Millimeter wave amplitude limiter with harmonic suppression characteristic

Abstract

The invention discloses a millimeter wave amplitude limiter with a harmonic suppression characteristic. The millimeter wave amplitude limiter comprises an input radio frequency transmission line, a first amplitude limiting PIN diode pair, a grounding metal via hole, a radio frequency matching circuit, a harmonic suppression unit, a second amplitude limiting PIN diode pair and an output radio frequency transmission line, the input radio frequency transmission line is connected with the output radio frequency transmission line through the radio frequency matching circuit; the first amplitude limiting PIN diode and the second amplitude limiting PIN diode pair are both connected with the radio frequency matching circuit; the radio frequency matching circuit is located at one side of the radio frequency matching circuit. The millimeter wave amplitude limiter with the harmonic suppression characteristic has the functions of an amplitude limiter and harmonic suppression at the same time, can save a harmonic suppression filter when being applied to a millimeter wave receiving circuit, optimizes the overall receiving performance, and has the advantages of simple structure and low cost.

Description

Technical Field

[0001] This application relates to the technical field of millimeter-wave circuits, and particularly to a millimeter-wave limiter with harmonic suppression characteristics. Background Art

[0002] Traditional passive limiters can only limit high-power RF signals. When the power level of the RF signal is slightly lower than the threshold level of the limiter; or when the frequency of the RF signal deviates from the operating frequency range of the limiter, the power limiting effect of the limiter will drop significantly. In millimeter-wave transceiver circuits, the final-stage transmitting chip not only outputs high-power RF signals but also outputs harmonic signals (mainly second harmonics) with a certain power level, and the harmonic signals with a certain power level can also damage the receiving circuit or affect the performance of the receiving circuit, mainly affecting the noise performance. Summary of the Invention

[0003] Aiming at the problem that the power limiting effect of traditional passive limiters on harmonic signals with a certain power level is not significant, the present invention proposes a millimeter-wave limiter with harmonic suppression characteristics.

[0004] This application discloses a millimeter-wave limiter with harmonic suppression characteristics, which includes an input RF transmission line, a first limiting PIN diode pair, a grounding metal via, an RF matching circuit, a harmonic suppression unit, a second limiting PIN diode pair, and an output RF transmission line; the input RF transmission line is connected to the output RF transmission line through the RF matching circuit; both the first limiting PIN diode and the second limiting PIN diode pair are connected to the RF matching circuit; the RF matching circuit is located on one side of the RF matching circuit.

[0005] Further, the first limiting PIN diode pair is composed of M diodes, the second limiting PIN diode pair is composed of N diodes, M is greater than N, and both M and N are positive integers; The M diodes are composed of a first branch and a second branch; the first branch and the second branch are symmetrically distributed on both sides of the RF matching circuit; the N diodes are composed of a third branch and a fourth branch; the third branch and the fourth branch are symmetrically distributed on both sides of the RF matching circuit.

[0006] Further, one end of the first branch and one end of the first branch are both connected to the RF matching circuit, and the other end of the first branch and the other end of the first branch are both connected to the grounding metal via to achieve the first limit of the RF signal; One end of the third branch and one end of the fourth branch are both connected to the RF matching circuit, and the other end of the third branch and the other end of the fourth branch are both connected to the grounding metal via to achieve the second limit of the RF signal.

[0007] Further, the input end of the input RF transmission line is used to input an RF signal, its output end is connected to the input end of the RF matching circuit, the output end of the RF matching circuit is connected to the input end of the output RF transmission line, and the output end of the RF transmission line is used to output an RF signal.

[0008] Further, the RF matching circuit is used to achieve RF impedance matching between the input RF transmission line and the output RF transmission line, and reduce the loss of the RF signal; The harmonic suppression unit is used to suppress the power of the harmonic signals entering the millimeter-wave limiter and reduce the influence of the harmonic signals on the subsequent circuits.

