JP2858078B2 - Answering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a response device capable of switching between two states of emitting or not emitting a harmonic signal in response to irradiation of a microwave signal.

[0002]

2. Description of the Related Art A conventional response device for emitting a harmonic signal in response to irradiation of a microwave signal has a closed loop formed including a high-frequency diode that generates a harmonic in response to the microwave signal. It is. Then, a harmonic signal generated when the response device passes through a gate device or the like that emits a microwave signal is incorporated in a system that detects the harmonic signal on the gate device side. As an application example of such a system, a gate device or the like for irradiating a microwave signal is installed at the entrance of a store, a response device is attached to the product, and when the product with the response device attached is taken out of the store. , A warning signal or the like can be generated by detecting a harmonic signal.

[0003]

In the conventional response device, a harmonic signal is always emitted in response to the irradiation of the microwave signal unless the built-in high-frequency diode is destroyed. Therefore, in order to take the product out of the store without generating an alarm or the like, the response device must be removed from the product or the device must be destroyed.

[0004] Even with such a conventional response device, there is no problem if the product once taken out of the store is not brought into the store again.

[0005] However, when the same product is repeatedly brought out and brought in like rental products, it is troublesome to remove the response device. Further, if the response device is destroyed, it cannot be used repeatedly, which is uneconomical.

The present invention has been made in view of the circumstances of such a conventional response device, and emits a high-frequency signal in response to microwave signal irradiation without destroying the device.
Alternatively, it is an object of the present invention to provide a response device capable of performing switching control so as not to fire.

[0007]

In order to achieve the above object, a response device according to the present invention is a response device that emits a harmonic signal in response to irradiation of a microwave signal. A high-frequency diode that reacts to generate harmonics, a capacitor, and a first antenna that resonates at a first frequency lower than the microwave are connected to form a closed loop, and a switch is provided in parallel with the capacitor; A switch control unit is provided which resonates at a second frequency different from the first frequency at a frequency lower than the microwave and makes the switch unit conductive.

The switch means is a transistor, and the switch control means includes a second antenna resonating at the second frequency, and a low-frequency diode connected to the base of the transistor and not reacting to the microwave. May be configured.

[0009]

[Work] Since a closed loop is formed by connecting a high-frequency diode, a capacitor, and a first antenna, if the high-frequency diode is zero-biased without being charged to the capacitor, the microwave signal is not irradiated. A harmonic signal may be emitted. Then, the first antenna in which the first antenna resonates
By irradiating the low frequency signal, this signal is rectified by the high frequency diode and charged to the capacitor, and the high frequency diode is reverse biased and cannot emit a harmonic signal in response to the irradiation of the microwave signal. . Further, by discharging the charging voltage of the capacitor by turning on the switch means, the high-frequency diode becomes zero-biased, and it becomes possible to emit a harmonic signal again.

The switching means is a transistor,
If the switch control means is formed by a second antenna that resonates at the second frequency and a low-frequency diode, when a signal of the second frequency is irradiated, the signal resonates at the second antenna and further lowers. The voltage is rectified by the frequency diode to make the transistor conductive, and the charged voltage of the capacitor is discharged.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a circuit diagram of an embodiment of a response device according to the present invention. FIG. 2A is a diagram for explaining an operation of emitting a harmonic signal, and FIG. It is a figure explaining operation which is not made to do.

[0012] First, in FIG. 1, one end of the capacitor 12 to the cathode of the high-frequency diode 10 capacitance between terminals such as a Schottky barrier diode is to respond to small microwave f ₀ of the signal is connected, a high frequency diode 10 between the anode of the capacitor 10 and the other end of the capacitor 12.
, A high-frequency diode 10, a capacitor 12, and a first loop antenna 14.
Form a closed loop. The first loop antenna 14 is formed so as to resonate with a signal having a _first frequency f ₁ lower than the microwave f ₀ , for example, several hundred KHz.

