JP2005198167A - Balanced line-unbalanced line connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a balanced line-unbalanced line connector which is available over wide bands. <P>SOLUTION: In a balanced line-unbalanced line connector 100, a high-pass filter 120 resulting from combining capacitors C<SB>H1</SB>, C<SB>H3</SB>and C<SB>H5</SB>of lumped constant and inductors L<SB>H2</SB>and L<SB>H4</SB>in so-called T-shape is connected by a Port-1 in parallel with a low-pass filter 130 resulting from combining Capacitors C<SB>L1</SB>, C<SB>L3</SB>and C<SB>L5</SB>of lumped constant and inductors L<SB>L2</SB>and L<SB>L4</SB>in so-called π-shape. Other ends thereof are defined as Port-2, Port-3. The high-pass filter is a phase shifter which is given by a fifth order function and designed to make a cutoff frequency f<SB>cH</SB>lower than a design frequency f<SB>0</SB>and to cause an output phase to become +90° relative to an input phase at the design frequency f<SB>0</SB>. The low-pass filter 130 is a phase shifter which is given by a fifth order function and designed to make a cutoff frequency f<SB>cL</SB>higher than the design frequency f<SB>0</SB>and to cause an output phase to become -90° relative to an input phase at the design frequency f<SB>0</SB>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a balanced line-unbalanced line connector that mutually converts power transmitted through a balanced line and an unbalanced line.

  As means for converting power transmitted through an unbalanced line typified by a coaxial line and a balanced line typified by a pair cable, there is a connector constituted by a lumped constant inductor (induction L) and a capacitor (capacitance C). . This connector is also used when connecting an unbalanced line and a balanced antenna represented by a dipole. Since the connector having this configuration can be manufactured with a chip inductor and a chip coil, there is an advantage that it can be manufactured in the same process as a matching circuit such as an amplifier in a circuit board.

  FIG. 10 shows a general configuration diagram of a balanced line-unbalanced line connector 900 according to the prior art. Port-1 connected to the unbalanced line is provided with a phase shifter 920 whose output phase is +90 degrees with respect to the desired frequency and a phase shifter 930 whose output phase is -90 degrees with respect to the input phase. Each is connected to Port-2 and Port-3 connected to the balanced line. The balanced line-unbalanced line connector 900 is configured so that the power input to the unbalanced port Port-1 is output with equal amplitude and opposite phase at the balanced ports Port-2 and Port-3. Designed.

A circuit diagram of this balanced line-unbalanced line connector 900 is shown in FIG. The phase shifter 920 is a high-pass filter given by a cubic function, and the phase shifter 930 is a low-pass filter given by a cubic function. A phase shifter (high-pass filter) 920 has one end connected to a connection point between capacitors C _H1 and C _H3 and capacitors C _H1 and C _H3 connected in series between Port-1 and Port-2, and the other end grounded. The derived L _H2 . A phase shifter (low-pass filter) 930 includes an induction L _L2 connected in series between Port-1 and Port-3, one end of each of which is a connection point between Port-1 and induction L _L2, and induction L _L2 and Port-3. The capacitors C _L1 and C _L3 are connected to a connection point between the other _ends and grounded at the other end.

An example of the characteristics of the balanced line-unbalanced line connector 900 of FIG. 11 is shown in FIG. FIG. A shows the reflection coefficient of Port-1, which is an unbalanced port. FIG. B indicates a transmission coefficient to the balanced ports Port-2 and Port-3. FIG. C shows the frequency characteristic of the phase difference between Port-2 and Port-3, which are balanced ports. In each figure, the horizontal axis is a frequency normalized by the design frequency _fe .

FIG. Like A, in the vicinity of the design frequency _fe , the reflection coefficient of Port-1, which is an unbalanced port, is small. FIG. Like B, the transmission coefficients to the balanced ports Port-2 and Port-3 are equal near the design frequency _fe , and the power input from Port-1 is equally distributed to Port-2 and Port-3 (- 3dB). FIG. As in C, the phase difference between the balanced ports Port-2 and Port-3 is about 180 degrees near the design frequency _fe . The balanced line-unbalanced line connector 900 can be designed using CAD software “APPCAD” manufactured by Agilent Technologies.