[0009] Further, the metal width of the harmonic suppression unit is much larger than that of the input RF transmission line, the RF matching circuit, and the output RF transmission line, so that its power capacity is much larger than that of the input RF transmission line, the RF matching circuit, and the output RF transmission line, to avoid burning the harmonic suppression unit by the RF signal current and the harmonic signal current; the directions of the metal widths of the harmonic suppression unit, the input RF transmission line, the RF matching circuit, and the output RF transmission line are perpendicular to the transmission direction of the RF signal.

[0010] Further, the harmonic suppression unit is used to introduce transmission zeros in the harmonic frequency range, so that the resonant signals in the harmonic frequency range cannot continue to transmit forward, thereby suppressing the harmonic signals; The suppression of the harmonic signals can be adjusted by changing the size, shape, or position of the harmonic suppression unit.

[0011] Further, when the power level of the RF signal input at the input end of the input RF transmission line is less than the threshold levels of the first limiting PIN diode pair and the second limiting PIN diode pair, the diodes in the first limiting PIN diode pair and the second limiting PIN diode pair are not turned on, and the influence of the harmonic suppression unit on the RF signal does not reach the preset value, and the RF signal passes through with low loss.

[0012] Further, when the power level of the RF signal input at the input end of the input RF transmission line is greater than the threshold level of the first limiting PIN diode pair, the diodes in the first limiting PIN diode pair are all turned on. After the diodes are turned on, they are connected to the ground metal vias, achieving a short-circuit effect, and reflecting the energy of the RF signal back to the input end of the input RF transmission line, thereby protecting the subsequent circuits; or, When the power level of the RF signal input at the input end of the input RF transmission line is greater than the threshold level of the second limiting PIN diode pair, the diodes in the second limiting PIN diode pair are all turned on. After the diodes are turned on, they are connected to the ground metal vias, achieving a short-circuit effect, and reflecting the energy of the RF signal back to the input end of the input RF transmission line, thereby protecting the subsequent circuits.

[0013] Further, when the power level of the RF signal input at the input end of the input RF transmission line is less than the threshold levels of the first limiting PIN diode pair and the second limiting PIN diode pair, and the power level of the harmonic signal is lower than the threshold levels of the first limiting PIN diode pair and the second limiting PIN diode pair, the diodes in the first limiting PIN diode pair and the second limiting PIN diode pair are not turned on. At this time, the harmonic suppression unit suppresses the harmonic signal, thereby protecting the subsequent circuit.

[0014] Due to the above technical solution, the present application has the following advantages: 1. A millimeter-wave limiter with harmonic suppression characteristics proposed by the present application has both the functions of a limiter and harmonic suppression. Applying it to a millimeter-wave receiving circuit can eliminate the harmonic suppression filter, optimize the overall receiving performance, and has the advantages of simple structure and low cost, and has great application value in millimeter-wave circuits.

[0015] 2. A millimeter-wave limiter with harmonic suppression characteristics proposed by the present application adds a harmonic suppression function without increasing the size. The harmonic suppression unit is located on one side of the RF matching circuit and has no physical connection with the circuit in the RF signal transmission direction, that is, there is no electrical conduction between the harmonic suppression unit and other RF circuits.

[0016] 3. Because the frequencies of the RF and harmonics are quite different, the harmonic signal frequency is multiple times that of the RF signal frequency. For example, the second harmonic is twice, and the third harmonic is three times. The frequency of the harmonic signal is quite different from that of the RF signal, that is, the frequency of the harmonic signal is much higher than that of the RF signal, and the frequency of the harmonic signal is far from that of the RF signal in the spectrum. The harmonic suppression unit will not have a great impact on the performance of the RF signal.

[0017] 4. The power capacity of the harmonic suppression unit is large, which improves the overall reliability and power capacity of the limiter. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of a millimeter-wave limiter with harmonic suppression characteristics according to an embodiment of the present application; Reference numerals: 1 is the input RF transmission line, 2 is the first limiting PIN diode pair, 3 is the grounding metal via, 4 is the RF matching circuit, 5 is the harmonic suppression unit, 6 is the second limiting PIN diode pair, and 7 is the output RF transmission line. Detailed implementation mode

[0020] The present application will be further described in conjunction with the accompanying drawings and embodiments. The described embodiments are only a part of the embodiments of the present application, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art shall fall within the scope of protection of the embodiments of the present application.

