JP2011160262A - Limiter circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a limiter circuit for a radar system having high leakage suppression characteristics and filter characteristics. <P>SOLUTION: The limiter circuit is a limiter circuit that uses a PIN diode for use in a microwave band, and includes a capacitor (6a or 6b), which has one end connected to an RF main line to offset the parasitic components and PIN diode connections (connections 7a and 8a or connections 7b and 8b) of antiparallel connection which are connected to the other end of the capacitor (6a or 6b). The capacitor is connected in series with the PIN diode connections between the RF main line and a ground. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a limiter circuit used in a radar apparatus, and more particularly to a limiter circuit using a PIN diode used in a microwave band.

FIG. 1 is a diagram illustrating a configuration of a general radar device (also referred to herein as a radar system).
As is well known, a radar apparatus (radar system) includes an antenna 100, a transmission / reception switch 200, a filter 300, a limiter circuit 400, a radar receiver (hereinafter also referred to as an RF receiver or simply a receiver) 500, and a radar transmitter ( (Hereinafter also referred to as RF transmitter or simply transmitter) 600.
The transmitter 600 includes an oscillator whose output is turned on and off to emit a series of radar pulses.
The radar pulse is supplied to the antenna 100 via the transmission / reception switch 200 and transmitted from the antenna 100 toward a target (not shown).
A reflected wave from a target received by the antenna 100 or a radio wave emitted from a jammer (not shown) is received by the receiver 500 via the transmission / reception switch 200, the filter 300, and the limiter circuit 400.

A receiver (RF receiver) 500 used in such a radar system generally includes circuit elements such as a low noise amplifier (LNA) that may be destroyed by a high-power RF (Radio Frequency) signal. It is known to include.
For example, the “RF signal leaking from the transmitter” and the “high-power RF signal input from the jammer” have a high incident energy level, so that the circuit elements of the receiver 500 may be destroyed. This is a threat to the circuit elements of the receiver 500.
Therefore, since the receiver 500 having a circuit element that may be destroyed by high incident energy needs to be protected from high incident energy, the limiter circuit 400 is disposed in the preceding stage.

The development of transmitter amplifier elements used in radar systems has progressed, and it has become possible to develop transmitters with high output even in a high frequency range.
Accordingly, in order to protect circuit elements such as a low noise amplifier (LNA), which is a component of the receiver, a limiter circuit arranged in front of the receiver has a leakage when high energy is incident. : Leakage) Suppression characteristics need to be improved.
In addition to the leakage energy leaking from the transmitter 600, there is also energy that is reflected by the antenna 100 and input to the filter 300 and the limiter circuit 400.
For example, when the radar apparatus is an active phased array radar, assuming the worst case, there may be a state where the antenna reflection coefficient is “1”. Therefore, the transmission energy of the transmitter 600 is entirely reduced by the filter 300 and the limiter circuit 400. It may be the energy that is input to.

  Furthermore, the “energy outside the frequency band used by the radar device” incident from a jammer or the like is lower than the incident energy at which the PIN diode operates and is sufficiently higher than the incident energy in the frequency band used by the radar device. Otherwise, the performance of the radar receiver will deteriorate.

JP 2008-22255 A

As a “limiter circuit using a PIN diode” which cancels out parasitic components generated in a high frequency region and improves leakage suppression performance, there is one disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2008-22255). In order to reduce the leakage power with respect to high incident energy, it is necessary to increase the number of PIN diodes or improve the leakage suppression characteristic per PIN diode.
However, in the former case (that is, when the PIN diode is multi-staged), the passage loss when passing through the limiter circuit increases at low incident energy, and the noise figure of the receiver is deteriorated. It is desired to have a technique for realizing a leakage suppression characteristic per stage of PIN diode.
Here, “PIN diode one stage” means that a “basic unit” of a limiter circuit described later is one stage.

For “energy outside the operating frequency band” lower than the incident energy at which the PIN diode operates, in addition to the limiter circuit, a circuit having a filter characteristic (that is, a filter) is arranged in front of the receiver and used. A configuration is generally used in which energy outside the frequency band is suppressed and deterioration of receiver performance is suppressed.
However, with the increase in the number of components between the antenna and the receiver, the passage loss increases and the noise figure of the receiver is deteriorated.
Therefore, it is desired to develop a limiter circuit having multiple characteristics such as “leakage suppression characteristics” and “filter characteristics”.

