diodes, a voltage regulator unit, a first inductor, a first capacitor, and a second capacitor.

[0037] The anode of the first PIN diode is electrically connected to the output terminal of the impedance matching circuit. The cathode of the first PIN diode is electrically connected to the anodes of the three second PIN diodes and the input terminal of the voltage regulator unit. The cathodes of the three second PIN diodes are all grounded. The output terminal of the voltage regulator unit is electrically connected to one end of the first inductor and one end of the second capacitor. The other end of the first inductor is electrically connected to the peripheral drive unit. The first capacitor is connected in series with the other end of the first inductor. The other end of the second capacitor is electrically connected to the peripheral drive unit.

[0038] As can be seen from the above description, the PIN diode array section is formed through the specific circuit design described above.

[0039] Preferably, the six first PIN diodes are arranged in a petal-like pattern around the circular matching section and electrically connected to the circular matching section.

[0040] As can be seen from the above description, the specific design described above can reduce the impact of diode parasitic capacitance on matching.

[0041] Preferably, the three second PIN diodes in the same branch channel structure are arranged at 3mm intervals.

[0042] As can be seen from the above description, the isolation is improved when the channel is turned off through the specific design described above.

[0043] Preferably, the voltage regulator unit includes a third PIN diode and a resistor connected in parallel, wherein the positive terminal of the third PIN diode is electrically connected to the negative terminal of the first PIN diode.

[0044] As can be seen from the above description, the voltage regulation function is formed through the specific circuit design. When there are unstable factors in the circuit, the influence of these unstable factors can be eliminated or reduced by connecting appropriate resistors and diodes in parallel.

[0045] Example 1

[0046] See Figures 1 to 3 The present invention provides a radio frequency switch, including an input power supply section 5 and a PIN diode array section 6, and also includes an impedance matching circuit 4. The input power supply section 5 is electrically connected to the PIN diode array section 6 through the impedance matching circuit 4.

[0047] The impedance matching circuit 4 described above consists of multiple rectangular matching sections connected in sequence and a circular matching section at one end. The dimensions of the rectangular matching sections are as follows: 0.93mm×0.33mm, 0.55mm×0.92mm, 0.74mm×0.82mm, 0.76mm×1.1mm, and 1mm×0.25mm, respectively. The diameter of the circular matching section is 0.7mm. The substrate corresponding to the impedance matching circuit is fabricated using RT / duroid® 5880 material.

[0048] The input power supply section 5 includes capacitor C1, capacitor C9, current-limiting resistor R8, and inductor L1;

[0049] One end of the inductor L1 is electrically connected to one end of the capacitor C1 and the impedance matching circuit, respectively.

[0050] The other end of the inductor L1 is electrically connected to one end of the capacitor C9 and one end of the current-limiting resistor R8, respectively; the other end of the capacitor C9 and the other end of the current-limiting resistor R8 are both grounded.

[0051] The PIN diode array section 6 includes six branch channel structures. Each branch channel structure includes one first PIN diode, three second PIN diodes, a voltage regulator unit, a first inductor, a first capacitor, and a second capacitor. The six first PIN diodes are arranged in a petal-like pattern around the circular matching junction and are electrically connected to it. The three second PIN diodes in the same branch channel structure are spaced 3 mm apart.

[0052] The anode of the first PIN diode is electrically connected to the output terminal of the impedance matching circuit. The cathode of the first PIN diode is electrically connected to the anodes of the three second PIN diodes and the input terminal of the voltage regulator unit. The cathodes of the three second PIN diodes are all grounded. The output terminal of the voltage regulator unit is electrically connected to one end of the first inductor and one end of the second capacitor. The other end of the first inductor is electrically connected to the peripheral drive unit. The first capacitor is connected in series with the other end of the first inductor. The other end of the second capacitor is electrically connected to the peripheral drive unit.

[0053] The voltage regulator unit includes a third PIN diode and a resistor connected in parallel. The anode of the third PIN diode is electrically connected to the cathode of the first PIN diode. When unstable factors exist in the circuit, the effects of these unstable factors can be eliminated or reduced by connecting a suitable resistor and diode in parallel.