Balanced line in FIG. 11 - unbalanced line connector 900, although it is effective in a narrow band, with a wide band up to about ± 25% of the design frequency f _e, the frequency away from the design frequency f _e, reflection Large (FIG. 12.A), large output loss on the low-pass filter 930 side (FIG. 12.B, the difference from the high-pass filter 920 is about 3 dB), and the phase difference deviates greatly from 180 degrees (FIG. 12.C). That was the problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize a balanced line-unbalanced line connector having a low loss over a wide band.

To solve the above problems, the means described in claim 1 includes a high-pass filter cutoff frequency f _cH, the low pass filter cut-off frequency f _cL connected in parallel, the balanced line and the balanced line for connecting the unbalanced line The unbalanced line connector, wherein the high-pass filter and the low-pass filter are each composed of a total of four or more inductances and capacitances at a certain frequency f ₀ (where f _cH <f ₀ <f _cL ). The difference between the output phase of the high-pass filter and the output phase of the low-pass filter is approximately 180 degrees.

The means described in claim 2 is characterized in that, at the frequency f ₀ , the output phase of the high-pass filter is 90 degrees and the output phase of the low-pass filter is −90 degrees. According to the third aspect of the present _invention , when the characteristic function of the filter with respect to the normalized frequency is F, f _cH , f ₀ , and f _cL are related to the following expressions (A) and (B). Where j is an imaginary unit and Re represents the real part of a complex number.

  The means described in claim 4 is characterized in that the characteristic function of the filter is a Butterworth characteristic. The balanced line according to any one of claims 1 to 3, wherein the means according to claim 5 is connected to a balanced antenna provided on an insulator surface of a moving body. -An unbalanced line connector.

  According to a sixth aspect of the present invention, there is provided a substrate, a high-pass filter and a low-pass filter formed on one surface of the substrate, and two throughs electrically connected to one end of each of the high-pass filter and the low-pass filter. A hole and two conductor patterns electrically connected to the two through holes and provided on the back surface of the substrate. The balanced antenna is electrically connected to the two conductor patterns provided on the back surface of the substrate. It is connected.

  According to a seventh aspect of the present invention, at least one of another filter and an amplifier is formed on the substrate, and the terminal on the side where the balanced antenna of the high pass filter and the low pass filter is not connected is the other filter and amplifier. It is characterized by being connected to at least one of the above.

  Since the high-pass filter and the low-pass filter are each composed of a total of four or more inductances and capacitances, the amount of each pass can be made flat over a wide frequency band. Also, if the difference between the output phase of the high-pass filter and the output phase of the low-pass filter is designed to be 180 degrees at a certain frequency, in a wide band including that frequency, for example, a frequency band of ± 25% centering on that frequency. The phase difference between the balanced ports can also be approximately 180 degrees. As a result, a broadband connector can be realized. Further, the bandwidth can be adjusted by the order of the functions of the high-pass filter and low-pass filter constituting the phase shifter, and the amplitude characteristic (passage amount) can be adjusted by the type of function. Therefore, by appropriately adjusting these parameters, a balanced line-unbalanced line connector that covers a desired bandwidth can be realized. (Claim 1)

  By means of claims 2 and 3, the high-pass filter and low-pass filter constituting claim 1 can be easily designed. In particular, since the amplitude characteristics (passage amount) are flattened over a wide band by designing based on the Butterworth characteristics as in the fourth aspect, it is possible to realize a balanced line-unbalanced line connector with even lower loss.

  According to the fifth aspect of the present invention, the broadband balanced antenna provided on the glass of the vehicle can be connected to the unbalanced cable without impairing the broadband characteristics. According to the sixth aspect, the balanced line-unbalanced line connector can be easily mounted on the balanced antenna provided on the glass of the vehicle. Further, according to the seventh aspect, since the filter and the amplifier are configured on the same substrate together with the balanced line-unbalanced line connector, the manufacturing cost can be reduced.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to a following example.

FIG. 1 is a circuit diagram showing a configuration of a balanced line-unbalanced line connector 100 according to a specific first embodiment of the present invention. The balanced line-unbalanced line connector 100 includes a lumped capacitor (capacitance) C _H1 , C _H3 and C _H5 , inductors (induction) L _H2 and L _H4 in a so-called T type, and a concentrated circuit. A constant capacitor (capacitance) C _L1 , C _L3 and C _L5 , inductors (induction) L _L2 and L _L4 are connected in parallel with a so-called π type low pass filter 130 through Port-1, and the other end of each is connected. Port-2 and Port-3. High-pass filter 120, which is given by the fifth-order function, the cutoff frequency f _cH is lower than the design frequency f _0, the output phase with respect to input phase at the design frequency f ₀ is designed to be a + 90 ° phase It is a vessel. On the other hand, the low-pass filter 130, which is given by the fifth-order function, the cutoff frequency f _cL is higher than the design frequency f _0, is designed such that the output phase with respect to input phase at the design frequency f ₀ is -90 degrees Phaser.

