JP2009200609A - Signal distributor and designing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make circuits compact and to improve reflection characteristics of an input terminal over a wide band. <P>SOLUTION: A signal distributor 1 includes an output unit 20 which has a plurality of output terminals 21 and a plurality of transmission lines 22 connecting the respective output terminals 21, and a transformer unit 30 which connects the input terminal 10 and the output unit 20 by a plurality of 1/4-wavelength transmission lines connected in series in stages in an equivalent circuit, and is characterized in that characteristic impedance of a transmission line 22 connected to one of the plurality of the output terminals 21 in the equivalent circuit from the direction of the input terminal 10 is equal to composite impedance of one or more output terminals 21, including the one output terminal 21, disposed farther from the input terminal 10 than the transmission line 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a signal distributor that distributes a microwave signal and a design method thereof.

  A Wilkinson power divider is well known as a circuit that distributes a microwave millimeter wave signal in the N direction (see Non-Patent Document 1 below). In the Wilkinson power divider, matching is achieved from any input / output terminal, and isolation between output terminals is also achieved. However, since the circuit has a three-dimensional structure when distributed in three or more directions, it is difficult to configure the circuit in a planar shape or to manufacture an integrated circuit. As a technique for solving this problem, a power combiner and a power distributor described in Patent Document 1 below are known.

  When distributing the input signal, it is required that no reflection component is generated for the input signal. As a planar configuration circuit that satisfies this requirement, a multi-distribution circuit with a transformer described in Non-Patent Documents 2 and 3 below and a Bagley-polygon power distributor described in Non-Patent Document 4 below are known. There is also known a circuit that feeds power from the back surface of the substrate with a coaxial cable and distributes signals radially on the surface of the substrate (Non-Patent Document 5 below).

In a conventional Bagley polygon power divider that divides an input signal by 2n + 1 (n is an integer), the transmission path length between adjacent output terminals is determined to be a half wavelength, so that the circuit tends to be large. In order to improve this point, there is a power distributor described in Japanese Patent Application No. 2006-313003. With this power distributor, circuit miniaturization can be realized and distribution characteristics can be improved.
http://www.microwaves101.com/encyclopedia/wilkinson_nway.cfm M. Kishihara, K. Yamane and I. Ohta, “Design of broadband microstrip-type multi-waypower dividers”, Asia-Pacific Microwave Conference, Proc., Vol.3, pp.1688-1691, Nov.2003. M. Kishihara, K. Yamane and I. Ohta, “DParallel processing of powell's optimization algorithm and its application to design of multi-way power dividers,” Asia-Pacific MicrowaveConference, Proc., 2005. http://www.dc2light.pwp.blueyonder.co.uk/Webpage/Hybridcouplers.htm#bagley ELHolzman, “An eiginvalue equation analysis of a symmetrical coax line to N-waywaveguide power divider,“ IEEE Trans. On MTT, Vol.42, No7, July 1994. Japanese Patent Laid-Open No. 9-289405

  However, in the power distributor described in the above Japanese Patent Application No. 2006-313003, the band where the reflection loss at the input terminal is a predetermined level or less (the band where the reflection characteristic at the input terminal is good) is narrow.

  The present invention has been made in order to solve the above problems, and provides a signal distributor and a design method thereof that can reduce the size of a circuit and improve reflection characteristics at an input terminal over a wide band. The purpose is to provide.

  The signal distributor of the present invention has an output terminal having a plurality of output terminals and a plurality of transmission lines connecting the output terminals, and a plurality of quarter wavelength transmission lines connected in series in multiple stages in an equivalent circuit. And a transformer section for connecting the output section, and for each of the plurality of output terminals in the equivalent circuit, the characteristic impedance of the transmission line connected to the one output terminal from the direction of the input terminal, and the one output terminal The combined impedance of one or more output terminals located in a direction away from the input terminal with respect to the transmission line is equal.

  According to such a signal distributor, since the transformer section is a multistage transformer in which a plurality of quarter-wave transmission lines are connected in series, compared with the case of a single stage transformer, The reflection loss is reduced over a wide band (reflection characteristics (input reflection characteristics) at the input terminal are improved over a wide band). Also, for each output terminal, the characteristic impedance of the transmission line connected to the one output terminal from the direction of the input terminal becomes equal to the combined impedance of one or more output terminals located in the direction away from the input terminal rather than the transmission line. Thus, by providing the transmission line between the output terminals, the length of the transmission line between the output terminals can be arbitrarily selected. As a result, the length of the transmission line between the output terminals can be shortened to reduce the circuit size. That is, with such a signal distributor, it is possible to reduce the circuit size and improve the reflection characteristics at the input terminal over a wide band.

  In the signal distributor of the present invention, the transformer section connects the first quarter wavelength transmission line, one end of which is connected to the input terminal, and the other end of the first quarter wavelength transmission line and the output section. Preferably, the line widths of the first quarter wavelength transmission line and the second quarter wavelength transmission line are equal to each other.

  In this case, since the line width of the 1/4 wavelength transmission line constituting the transformer section is constant, the signal distributor can be easily manufactured.