Further, N
The PN transistor 16 is connected. The collector of the transistor 16 is connected to one end of the capacitor 12 connected to the cathode of the high-frequency diode 10, and the emitter of the transistor 16 is connected to the other end of the capacitor 12. The cathode of a low-frequency diode 18 such as a silicon diode that does not react to the microwave f ₀ is connected to the base of the transistor 16. Then, a second loop antenna 20 is interposed between the anode of the low-frequency diode 18 and the emitter of the transistor 16. This second loop antenna 20 has a microwave f
_A second frequency f ₂ lower than ₀ and different from the _first frequency f ₁
Is formed so as to resonate with the signal of The signal of the second frequency f ₂ does not resonate at the first loop antenna 14, and the signal of the first frequency f ₁ does not resonate at the second loop antenna 20.

In such a configuration, when the capacitor 12 is not charged, the high-frequency diode 10
Is a zero bias, and when a signal of the microwave f ₀ is irradiated, as shown in FIG.
_Thus, the signal of ₀ is rectified, and signals of the second and third harmonics 2f ₀ and 3f ₀ are emitted.

When a signal of the first frequency f ₁ is irradiated, the signal is resonated by the first loop antenna 14, further rectified by the high-frequency diode 10, and charged in the capacitor 12. Here, the signal of the _first frequency f ₁ is not resonated by the second loop antenna 20, and the transistor 16 is non-conductive. Therefore, as shown in FIG. 2B, the high-frequency diode 10 is reverse-biased by the charging voltage Vc of the capacitor 12 to be in a linear region, and does not emit harmonics even when irradiated with the microwave f ₀ signal.

Further, when a signal of the second frequency f ₂ is irradiated, the signal is resonated by the second loop antenna 20 and rectified by the low-frequency diode 18 to make the transistor 16 conductive. Then, the charging voltage of the capacitor 12 is discharged, the high-frequency diode 10 becomes zero bias, the harmonic again by irradiation of microwave f ₀ 2
f ₀ and 3f ₀ are fired. Here, the signal of the _second frequency f ₂ is not resonated by the first loop antenna 14 and the capacitor 12 is not charged.

As described above, in the response device of the present invention, by irradiating the signals of the first and second frequencies f ₁ and f ₂ , the higher harmonic wave is generated with respect to the irradiation of the microwave f ₀ signal. Switching control can be repeatedly performed so as to fire or not to fire. Therefore, as a response device attached to a rental product or the like, it can be used repeatedly, and the trouble of removing the product from the product is omitted, which is extremely convenient in practical use.

FIG. 3 is a circuit diagram of another embodiment of the response device according to the present invention. In FIG. 3, the same reference numerals are given to the same circuit elements as those in FIG. 1, and duplicate description will be omitted.

The other embodiment shown in FIG. 3 differs from that of FIG. 1 in that the connection directions of the high frequency diode 10 and the low frequency diode 18 are reversed,
That is, a PNP transistor 22 is connected instead of the N transistor 16. The operation of the other embodiment shown in FIG. 3 is the same as that shown in FIG.

FIG. 4 is a circuit diagram of another embodiment of the response device according to the present invention. 4, the same circuit elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

4 differs from that shown in FIG. 1 in that the normally open contact 2 of the reed switch 24 is connected in parallel with the capacitor 12 in place of the transistor 16.
4a is connected to the coil 24 of the reed switch 24.
b is that the second loop antenna 20 is connected. Note that the low-frequency diode 18 is omitted.

In such a configuration, when a signal of the second frequency f ₂ is irradiated, the signal is transmitted to the second loop antenna 20.
, The coil 24b is excited, and the normally open contact 24a of the reed switch 24 is closed. Therefore, the charging voltage of the capacitor 12 is discharged.