FIG. 2 shows transmission characteristics of the balanced line-unbalanced line connector 100 when the high-pass filter 120 and the low-pass filter 130 are designed to have fifth-order Butterworth characteristics. FIG. A is a graph showing the reflection coefficient of Port-1, which is an unbalanced port. FIG. B is a graph showing the transmission coefficient to Port-2 and Port-3 which are balanced ports. FIG. C is a graph showing the frequency characteristics of the phase difference between Port-2 and Port-3 which are balanced ports. In each figure, the horizontal axis is a frequency normalized by the design frequency f ₀ .

The balanced line-unbalanced line connector 100 of FIG. Like A, in the vicinity of the design frequency f ₀ , the reflection coefficient of Port-1, which is an unbalanced port, is small, and the reflection coefficient is −10 dB or less in a wide band of ± 25% of the design frequency f ₀ . That is, the reflection coefficient is small in a wide band of ± 25% of the design frequency f ₀ . In addition, FIG. Like B, the transmission coefficients to the balanced ports Port-2 and Port-3 are almost equal around the design frequency f ₀ , and the difference between them is about 1 dB in a wide band of ± 25% of the design frequency f _0. It is. That is, the power inputted from Port-1 is found to be substantially uniform distribution to Port-2 and Port-3 in ± 25% wider band design frequency f _0. In addition, FIG. As and C, the phase difference at Port-2 and Port-3 is a balanced port is 180 degrees at the design frequency f _0, and becomes substantially 180 degrees in the ± 25% of the wide band design frequency f ₀ ing. That is, the phase difference between Port-2 and Port-3, which are balanced ports, is approximately 180 degrees in a wide band of ± 25% of the design frequency f ₀ . These features of the present invention become clearer when FIG. 2 and FIG. 12 are compared. That is, FIG. As shown in FIG. 2B, the output loss difference between the low-pass filter 930 and the high-pass filter 920 of the balanced line-unbalanced line connector 900 is about 3 dB at maximum. As in B, the balanced line-unbalanced line connector 100 shows an improvement of about 1 dB and about 2 dB. FIG. As shown in FIG. 2, the output phase difference between the low-pass filter 930 and the high-pass filter 920 of the balanced line-unbalanced line connector 900 is about 23 degrees at maximum. As in B, the balanced line-unbalanced line connector 100 was improved to 1/3, about 7 degrees.

  In the first embodiment, a high-pass filter and a low-pass filter designed based on the fifth-order Butterworth characteristic (a total of five capacitors and capacitors) are used. The effect of the present invention is exhibited by the above configuration (capacitor and capacitor (inductive) in total of 4 or more).

  FIG. A, FIG. B is a circuit diagram showing the configuration of high-pass filters 120 and 121 that are phase shifters for setting the output phase to the input phase to +90 degrees. FIG. A is a so-called T type, FIG. B is a so-called π-type, and either can be used as a high-pass filter having the same fifth-order Butterworth characteristic. Hereinafter, the characteristics of the T-type high pass filter will be described.

Fig. 4 shows the pass characteristics (butterworth characteristics) and phase characteristics of the T-type high-pass filter. A, FIG. Each is shown in B. The frequency _normalized by the cut-off frequency _fcH is taken as the horizontal axis. FIG. A, FIG. In B, “2 ^nd ”, “3 ^rd ”, “4 ^th ”, “5 ^th ” and “6 ^th ” are high pass based on Butterworth characteristics of the second, third, fourth, fifth and sixth orders, respectively. With the characteristics of the filter, a total of 2, 3, 4, 5 and 6 capacitors (capacitance) and inductors (induction) constitute a T-type circuit. For reference, the characteristics of the phase shifter (high-pass filter 920) of the balanced line-unbalanced line connector 900 of FIG. 11 are also normalized as the design frequency _fe and indicated as “Conv.”.