  The present invention has been made to solve such a problem, and it is said that “an improved leakage suppression characteristic for high incident energy and a filter characteristic for low incident energy”. It is an object of the present invention to provide a limiter circuit having characteristics.

The limiter circuit according to the present invention is a limiter circuit using a PIN diode used in a microwave band, and is connected to a capacitor having one end connected to the RF main line to cancel parasitic components and the other end of the capacitor. An anti-parallel PIN diode connection body,
The capacitor and the PIN diode connection body are connected in series between the RF main line and the ground.

  The limiter circuit according to the present invention is a limiter circuit using a PIN diode used in the microwave band, and is an anti-parallel PIN diode having one end connected to the RF main line and the other end connected to the ground. A connection body and an inductor connected in parallel to the PIN diode connection body between the RF main line and the ground are provided.

According to the present invention, when high energy is incident on the limiter circuit, the leakage suppression characteristics per PIN diode stage can be improved without increasing the number of PIN diode stages. Can be improved.
In addition, when low energy is incident, the limiter circuit itself has filter characteristics, so that it is possible to reduce the filter that is a component provided in the previous stage of the receiver, or simplify the internal configuration of the filter itself. Transmission loss can be reduced.
As a result, it is possible to reduce the passage loss in the front stage of the receiver and improve the noise figure of the receiver.

It is a figure which shows the structure of a general radar system. It is a figure which shows the structure of the limiter circuit by Embodiment 1 of this invention. 4 is an “equivalent circuit at low incident energy” of the limiter circuit according to the first embodiment. 3 is an “equivalent circuit at high incident energy” of the limiter circuit according to the first embodiment. It is a figure for demonstrating operation | movement of the anti-parallel connection PIN diode at the time of high incident energy. It is a figure which shows the input / output characteristic of the limiter circuit by the limiter circuit of a prior art, and the limiter circuit by this invention (this invention). FIG. 6 is a diagram illustrating a configuration of a limiter circuit according to a second embodiment. FIG. 6 is a diagram illustrating a configuration of a limiter circuit according to a third embodiment. 4 is an “equivalent circuit at low incident energy” of the limiter circuit according to the third embodiment. 4 is an “equivalent circuit at high incident energy” of the limiter circuit according to the third embodiment. FIG. 10 is a diagram illustrating a configuration of a limiter circuit according to a fourth embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the drawings, the same reference numerals indicate the same or equivalent ones.
Embodiment 1 FIG.
For example, as shown in FIG. 1, the limiter circuit 400 used in a high-frequency band such as a microwave band is arranged in a stage preceding the receiver 500 in the radar system.
Note that the limiter circuit 400 is configured so that an excessive level signal such as a signal leaked when the transmitter 600 transmits a radar pulse or a radar pulse signal reflected from a short-range target is not directly applied to the radar receiver. A circuit for protecting a radar receiver.

FIG. 2 is a diagram showing a configuration of the limiter circuit according to the first embodiment of the present invention.
In FIG. 2, “A” is an input terminal of a limiter circuit disposed on the RF main line, and “B” is an output terminal of the limiter circuit.
The “RF main line” is a line through which a signal (RF signal) received by the radar apparatus is sent to the receiver.
The limiter circuit according to the present embodiment is arranged to be connected to a first basic unit (described later) 10a arranged to be connected to the input terminal A side on the RF main line and to an output terminal B side on the RF main line. The second basic unit 10b is connected to the main line between the connection point Ca where the first basic unit 10a is connected to the RF main line and the connection point Cb where the second basic unit 10b is connected to the RF main line. And a connected matching circuit 9a.

In order to allow the impedances of the first and second basic units constituting the limiter circuit to be considered as “one element constituting the filter”, matching is performed so that the filter characteristics can be obtained in the matching circuit.
With such a configuration, it is possible to set a “frequency band desired to pass” and a “frequency band desired to be suppressed”.