A signal distributor design method of the present invention includes a signal output unit having a plurality of output terminals and a plurality of transmission lines connecting the output terminals, and a transformer unit connecting the input terminals and the output unit. A signal distributor design method in an information processing apparatus for designing a distributor, wherein an input terminal impedance at an input terminal, the number of output terminals, and an allowable reflection coefficient corresponding to an allowable reflection amount in a pass band of the signal distributor. Based on the reception step for receiving input and the number of input terminal impedances and output terminals received in the reception step, the following equation (1)
_{Z 1 = 2Z 0, Z 2} = 2Z 0/3, ..., Z k = 2Z 0 / (N-2) ... (1)
However, k = (N−1) / 2
(In the formula, Z ₀ represents the input terminal impedance, and N represents the number of output terminals.)
Based on the first calculation step for calculating the characteristic impedance Z _k of the plurality of transmission lines connecting the output terminals, and the input terminal impedance and the number of output terminals received in the receiving step, the following equation (2)
Z _in = Z ₀ / (2n + 1) (2)
However, n = (N−1) / 2
(In the formula, Z ₀ represents the input terminal impedance, and N represents the number of output terminals.)
The second calculation step of calculating the load Z _in at the connection point between the transformer unit and the output unit, the input terminal impedance and the allowable reflection coefficient received in the reception step, and the load calculated in the second calculation step Based on the following formulas (3) and (4)
ρ _m ² = {(K _0L −K ₁₂ ² ) / (K _0L + K ₁₂ ² )} ² (3)
(Wherein ρ _m represents the allowable reflection coefficient, K _0L represents the ratio between the load and the input terminal impedance, and K ₁₂ represents the characteristic impedance of the first quarter wavelength transmission line constituting the transformer section and the first impedance. 2 represents the ratio of the characteristic impedance of the 1/4 wavelength transmission line to 1/2, that is, K _0L = Z _in / Z ₀ , K ₁₂ = (Z _m2 / 2) / Z _m1 )
Z _m1 (Z _m2 / 2) = Z ₀ Z _in (4)
(In the formula, Z ₀ represents the input terminal impedance, and Z _in represents the load.)
To calculate a characteristic impedance Z _m1 of the first quarter-wave transmission line and a characteristic impedance Z _{m2 of} the second quarter-wave transmission line, and a first calculation step and a third calculation step. And an output step for outputting the characteristic impedance calculated in (1).

  According to such a signal distributor design method, by inputting the input terminal impedance at the input terminal, the number of output terminals, and the allowable reflection coefficient corresponding to the allowable reflection amount in the pass band of the signal distributor, the above signal is obtained. The characteristic impedance of each transmission line constituting the distributor can be calculated. In other words, it is possible to design a signal distributor that can reduce the circuit size and improve the reflection characteristics at the input terminal over a wide band.

A signal distributor design method of the present invention includes a signal output unit having a plurality of output terminals and a plurality of transmission lines connecting the output terminals, and a transformer unit connecting the input terminals and the output unit. A method for designing a signal distributor in an information processing apparatus for designing a distributor, which is accepted at an accepting step for accepting input of an input terminal impedance at an input terminal, the number of output terminals, and a line parameter ratio, and at an accepting step. Based on the input terminal impedance and the number of output terminals, the following formula (5)
_{Z 1 = 2Z 0, Z 2} = 2Z 0/3, ..., Z k = 2Z 0 / (N-2) ... (5)
However, k = (N−1) / 2
(In the formula, Z ₀ represents the input terminal impedance, and N represents the number of output terminals.)
Based on the first calculation step for calculating the characteristic impedance Z _k of the plurality of transmission lines connecting the output terminals, and the input terminal impedance and the number of output terminals received in the reception step, the following equation (6)
Z _in = Z ₀ / (2n + 1) (6)
However, n = (N−1) / 2
(In the formula, Z ₀ represents the input terminal impedance, and N represents the number of output terminals.)
The second calculation step of calculating the load Z _in at the connection point between the transformer unit and the output unit, the input terminal impedance and the line parameter ratio received in the reception step, and the load calculated in the second calculation step Based on the following formulas (7) and (8)
(Z _m2 / 2) = K ₁₂ Z _m1 (7)
(Wherein, K ₁₂ represents a line parameter ratio.)
Z _m1 (Z _m2 / 2) = Z ₀ Z _in (8)
(In the formula, Z ₀ represents the input terminal impedance, and Z _in represents the load.)
To calculate a characteristic impedance Z _m1 of the first quarter-wave transmission line and a characteristic impedance Z _{m2 of} the second quarter-wave transmission line, and a first calculation step and a third calculation step. And an output step for outputting the characteristic impedance calculated in (1).

  According to such a signal distributor design method, by inputting the input terminal impedance at the input terminal, the number of output terminals, and the line parameter ratio, the characteristic impedance of each transmission line constituting the signal distributor can be reduced. It can be calculated. That is, the circuit can be miniaturized and the reflection characteristics at the input terminal can be improved over a wide band, and the width of the first quarter wavelength transmission line and the second quarter wavelength transmission line can be improved. It is possible to design a signal distributor having the same width as

  According to such a signal distributor and its design method, a multistage transformer is introduced, and the characteristic impedance is specified instead of the length of the transmission line between the output terminals, so that the circuit can be reduced in size. At the same time, the reflection characteristics at the input terminal can be improved over a wide band.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  First, the configuration of the signal distributor 1 according to the embodiment will be described with reference to FIG. FIG. 1 is a plan view of a signal distributor 1 according to the embodiment. The signal distributor 1 connects an input terminal 10 to which a microwave signal is input, five output terminals 21 provided in a line along the width direction of the signal distributor, and each output terminal 21. An output unit 20 having a plurality of transmission lines 22 and a transformer unit 30 for connecting the input terminal 10 and the output unit 20 are provided. The shape of the signal distributor 1 is symmetric when viewed from the input terminal 10. The number of output terminals 21 is not limited as long as it is an odd number.