With regard to amplitude, when increasing the order, although it is cut-off frequency f _cH In throughput -3 dB, attenuation of the blocking region is below the cutoff frequency f _cH large, it is known that may showing a steep filter characteristic. On the other hand, regarding the phase, when the order is increased, the frequency at which the phase becomes +90 degrees increases. For example, when the phase shifter is configured with a high-pass filter having a fifth order Butterworth characteristic, the frequency at which the phase is +90 degrees is 2.13 _fcH . A flat pass characteristic is obtained in a relatively wide frequency band centered on this frequency. In fact, f ₀ = 2.13f _cH Distant, Figure 4. A, FIG. When the 5th-order graph of B is renormalized by f ₀ , FIG. C, FIG. Like D. In practice, if the function is higher than the fourth order, the loss is as low as 0.1 dB or less over a wide band.

The output phase θ _H of the high-pass filter having Butterworth characteristics is given by the following equation (a), where F is the Butterworth function for the normalized frequency, Re is the real part of the complex number, and Im is the imaginary part of the complex number. It is done.

The output phase θ _H of the high-pass filter becomes 90 degrees when the denominator in arctan of equation (a) becomes 0, and therefore when the following equation (A) holds.

  Exactly the same goes for the low-pass filter. FIG. A, FIG. B is a circuit diagram showing low-pass filters 131 and 130 that are phase shifters for setting the output phase to −90 degrees with respect to the input phase. FIG. A is a so-called T type, FIG. B is a so-called π-type, and either can be used as a low-pass filter having the same fifth-order Butterworth characteristic. Hereinafter, the characteristics of the T-type low-pass filter will be described.

Fig. 6 shows the pass characteristics (butterworth characteristics) and phase characteristics of the T-type low-pass filter. A, FIG. Each is shown in B. The frequency normalized by the cutoff frequency _fcL is taken as the horizontal axis. FIG. A, FIG. In B, “2 ^nd ”, “3 ^rd ”, “4 ^th ”, “5 ^th ” and “6 ^th ” are low pass based on the Butterworth characteristics of the second, third, fourth, fifth and sixth orders, respectively. With the characteristics of the filter, a total of 2, 3, 4, 5 and 6 capacitors (capacitance) and inductors (induction) constitute a T-type circuit. For reference, the characteristics of the phase shifter (low-pass filter) 930 of the balanced line-unbalanced line connector 900 of FIG. 11 are also normalized as the design frequency _fe and indicated as “Conv.”.

With regard to amplitude, when increasing the order, although it is cut-off frequency f _cL the throughput -3 dB, attenuation of the blocking region is cut-off frequency f _cL or larger, it is known that may showing a steep filter characteristic. On the other hand, regarding the phase, when the order is increased, the frequency at which the phase becomes −90 degrees decreases. For example, when a phase shifter by a low-pass filter of the fifth order Butterworth characteristics, the frequency of the phase going to -90 °, a 0.47f _cL. A flat pass characteristic can be obtained in a relatively wide frequency band centered on this frequency. In fact, f ₀ = 0.47f _cL Distant, Figure 6. A, FIG. When the 5th-order graph of B is renormalized by f ₀ , FIG. C, FIG. Like D. In practice, if the function is higher than the fourth order, the loss is as low as 0.1 dB or less over a wide band.

The output phase θ _L of the low-pass filter having Butterworth characteristics is given by the following equation (b), where F is the Butterworth function with respect to the normalized frequency, Re is the real part of the complex number, and Im is the imaginary part of the complex number. It is done.

The output phase θ _L of the low-pass filter becomes −90 degrees when the denominator in arctan of equation (a) becomes 0, and therefore when the following equation (B) holds.

  In the above embodiment, the filter characteristic function is a Butterworth function, but other functions such as a Chebyshev function, a Bessel function, and an elliptic function may be used.

  The present embodiment shows an example in which the balanced line-unbalanced line connector 100 of the first embodiment is connected to a balanced antenna 200 provided on a glass of a vehicle. As shown in FIG. 7, the left side and the right side of the upper part of the windshield 1 of the sedan type vehicle 1000, ie, the vicinity of the ceiling part 2, and the left side and the right part of the upper part of the rear glass 3, ie, the vicinity of the ceiling part 2. In addition, a total of four balanced antennas 200 are mounted. In FIG. 7, a dipole is illustrated as an example of the balanced antenna 200.

