JP5404375B2 - Balance-unbalance converter - Google Patents

Description

  The present invention relates to a balanced-unbalanced converter having a function of converting one input signal into a pair of balanced signals and outputting them, and in particular, a compact balanced-unbalanced type having excellent electrical characteristics in a high frequency region. It relates to a converter.

  A rat race circuit is a circuit having a function of converting one input signal into a pair of balanced signals (differential signals) and outputting the same, and a function of changing a port from which an output signal is output according to a phase difference between two input signals. Are known. A rat race circuit is a circuit in which four input / output ports are provided at a specific position of an annular transmission line having a specific length, and a structure using a stripline or a microstrip line as an annular transmission line is known. (For example, refer to Patent Document 1).

JP 2001-292012 JP

  However, the conventional rat race circuit as proposed in Patent Document 1 has several problems as follows.

  The first problem is that the characteristics deteriorate as the electric signal used has a higher frequency. Since the conventional rat race circuit uses a strip line or a microstrip line to form an annular transmission line, the transmission loss in the annular transmission line increases as the frequency increases, and this increases the loss in the rat race circuit. There was a problem that.

  The second problem is that the size increases. Since the rat race circuit requires an annular transmission line and an input / output line extending radially from the circuit, there is a problem that the size is increased. In particular, in order to solve the first problem described above, there is a problem that if an annular transmission line is formed using a rectangular waveguide having excellent transmission characteristics in a high frequency region, the size is further increased. .

  The present invention has been devised in view of such problems in the prior art, and an object thereof is to provide a compact balanced-unbalanced converter having excellent electric characteristics in a high-frequency region.

  The balanced-unbalanced converter of the present invention includes a dielectric substrate, a lower conductor layer disposed on the lower surface of the dielectric substrate, an upper conductor layer disposed on the upper surface of the dielectric substrate, and a high-frequency signal propagation direction. The upper conductor layer includes two rows of through conductor groups for side walls arranged to electrically connect the upper conductor layer and the lower conductor layer at a repetition interval of less than half of the wavelength of the high-frequency signal. , A waveguide-type line portion in which the high-frequency signal is transmitted by a waveguide region surrounded by the lower conductor layer and the two rows of through-wall conductor groups, and a balanced signal on the lower or upper surface of the dielectric substrate And a balanced line portion in which a pair of line conductors capable of transmitting are spaced apart, and the waveguide-type line portion has a propagation direction of the high-frequency signal between the two rows of through-conductor groups for side walls. Along the frequency of less than half of the wavelength of the high-frequency signal. The first and second high-frequency signals can be propagated in the TE10 mode by first separating wall through conductor groups arranged to electrically connect the upper conductor layer and the lower conductor layer at a distance from each other. A first portion in which the waveguide region is divided into the waveguide, and one waveguide connected to the first portion and capable of propagating the high-frequency signal in the TE10 mode and the TE20 mode throughout the waveguide region. A repetition of less than half of the wavelength of the high-frequency signal along the propagation direction of the high-frequency signal between the configured second portion and the two rows of side-wall through conductor groups connected to the second portion The third and fourth high-frequency signals can be propagated in the TE10 mode by the second through-wall through-wall conductor group arranged to electrically connect the upper conductor layer and the lower conductor layer at intervals. Waveguide into the waveguide A third part having a divided region, and a fourth part connected to the third part and configured as one waveguide capable of propagating the high-frequency signal in the TE10 mode and the TE20 mode throughout the waveguide region; The second portion is configured such that a difference between a phase shift amount of the high frequency signal passing in the TE10 mode and a phase shift amount of the high frequency signal passing in the TE20 mode is set to 90 °, The third and fourth waveguides each have a difference in phase shift amount of the high-frequency signal passing through the TE10 mode at 90 °, and the side of the fourth portion connected to the third portion At the opposite end, the pair of line conductors are connected to the lower conductor layer or the upper conductor layer located on the surface of the dielectric substrate on which the pair of line conductors are disposed, and the waveguide Connects the line section and the balanced line section And it is characterized in that they are. According to the balanced-unbalanced converter of this example having such a configuration, when a high-frequency signal is input from the outside to the first or second waveguide, the third and fourth through the second portion. High-frequency signals having a phase difference of 90 ° are input to the waveguide, and high-frequency signals having a phase difference of 180 ° are input to the pair of line conductors of the balanced line section via the fourth portion and output as they are. Therefore, a balanced-unbalanced converter having a function of converting one input signal into a pair of balanced signals (differential signals) and outputting the same can be obtained.