  The transformer section 30 includes a linear transmission line (first quarter-wave transmission line) 31 having one end connected to the input terminal 10 and an arc-shaped transmission line connected to the other end of the transmission line 31. (Second quarter wavelength transmission line) 32. The other end of the transmission line 31 is connected to the center of the transmission line 32, and the end of the transmission line 32 (connection to the output unit 20) is disposed in the opposite direction to the input terminal 10 when viewed from the center. Has been. That is, the transformer section 30 branches in two directions on the transmission line 32. The length of the transmission line 31 and the length from the center part to the end part of the transmission line 32 are both 1/4 wavelengths of the center frequency (1 GHz), and their widths are designed to be equal to each other. . As described above, the signal distributor 1 is a signal distributor using a two-stage quarter-wave transformer.

  FIG. 2 is a diagram illustrating a circuit pattern of the signal distributor 1. Transmission lines 22, 31 and 32 are microstrip lines. The substrate thickness is 0.965 mm, and the relative dielectric constant of the substrate is 2.6. The thickness of the transmission line (copper foil thickness) is 0.018 mm. As shown in FIG. 2, the transmission line portion has a length from the input terminal 10 to the output terminal 21 of 115.4 mm and an overall width of 59.12 mm. The length and width of the transmission line 31 are 50.04 mm and 5 mm, respectively, the inner diameter and outer diameter of the arc drawn by the transmission line 32 are 24.25 mm and 29.25 mm, respectively, and the width of the transmission line 32 is 5 mm. It is. However, the design of the signal distributor 1 is not limited to the above values, and the dimensions may be changed as necessary.

  Hereinafter, for convenience of explanation, the input terminal 10 is also referred to as input terminal # 1, and the output terminal 21 is also referred to as output terminals # 2, # 3,..., # 6 in order from the right side of FIG. reference). Further, a transmission line connecting the output terminals # 3 and # 4 is 22a, a transmission line connecting the output terminals # 4 and # 5 is 22b, a transmission line connecting the output terminals # 2 and # 3 is 22c, and an output terminal # The transmission line connecting 5 and # 6 is also referred to as 22d. The lengths of the transmission lines 22a and 22b are 13.26 mm, and the lengths of the transmission lines 22c and 22d are 12.54 mm.

  FIG. 3 is a diagram showing a generalized equivalent circuit of the signal distributor 1. An equivalent circuit of a distributor such as the signal distributor 1 that is symmetrical with respect to the input terminal is shown in FIG. 3 in consideration of the symmetry of the shape. Position P0 in FIG. 3 corresponds to output terminal # 4, and position P1 corresponds to output terminals # 3 and # 5. Although not shown in FIG. 3, the position P2 corresponds to the output terminals # 2 and 6 in FIG.

The input terminal impedance and the load impedance of the output terminals # 2 to # 6 are Z ₀ (Ω). At this time, the transmission line 22a, the characteristic impedance _{Z 1} and 22b are
Z ₁ = 2Z ₀
Indicated by That is, the characteristic impedance of the transmission lines 22a and 22b connected from the direction of the input terminal # 1 to the output terminal # 4 is equal to twice the load impedance of the output terminal # 3. The length L1 of the transmission lines 22a and 22b is 13.26 mm in the signal distributor 1, but is not limited to this and can be arbitrarily determined.

Further, the characteristic impedance _{Z 2} of the transmission lines 22c and 22d are
Z ₂ = _2Z 0/3
Indicated by That is, the characteristic impedance of the transmission lines 22c and 22d connected from the direction of the input terminal # 1 to the output terminal # 3 (# 5) is equal to twice the combined impedance of the output terminals # 3, # 4, and # 5. The length L2 of the transmission lines 22c and 22d is 12.54 mm in the signal distributor 1, but this length can also be arbitrarily determined.

The general formula indicating the characteristic impedance of the transmission line 22 between the output terminals 21 is expressed by the above formula (1) (the same applies to the above formula (5)). Further, the load Z _in at the position Pn (connection point between the transformer section 30 and the output section 20) in FIG. 3 is expressed by the above formula (2) (the above formula (6) is the same).

Next, a method for determining the characteristic impedances Z _m1 and Z _m2 of the transmission line 31 and the transmission line 32 constituting the transformer unit 30, that is, a method for determining the transformer unit 30 will be described. The characteristic impedance at the time of manufacturing the transmission line 32, which is the second-stage transmission line, is Z _m2 . However, since the transmission line 32 is separated in two directions from the connection with the transmission line 31, the transmission on the equivalent circuit is performed. The characteristic impedance of the line 32 is indicated by Z _m2 / 2.

FIG. 4 is a graph showing the reflection characteristics of a Chebyshev type two-stage quarter-wave transformer, where the vertical axis represents the reflection loss and the horizontal axis represents the electrical length. The specific bandwidth is w _T = (π−2θ _m ) / (π / 2), and the lower and upper electric lengths of the passband (section where the reflection loss is equal to or lower than a predetermined level) are θ _m and π−θ _m , respectively. The lower and upper electrical lengths at which no reflection occurs are denoted by θ _z and π−θ _z , respectively. Further, the reflection loss at θ = 0, π is G _ro, and the allowable reflection amount in the passband is G _rm . Length of the transmission line 31 and 32 La, Lb are respectively λ _0/4 (λ ₀ is the center frequency wavelength).

