JP3140736B2 - Group delay time compensation type band pass filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a band-pass filter used for broadcasting equipment such as a television method, and more particularly to a band-pass filter having good group delay time deviation characteristics within a pass band.
The present invention relates to a group delay time compensation type bandpass filter having a steep attenuation characteristic.

[0002]

2. Description of the Related Art Conventionally, in television broadcasting equipment in the VHF band, in order to remove unnecessary waves such as IM waves (intermodulation waves), an elliptic function type using a λ / 4 coaxial resonator as a resonator is used. Band pass filter (Band pass filter; hereinafter, BP)
Called F. ) Is used. FIG. 25 is a plan view showing an upper surface of an elliptic function type BPF using a conventional coaxial resonator, and FIGS. 26, 27, and 28 are cross-sectional views of main parts showing a schematic configuration of the BPF shown in FIG. . FIG. 26 is a cross-sectional view of an essential part taken along line AA ′ shown in FIG.
FIG. 28A is a cross-sectional view of a main part taken along line BB ′ shown in FIG. 26, FIG. 28A is a cross-sectional view of a main part cut along line CC ′ shown in FIG. 25, and FIG. FIG. 28C is a cross-sectional view of a main part taken along line DD ′ shown in FIG. 25, and FIG.
It is principal part sectional drawing cut | disconnected by the E 'line.

In FIGS. 25 to 28, 1 is an external conductor, 2 is a partition, 5a and 5b are capacitive elements constituting a sub-coupling circuit, 7 is a U-shaped loop element forming a sub-coupling circuit,
8 is an input (or output) coupling loop, 9a to 9h are rock nights, 11a is an input (or output) terminal, 11b is an output (or input) terminal, 20a to 20h is a λ / 4 coaxial resonator, 21a to 21h is Drive screws, 22a to 22h are resonance frequency adjusting elements, and 23a to 23h are internal conductors.

The elliptic function type BPF using the conventional coaxial resonator has an inner conductor (23a to 23a) inside an outer conductor 1.
h) is built in, and the adjusting elements (22a to 22h) are attached to the outer conductor 1 by rock nights (9a to 9h) so as to face the inner conductors (23a to 23h). The input (or output) terminal 11a and the output (or input) terminal 11b are, for example,
The outer conductor, which consists of coaxial connectors and forms each coaxial connector,
It is connected to an external conductor 1 constituting a resonator. In this conventional elliptic function type BPF using a coaxial resonator, the coaxial resonators (10a to 10h) are arranged in a U-shape, and the respective coaxial resonators (10a to 10h) are mainly coupled by a magnetic coupling circuit. I do. Also, the coaxial resonator (20c) and the coaxial resonator (20
f) is sub-coupled with a capacitive element 5a to form a coaxial resonator (2).
0b) and the coaxial resonator (20g) are sub-coupled with a U-shaped loop element 7, and the coaxial resonator (20a) and the coaxial resonator (20h) are sub-coupled with a capacitive element 5b. ing.

[0005]

A digital television signal to be started has a large number of segments (13 segments) and a small segment interval (432 KH).
z), many IM waves are generated near the target signal wave.
Further, depending on the modulation method, a BPF to be used is required to have a small amplitude deviation and a group delay time deviation in a pass band and a frequency characteristic having a steep attenuation characteristic. Elliptic function type BP using the coaxial resonator shown in FIGS.
F is B, which emphasizes the attenuation characteristics of analog TV signals, etc.
Suitable for PF. However, the elliptic function type BPF using the coaxial resonator shown in FIGS.
There is a problem that the amplitude deviation and the group delay time deviation in the pass band are large, and are not suitable for a BPF for digital television signals requiring the above-mentioned frequency characteristics.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and an object of the present invention is to provide a group delay time compensating band-pass filter which compensates for group delay time characteristics and provides a pass band. It is an object of the present invention to provide a technique capable of reducing an amplitude deviation and a group delay time deviation in the above.