  In the balanced-unbalanced converter according to the present invention, in the configuration described above, the first and second waveguides are spaced apart from each other through the side wall through conductor group and the first separation wall through conductor group. The high-frequency signal is set to be equal, and the second portion has the high-frequency signal so that a difference between a phase shift amount of the high-frequency signal passing in the TE10 mode and a phase shift amount of the high-frequency signal passing in the TE20 mode is 90 °. The length of the signal propagation direction and the interval between the two side wall through conductor groups are set, and the third and fourth waveguides pass through the side wall through conductor group and the second separation wall through hole. The length of the high-frequency signal in the propagation direction and each of the side walls are such that the distance from the conductor group is different from each other and the difference in phase shift amount of the high-frequency signal passing through each of them in the TE10 mode is 90 °. Penetrating conductor group and the second The distance between the separating wall through conductor group is set is characterized in. According to the balanced-unbalanced converter of this example having such a configuration, the width of each waveguide (the through-conductor group for the side wall and each separation wall) can be obtained without partially changing the dielectric constant in the waveguide region. Easy to manufacture because the phase shift amount of each waveguide can be set by the distance between the through-conductor group for use or the distance between the two through-hole conductor groups for the side wall) and the length (length in the propagation direction of the high-frequency signal) A balanced-unbalanced converter can be obtained.

  In this specification, the propagation direction of a high-frequency signal is a direction that includes both the direction in which the high-frequency signal propagates and the opposite direction, and is a direction that substantially coincides with the direction in which the two side walls extend.

  According to the balanced-unbalanced converter of the present invention having the above-described configuration, a small-sized balanced-unbalanced converter having excellent electric characteristics in a high frequency region can be obtained.

It is a perspective view which shows typically the balance-unbalance converter of an example of embodiment of this invention. It is a top view which shows typically the balance-unbalance converter shown in FIG. It is a graph which shows the electrical property of the balance-unbalance converter of an example of embodiment of this invention. It is a graph which shows the electrical property of the balance-unbalance converter of an example of embodiment of this invention.

  Hereinafter, the balanced-unbalanced converter of the present invention will be described in detail with reference to the accompanying drawings.

(Example of embodiment)
FIG. 1 is a perspective view schematically showing a balanced-unbalanced converter as an example of the first embodiment of the present invention. FIG. 2 is a plan view schematically showing the balanced-unbalanced converter shown in FIG. 1 and 2 show a state in which the dielectric substrate and the upper conductor layer (upper tube wall) are seen through for easy understanding of the structure.

  As shown in FIGS. 1 and 2, the balanced-unbalanced converter of this example includes a dielectric substrate (not shown), a lower conductor layer 31, an upper conductor layer (not shown), and a through conductor group for side walls. 33a, 33b, first and second separation wall through conductor groups 35a, 35b, a matching through conductor group 37, and a pair of line conductors 51a, 51b. Further, the balanced-unbalanced converter of this example includes a waveguide-type line portion 40 configured by first to fourth portions 41 to 44 sequentially connected along a propagation direction of a high-frequency signal, and a waveguide The balanced line portion 50 is connected to the fourth portion 44 of the mold line portion 40.

  A dielectric substrate (not shown) is composed of one or a plurality of dielectric layers. The dielectric constant of the dielectric substrate is set to be equal in each part of the dielectric substrate.