First, the impedance ratios K _0L and K ₁₂ are respectively defined as follows. That is, K _0L is the ratio of the load at the position Pn to the input terminal impedance Z ₀ , and K ₁₂ is the ratio of the characteristic impedance of the transmission line 32 to the characteristic impedance of the transmission line 31. .
_{K 0L = Z in / Z 0} , K 12 = (Z m2 / 2) / Z m1

Further, the transmission characteristic from the input terminal 10 to the position Pn in FIG. 3 is defined by the following equation.
_{^{| S 12 | 2 = 1 /}} {1 + h m 2 T 2 2 (x)}
Where T ₂ (x) = 2x ² −1, x = cos θ / cos θ _m

Further, assuming that the absolute value of the reflection coefficient is ρ and the absolute values of the reflection coefficients corresponding to G _ro and G _rm are ρ ₀ and ρ _m , the value ρ _m is expressed by the above equation (3), and the value ρ , Ρ ₀ are defined as follows.
ρ ² = 1− | S ₁₂ | ²
ρ ₀ ² = {(K _0L −1) / (K _0L +1)} ²

Since ρ = ρ _m when θ = θ _m ,
h _m ² = ρ _m ² / (1-ρ _m ² )

When θ = 0 or π, h ₀ ² = h _m ² T ₂ ² (x ₀ ), x ₀ = ± 1 / cos θ _m
Then, from ρ = ρ ₀ , h ₀ ² = ρ ₀ ² / (1-ρ ₀ ² ) = (K _0L −1) ² / 4K _0L

θ = θ _z , that is, the following equation and the above equation (4) (the same applies to the above equation (8)) are derived from the real part / imaginary part condition in the case of perfect matching.
tan ² (θ _z ) = K ₁₂ (K _0L −1) / (K _0L −K ₁₂ ² ) (9)

であり、このとき次式が成立する。
ｈ_ｍ ^２＝ｈ_０ ^２ｃｏｔ^４θ_ｚ In addition, T ₂ (x) = 0 must be satisfied at the time of perfect matching.

At this time, the following equation holds.
h _m ² = h ₀ ² cot ⁴ θ _z

  A design method (hereinafter referred to as “first design method”) focusing on the allowable reflection amount (or specific bandwidth) in the passband will be described based on the series of theories described above.

First, when the allowable reflection coefficient ρ _m , the input terminal impedance Z _0, and the load Z _in at the position Pn are given, the impedance ratio K ₁₂ is determined from the above equation (3), and the above equation (4) is used. Thus, the characteristic impedance Z _m1 of the transmission line 31 and the characteristic impedance Z _m2 of the transmission line 32 can be determined. In addition, since θ _z and θ _m are determined from h ₀ and h _m , the specific bandwidth w _T is derived from the following equation.
w _T = 2-4θ _m / π

Further, when the specific bandwidth w _T , the input terminal impedance Z _0, and the load Z _in at the position Pn are given, values are determined in the order of θ _m , θ _z , h ₀ ² , h _m ² , and ρ _m. Therefore, the characteristic impedance Z _m1 of the transmission line 31 and the characteristic impedance Z _m2 of the transmission line 32 can also be determined.

Next, a design method (hereinafter referred to as “second design method”) focusing on two frequencies f ₁ and f ₂ (f ₂ = uf ₁ ) will be described. Here, it is assumed that no reflection occurs at the frequencies f ₁ and f ₂ . According to the reference (C.Monzon, "A small dual-frequency transformer in two sections," IEEE Trans. Microwave Theory Tech., Vol.51, no.4, pp.1157-1161, Apr. 2003) The lengths La and Lb of 31 and 32 are equal to each other, and θ _z1 + θ _z2 = π holds for the electrical lengths θ _z1 = β ₁ La and θ _z2 = β ₂ Lb at the frequencies f ₁ and f ₂ . Since θ _z2 = uθ _z1 when f ₂ = uf ₁ , θ _z1 = π / (1 + u) and θ _z2 = uπ / (1 + u). From these, the following formula is established.
La = Lb = λ ₁ / {2 (1 + u)}
Note that λ ₁ is the lower wavelength at which no reflection occurs. If u = 2 La + Lb = λ 1/3 , and the total length of the transmission line 31 and 32, a 1/3 wavelength for frequencies lower at which no reflection.

(La + Lb) / λ ₁ = β ₁ / (β ₁ + β ₂ ) = f ₁ / (f ₁ + f ₂ )
Therefore, when f ₀ = (f ₁ + f ₂ ) / 2,
La = Lb = λ _0/4
It becomes.

Therefore, in the second design method, assuming that the average of the lower and upper frequencies that are non-reflective is the center frequency, the transmission lines 31 and 32 are ¼ wavelength lines with respect to the center frequency f ₀ , and θ _z = Sadamari is theta _z by _{β 1 La = πf 1 / 2f} 0, eventually resulting in the first design method.

Next, a design method focusing on the line parameters of the transmission lines 31 and 32 (hereinafter referred to as “third design method”) will be described. In this case, first, the center frequency f ₀ is set, and the above equation (7) is applied to the above equation (8) on the assumption that the line parameter ratio K ₁₂ is given, and the following equation Z _m1 ² = Z ₀ Z _in / K ₁₂ (11)
As a result, Z _m1 and Z _m2 are immediately determined.