  FIG. 8 shows a configuration diagram of a balanced antenna 200 provided on glass, a circuit board 290 on which a balanced line-unbalanced line connector 100 is mounted, and an unbalanced cable (coaxial cable) 210. The two terminals 220 and 230 of the balanced antenna 200 are electrically connected to terminals (Port-2 and Port-3 in FIG. 1) to the balanced line of the balanced line-unbalanced line connector 100 provided on the circuit board 290. It is connected to the. An unbalanced cable (coaxial cable) 210 is electrically connected to a terminal (Port-1 in FIG. 1) to the unbalanced line of the balanced line-unbalanced line connector 100 provided on the circuit board 290.

  The connection between the balanced antenna 200, the circuit board 290 on which the balanced line-unbalanced line connector 100 is mounted, and the unbalanced cable (coaxial cable) 210 will be described in detail with reference to FIG. FIG. A is a schematic cross-sectional view showing a configuration of a circuit board 290 on which a balanced antenna 200 provided on the windshield 1 or the rear glass 3 and a balanced line-unbalanced line connector 100 are mounted.

  FIG. Like A, the circuit board 290 has the balanced line-unbalanced line connector 100 mounted on the surface of the base 291. In addition, conductors 211, 221, and 231 are provided on the surface of the base 291 of the circuit board 290, through which the core wire of the unbalanced cable (coaxial cable) 210 and the Port- of the balanced line-unbalanced line connector 100 are respectively connected. 1. The terminal 220 of the balanced antenna 200 and Port-2 of the balanced line-unbalanced line connector 100, and the terminal 230 of the balanced system antenna 200 and Port-3 of the balanced line-unbalanced line connector 100 are electrically connected. It is connected. This is shown in FIG. B is shown in plan view.

  FIG. Like A, the base 291 of the circuit board 290 is provided with through-holes 222 and 232 filled with conductors, so that the conductors 221 and 231 provided on the surface of the base 291 and the back of the base 291 are provided. The conductors 223 and 233 are electrically connected. A conductor plate 250 serving as a ground is also provided on the back surface of the base 291 of the circuit board 290. The conductor plate 250 serving as the ground is connected to the ground of the unbalanced cable (coaxial cable) 210. This is shown in FIG. Shown in C.

  FIG. Like A, the conductors 223 and 233 provided on the back surface of the base 291 of the circuit board 290 are terminals 220 of the balanced antenna 200 provided on the windshield 1 or the rear glass 3 via the solder balls 224 and 234, respectively. And 230 are electrically connected. A plan view of the terminals 220 and 230 of the balanced antenna 200 provided on the windshield 1 or the rear glass 3 is shown in FIG. Shown in D. FIG. D is a plan view of the windshield 1 or the rear glass 3 on the vehicle interior side, and a dotted line frame portion denoted by a reference numeral 290 'means that the back surface of the base 291 of the circuit board 290 faces the position.

  According to the configuration of the present embodiment, the connector can be easily mounted on the balanced antenna provided on the glass of the vehicle. In FIG. 9, only the balanced line-unbalanced line connector 100 is mounted on the circuit board 290. However, if other components such as a filter and an amplifier are configured on the same circuit board, the manufacturing cost is reduced. Can do.

The circuit diagram which shows the structure of the balanced line-unbalanced line connector 100 which concerns on the specific 1st Example of this invention. 2. A is a graph showing the reflection coefficient of Port-1, which is an unbalanced port of the first embodiment. B is a graph showing transmission coefficients to Port-2 and Port-3, which are balanced ports of the first embodiment. C is a graph showing the frequency characteristics of the phase difference between Port-2 and Port-3 which are balanced ports of the first embodiment. 3. 2A is a circuit diagram showing the configuration of the high-pass filter 120; B is a circuit diagram showing a configuration of a high-pass filter 121. FIG. The graph which shows the passage characteristic (butterworth characteristic) of a high pass filter. The graph which shows the phase characteristic of a high pass filter. FIG. The graph which renormalized the 5th-order characteristic of A with the frequency from which a phase will be +90 degree | times. FIG. The graph which renormalized the 5th-order characteristic of B with the frequency from which a phase becomes +90 degree | times. 3. 2A is a circuit diagram showing the configuration of the low-pass filter 131; B is a circuit diagram showing a configuration of the low-pass filter 130. FIG. The graph which shows the passage characteristic (Butterworth characteristic) of a low-pass filter. The graph which shows the phase characteristic of a low-pass filter. FIG. The graph which renormalized the 5th-order characteristic of A with the frequency from which a phase will be +90 degree | times. FIG. The graph which renormalized the 5th-order characteristic of B with the frequency from which a phase becomes +90 degree | times. The sketch which shows the position of the die ball antenna provided in the vehicle. FIG. 3 is a configuration diagram of a balanced antenna provided on glass, a circuit board on which a balanced line-unbalanced line connector connected thereto, and an unbalanced cable (coaxial cable) 210 are mounted. 9. 8. A is a schematic cross-sectional view showing the configuration of a circuit board on which a balanced antenna and a balanced line-unbalanced line connector are mounted; B is a plan view of the surface of the base 291 of the circuit board 290; C is a front view of the back surface of the substrate 291 of the circuit board 290; D is a view of the glass interior in the vicinity of the terminal of the balanced antenna. The general block diagram of a balanced line-unbalanced line connector. The circuit diagram of the balanced line-unbalanced line connector of a prior art example. 12 A is a graph showing the reflection coefficient of Port-1, which is an unbalanced port of a conventional example; B is a graph showing transmission coefficients to Port-2 and Port-3, which are balanced ports of the conventional example; C is a graph showing the frequency characteristics of the phase difference between Port-2 and Port-3, which are balanced ports of the conventional example.