  In the waveguide line section 40, the lower conductor layer 31 is disposed on the lower surface of a dielectric substrate (not shown) and functions as a tube wall on the lower side of the waveguide line section 40. The upper conductor layer (not shown) is disposed on the upper surface of the dielectric substrate (not shown), and functions as the upper tube wall of the waveguide line section 40. The two rows of through-hole conductor groups 33a and 33b electrically connect the lower conductor layer 31 and the upper conductor layer (not shown) at a repetition interval less than ½ of the wavelength of the high-frequency signal in the propagation direction of the high-frequency signal. It arrange | positions so that it may connect and functions as two side walls of the waveguide type | mold line part 40. FIG. In the waveguide line section 40, a high-frequency signal propagates through a waveguide region surrounded by the lower conductor layer 31, an upper conductor layer (not shown), and the two sidewall through conductor groups 33a and 33b. The first and second separation wall through conductor groups 35a and 35b have a repetition interval of less than half the wavelength of the high frequency signal in the propagation direction of the high frequency signal between the two rows of through wall conductor groups 33a and 33b. The lower conductor layer 31 and the upper conductor layer (not shown) are arranged so as to be electrically connected, and function as a separation wall that divides the waveguide region in the width direction.

  In the first portion 41, a waveguide region is divided into a first waveguide 41a and a second waveguide 41b through which a high-frequency signal can propagate in the TE10 mode by the first separating wall through conductor group 35a. That is, the widths of the first and second waveguides 41a and 41b indicated by W1 and W2 in FIG. 2 (the distance between the side wall through conductor groups 33a and 33b and the first separation wall through conductor group 35a) are: It is set to be larger than ½ of the wavelength λ of the high frequency signal and smaller than λ. Further, the first and second waveguides 41a and 41b are equal in width (W1, W2) and length (L1) to each other, so that a high-frequency signal passing through each of them in the TE10 mode can be transferred. The phase amounts are set to be equal to each other.

  The second portion 42 is connected to the first portion 41 and constitutes one waveguide through which the high-frequency signal can propagate in the TE10 mode and the TE20 mode over the entire waveguide region. That is, the width of the waveguide of the second portion 42 (interval between the side wall through conductor groups 33a and 33b) indicated by W3 in FIG. 2 is set to be larger than the wavelength λ of the high-frequency signal and 1.5λ or less. Further, the second portion 42 has a length in the propagation direction of the high frequency signal so that a difference between the phase shift amount of the high frequency signal passing in the TE10 mode and the phase shift amount of the high frequency signal passing in the TE20 mode is 90 °. (L2) and the waveguide width (W3) are set. Note that the amount of phase shift of the high-frequency signal passing through the second portion 42 is the amount of phase shift when passing through the connection portion between the first portion 41 and the third portion 43 and the amount of phase shift caused by propagating through the second portion 42. The phase shift amount of the high frequency signal passing in the TE10 mode is 90 ° larger than the phase shift amount of the high frequency signal passing in the TE20 mode.

  In the third portion 43, the waveguide region is divided into a third waveguide 43a and a fourth waveguide 43b through which a high-frequency signal can propagate in the TE10 mode by the second through-wall group 35b for the separation wall. That is, the width of the third waveguide 43a indicated by W4 in FIG. 2 (the distance between the side wall through conductor group 33a and the second separation wall through conductor group 35b) and the fourth waveguide 43b indicated by W5. The width (the distance between the side wall through conductor group 33b and the second separation wall through conductor group 35b) is set to be larger than ½ of the wavelength λ of the high frequency signal and smaller than λ. The third waveguide 43a and the fourth waveguide 43b have different waveguide widths (W4, W5), and the difference in the amount of phase shift of the high-frequency signal that passes through each of them in the TE10 mode. The length in the propagation direction of the high-frequency signal (L3) and the width of each waveguide (W4, W5) are set so that is 90 °.

Here, in order for the phase difference of the high-frequency signal passing through the third waveguide 43a and the fourth waveguide 43b to be 90 °, the in-tube wavelength in the third waveguide 43a is set to λ ₃ [m], When the guide wavelength in the waveguide 43b is λ ₄ [m], and the lengths of the third waveguide 43a and the fourth waveguide 43b in the high-frequency propagation direction are L ₃ [m],
L ₃ = (4 | λ ₃ ^-1 -λ ₄ ^-1 |) ^-1 (1)
Should be satisfied. Further, since the guide wavelength varies depending on the width of the waveguide, the frequency of the high-frequency signal is f [Hz], the speed of light is C [m / s], the relative permittivity of the waveguide region is Er, and the third waveguide 43a. Is W ₄ [m] and the width of the fourth waveguide 43b is W ₅ [m], the above equation (1) is as follows.