Further, ρ _m ² is determined from the above equation (3), and the allowable reflection amount G _rm in the passband is determined. In addition, since a quarter wavelength transmission line is used for the frequency f ₀ ,
θ _z1 = 0.5π (f ₁ / f ₀ )
θ _z2 = π−θ _z1 = 0.5π (f ₂ / f ₀ ) (12)
From the above equation (9), the lower frequency and the upper frequency that are non-reflective are determined, and further, the specific bandwidth w _T is determined by the above equation (10). In this way, by giving the condition that Z _m2 / 2 = Z _m1 K ₁₂ to the line parameters, the allowable reflection amount G _{rm in} the passband, the lower and upper frequencies that become non-reflective, and the specific bandwidth w _T are unique. Determined.

For example, when _{K 12 = 1/2, Z} 0 = 50, Z in = Z 0/5, Z m1 = 31.62 the above equation (11), and Z _{m @ 2} = 31.62. Further, ρ _m ² is determined from K _0L = 1/5, K ₁₂ = 1/2, and G _rm = −19.1 (dB). Furthermore, tan ² θ _z1 = 8 from the above equation (9), and f ₁ / f ₀ = 0.784 and f ₂ / f ₀ = 1.216 from the above equation group (12).

Next, the characteristics of the signal distributor 1 will be described with reference to FIGS. Here, in particular, the following three points will be described.
(1) Improving the reflection characteristics at the input terminal over a wide band (widening of the input reflection characteristics)
(2) Realization of multi-frequency sharing (multi-band) (3) Easy circuit manufacturing

First, the widening of the input reflection characteristics will be described with reference to FIGS. FIG. 5 is a graph showing the theoretical values of the reflection characteristics and distribution characteristics of the signal distributor 1 and the conventional signal distributor (described in the specification of Japanese Patent Application No. 2006-313003). Normalized frequency. FIG. 6 is a graph showing the theoretical values of the phase characteristics of the signal distributor 1 and the conventional signal distributor (described in the specification of Japanese Patent Application No. 2006-313003). The vertical axis is the phase difference, and the horizontal axis is the normalized frequency. is there. In FIG. 5, the reflection characteristics (S ₁₁ ) and distribution characteristics (S ₂₁ , S ₃₁ , S ₄₁ ) of the signal distributor 1 are indicated by solid lines. Further, the reflection characteristic (S ₁₁ ) and distribution characteristic (S ₂₁ , S ₃₁ , S ₄₁ ) of a signal distributor (conventional example) using a one-stage quarter wavelength transformer are indicated by a one-dot chain line.

The S parameter S ₂₁ indicates the distribution characteristic of the signal flowing from the input terminal # 1 to the output terminal # 2 (# 6), and the S parameter S ₃₁ is from the input terminal # 1 to the output terminal # 3 (# 5). The distribution characteristic of the flowing signal is shown, and the S parameter S ₄₁ indicates the distribution characteristic of the signal flowing from the input terminal # 1 to the output terminal # 4.

In implementing the bandwidth of the input reflection characteristics, the input terminal impedance Z _{0 =} 50 [Omega, the entire load end impedance in the equivalent circuit and Z _0/5, the reflection loss in the pass band in order to -20dB or less The characteristic impedance of the transmission line 31 was Z _m1 = 31.80Ω, and the characteristic impedance of the transmission line 32 was Z _m2 = 31.45Ω (15.72Ω on the equivalent circuit). The reflection loss of −20 dB is a specification that is generally used in a microwave signal distributor.

In this case, as shown in FIG. 5, the frequency domain Da in the pass band of the signal distributor 1 using the two-stage quarter-wave transformer is that of the signal distributor using the one-stage quarter-wave transformer. (Db) is enlarged. That is, the input reflection characteristics are improved over a wide band. Also, with respect to the distribution characteristics, the signal distributor 1 is maintained at a constant level over a wider band than the conventional one, and is improved. On the other hand, as shown in FIG. 6, the phase difference Arg (S ₂₁ / S ₄₁ ) and Arg (S ₂₁ / S ₃₁ ) are not changed between the signal distributor 1 and the conventional one, and the phase difference is linear. Transition to.

Next, realization of multi-frequency sharing will be described with reference to FIG. FIG. 7 is a graph showing the theoretical values of the reflection characteristics and distribution characteristics of the signal distributor 1, wherein the vertical axis represents these characteristics, and the horizontal axis represents the normalized frequency. In FIG. 7, the reflection characteristic (S ₁₁ ) of the signal distributor 1 is indicated by a solid line, and the distribution characteristics (S ₂₁ , S ₃₁ , S ₄₁ ) are indicated by a broken line.

In the realization of multiband, the input terminal impedance was Z _{0 =} 50 [Omega, the entire load end impedance in the equivalent circuit and Z _0/5. Further, the characteristic impedance of the transmission line 31 is set to Z _m1 = 28.87Ω so that the non-reflective lower frequency is f ₁ = 2/3 and the upper frequency is f ₂ = 2f ₁ = 4/3. The characteristic impedance of the transmission line 32 was set to Z _m2 = 34.64Ω (17.32Ω on the equivalent circuit). The center frequency is set to f ₀ = (f ₁ + f ₂ ) / 2 = 1.

In this case, as shown in FIG. 7, the signal distributor 1 can distribute the signals of the two frequencies f ₁ and f ₂ without reflection (multibanding can be realized). Insertion losses S ₂₁ , S ₃₁ , and S _{41 at} frequencies f ₁ and f ₂ are −6.99 dB.