[0007] The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0008]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, the present invention provides an external conductor,
N (N ≧ 6) from the first provided in a U-shape in the body
Two coaxial resonators, each n (n <N) th positioned coaxial resonators, the shape of the turning point of the U up to th,
When the (n + 1) -th coaxial resonator, the first or
(N-1) th coaxial resonator and the (n + 2) th coaxial resonator.
And a partition wall provided between the first and Nth coaxial resonators
Having a main coupling between the coaxial resonators by a magnetic coupling circuit.
Group delay time compensating band-pass filter
Serial between the (n-1) th coaxial resonator and (n + 2) -th coaxial resonators, and, between the (n-2) th coaxial resonator and (n + 3) th coaxial resonator , Capacitive element,
Alternatively, the coaxial resonator is provided in the longitudinal direction of the inner conductor.
At the part penetrating the partition wall
The longitudinal direction of the inner conductor of each coaxial resonator of the partition
Both ends are electrically connected to the partition at different positions
It is characterized in that it is sub-coupled by an S-shaped loop element that is electrically connected .

[0010]

[0011]

[0012]

[0013]

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, components having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted.

[First Embodiment] FIGS. 1 and 2 are cross-sectional views of a main part showing a schematic configuration of a group delay time compensating band-pass filter according to a first embodiment of the present invention. FIG. 1 is a cross-sectional view of a main part of the same part as FIG. 27, and FIG.
FIG. 2B is a sectional view of a main part of the same part as FIG. 8A, FIG. 2B is a cross-sectional view of a main part of the same part as FIG. 28B, and FIG.
FIG. 29 is an essential part cross-sectional view of the same place as in FIG. 28 (c). In the present embodiment, a plan view of the same portion as in FIG. 25 and a cross-sectional view of a main portion of the same portion as in FIG. 26 are the same as in FIGS. .

1 and 2, reference numeral 5 denotes a capacitive element forming a sub-coupling circuit, 6 denotes an S-shaped loop element forming a sub-coupling circuit. Is the same. Group delay time compensation type BPF of the present invention
In this case, the coaxial resonators (20a to 20h) are arranged in a U-shape, and the respective coaxial resonators (20a to 20h) are main-coupled by a magnetic coupling circuit. In, the input / output coupling circuit may be capacitive coupling or magnetic coupling (loop), but in this embodiment,
The case of magnetic coupling will be described. Furthermore, in the group delay time compensating BPF of the present embodiment, the number (N) of coaxial resonators needs to be 6 (N ≧ 6) or more. In the present embodiment, the case where N = 8 is used. explain.

FIG. 3 is a circuit diagram showing an equivalent circuit of an elliptic function type BPF using the conventional coaxial resonator shown in FIGS. 25 to 28, and FIG. 4 is a conversion equivalent of the equivalent circuit shown in FIG. Circuit. The capacitances (Ca to Ch) shown in FIG.
Are the adjusting elements (22a to 22h) and the internal conductors (23
a to 23h), and 8a is an input (or output) coupling loop, 8b
Indicates an output (or input) coupling loop. In the conventional elliptic function type BPFs shown in FIGS. 25 to 28, two of the coaxial resonators arranged in a U-shape are replaced with two coaxial resonators located at a turning point by an n-th resonator ( 20d resonator) and (n + 1) th resonator (20e resonator)
Outside the pass band (attenuation band), (n
-1) th resonator (resonator of 20c) and (n + 2)
An electromagnetic field generated in the (n + 2) th resonator by the main coupling circuit between the second resonator (20f resonator) and a sub-coupling circuit including a capacitive element (5a) smaller than the coupling coefficient of the main coupling circuit Therefore, the electromagnetic field generated in the (n + 2) -th resonator has a phase opposite to that of the electromagnetic field. Therefore, an attenuation pole (attenuation pole) is generated at a pair of frequencies at which the amplitudes of both electromagnetic fields are equal to each other.

Similarly, the (n-2) th resonator (20b
Between the (n + 3) -th resonator (20 g resonator) and the (n + 3) -th resonator (20 g resonator), the electromagnetic field generated in the (n + 3) -th resonator by the main coupling circuit, and the The electromagnetic fields generated in the (n + 3) -th resonator by the coupling circuit also have the opposite phases, so that an attenuation pole (attenuation pole) is generated at a pair of frequencies where the amplitudes of the two electromagnetic fields are equal to each other. Also, the (n-3) th resonator (20
between the (a) resonator and the (n + 4) th resonator (20h resonator), the electromagnetic field generated in the (n + 4) th resonator by the main coupling circuit and smaller than the coupling coefficient of the main coupling circuit By the sub-coupling circuit including the capacitive element (5b), (n +
4) Since the electromagnetic fields generated in the third resonator also have phases opposite to each other, an attenuation pole (attenuation pole) is generated at a pair of frequencies where the amplitudes of both electromagnetic fields are equal to each other. Thus, the elliptic function type BPF shown in FIGS.
By adjusting the amount of coupling by each sub-coupling circuit, a pair or three pairs of attenuation poles can be generated. Such an elliptic function type BPF shown in FIGS. 25 to 28 has a deviation in the pass band for both the amplitude characteristic and the group delay time characteristic as shown in FIG. There was a disadvantage of being large.