L ₃ = W ₄ W ₅ C | 2W ₅ (4W ₄ ² f ² Er-C ² ) ^0.5 -2W ₄ (4W ₅ ² f ² Er-C ² ) ^0.5 | ^-1 (2)
In other words, so as to satisfy the above expression (2), the width W ₄ of the third waveguide _43a, the width W ₅ and the third and fourth waveguides 43a of the fourth waveguide 43 b, 43 b of the high-frequency propagation direction of the length by setting L _3, the phase difference between the high-frequency signal passing through the third waveguide 43a and the fourth waveguide 43b can be 90 °.

Incidentally, the equilibrium of this example - in the unbalanced transformer, the width W ₄ of the third waveguide 43a is smaller than the width W ₅ of the fourth waveguide 43 b, the tube in the third waveguide 43a The wavelength λ ₃ is set larger than the guide wavelength λ ₄ in the fourth waveguide 43b. That is, the phase shift amount of the high frequency signal passing through the third waveguide 43a in the TE10 mode is set to be 90 ° smaller than the phase shift amount of the high frequency signal passing through the fourth waveguide 43b in the TE10 mode.

  Further, a matching through conductor group 37 for connecting the lower conductor layer 31 and the upper conductor layer (not shown) is provided between the third portion 43 and the fourth portion 44, and the third portion 43 And the fourth portion 44 for impedance matching and high-frequency signal distribution ratio adjustment.

  The fourth portion 44 is connected to the third portion 43, and constitutes one waveguide through which the high-frequency signal can propagate in the TE10 mode and the TE20 mode over the entire waveguide region. That is, the width of the waveguide of the fourth portion 44 (interval between the side wall through conductor groups 33a and 33b) indicated by W6 in FIG. 2 is set to be larger than the wavelength λ of the high frequency signal and not more than 1.5λ. The length (L4) of the waveguide of the fourth portion 44 is set as appropriate.

  In the balanced line section 50, a pair of line conductors 51a and 51b capable of transmitting a balanced signal are disposed on the lower surface of a dielectric substrate (not shown) with a gap therebetween. One end of each of the pair of line conductors 51 a and 51 b is connected to the lower conductor layer 31 at the end of the fourth portion 44 opposite to the side connected to the third portion 43. One end of the pair of line conductors 51a and 51b is connected to the central portion of the waveguide of the fourth portion 44 (the central portion between the two side wall through conductor groups 33a and 33b). A connection portion between the lower conductor layer 31 and the pair of line conductors 51a and 51b is a connection portion between the waveguide line portion 40 and the balanced line portion 50. Further, on the upper surface of the dielectric substrate (not shown), the upper conductor layer (not shown) of the waveguide type line portion 40 is extended to the balanced line portion 50, and the electric field is transferred to the dielectric substrate at the balanced line portion 50. It serves to improve the connection between the waveguide-type line unit 40 and the balanced line unit 50 by being unevenly distributed in (not shown).

  Next, the operation of the balanced-unbalanced converter of this example having such a configuration will be described. The high-frequency signal input from the external circuit to the first waveguide 41a propagates through the second portion 42 in both the TE10 mode and the TE20 mode, and is input to the third waveguide 43a and the fourth waveguide 43b. The At this time, since the difference between the phase shift amount of the high-frequency signal passing in the TE10 mode and the phase shift amount of the high-frequency signal passing in the TE20 mode is set to 90 ° in the second portion 42, the third waveguide The phase difference between the high frequency signal input to 43a and the high frequency signal input to the fourth waveguide 43b is approximately 90 °. That is, the phase of the high-frequency signal input to the third waveguide 43a is delayed by 90 ° from the phase of the high-frequency signal input to the fourth waveguide 43b. Further, the positions of the through-hole conductor groups 33a and 33b for side walls are finely adjusted so that the amplitude of the high-frequency signal input to the third waveguide 43a is equal to the amplitude of the high-frequency signal input to the fourth waveguide 43b. Has been. Note that the high-frequency signal input from the first waveguide 41a to the second portion 42 is hardly output to the second waveguide 41b because the TE10 mode and the TE20 mode cancel each other.