Next, using FIG. 8 to FIG. FIG. 8 is a graph showing the theoretical value and the measured value of the reflection characteristic (S ₁₁ ) of the signal distributor 1, where the vertical axis is the reflection characteristic and the horizontal axis is the frequency. 9A to 9C are graphs showing theoretical values and measured values of the distribution characteristics (S ₁₂ , S ₁₃ , S ₁₄ ) of the signal distributor 1. In each graph, the vertical axis represents the distribution characteristics and the horizontal axis. Is the frequency. FIG. 10 is a graph showing theoretical values and measured values of the phase characteristics of the signal distributor 1, where the vertical axis represents the phase difference and the horizontal axis represents the frequency. 8 to 10, the theoretical value is indicated by a solid line, and the measured value is indicated by a broken line.

The size of the manufactured signal distributor 1 is the same as that shown in FIG. Input impedance load end impedance of the entire in _Z 0 = _50Ω, the equivalent circuit is _Z 0/5. At this time, the characteristic impedance of the transmission lines 22a and 22b is 100Ω, and the characteristic impedance of the transmission lines 22c and 22d is 33.3Ω. The characteristic impedance Z _m1 of the transmission line 31 and the characteristic impedance Z _m2 of the transmission line 32 are 31.62Ω (the characteristic impedance of the transmission line 32 is 15.81Ω on the equivalent circuit). At this time, the reflection loss at a center frequency of 1 GHz was -19.03 dB. Thus, as shown in FIG. 2, even when the line widths of the transmission lines 31 and 32 are made equal and both characteristic impedances are the same, the reflection loss can be suppressed, so that the signal distribution that realizes a wide band of input reflection characteristics The container 1 can be easily manufactured.

  Next, the signal distributor design method according to the embodiment will be described with reference to FIGS. FIG. 11 is a diagram illustrating a configuration of the information processing apparatus 40 used for designing the signal distributor according to the embodiment. FIG. 12 is a flowchart showing a design procedure of the signal distributor 1.

  The design of the signal distributor 1 as shown in FIG. 1 is executed by an information processing apparatus 40 such as a workstation or a PC (Personal Computer). The information processing device 40 includes a central processing unit (CPU) 41, a hard disk device 42 for storing programs and data, a main memory 43, an input device 44 such as a keyboard and a mouse, a CRT (Cathode And a reading device 47 that reads a recording medium 46 such as a magnetic tape or a ROM. The hard disk device 42, the main memory 43, the input device 44, the display device 45, and the reading device 47 are all connected to the central processing unit 41.

  In the information processing apparatus 40, a recording medium 46 storing a program is loaded into a reading device 47, and the program is read from the recording medium 46 and stored in the hard disk device 42. Subsequently, the program stored in the hard disk device 42 is developed and executed on the main memory 43 by the central processing unit 41, and the signal distributor designing method according to the present embodiment is executed. Note that the design method according to the present embodiment may be executed only by an apparatus, not by a program as described above. All of the series of processes described below may be executed by the information processing apparatus, or a part of the series of processes may be executed by the information processing apparatus.

The design of the signal distributor executed by the information processing apparatus 40 will be described. First, the input device 44 and the reading device 47 accept the input terminal impedance Z ₀ and the number N of output terminals 21, and accept the input of the allowable reflection coefficient ρ _m , the upper lower frequency ratio u, or the line impedance ratio K _12. (Step S11, reception step). Of course, the reception of data may be realized by reading data stored in the hard disk device 42 in advance. For example, the allowable reflection coefficient ρ _m calculated from the passband allowable reflection amount G _rm and the specific bandwidth w _T and stored in the hard disk device 42 may be received.

Subsequently, based on the received data, the characteristic impedance Z _k of the transmission line 22 between the output terminals 21 and the load Z _in at the connection point (position Pn in FIG. 3) between the transformer unit 30 and the output unit 20. Is calculated (step S12, first calculation step, second calculation step). This calculation is performed by executing on the central processing unit 41 a program in which the above equations (1) and (2) are implemented.

Subsequently, the characteristic impedance of the transmission lines 31 and 32 constituting the transformer section 30 is calculated (step S13, third calculation step). For example, the characteristic impedance of the transmission lines 31 and 32 is calculated by giving the input terminal impedance Z ₀ , the allowable reflection coefficient ρ _m , and the load Z _in to a program in which the above equations (3) and (4) are implemented. Moreover, the characteristic impedance of the transmission lines 31 and 32 is calculated by giving the input terminal impedance Z ₀ , the line parameter ratio K ₁₂ , and the load Z _in to a program in which the above equations (7) and (8) are implemented. Furthermore, by giving the input terminal impedance Z ₀ , the upper and lower frequency ratio u, and the load Z _in to a program that implements the above equation (9), K ₁₂ is determined from the relationship θ _z = π / (1 + u). , It can be linked to the above calculation procedure.

  Then, the data calculated in steps S12 and S13 is output to the display device 45, the hard disk device 42, etc. (step S14, output step). Thereby, the user of information processor 40 can acquire the characteristic impedance of each transmission line which determines the composition of a signal distributor.