Explanation of symbols

100: balanced line-unbalanced line connector 120, 121: high pass filter (90 degree phase shifter)
130, 131: Low-pass filter (-90 degree phase shifter)
C _H1 , C _H2 , C _H3 , C _H4 , C _H5 : Capacitors constituting the high-pass filter L _H1 , L _H2 , L _H3 , L _H4 , L _H5 : Induction constituting the high-pass filter C _L1 , C _L2 , C _L3 , C _L4 , C _L5 : Capacities constituting a low-pass filter L _L1 , L _L2 , L _L3 , L _L4 , L _L5 : Guidance constituting a low-pass filter 1000: Vehicle (moving body)
1: Vehicle windshield 2: Vehicle ceiling 3: Vehicle rear glass 200: Dipole antenna (balanced antenna)
220, 230: Dipole antenna terminal 210: Coaxial cable (unbalanced cable)
290: Circuit board 291: Substrate 211, 221, 231: Conductor provided on the surface of the substrate 222, 232: Through hole filled with conductor provided on the substrate 223, 233: Conductor provided on the back surface of the substrate 224, 234: Solder ball 250: Conductor plate serving as a ground provided on the back surface of the substrate 290 ′: Area facing the back surface of the circuit board substrate on the windshield or rear glass vehicle interior side

Claims (7)

And the high-pass filter cutoff frequency f _cH, the low pass filter cut-off frequency f _cL connected in parallel, the balanced line and the balanced line connecting the unbalanced line - a unbalanced line connector,
The high-pass filter and the low-pass filter are each composed of four or more total inductors and capacitors,
Balanced line-unbalanced characterized in that the difference between the output phase of the high-pass filter and the output phase of the low-pass filter at a certain frequency f ₀ (where f _cH <f ₀ <f _cL ) is approximately 180 degrees. Line connector. 2. The balanced line-unbalanced line connector according to claim 1, wherein an output phase of the high-pass filter is 90 degrees and an output phase of the low-pass filter is −90 degrees at the frequency f ₀ . _Assuming that the characteristic function of the filter with respect to the normalized frequency is F, f _cH , f ₀ , and f _cL satisfy the relationship of the following expressions (A) and (B), where j is an imaginary unit and Re is a complex number The balanced line-unbalanced line connector according to claim 1, wherein the balanced line-unbalanced line connector represents a real part.

4. The balanced line-unbalanced line connector according to claim 3, wherein the characteristic function of the filter is a Butterworth characteristic. The balanced line-unbalanced line connector according to any one of claims 1 to 4, wherein the balanced line-unbalanced line connector is connected to a balanced antenna provided on an insulating surface of a moving body. A substrate,
The high pass filter and the low pass filter formed on one surface of the substrate;
Two through holes electrically connected to one end of each of the high pass filter and the low pass filter;
Two conductive patterns electrically connected to the two through holes and provided on the back surface of the substrate;
6. The balanced line-unbalanced line connector according to claim 5, wherein the balanced antenna is electrically connected to two conductor patterns provided on the back surface of the substrate. At least one of another filter and an amplifier is formed on the substrate,
7. The balanced line-unconnected device according to claim 6, wherein a terminal of the high-pass filter and the low-pass filter to which the balanced antenna is not connected is connected to at least one of the other filter and the amplifier. Balance line connector.

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