  The high-frequency signals input from the second portion 42 to the third waveguide 43a and the fourth waveguide 43b propagate in the TE10 mode through the third waveguide 43a and the fourth waveguide 43b, respectively. Entered in portion 44. At this time, the phase shift amount of the high-frequency signal passing through the third waveguide 43a in the TE10 mode is set to be 90 ° smaller than the phase shift amount of the high-frequency signal passing through the fourth waveguide 43b in the TE10 mode. Therefore, the phase of the high-frequency signal output from the third waveguide 43a to the fourth portion 44 is different from the phase of the high-frequency signal output from the fourth waveguide 43b to the fourth portion 44 by 180 °. Become a thing. In this way, high-frequency signals having the same amplitude and different phases by 180 ° are input from the third waveguide 43a and the fourth waveguide 43b to the fourth portion 44.

  The input high-frequency signal propagates through the fourth portion 44 in the TE20 mode and is input as it is to the pair of line conductors 51a and 51b. Therefore, the high frequency signal input to the line conductor 51a and the high frequency signal input to the line conductor 51b have the same amplitude and a phase difference of 180 °.

  The input high-frequency signal propagates through the pair of line conductors 51a and 51b, and is output to the outside from the pair of line conductors 51a and 51b. At this time, the pair of line conductors 51a and 51b are set to be equal in both width and length so that the phase shift amounts of the high-frequency signals passing through the pair of line conductors 51a and 51b are equal to each other. The pair of high-frequency signals output from the signal are balanced signals (differential signals) having the same amplitude and different phases by 180 °.

  Thus, according to the balanced-unbalanced converter of this example, the high-frequency signal input to the first waveguide 41a is converted into a pair of balanced signals (differential signals), and a pair of line conductors 51a, 51b can be output. When a balanced signal is input to the pair of line conductors 51a and 51b, a high-frequency signal can be output from the first waveguide 41a by a process reverse to the above-described process.

  When a high-frequency signal is input from the external circuit to the second waveguide 41b, the high-frequency signal propagates through the second portion 42 in both the TE10 mode and the TE20 mode and is input to the third waveguide 43a. Is a phase advanced by 90 ° from the high-frequency signal input to the fourth waveguide 43b. Since the phase shift amount of the high frequency signal passing through the third waveguide 43a in the TE10 mode is set to be 90 ° smaller than the phase shift amount of the high frequency signal passing through the fourth waveguide 43b in the TE10 mode, The high frequency signal output from the third waveguide 43a to the fourth portion 44 is a signal having the same phase as the high frequency signal output from the fourth waveguide 43b to the fourth portion 44. High-frequency signals having the same phase and amplitude input from the third waveguide 43a and the fourth waveguide 43b propagate through the fourth portion 44 in the TE10 mode and are input to the pair of line conductors 51a and 51b as they are. . Therefore, the high-frequency signal input to the line conductor 51a and the high-frequency signal input to the line conductor 51b are signals having the same homologous amplitude. Since the pair of line conductors 51a and 51b are set so that the phase shift amounts of the high-frequency signals passing through the pair of line conductors 51a and 51b are equal to each other, the pair of high-frequency signals output from the pair of line conductors 51a and 51b are also the same. It becomes a signal of homologous amplitude.

  Thus, according to the balanced-unbalanced converter of the present example, the high-frequency signal input to the second waveguide 41b is converted into a pair of signals having the same homologous amplitude, and the pair of line conductors 51a and 51b are used. Can be output. When a high-frequency signal having the same amplitude is input to the pair of line conductors 51a and 51b from the outside, the high-frequency signal can be output from the second waveguide 41b by a process reverse to the above-described process.

  Further, when the phase difference φ of the signals input from the outside to the pair of line conductors 51a and 51b is 0 <φ <180 °, the high-frequency signal propagates through the fourth portion 44 in both the TE10 mode and the TE20 mode. To do. A high-frequency signal can be output from both the first waveguide 41a and the second waveguide 41b via the third and fourth waveguides 43a and 43b and the second portion 42. At this time, the distribution ratio of the high-frequency signals output from the first waveguide 41a and the second waveguide 41b can be changed by changing the phase difference between the signals input to the pair of line conductors 51a and 51b. it can.

  As described above, according to the balanced-unbalanced converter of this example, a balanced-unbalanced converter having various functions similar to the rat race circuit can be obtained. Further, the dimension in the width direction is very small as compared with the rat race circuit, and the transmission loss in the high frequency region is very small as compared with the conventional rat race circuit using the stripline or the microstrip line. In this manner, a small balanced-unbalanced converter having excellent electrical characteristics in the high frequency region can be obtained.