[0054] Specifically, the six branch road corridor structures are the first branch road corridor structure, the second branch road corridor structure, the third branch road corridor structure, the fourth branch road corridor structure, the fifth branch road corridor structure, and the sixth branch road corridor structure;

[0055] In the first branch channel structure, the first PIN diode is diode D1, the three second PIN diodes are diode D8, diode D14 and diode D20, the first inductor is inductor L2, the first capacitor is capacitor C10, the second capacitor is capacitor C2, the third PIN diode in the voltage regulator unit is diode D26, and the resistor is resistor R1.

[0056] In the second branch channel structure, the first PIN diode is diode D2, the three second PIN diodes are diode D9, diode D15 and diode D21, the first inductor is inductor L3, the first capacitor is capacitor C11, the second capacitor is capacitor C3, the third PIN diode in the voltage regulator unit is diode D27, and the resistor is resistor R2.

[0057] In the third branch channel structure, the first PIN diode is diode D3, the three second PIN diodes are diode D10, diode D16 and diode D22, the first inductor is inductor L4, the first capacitor is capacitor C12, the second capacitor is capacitor C4, the third PIN diode in the voltage regulator unit is diode D28, and the resistor is resistor R3.

[0058] In the fourth branch channel structure, the first PIN diode is diode D4, the three second PIN diodes are diodes D11, D17 and D23, the first inductor is inductor L5, the first capacitor is capacitor C13, the second capacitor is capacitor C5, the third PIN diode in the voltage regulator unit is diode D29, and the resistor is resistor R4.

[0059] In the fifth branch channel structure, the first PIN diode is diode D5, the three second PIN diodes are diodes D12, D18 and D24, the first inductor is inductor L6, the first capacitor is capacitor C14, the second capacitor is capacitor C6, the third PIN diode in the voltage regulator unit is diode D30, and the resistor is resistor R5.

[0060] In the sixth branch channel structure, the first PIN diode is diode D6, the three second PIN diodes are diodes D13, D19 and D25, the first inductor is inductor L7, the first capacitor is capacitor C15, the second capacitor is capacitor C7, the third PIN diode in the voltage regulator unit is diode D31, and the resistor is resistor R6.

[0061] The radio frequency switch of this invention has a higher bandwidth, breaking through the limitation of traditional broadband PIN switches that can only reach 18GHz. The operating frequency is 2~21GHz; VSWR ≤2.2dB; insertion loss ≤5dB; isolation >60dB.

[0062] In this embodiment, the 2~21GHz broadband RF switch uses a CNC-machined aluminum shielding box with overall natural-color conductive oxidation and a 1µm gold plating on the interior of the shielding box. The gold plating layer is used to bond the microwave circuit. The microwave signal input and output ports are connected to SMA connectors. The back of the shielding box contains a drive circuit, which is connected to the RF switch via a power supply insulator. The microwave devices are connected via bonding. An impedance matching circuit is introduced into the RF switch to achieve spread spectrum up to 21GHz.

[0063] The 2~21GHz broadband RF switch consists of a shielding box 1, an RF switch, a driver circuit, and high / low frequency connectors. One end of the shielding box 1 has an input terminal 2, and the opposite end has six output terminals 3.

[0064] Capacitors C1 and C9, current-limiting resistor R8, and inductor L1 are combined to form the input power supply section 5. The inductor L1 is connected to resistor R8 and then grounded to provide a DC bias voltage. Capacitors C1 and C9 are used to block DC and allow RF signals to pass through. The capacitors, inductors, and microstrip lines are connected by gold wire bonding. 25um gold wire is used to meet the requirements of high frequency and low loss.

[0065] The PIN diodes D1 to D6 are arranged in a petal-like pattern, and the diode beam leads are directly bonded to the microstrip line. Each branch channel has three PIN diodes spaced 3mm apart and grounded to improve isolation when the channel is turned off.