The first basic unit 10a includes a "capacitor 6a that cancels parasitic components" having one end connected to a connection point Ca for connecting to the RF main line, an anode connected to the other end of the capacitor 6a, and a cathode The first PIN diode 7a is connected to the ground, and the second PIN diode 8a is connected to the other end of the capacitor 6a and the anode is connected to the ground.
Here, since the first PIN diode 7a and the second PIN diode 8a are connected in parallel in opposite directions, the first PIN diode 7a and the second PIN diode 8a are “anti-parallel”. Say "connected".
Similar to the first basic unit 10a, the second basic unit 10b includes a "capacitor 6b that cancels parasitic components" whose one end is connected to a connection point Cb for connection to the RF main line, and an anode that is a capacitor 6b. The first PIN diode 7b is connected to the other end of the capacitor, the cathode is connected to the ground, and the second PIN diode 8b is connected to the other end of the capacitor 6b and the anode is connected to the ground. ing.

FIG. 3 shows a limiter circuit when the matching circuit 9a having a configuration in which the matching inductor 11 and the matching capacitor 12 are connected in series is applied, and shows an equivalent circuit of the limiter circuit when low energy is incident. ing.
When the incident energy is low, the anti-parallel PIN diode is represented by the junction capacitance between the parasitic inductor and the PIN diode generated by a gold wire or the like necessary for mounting.
Accordingly, the equivalent circuit of the first basic unit 10a includes a “capacitor 6a that cancels the parasitic component” having one end connected to the connection point Ca, a parasitic inductor 13a having one end connected to the other end of the capacitor 6a, This is expressed as a series connection of a junction capacitance 14a of a PIN diode connected to the other end of the inductor 13a and the ground.
Similarly, an equivalent circuit of the second basic unit 10b includes a "capacitor 6b that cancels parasitic components" having one end connected to the connection point Cb, a parasitic inductor 13b having one end connected to the other end of the capacitor 6b, The other end of the parasitic inductor 13b and the junction capacitance 14b of the PIN diode connected to the ground are represented as being connected in series.
In this embodiment, as shown in FIG. 3, the matching circuit 9a includes a matching inductor 11 and a matching capacitor 12 connected in series.

The limiter circuit according to the present embodiment is represented by an equivalent circuit as shown in FIG. 3 when the incident energy is low.
That is, the equivalent circuit when the incident energy of the limiter circuit according to the present embodiment is low is the matching circuit 9a in which the matching series inductor 11 and the matching series capacitor 12 are connected in series, and the input terminal A side of the matching circuit 9a. Connected to the capacitor 6a for canceling the parasitic component, the parasitic inductor 13a, the first basic unit 10a represented by the junction capacitance 14a of the PIN diode, and the output terminal B side of the matching circuit 9a, the parasitic component is It consists of a capacitor 6b to cancel, a parasitic inductor 13b, and a second basic unit 10b represented by a junction capacitance 14b of a PIN diode.
Therefore, the limiter circuit according to the present embodiment has a filter characteristic when the incident energy is low, and acts as a band suppression filter.

FIG. 4 shows a limiter circuit when the matching circuit 9a having a configuration in which the matching inductor 11 and the matching capacitor 12 are connected in series is applied, and shows an equivalent circuit of the limiter circuit when high energy is incident. ing.
When the input to the limiter circuit is high incident energy, the PIN diodes connected in anti-parallel (that is, the PIN diode 7a and the PIN diode 8a or the PIN diode 7b and the PIN diode 8b) are expressed as a resistance (ON resistance). .
When the input to the limiter circuit is high incident energy, the parasitic inductor 13a (FIG. 3 or 4A) generated by the capacitor 6a that cancels out the parasitic component of the first basic unit 10a and the gold wire required for mounting. 4), the first basic unit 10a has a resistance (on-resistance) 15a as shown in FIG. 4B. Is represented only by

Similarly, when the input to the limiter circuit is high in incident energy, the radar device includes a capacitor 6b that cancels the parasitic component of the second basic unit 10b and a parasitic inductor 13b that is generated by a gold wire that is necessary for mounting. Since it resonates in series at the frequency of the signal to be used and becomes a short circuit in terms of RF, the second basic unit 10b is also represented by only the resistance (on resistance) 15b as shown in FIG. 4B.
That is, FIG. 4B shows an equivalent circuit of a limiter circuit in the case where a high energy signal is incident and the first basic unit and the second basic unit are expressed only by resistors.
Therefore, when the input to the limiter circuit is high incident energy, the equivalent circuit of the limiter circuit is a state in which only a resistor is connected between the RF main line and the ground, as shown in FIG. 4B. Thus, the limiter circuit obtains a good leakage suppression characteristic.