  As described above, according to the present embodiment, the transformer section 30 is a multistage transformer in which a plurality of quarter wavelength transmission lines 31 and 32 are connected in series. In comparison, the reflection loss at the input terminal 10 is reduced over a wide band (the reflection characteristic (input reflection characteristic) at the input terminal is improved over a wide band). Further, for each output terminal 21, one or more output terminals whose characteristic impedance of the transmission line 22 connected to the one output terminal 21 from the direction of the input terminal 10 is located in a direction farther from the input terminal 10 than the transmission line 22 is. By providing the transmission line 22 between the output terminals 21 so as to be equal to the combined impedance of 21, the length of the transmission line 22 between the output terminals 21 can be arbitrarily selected. As a result, the length of the transmission line between the output terminals 21 can be shortened to reduce the circuit size. That is, according to the signal distributor 1, it is possible to reduce the size of the circuit and improve the reflection characteristics at the input terminal 10 over a wide band.

  Moreover, according to this embodiment, you may make the line | wire width of the transmission lines 31 and 32 which comprise the transformer part 30 constant. In this case, the signal distributor 1 can be easily manufactured.

Further, according to the present embodiment, by inputting the allowable reflection coefficient ρ _m , the upper and lower frequency ratio u or the line parameter ratio K ₁₂ together with the input terminal impedance Z ₀ and the number N of output terminals, the signal distributor 1 The characteristic impedance of each transmission line that constitutes can be calculated. That is, it is possible to design a signal distributor that can reduce the size of the circuit, facilitate the manufacture, and realize a dual-frequency compatible circuit, or can improve the reflection characteristics at the input terminal over a wide band. .

  The present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above embodiment. The present invention can be modified in various ways as described below without departing from the scope of the invention.

In the above embodiment, the signal distributor 1 includes the two-stage quarter-wave transformer (transformer unit 30). However, the transformer unit is configured by connecting three or more transmission lines having different line parameters in multiple stages. It may be configured. For example, as shown in FIG. 13, the signal distributor may include a transformer section having three types of transmission lines. The signal distributor 2 shown in FIG. 13 includes an input terminal # 11 and five output terminals # 12 to # 16, and the transformer unit 50 has a linear transmission line 51 having one end connected to the input terminal # 11. A linear transmission line 52 having one end connected to the other end of the transmission line 51 and extending in the same direction as the transmission line 51, and an arcuate transmission line 53 connected to the other end of the transmission line 52. ing. The characteristic impedances of the transmission lines 51 to 53 were set to 33.27Ω, 22.36Ω, and 30.06Ω, respectively. Further, the electrical angles of the transmission lines 51 to 53 at the lower frequency f ₁ were set to 1.13, 0.44, and 1.13, respectively.

Figure 14 is a graph showing the reflection characteristic S ₁₁ and dispensing characteristics S _21, S _31, S ₄₁ of the signal splitter 2, the vertical axis represents the reflection characteristic and dispensing characteristics, the horizontal axis represents the normalized frequency. As shown in FIG. 14, the signal distributor 2 can realize multiband for the frequencies f ₁ , f ₂ = 1.4f ₁ , and f ₃ = 3f ₁ . On the other hand, the conventional signal distributor (see References 1 to 4 below) having a half-wave line as a constituent element uses the impedance non-conversion function of the half-wave line corresponding to a single frequency. Not suitable for circuits that are non-reflective at frequency.
(Reference 1) I. Sakagami, T. Wuren, M. Fujii and Y. Tomoda, "A new type of multi-way microwave power divider based on bagley polygon power divider," 2006 Asia-Pacific Microwave Conf., Vol. pp.1353-1356, Yokohama, Japan (Dec.2006)
(Reference 2) http://www.dec2light.pwp.blueyonder.co.uk/Webpage/Hybridcouplers.htm#baglay
(Reference 3) Tahara, Iwata, Sasaki, Ohashi, “Waveguide Series Power Distributor with Iris at Probe Coupling” 2006 IEICE Electronics Society Conference, C-2-39, p.58, 2006
(Reference 4) Abe, Tahara, Yoneda, Ohashi, “Narrow wall probe insertion type waveguide power divider using base” IEICE Technical Report, MW2007-131, pp.29-34, Dec. 2007

  In the signal distributor 2 shown in FIG. 13, the transmission line 53 branches in two directions from the connection point with the transmission line 52, but the transformer section is designed so as to branch from the transmission line 52 in two directions. May be.

It is a top view of the signal distributor concerning an embodiment. It is a figure which shows the circuit pattern of the signal divider | distributor shown in FIG. It is a figure which shows what generalized the equivalent circuit of the signal distributor. It is a graph which shows the reflective characteristic of a Chebyshev type | mold 2 step | paragraph 1/4 wavelength transformer. It is a graph for comparing a reflection characteristic and a distribution characteristic with a signal distributor and a conventional one. It is a graph for comparing a phase characteristic with a signal distributor and a conventional one. It is a graph which shows the theoretical value of the reflection characteristic and distribution characteristic of a signal divider | distributor corresponding to 2 frequencies. It is a graph which shows the theoretical value and measured value of the reflective characteristic of a signal distributor. It is a graph which shows the theoretical value and measured value of the distribution characteristic of a signal distributor. It is a graph which shows the theoretical value and measured value of the phase characteristic of a signal distributor. It is a figure which shows the structure of information processing apparatus. It is a flowchart which shows the design procedure of the signal distributor by the information processing apparatus shown in FIG. It is a figure which shows the circuit pattern of the signal distributor which concerns on a modification. 14 is a graph showing theoretical values of reflection characteristics and distribution characteristics of the 3-frequency signal distributor shown in FIG. 13.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 2 ... Signal distributor, 10 ... Input terminal, 20 ... Output part, 21 ... Output terminal, 22 ... Transmission line which connects between output terminals, 30, 50 ... Transformer part, 31 ... Transmission line (1st 1/4 wavelength transmission line), 32 ... transmission line (second 1/4 wavelength transmission line), 40 ... information processing device, 51 to 53 ... transmission line (1/4 wavelength transmission line).