[0021] See Figure 1 , the present application provides an embodiment of a millimeter-wave limiter with harmonic suppression characteristics, which includes an input RF transmission line 1, a first limiting PIN diode pair 2, a ground metal via 3, an RF matching circuit 4, a harmonic suppression unit 5, a second limiting PIN diode pair 6, and an output RF transmission line 7; the input RF transmission line 1 is connected to the output RF transmission line 7 through the RF matching circuit 4; both the first limiting PIN diode and the second limiting PIN diode pair 6 are connected to the RF matching circuit 4; the RF matching circuit 4 is located on one side of the RF matching circuit 4. Among them, the harmonic suppression unit has no physical connection with the circuit in the RF signal transmission direction, that is, there is no electrical conduction between the harmonic suppression unit 5 and other RF circuits (such as the input RF transmission line 1, etc.).

[0022] Optionally, the first limiting PIN diode pair 2 is composed of M diodes, the second limiting PIN diode pair 6 is composed of N diodes, M is greater than N, and both M and N are positive integers; The M diodes are composed of a first branch and a second branch; the first branch and the second branch are symmetrically distributed on both sides of the RF matching circuit 4; the N diodes are composed of a third branch and a fourth branch; the third branch and the fourth branch are symmetrically distributed on both sides of the RF matching circuit 4.

[0023] Since the number of diodes in the second limiting PIN diode pair 6 is less than the number of diodes in the first limiting PIN diode pair 2, the transmission loss of the limiter can be reduced. The first limiting PIN diode pair 2 mainly suppresses signals with larger power and requires a larger number of PIN diodes; the second limiting PIN diode pair 6 mainly limits the power at the output end and requires a smaller number of PIN diodes.

[0024] Optionally, one end of the first branch and one end of the first branch are both connected to the RF matching circuit 4, and the other end of the first branch and the other end of the first branch are both connected to the ground metal via 3 to achieve the first limit of the RF signal; One end of the third branch and one end of the fourth branch are both connected to the RF matching circuit 4, and the other end of the third branch and the other end of the fourth branch are both connected to the ground metal via 3 to achieve the second limit of the RF signal.

[0025] In the embodiments of the present application, the first limiting PIN diode pair 2 and the second limiting PIN diode pair 6 jointly suppress the harmonic signals in the millimeter-wave limiter.

[0026] Optionally, the input end of the input RF transmission line 1 is used to input RF signals, its output end is connected to the input end of the RF matching circuit 4, and the output end of the RF matching circuit 4 is connected to the input end of the output RF transmission line 7. The output end of the RF transmission line is used to output RF signals.

[0027] Optionally, when the RF signal is input from the input RF transmission line 1, the RF matching circuit 4 is used to achieve the RF impedance matching of the limiter, reduce the loss of the RF signal, and output the RF signal through the output RF transmission line 7.

[0028] Optionally, the RF matching circuit 4 is used to achieve the RF impedance matching between the input RF transmission line 1 and the output RF transmission line 7, and reduce the loss of the RF signal; The harmonic suppression unit 5 is used to suppress the power of the harmonic signals entering the millimeter-wave limiter and reduce the influence of the harmonic signals on the subsequent circuits.

[0029] Optionally, the metal width of the harmonic suppression unit 5 is much larger than the metal widths of the input RF transmission line 1, the RF matching circuit 4, and the output RF transmission line 7, so that its power capacity is much larger than the power capacities of the input RF transmission line 1, the RF matching circuit 4, and the output RF transmission line 7, to avoid burning the harmonic suppression unit 5 by the RF signal current and the harmonic signal current; the directions of the metal widths of the harmonic suppression unit 5, the input RF transmission line 1, the RF matching circuit 4, and the output RF transmission line 7 are perpendicular to the transmission direction of the RF signal.