  In addition, according to the balanced-unbalanced converter of this example, the widths of the first and second waveguides 41a and 41b are set to be equal to each other, and the second portion 42 is a high-frequency signal that passes in the TE10 mode. The width and length are set so that the difference between the phase shift amount and the phase shift amount of the high-frequency signal passing through the TE20 mode is 90 °, and the third and fourth waveguides 43a and 43b are respectively Since the respective widths and lengths are set so that the difference in phase shift amount of the high-frequency signal passing through the TE10 mode in the TE10 mode is 90 °, the dielectric constant in the waveguide region may be partially different. Since the phase shift amount of each waveguide can be set, a balanced-unbalanced converter that can be easily manufactured can be obtained.

  Further, according to the balanced-unbalanced converter of this example having the above-described configuration, the balanced-unbalanced converter can be formed on a dielectric substrate (not shown) using a known tape multilayer technology. Thus, a balanced and unbalanced converter that is small and easy to manufacture can be obtained.

  In the balanced-unbalanced converter of this example, the relative permittivity of the dielectric substrate is, for example, about 2-20. The material of the dielectric substrate is not particularly limited as long as it has a characteristic that does not hinder the transmission of high-frequency signals. A resin such as glass epoxy can be used, but a balanced-unbalanced converter can be used. It is desirable to use dielectric ceramics from the viewpoints of accuracy in forming and ease of manufacturing. The lower conductor layer 31 and the upper conductor layer (not shown) are made of a highly conductive metal and have a thickness of, for example, about 3 μm to 50 μm. The repetition interval between the side wall through conductor groups 33a and 33b and the first and second separation wall through conductor groups 35a and 35b is less than ½ of the wavelength of the high frequency signal from the viewpoint of preventing leakage of the high frequency signal. It is necessary that it is less than ¼. Via holes and through holes can be used as the side wall through conductor groups 33a and 33b and the first and second separation wall through conductor groups 35a and 35b, and the diameter thereof is, for example, about 0.05 mm to 0.5 mm. .

  The balanced-unbalanced converter of this example can be manufactured as follows, for example. First, using a slurry obtained by adding and mixing a suitable organic solvent and solvent to a ceramic raw material powder mainly composed of glass, alumina, aluminum nitride, etc., a ceramic green sheet is formed by a doctor blade method or a calender roll method. Make it. Next, through holes for forming the side wall through conductor groups 33a and 33b and the first and second separation wall through conductor groups 35a and 35b are formed in the obtained ceramic green sheet using a punching machine or the like. A paste made by adding an appropriate oxide, organic solvent, etc. such as alumina, silica, magnesia, etc. to metal powder is filled into the through-holes by thick film printing and applied to the surface of the ceramic green sheet. To produce a ceramic green sheet with a conductive paste. Next, the obtained ceramic green sheets with a conductive paste are laminated and pressed using a hot press apparatus to form a laminate. And when the dielectric layer is made of glass ceramics, the obtained laminate is about 850 ° C. to 1000 ° C., alumina ceramics is about 1500 ° C. to 1700 ° C., and aluminum nitride ceramics is about 1600 ° C. to 1900 ° C. It is produced by firing at a peak temperature of about. The metal powder is preferably copper, gold or silver when the dielectric layer is glass ceramic, and tungsten or molybdenum when the dielectric layer is alumina ceramic or aluminum nitride ceramic.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, in the example of the embodiment described above, the width (W4) of the third waveguide 43a is made smaller than the width (W5) of the fourth waveguide 43b, and the third waveguide 43a is changed to the TE10 mode. In this example, the phase shift amount of the high-frequency signal passing through is set 90 ° smaller than the phase shift amount of the high-frequency signal passing through the fourth waveguide 43b in the TE10 mode. However, the present invention is not limited to this. . The third phase is set so that the phase shift amount of the high-frequency signal passing through the third waveguide 43a in the TE10 mode is 90 ° larger than the phase shift amount of the high-frequency signal passing through the fourth waveguide 43b in the TE10 mode. The width (W4) of the waveguide 43a may be larger than the width (W5) of the fourth waveguide 43b. In such a case, the relationship between the first waveguide 41a and the second waveguide 41b is reversed with respect to the balanced-unbalanced converter of the example of the embodiment described above. For example, when a high frequency signal is input to the second waveguide 41b, a balanced signal (differential signal) can be output from the pair of line conductors 51a and 51b.