The electrical length between the basic units constituting the limiter circuit including the matching inductor 11 and the matching capacitor 12 is relatively good if it is 30 to 150 degrees with respect to the frequency of the signal used by the limiter circuit. Leakage suppression characteristics can be obtained.
By the way, the electrical length between the basic units constituting the limiter circuit is generally composed of 90 degrees (λg / 4) of the frequency to be used, but in practice, if the electrical length is 30 to 150 degrees, When phase synthesis is performed, the leakage is not greatly deteriorated compared to the electrical length of 90 degrees.
Therefore, by setting the electrical length between basic units to 30 to 150 degrees, the degree of freedom in designing the matching circuit is expanded.

FIG. 5 is a diagram for explaining the operation principle of the PIN diode 7 and the PIN diode 8 connected in antiparallel when the incident energy is high.
FIG. 5 shows either the first basic unit 10a or the second basic unit 10b.
Therefore, for example, the PIN diode 7 in FIG. 5 is either the PIN diode 7a or the PIN diode 7b described above.
Similarly, the PIN diode 8 in FIG. 5 is either the PIN diode 8a or the PIN diode 8b described above.
The RF signal has an amplitude of “positive” or “negative” with respect to the reference potential (that is, the potential of the ground), but when the RF signal is positive with respect to the reference potential, as shown in FIG. Further, the PIN diode 7 whose cathode side is grounded (that is, the PIN diode 7a or PIN diode 7b) is turned on, and the PIN diode 8 whose anode side is grounded (that is, the PIN diode 8a or PIN diode 8b) acts as a DC return circuit. To do.

When the RF signal is negative with respect to the reference potential, as shown in FIG. 5B, the PIN diode 8 whose anode side is grounded is turned on, and the PIN diode 7 whose cathode side is grounded is used as a DC return circuit. Works.
In FIGS. 5A and 5B, 15 represents an on-resistance and 16 represents a DC return resistance.
Thus, the limiter circuit according to the present embodiment has a leakage suppression characteristic with both positive and negative amplitudes with respect to the reference potential of the RF signal.

On the other hand, in the case of the configuration as in the prior art (Patent Document 1) in which the DC return circuit is connected in parallel to the PIN diode in which the anode is connected to the RF main line and the cathode is connected to the ground, the RF signal is positive with respect to the reference potential. Sometimes the PIN diode is turned on and acts as a resistor, so that it has a leakage suppression characteristic.
However, when the RF signal is negative with respect to the reference potential, the PIN diode does not turn on and acts as a capacitor that is a parasitic component of the PIN diode, and therefore does not have leakage suppression characteristics.

FIG. 6 compares the input / output characteristics of the limiter circuit in the proposed technique (the present invention) and the prior art, and is a diagram for explaining the effect of the basic unit portion constituting the limiter circuit.
It can be said that the limiter circuit is a better limiter circuit when the output power (Output Power) is smaller than the input power (Input Power).
Therefore, when the output power at the same input power (Input Power) is compared, the difference (that is, the “prior art output power” and the “output power of the present invention” at the same input power). It can be said that the difference itself is the effect of the invention.

As described above, the limiter circuit according to the present embodiment is a limiter circuit using a PIN diode used in the microwave band, and includes a capacitor whose one end is connected to the RF main line and cancels the parasitic component, An anti-parallel PIN diode connection body connected to the other end of the capacitor, and the capacitor and the PIN diode connection body are connected in series between the RF main line and the ground.
Therefore, the limiter circuit according to the present embodiment can improve the leakage suppression characteristic for high incident energy.

In addition, the limiter circuit according to the present embodiment has a basic unit configuration including a capacitor and a PIN diode connection body, and the basic unit configuration includes a plurality of matching units arranged on the RF main line via a matching circuit. Stage connected.
Therefore, the limiter circuit according to the present embodiment can further improve the leakage suppression characteristic with respect to high incident energy.
The matching circuit of the limiter circuit according to the present embodiment has a configuration in which an inductor and a capacitor are connected in series.
Therefore, the limiter circuit according to the present embodiment functions as a band suppression filter for low incident energy.