[0030] Optionally, the harmonic suppression unit 5 is used to introduce transmission zeros in the harmonic frequency range, so that the resonant signals in the harmonic frequency range cannot continue to be transmitted forward, thereby suppressing the harmonic signals; By changing the size, shape, or position of the harmonic suppression unit 5, the suppression of the harmonic signals can be adjusted.

[0031] Optionally, when the power level of the RF signal input at the input end of the input RF transmission line 1 is less than the threshold levels of the first limiting PIN diode pair 2 and the second limiting PIN diode pair 6, the diodes in the first limiting PIN diode pair 2 and the second limiting PIN diode pair 6 are not turned on, and the influence of the harmonic suppression unit 5 on the RF signal does not reach the preset value, and the RF signal passes through with low loss.

[0032] Optionally, when the power level of the radio frequency signal input at the input end of the input radio frequency transmission line 1 is greater than the threshold level of the first limiting PIN diode pair 2, the diodes in the first limiting PIN diode pair 2 are all turned on. After the diodes are turned on, they are connected to the ground metal via hole 3 to achieve a short-circuit effect, reflecting the energy of the radio frequency signal back to the input end of the input radio frequency transmission line 1, thereby protecting the subsequent circuit; or, When the power level of the radio frequency signal input at the input end of the input radio frequency transmission line 1 is greater than the threshold level of the second limiting PIN diode pair 6, the diodes in the second limiting PIN diode pair 6 are all turned on. After the diodes are turned on, they are connected to the ground metal via hole 3 to achieve a short-circuit effect, reflecting the energy of the radio frequency signal back to the input end of the input radio frequency transmission line 1, thereby protecting the subsequent circuit.

[0033] Optionally, when the power level of the radio frequency signal input at the input end of the input radio frequency transmission line 1 is less than the threshold levels of the first limiting PIN diode pair 2 and the second limiting PIN diode pair 6, and the power level of the harmonic signal is lower than the threshold levels of the first limiting PIN diode pair 2 and the second limiting PIN diode pair 6, the diodes in the first limiting PIN diode pair 2 and the second limiting PIN diode pair 6 are not turned on. At this time, the harmonic suppression unit 5 suppresses the harmonic signal, thereby protecting the subsequent circuit.

[0034] The reasons for harmonic generation in this application include harmonic signals generated when the amplifier outside the limiter operates. The limiter is usually applied in the TR transceiver link to protect the receiving link from being burned by power. There are high-power amplifiers at the end of the transmitting link. When the power amplifier operates in saturation, harmonic signals are often generated. This application can not only suppress the harmonic signal, but also suppress the interference signal outside the limiter whose frequency is within the harmonic frequency range.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present application can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present application should be covered by the protection scope of the claims of the present application.

Claims

1. A millimeter wave limiter with harmonic suppression characteristics, characterized in that: It includes an input RF transmission line, a first limiting PIN diode pair, a grounded metal via, a RF matching circuit, a harmonic suppression unit, a second limiting PIN diode pair, and an output RF transmission line; the input RF transmission line is connected to the output RF transmission line through the RF matching circuit; the first limiting PIN diode and the second limiting PIN diode pair are both connected to the RF matching circuit; the RF matching circuit is located on one side of the RF matching circuit.

2. The millimeter wave limiter with harmonic suppression characteristics according to claim 1, characterized in that: The first limiting PIN diode pair is composed of M diodes, and the second limiting PIN diode pair is composed of N diodes, where M is greater than N, and both M and N are positive integers; The M diodes are composed of a first branch and a second branch; the first branch and the second branch are symmetrically distributed on both sides of the radio frequency matching circuit; the N diodes are composed of a third branch and a fourth branch; the third branch and the fourth branch are symmetrically distributed on both sides of the radio frequency matching circuit.