Claims (4)

An output section having a plurality of output terminals and a plurality of transmission lines connecting between the output terminals;
A transformer section for connecting the input terminal and the output section by a plurality of quarter wavelength transmission lines connected in series in multiple stages in an equivalent circuit;
With
For each of the plurality of output terminals in the equivalent circuit, the characteristic impedance of the transmission line connected to the one output terminal from the direction of the input terminal, and the transmission line including the one output terminal are further away from the input terminal than the transmission line The combined impedance of one or more output terminals located in the direction is equal,
A signal distributor characterized by that. The transformer section includes a first quarter wavelength transmission line having one end connected to the input terminal, and a second first section connecting the other end of the first quarter wavelength transmission line and the output section. / 4 wavelength transmission line and a two-stage transformer,
Line widths of the first quarter wavelength transmission line and the second quarter wavelength transmission line are equal to each other,
The signal distributor according to claim 1. In an information processing apparatus for designing a signal distributor including an output unit having a plurality of output terminals and a plurality of transmission lines connecting between the output terminals, and a transformer unit connecting the input terminal and the output unit, A method of designing a signal distributor,
An accepting step of receiving an input of an allowable reflection coefficient corresponding to an input terminal impedance at the input terminal, the number of the output terminals, and an allowable reflection amount in a pass band of the signal distributor;
Based on the input terminal impedance and the number of output terminals received in the receiving step, the following formula (1)
_{Z 1 = 2Z 0, Z 2} = 2Z 0/3, ..., Z k = 2Z 0 / (N-2) ... (1)
However, k = (N−1) / 2
(In the formula, Z ₀ represents the input terminal impedance, and N represents the number of the output terminals.)
A first calculation step of calculating characteristic impedances Z _k of a plurality of transmission lines connecting between the output terminals,
Based on the input terminal impedance and the number of output terminals received in the receiving step, the following formula (2)
Z _in = Z ₀ / (2n + 1) (2)
However, n = (N−1) / 2
(In the formula, Z ₀ represents the input terminal impedance, and N represents the number of the output terminals.)
A second calculation step of calculating a load Z _in at a connection point between the transformer unit and the output unit;
Based on the input terminal impedance and allowable reflection coefficient received in the reception step and the load calculated in the second calculation step, the following equations (3) and (4)
ρ _m ² = {(K _0L −K ₁₂ ² ) / (K _0L + K ₁₂ ² )} ² (3)
(Wherein ρ _m represents the allowable reflection coefficient, K _0L represents the ratio between the load and the input terminal impedance, and K ₁₂ represents the first quarter-wave transmission line of the transformer section. It represents the ratio of the characteristic impedance to 1/2 the characteristic impedance of the second quarter wavelength transmission line, that is, K _0L = Z _in / Z ₀ , K ₁₂ = (Z _m2 / 2) / Z _m1 )
Z _m1 (Z _m2 / 2) = Z ₀ Z _in (4)
(In the formula, Z ₀ represents the input terminal impedance, and Z _in represents the load.)
Calculating a characteristic impedance Z _m1 of the first quarter-wave transmission line and a characteristic impedance Z _{m2 of} the second quarter-wave transmission line by:
An output step of outputting the characteristic impedance calculated in the first calculation step and the third calculation step;
A method of designing a signal distributor, comprising: In an information processing apparatus for designing a signal distributor including an output unit having a plurality of output terminals and a plurality of transmission lines connecting between the output terminals, and a transformer unit connecting the input terminal and the output unit, A method of designing a signal distributor,
An accepting step of accepting input of input terminal impedance at the input terminal, number of the output terminals, and line parameter ratio;
Based on the input terminal impedance and the number of output terminals received in the receiving step, the following equation (5)
_{Z 1 = 2Z 0, Z 2} = 2Z 0/3, ..., Z k = 2Z 0 / (N-2) ... (5)
However, k = (N−1) / 2
(In the formula, Z ₀ represents the input terminal impedance, and N represents the number of the output terminals.)
A first calculation step of calculating characteristic impedances Z _k of a plurality of transmission lines connecting between the output terminals,
Based on the input terminal impedance and the number of output terminals received in the receiving step, the following equation (6)
Z _in = Z ₀ / (2n + 1) (6)
However, n = (N−1) / 2
(In the formula, Z ₀ represents the input terminal impedance, and N represents the number of the output terminals.)
A second calculation step of calculating a load Z _in at a connection point between the transformer unit and the output unit;
Based on the input terminal impedance and the line parameter ratio received in the reception step and the load calculated in the second calculation step, the following equations (7) and (8)
(Z _m2 / 2) = K ₁₂ Z _m1 (7)
(Where K ₁₂ represents the line parameter ratio)
Z _m1 (Z _m2 / 2) = Z ₀ Z _in (8)
(In the formula, Z ₀ represents the input terminal impedance, and Z _in represents the load.)
Calculating a characteristic impedance Z _m1 of the first quarter-wave transmission line and a characteristic impedance Z _{m2 of} the second quarter-wave transmission line by:
An output step of outputting the characteristic impedance calculated in the first calculation step and the third calculation step;
A method of designing a signal distributor, comprising:

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