Although the limiter circuit according to the first embodiment described above shows a case where the first basic unit and the second basic unit are connected in two stages via a matching circuit arranged on the RF main line. The basic unit may be only one stage or three or more stages.
Further, the basic unit may be only one stage, the matching circuit may be omitted, and only the leakage suppression effect may be obtained for high incident energy.
The same applies to other embodiments described later.

Embodiment 2. FIG.
FIG. 7 is a diagram showing the configuration of the limiter circuit according to the second embodiment, and is a diagram showing a limiter circuit to which the matching inductor 11 is applied as the matching circuit 9b.
That is, the limiter circuit according to the present embodiment is basically the same as the configuration of the limiter circuit according to the first embodiment described above, but the matching circuit 9b is configured by only the matching inductor 11. .
Since the configurations of the first basic unit 10a and the second basic unit 10b and their equivalent circuits are the same as those in the first embodiment, the description thereof is omitted.

In the limiter circuit according to the present embodiment, when the incident energy is low, the matching inductor 11, the capacitors (6a, 6b) for canceling the parasitic components, the parasitic inductors (13a, 13b), and the junction capacitance (14a, 14b) of the PIN diode are used. ) Acts as a low-pass filter.
When the input to the limiter circuit is high in incident energy, only the resistor is connected between the RF main line and the ground as in the case of the first embodiment described above, and the limiter circuit has a good leakage current. Get suppression characteristics.

As described above, the matching circuit of the limiter circuit according to the present embodiment is composed only of inductors.
Therefore, the limiter circuit according to this embodiment acts as a low-pass filter for low incident energy.

Embodiment 3 FIG.
FIG. 8 is a diagram showing a configuration of a limiter circuit according to the third embodiment.
The basic configuration of the limiter circuit according to the present embodiment is the same as that of the limiter circuit according to the first or second embodiment, and is a first basic circuit that is connected to the input terminal A side on the RF main line. A unit 10a, a second basic unit 10b arranged to be connected to the output terminal B side on the RF main line, a connection point Ca where the first basic unit 10a is connected to the RF main line, and a second basic unit 10b. Is composed of a matching circuit 9c cascaded to the main line between the connection point Cb connected to the RF main line.

In the first embodiment or the second embodiment described above, the first basic unit 10a includes the “capacitor 6a for canceling parasitic components” having one end connected to the connection point Ca for connection to the RF main line, the anode Is connected to the other end of the capacitor 6a, the first PIN diode 7a having the cathode connected to the ground, and the second PIN diode 8a having the cathode connected to the other end of the capacitor 6a and the anode connected to the ground. It consists of
The second basic unit 10b includes a "capacitor 6b for canceling parasitic components" having one end connected to a connection point Cb for connecting to the RF main line, an anode connected to the other end of the capacitor 6b, and a cathode The first PIN diode 7b is connected to the ground, and the second PIN diode 8b is connected to the other end of the capacitor 6b and the anode is connected to the ground.

However, in the present embodiment, the first basic unit and the second basic unit are replaced with capacitors (6a, 6b) that cancel the parasitic components generated in the high frequency region, and inductors that reduce the parasitic components are used. Yes.
As shown in FIG. 8, in the present embodiment, the first basic unit 10a includes a first PIN diode in which an anode is connected to a connection point Ca for connecting to an RF main line, and a cathode is connected to the ground. 7a and a second PIN diode 8a having a cathode connected to the connection point Ca and an anode connected to the ground, an anti-parallel PIN diode connection body, and an inductor connected in parallel with the PIN diode connection body In this case, the first inductor 17a is connected to the connection point Ca at one end and to the ground at the other end.

Similarly, in the second basic unit 10b, the anode is connected to the connection point Cb for connecting to the RF main line, the cathode is connected to the ground, and the cathode is connected to the connection point Cb. An anti-parallel PIN diode connection body comprising a second PIN diode 8b having an anode connected to the ground, and an inductor connected in parallel with the PIN diode connection body, one end of which is connected to the connection point Cb And the second inductor 17b having the other end connected to the ground.
The first inductor 17a or the second inductor 17b is arranged in order to reduce “a parasitic component equivalent to or smaller than the parasitic component of the PIN diode connector” generated in a high frequency region.
In the limiter circuit according to the present embodiment, the first basic unit 10a and the second basic unit 10b are cascade-connected to the RF main line as in the first or second embodiment described above. To the RF main line.