FIG. 5 is a circuit diagram of still another embodiment of the response device according to the present invention. 5, the same circuit elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

In another embodiment shown in FIG. 5, the difference from the one shown in FIG. 1 is that the first and second microstrip antennas 26 and 20 are replaced with the first and second microstrip antennas 26 and 20. , 28 are used, and the first and second resonance circuits 30, 32 are used. First microstrip antenna 26 and first resonance circuit 30
Is formed to resonate with the signal of the first frequency f ₁ ,
A second microstrip antenna 28 and the second resonant circuit 32 is formed so as to resonate in a second frequency f ₂ of the signal. Then, the high-frequency diode 10, the capacitor 12, and the first resonance circuit 30 are connected in series to form a closed loop, and the first resonance circuit 30 is further connected to the first microstrip antenna 26. A low-frequency diode 18 and a second resonance circuit 32 are interposed in series between the base and the emitter of the transistor 16, and a second microstrip antenna 28 is connected to the second resonance circuit 32.

In this configuration, when the signal of the first frequency f ₁ is irradiated, the signal is received by the first microstrip antenna 26, further resonated by the first resonance circuit 30, and rectified by the high-frequency diode 10. Thus, the capacitor 12 is charged. When a signal of the second frequency f ₂ is irradiated, the signal is received by the second microstrip antenna 28, resonated by the second resonance circuit 32, rectified by the low-frequency diode 18, and Is conducted. If the transponder of the present invention is formed in the shape of a card, the first and second microstrip antennas 26 and 28 as antennas are advantageous for forming a thin shape. Further, by providing the first and second resonance circuits 30 and 32, it is possible to select even if the first and second frequencies f ₁ and f ₂ are close to each other. Here, if the signal of the second frequency f ₂ cannot be received by the first microstrip antenna 26 and the signal of the first frequency f ₁ cannot be received by the second microstrip antenna 30, The two resonance circuits 30 and 32 need not be provided. Further, instead of the first and second microstrip antennas 26 and 28, any antenna such as a rod antenna may be used.

In the above embodiment, the transistor 1
6, 22 and the reed switch 24 are used as the switch means, but the present invention is not limited to this, and any structure may be used as long as the charge voltage of the capacitor 12 can be appropriately discharged. The switch control means may have any structure capable of controlling the switch means. For example, a phototransistor, a Hall element, or the like may be used as the switch means, and the switch control means may be one that irradiates and blocks light, or one that applies a magnetic field.

[0027]

As described above, since the response device of the present invention is constituted, the following special effects can be obtained.

In the response device according to the first aspect, it is possible to arbitrarily switch between two states in which the harmonic signal is emitted or not emitted in response to the irradiation of the microwave signal.

Further, in the response device according to the second aspect, the switch means and the switch control means for canceling the state in which the harmonic signal is not emitted in response to the irradiation of the microwave signal can be formed by a simple circuit.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an embodiment of a response device according to the present invention.

2A is a diagram illustrating an operation of emitting a harmonic signal, and FIG. 2B is a diagram illustrating an operation of not emitting a harmonic signal.

FIG. 3 is a circuit diagram of another embodiment of the response device of the present invention.

FIG. 4 is a circuit diagram of another embodiment of the response device of the present invention.

FIG. 5 is a circuit diagram of still another embodiment of the response device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 High frequency diode 12 Capacitor 14 First loop antenna 16, 22 Transistor 18 Low frequency diode 20 Second loop antenna 24 Reed switch 26 First microstrip antenna 28 Second microstrip antenna

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-275386 (JP, A) JP-A-7-35845 (JP, A) JP-A-3-6481 (JP, A) JP-A-3-3581 269286 (JP, A)

Claims (2)

(57) [Claims] 1. A responding device for emitting a harmonic signal in response to irradiation of a microwave signal, comprising: a high-frequency diode and a capacitor for generating a harmonic in response to the microwave signal; and a capacitor lower than the microwave. A closed loop is formed by connecting to a first antenna that resonates at a first frequency, a switch is provided in parallel with the capacitor, and a second frequency different from the first frequency at a frequency lower than the microwave is provided. A response device comprising switch control means for causing the switch means to conduct by resonating. 2. The response device according to claim 1, wherein said switch means is a transistor, and said switch control means is connected to a second antenna resonating at said second frequency and a base of said transistor. And a low-frequency diode that does not react to the microwave.