3. The millimeter wave limiter with harmonic suppression characteristics according to claim 2, characterized in that: One end of the first branch and one end of the first branch are both connected to the RF matching circuit, and the other end of the first branch and the other end of the first branch are both connected to the grounded metal via, so as to achieve the first amplitude limiting of the RF signal; One end of the third branch and one end of the fourth branch are both connected to the RF matching circuit, and the other end of the third branch and the other end of the fourth branch are both connected to the grounded metal via to achieve a second amplitude limitation of the RF signal.

4. The millimeter wave limiter with harmonic suppression characteristics according to claim 1, characterized in that: The input end of the input RF transmission line is used to input RF signals, and its output end is connected to the input end of the RF matching circuit. The output end of the RF matching circuit is connected to the input end of the output RF transmission line, and the output end of the RF transmission line is used to output RF signals.

5. The millimeter wave limiter with harmonic suppression characteristics according to claim 1, characterized in that: The RF matching circuit is used to achieve RF impedance matching between the input RF transmission line and the output RF transmission line to reduce the loss of RF signals; The harmonic suppression unit is used to suppress the power of the harmonic signal entering the millimeter wave limiter and reduce the influence of the harmonic signal on the subsequent circuit.

6. The millimeter wave limiter with harmonic suppression characteristics according to claim 1, characterized in that: The metal width of the harmonic suppression unit is greater than the metal width of the input RF transmission line, the RF matching circuit and the output RF transmission line, so that its power capacity is greater than the power capacity of the input RF transmission line, the RF matching circuit and the output RF transmission line to prevent the RF signal current and the harmonic signal current from burning the harmonic suppression unit; the direction of the metal width of the harmonic suppression unit, the input RF transmission line, the RF matching circuit and the output RF transmission line is perpendicular to the transmission direction of the RF signal.

7. The millimeter wave limiter with harmonic suppression characteristics according to claim 1, characterized in that: The harmonic suppression unit is used to introduce a transmission zero point within the harmonic frequency range, so that the resonant signal within the harmonic frequency range cannot continue to be transmitted forward, thereby suppressing the harmonic signal; The suppression of harmonic signals can be adjusted by changing the size, shape or position of the harmonic suppression unit.

8. The millimeter wave limiter with harmonic suppression characteristics according to any one of claims 1 to 7, characterized in that: When the power level of the RF signal input to the input end of the input RF transmission line is less than the threshold levels of the first limiting PIN diode pair and the second limiting PIN diode pair, the diodes in the first limiting PIN diode pair and the second limiting PIN diode pair are not turned on, and the influence of the harmonic suppression unit on the RF signal does not reach the preset value, and the RF signal passes with low loss.

9. The millimeter wave limiter with harmonic suppression characteristics according to any one of claims 1 to 7, characterized in that: When the power level of the RF signal input to the input end of the input RF transmission line is greater than the threshold level of the first limiting PIN diode pair, the diodes in the first limiting PIN diode pair are all turned on, and after the diodes are turned on, they are connected to the grounded metal vias to achieve a short-circuit effect, reflecting the energy of the RF signal back to the input end of the input RF transmission line, thereby protecting the subsequent circuits; or, When the power level of the RF signal input to the input end of the input RF transmission line is greater than the threshold level of the second limiting PIN diode pair, the diodes in the second limiting PIN diode pair are all turned on. After the diodes are turned on, they are connected to the grounded metal vias to achieve a short-circuit effect, reflecting the energy of the RF signal back to the input end of the input RF transmission line, thereby protecting the subsequent circuits.

10. The millimeter wave limiter with harmonic suppression characteristics according to any one of claims 1 to 7, characterized in that: When the power level of the RF signal input to the input end of the input RF transmission line is less than the threshold levels of the first limiting PIN diode pair and the second limiting PIN diode pair, and the power level of the harmonic signal is lower than the threshold levels of the first limiting PIN diode pair and the second limiting PIN diode pair, the diodes in the first limiting PIN diode pair and the second limiting PIN diode pair are not turned on. At this time, the harmonic signal is suppressed by the harmonic suppression unit, thereby protecting the subsequent circuit.

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