FIG. 9 shows a limiter circuit when a matching inductor 18 and a matching capacitor 19 connected in parallel are applied as the matching circuit 9c, and shows an equivalent circuit when low energy is incident. .
When the incident energy is low, the first basic unit 10a and the second basic unit 10b are represented by a configuration in which a PIN diode connected in anti-parallel is connected in series with a junction capacitance of a parasitic inductor and a PIN diode. On the other hand, when the matching circuit 9c in which the inductor and the capacitor are connected in parallel is used, the limiter circuit acts as a band pass filter.

FIG. 10 shows a limiter circuit when a matching parallel inductor 18 and a matching parallel capacitor 19 connected in parallel to the matching circuit 9 are applied, and shows an equivalent circuit when high energy is incident.
When the incident energy is high, as shown in FIG. 10A, the PIN diodes 7a and 8a or the PIN diodes 7b and 8b connected in antiparallel are expressed as ON resistance.
Also, in the microwave band, the impedance required by the parasitic inductors 13a and 13b generated by the gold wires required for mounting is sufficiently larger than the on-resistances 15a and 15b of the PIN diode. Parasitic inductors 13a and 13b generated by wires or the like are dominant (as shown in FIG. 10B, the on-resistances 15a and 15b can be ignored in terms of an equivalent circuit), and the parasitic inductors 13a and 13b are short-circuited in terms of RF. It will be difficult to do.
However, by connecting in parallel the inductors 17a and 17b that reduce the parasitic components equivalent to or smaller than the parasitic inductors 13a and 13b, the impedance can be reduced, and a good leakage suppression characteristic can be obtained.
The electrical length between the first basic unit 10a and the second basic unit 10b constituting the limiter including the matching parallel inductor 18 and the matching parallel capacitor 19 connected in parallel is the signal length used by the radar device. If it is 30 to 150 degrees with respect to the frequency, a relatively good leakage suppression characteristic can be obtained.

As described above, the limiter circuit according to the present embodiment is a limiter circuit using a PIN diode used in the microwave band, and has one end connected to the RF main line and the other end connected to the ground. A parallel-connected PIN diode connection body and an inductor for reducing parasitic components connected in parallel to the PIN diode connection body between the RF main line and the ground are provided.
Therefore, the limiter circuit according to the present embodiment can also obtain a good leakage suppression characteristic with respect to high incident energy.
In addition, the limiter circuit according to the present embodiment has a basic unit configuration composed of an inductor and a PIN diode connection body, and the basic unit configuration is arranged in a plurality of stages via a matching circuit disposed on the RF main line. It is connected.
Therefore, the limiter circuit according to the present embodiment can further improve the leakage suppression characteristic with respect to high incident energy.
The matching circuit of the limiter circuit according to the present embodiment has a configuration in which an inductor and a capacitor are connected in parallel.
Therefore, the limiter circuit according to the present embodiment acts as a band pass filter for low incident energy.

Embodiment 4 FIG.
FIG. 11 is a diagram illustrating a configuration of a limiter circuit according to the fourth embodiment. FIG. 11 illustrates a limiter circuit in a case where a matching circuit 9d including only a matching capacitor is applied as the matching circuit illustrated in FIG. Yes.
The basic configuration of the limiter circuit according to the present embodiment is the same as that of the limiter circuit according to the third embodiment, and the first basic unit 10a disposed on the input terminal A side on the RF main line is connected to the RF circuit. The second basic unit 10b arranged to be connected to the output terminal B side on the main line, the connection point Ca where the first basic unit 10a is connected to the RF main line, and the second basic unit 10b are the RF main line. The matching circuit 9d is connected to the main line in cascade with the connection point Cb to be connected.

  In the present embodiment, the first basic unit 10a includes a first PIN diode 7a having an anode connected to a connection point Ca for connecting to the RF main line and a cathode connected to the ground, and a connection point Ca. Anti-parallel-connected PIN diode connection comprising a second PIN diode 8a having a cathode connected and an anode connected to the ground, and an inductor connected in parallel with the PIN diode connection, with one end connected The point Ca is composed of a first inductor 17a having the other end connected to the ground.