  In the above-described embodiment, the pair of line conductors 51a and 51b is connected to the lower conductor layer 31, but the pair of line conductors 51a and 51b is connected to the upper conductor layer (not shown). ) May be connected.

  Furthermore, in the example of the embodiment described above, the upper conductor layer (not shown) disposed on the upper surface of the dielectric substrate (not shown) of the waveguide type line portion 40 is extended to the balanced line portion 50. However, another ground conductor may be disposed on the upper surface of the dielectric substrate (not shown) in the balanced line portion 50. In some cases, the ground conductor may not be disposed.

  Furthermore, in the example of the above-described embodiment, the example in which the difference in the amount of phase shift of the waveguide is caused by the difference in the shape of the waveguide is shown, but the present invention is not limited to this. For example, a difference in the amount of phase shift of the waveguide may be caused by a difference in dielectric constant in the waveguide.

  Next, a specific example of the balanced-unbalanced converter of the present invention will be described.

  The electrical characteristics of the balanced-unbalanced converter shown in FIGS. 1 and 2 were simulated. In the simulation, the dielectric substrate had a relative dielectric constant of 9.4 and a thickness of 0.15 mm. The side wall through conductor groups 33a and 33b and the first and second separation wall through conductor groups 35a and 35b were via holes having a diameter of 0.1 mm. The arrangement pitch of the through conductors of the side wall through conductor groups 33a and 33b and the first and second separation wall through conductor groups 35a and 35b was set to 0.3 mm at the interval between the centers of the adjacent through conductors. The widths (W1, W2) of the first and second waveguides 41a, 41b are both 1.05 mm, the width (W3) of the second portion 42 is 1.61 mm, and the width (W4) of the third waveguide 43a. Was 0.75 mm, the width (W5) of the fourth waveguide 43b was 1.05 mm, and the width (W6) of the fourth portion 44 was 1.68 mm. The length (L1) of the first and second waveguides 41a and 41b is 1.04 mm, the length (L2) of the second portion 42 is 1.31 mm, and the length of the third and fourth waveguides 43a and 43b. The length (L3) was 1.54 mm, and the length (L4) of the fourth portion 44 was 2.3 mm.

  Then, the outer ends of the pair of line conductors 51a and 51b are port 1, the outer end of the second waveguide 41b is port 2, the outer end of the first waveguide 41a is port 3, and the passage between the ports is performed. The characteristics were simulated.

  First, the passage characteristic to port 2 (S21) and the passage characteristic to port 3 (S31) when a differential signal was input to port 1 were obtained. FIG. 3 is a graph showing the results, in which the horizontal axis represents frequency and the vertical axis represents amplitude. According to the graph shown in FIG. 3, when a balanced signal (differential signal) is input to the port 1 (the pair of line conductors 51a and 51b), a high-frequency signal is output from the port 3 via the first waveguide 41a. Although it is output satisfactorily, it can be seen that almost no high-frequency signal is output from the port 2 connected to the second waveguide 41b. Further, it can be seen from this result that when a high frequency signal is input from the outside to the first waveguide 41a, a balanced signal is output from the pair of line conductors 51a and 51b.

  Next, the passage characteristic to port 2 (S21) and the passage characteristic to port 3 (S31) when an in-phase signal was input to port 1 were obtained. FIG. 4 is a graph showing the results, in which the horizontal axis represents frequency and the vertical axis represents amplitude. According to the graph shown in FIG. 4, when an in-phase signal is input to port 1 (a pair of line conductors 51a and 51b), a high-frequency signal is satisfactorily output from port 2 via the second waveguide 41b. However, it can be seen that almost no high-frequency signal is output from the port 3 connected to the first waveguide 41a. Further, it can be seen from this result that when a high-frequency signal is input from the outside to the second waveguide 41b, an in-phase signal is output from the pair of line conductors 51a and 51b.