[0066] A set of PIN diodes and a 50Ω resistor are connected in parallel at the branch port. The inductor is connected to the drive unit through an insulator. A chip capacitor is added after each inductor for decoupling. When the PIN diode is forward biased, the signal is transmitted through the PIN diode. When the PIN diode is reverse biased, the signal is consumed by the 50Ω load. A chip capacitor is added at the end of the branch to block DC. The resulting absorption combination has higher isolation between branches and will not affect each other.

[0067] A set of impedance matching circuits M1 is introduced into the common port. Figure 1 As shown, the impedance matching circuit M1 is fabricated using an RT / duroid® 5880. The matching circuit consists of rectangular matching sections of 0.93mm*0.33mm, 0.55mm*0.92mm, 0.74mm*0.82mm, 0.76mm*1.1mm, and 1mm*0.25mm connected sequentially. The final node is a circle with a diameter of 0.7mm for mounting diodes. The diodes are arranged in a petal-like pattern with the 0.7mm center to reduce the impact of diode parasitic capacitance on the matching.

[0068] The drive unit uses a PD4-HV-10 / 40 high-speed driver, with the power supply pins led out via solder pins. A 100Ω resistor is added between the driver and the feeding inductor for current limiting. The microwave signal input and output terminals are connected via external SMA connectors to the insulators, and the drive unit is fed by DC sintered insulators.

[0069] This utility model has been described with reference to the above-described embodiments and accompanying drawings. However, the above embodiments are merely examples for implementing this utility model. It must be noted that the disclosed embodiments do not limit the scope of this utility model. On the contrary, modifications and equivalent provisions included in the spirit and scope of the claims are all included within the scope of this utility model.

Claims

1. An impedance matching circuit, characterized in that: It consists of multiple rectangular matching sections connected in sequence and a circular matching section at the end. The dimensions of each rectangular matching section are 0.93mm×0.33mm, 0.55mm×0.92mm, 0.74mm×0.82mm, 0.76mm×1.1mm and 1mm×0.25mm respectively, and the diameter of the circular matching section is 0.7mm.

2. The impedance matching circuit according to claim 1, characterized in that: The substrate corresponding to the impedance matching circuit is made of RT / duroid® 5880 material.

3. A radio frequency switch, comprising an input power supply section and a PIN diode array section, characterized in that: It also includes the impedance matching circuit as described in any one of claims 1 to 2, wherein the input power supply section is electrically connected to the PIN diode array section through the impedance matching circuit.

4. A radio frequency switch according to claim 3, characterized in that, The input power supply section includes capacitor C1, capacitor C9, current-limiting resistor R8, and inductor L1; One end of the inductor L1 is electrically connected to one end of the capacitor C1 and the impedance matching circuit, respectively. The other end of the inductor L1 is electrically connected to one end of the capacitor C9 and one end of the current-limiting resistor R8, respectively; the other end of the capacitor C9 and the other end of the current-limiting resistor R8 are both grounded.

5. A radio frequency switch according to claim 3, characterized in that, The PIN diode array includes six branch channel structures, each of which includes a first PIN diode, three second PIN diodes, a voltage regulator unit, a first inductor, a first capacitor, and a second capacitor. The anode of the first PIN diode is electrically connected to the output terminal of the impedance matching circuit. The cathode of the first PIN diode is electrically connected to the anodes of the three second PIN diodes and the input terminal of the voltage regulator unit. The cathodes of the three second PIN diodes are all grounded. The output terminal of the voltage regulator unit is electrically connected to one end of the first inductor and one end of the second capacitor. The other end of the first inductor is electrically connected to the peripheral drive unit. The first capacitor is connected in series with the other end of the first inductor. The other end of the second capacitor is electrically connected to the peripheral drive unit.

6. A radio frequency switch according to claim 5, characterized in that, The six first PIN diodes are arranged in a petal-like pattern around the circular matching junction and are electrically connected to the circular matching junction.

7. A radio frequency switch according to claim 5, characterized in that, The three second PIN diodes in the same branch channel structure are arranged at 3mm intervals.

8. A radio frequency switch according to claim 5, characterized in that, The voltage regulator unit includes a third PIN diode and a resistor connected in parallel. The positive terminal of the third PIN diode is electrically connected to the negative terminal of the first PIN diode.

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