Similarly, in the second basic unit 10b, the anode is connected to the connection point Cb for connecting to the RF main line, the cathode is connected to the ground, and the cathode is connected to the connection point Cb. An anti-parallel PIN diode connection body comprising a second PIN diode 8b having an anode connected to the ground, and an inductor connected in parallel with the PIN diode connection body, one end of which is connected to the connection point Cb And the second inductor 17b having the other end connected to the ground.
As described in the third embodiment, the first inductor 17a or the second inductor 17b generates “a parasitic component equivalent to or smaller than the parasitic component of the PIN diode connection body” generated in a high frequency region. It is arranged to reduce.
In the limiter circuit according to the present embodiment, the first basic unit 10a and the second basic unit 10b are connected to the RF main line via a “matching circuit 9d including only the capacitor 20” cascaded to the RF main line. It is connected to the.

When the incident energy is low, the first basic unit 10a and the second basic unit 10b are configured such that the anti-parallel PIN diode is a junction capacitance between the parasitic inductor and the PIN diode generated by a gold wire or the like required for mounting. Are connected in series, and include a capacitor 20 of the matching circuit 9d, inductors 17a and 17b that reduce parasitic components, parasitic inductors 13a and 13b, and junction capacitances 14a and 14b of PIN diodes. Acts as
When the incident energy is high, the operation is the same as that of the limiter circuit according to the third embodiment.

As described above, the matching circuit of the limiter circuit according to the present embodiment is composed only of capacitors.
Therefore, the limiter circuit according to the present embodiment acts as a high-pass filter for low incident energy.
In addition, the limiter circuit according to the present embodiment has a leakage suppression characteristic for high incident energy.

  The present invention is useful for realizing a limiter circuit for a microwave band having leakage suppression characteristics for high incident energy and filter characteristics for low incident energy.

6, 6a, 6b Capacitors for canceling parasitic components 7, 7a, 7b, 8a, 8b PIN diodes 9a, 9b, 9c, 9d, matching circuit 10a, 10b Basic unit constituting limiter circuit 11, 18 Inductor of matching circuit 12 , 19, 20 Capacitor of matching circuit 13, 13a, 13b Parasitic inductor added to PIN diode 14a, 14b Junction capacitance of PIN diode 15, 15a, 15b On-resistance of PIN diode 16 DC return circuit 17a, 17b Reduced parasitic components Inductor A input terminal B output terminal D
Ca Connection point between the first basic unit and the RF main line Cb Connection point between the second basic unit and the RF main line 100 Antenna 200 Transmission / reception switch 300 Filter 400 Limiter circuit 500 Receiver 600 Transmitter

Claims (8)

A limiter circuit using a PIN diode used in the microwave band,
A capacitor having one end connected to the RF main line to cancel the parasitic component, and an anti-parallel PIN diode connection connected to the other end of the capacitor;
The limiter circuit, wherein the capacitor and the PIN diode connection body are connected in series between the RF main line and the ground.   A structure composed of the capacitor and the PIN diode connection body is a basic unit structure, and the basic unit structure is connected in multiple stages via a matching circuit disposed on the RF main line. The limiter circuit according to claim 1.   The limiter circuit according to claim 1, wherein the matching circuit has a configuration in which an inductor and a capacitor are connected in series.   The limiter circuit according to claim 1, wherein the matching circuit includes only an inductor. A limiter circuit using a PIN diode used in the microwave band,
An anti-parallel PIN diode connection body having one end connected to the RF main line and the other end connected to the ground;
A limiter circuit comprising an inductor connected in parallel to the PIN diode connector between the RF main line and the ground.   A structure composed of the inductor and the PIN diode connection body is a basic unit structure, and the basic unit structure is connected in a plurality of stages via a matching circuit disposed on the RF main line. The limiter circuit according to claim 5.   7. The limiter circuit according to claim 5, wherein the matching circuit has a configuration in which an inductor and a capacitor are connected in parallel.   7. The limiter circuit according to claim 5, wherein the matching circuit is composed of only a capacitor.

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