  From these results, it was confirmed that when a high-frequency signal was input from the outside to the first waveguide 41a, a balanced signal (differential signal) was output from the pair of line conductors 51a and 51b. Further, it was confirmed that when a high frequency signal was input from the outside to the second waveguide 41b, an in-phase signal was output from the pair of line conductors 51a and 51b. Further, the intensity of the high-frequency signal output from the first waveguide 41a and the second waveguide 41b is changed by changing the phase relationship between the pair of high-frequency signals input to the pair of line conductors 51a and 51b. It was confirmed that it was possible. Thereby, the effectiveness of the present invention was confirmed.

31: Lower conductor layer
33a, 33b: Side wall through conductor group
35a: First through wall through conductor group
35b: Second through wall through conductor group
40: Waveguide type line section
41: 1st part
42: Second part
43: Third part
44: Fourth part
41a: first waveguide
41b: second waveguide
43a: third waveguide
43b: Fourth waveguide
50: balanced line section
51a, 51b: Line conductor

Claims (2)

A dielectric substrate, a lower conductor layer disposed on the lower surface of the dielectric substrate, an upper conductor layer disposed on the upper surface of the dielectric substrate, and less than half of the wavelength of the high-frequency signal in the propagation direction of the high-frequency signal 2 side wall through conductor groups arranged to electrically connect the upper conductor layer and the lower conductor layer at repeated intervals, the upper conductor layer, the lower conductor layer, and the two rows A waveguide-type line section in which the high-frequency signal is transmitted by a waveguide region surrounded by a through-hole conductor group for side walls and a pair of line conductors capable of transmitting a balanced signal on the lower surface or the upper surface of the dielectric substrate are spaced from each other. With a balanced line section that is open,
The waveguide line section is
The upper conductor layer and the lower conductor layer are electrically connected between the two rows of through-hole conductor groups for the sidewalls along the propagation direction of the high-frequency signal at a repetition interval of less than half of the wavelength of the high-frequency signal. A first portion in which the waveguide region is divided into first and second waveguides through which the high-frequency signal can propagate in a TE10 mode by a first through-wall group for separation walls arranged so as to
A second portion that is connected to the first portion and is configured to have a single waveguide capable of propagating the high-frequency signal in the TE10 mode and the TE20 mode throughout the waveguide region;
Between the two rows of through-wall conductor groups connected to the second portion, the upper conductor layer and the upper conductor layer at a repetitive interval of less than half of the wavelength of the high-frequency signal along the propagation direction of the high-frequency signal The waveguide region is formed in the third and fourth waveguides through which the high-frequency signal can propagate in the TE10 mode by the second through-wall group of separation walls arranged so as to electrically connect the lower conductor layers. A third part divided;
A fourth portion configured by one waveguide connected to the third portion and capable of propagating the high-frequency signal in the TE10 mode and the TE20 mode in the entire waveguide region;
In the second portion, the difference between the phase shift amount of the high frequency signal passing in the TE10 mode and the phase shift amount of the high frequency signal passing in the TE20 mode is set to 90 °,
In the third and fourth waveguides, the difference in phase shift amount of the high-frequency signal passing through each in the TE10 mode is set to 90 °,
The lower conductor layer or the upper conductor layer located on the surface of the dielectric substrate opposite to the side connected to the third portion of the fourth portion, on the surface on which the pair of line conductors are disposed. The balanced-unbalanced converter is characterized in that the pair of line conductors are connected to each other, and the waveguide line section and the balanced line section are connected. In the first and second waveguides, the interval between the side wall through conductor group and the first separation wall through conductor group is set to be equal to each other,
The second portion has a length in the propagation direction of the high-frequency signal so that a difference between a phase shift amount of the high-frequency signal passing in the TE10 mode and a phase shift amount of the high-frequency signal passing in the TE20 mode is 90 °. And the interval between the two side wall through conductor groups is set,
In the third and fourth waveguides, the interval between the side wall through conductor group and the second separation wall through conductor group is different from each other, and the transfer of the high-frequency signal passing through each in the TE10 mode is different. The length in the propagation direction of the high-frequency signal and the distance between each of the side wall through conductor groups and the second separation wall through conductor group are set so that the phase amount difference is 90 °. The balanced-unbalanced converter according to claim 1.

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