FIG. 6 is a circuit diagram showing an equivalent circuit of the group delay time compensation type BPF of this embodiment, and FIG. 7 is a conversion equivalent circuit of the equivalent circuit shown in FIG. In the group delay time compensating BPF of the present embodiment, each resonator is formed of a coaxial resonator, and each resonator is magnetically coupled, similarly to the conventional elliptic function type BPF shown in FIGS. Mainly joined. In the group delay time compensating BPF of the present embodiment, two of the coaxial resonators arranged in a U-shape are connected to the n-th resonator (20d ) And the (n + 1) th resonator (20
e), the group delay time compensating BPF of the present embodiment includes the (n−2) th resonator (20b resonator) and the (n + 3) th resonator (20g resonance). U-shaped loop element 7 as a sub-coupling circuit between
Instead of using an S-shaped loop element 6, (n
-3) th resonator (resonator of 20a), and (n + 4)
The present embodiment differs from the elliptic function type BPF shown in FIGS. 25 to 28 in that a normal U-shaped loop element 7 is used as a sub-coupling circuit between the BPF and the second resonator (resonator of 20h). .

In each of the mutual inductance circuits (M41, M42, M71, M72) shown in FIGS.
The coil on the loop element side (the side directly connecting the mutual inductance circuits by skipping a plurality of circuit elements) constituting the sub-coupling circuit is a secondary coil, and the remaining coils are primary coils. In this case, the sub-coupling voltage induced in the primary coil of the mutual inductance circuit M72 by the mutual inductance circuit (M71, M72) shown in FIG. 7 and the mutual inductance circuit M42 by the mutual inductance circuit (M41, M42) shown in FIG. Comparing with the sub-coupling voltage induced in the primary coil of FIG. That is, as shown in FIG.
2) When an S-shaped loop element 6 is used as a sub-coupling circuit between the (n) -th resonator and the (n + 3) -th resonator, a sub-coupling voltage induced in the (n + 3) -th resonator Is, as shown in FIG. 3, an (n-2) th resonator,
As a sub-coupling circuit with the (n + 3) th resonator, U
When the loop element 7 having a V-shape is used, the phase is 18 times lower than the sub-coupling voltage induced in the (n + 3) th resonator.
0 ° will be different. In the present invention, the S-shaped loop element 6 is, as shown in FIG.
The upper and lower sides of the loop element mean that the both ends of the loop element are electrically and mechanically connected to the partition 2.

Also in the group delay time compensation type BPF of this embodiment, (n-
An electromagnetic field generated in the (n + 2) -th resonator by the main coupling circuit between the (1) -th resonator (resonator of 20c) and the (n + 2) -th resonator (resonator of 20f), The electromagnetic field generated in the (n + 2) -th resonator by the sub-coupling circuit composed of the capacitive element (5) smaller than the coupling coefficient of the coupling circuit has opposite phases to each other, and therefore, a pair of electromagnetic fields having the same amplitude. An attenuation pole is generated at the frequency. However, between the (n−2) th resonator (20b resonator) and the (n + 3) th resonator (20g resonator), the (n + 3) th resonator is generated by the main coupling circuit. The electromagnetic field and the electromagnetic field generated in the (n + 3) th resonator by the sub-coupling circuit composed of the S-shaped loop element 6 have the same phase as each other, so that at a pair of frequencies where the amplitudes of both electromagnetic fields are equal to each other , No attenuation pole is generated. Also, the group delay time compensation type B of the present embodiment
In the PF, between the (n−3) th resonator (resonator of 20a) and the (n + 4) th resonator (resonator of 20h), the resonator (20a) → the resonator ( 20b) →
By the path of the resonator (20g) → the resonator (20h), (n
Since the electromagnetic field generated in the (+4) -th resonator and the electromagnetic field generated in the (n + 4) -th resonator by the sub-coupling circuit including the U-shaped loop element 7 have opposite phases, the amplitudes of the two electromagnetic fields are different. Are equal to each other at a pair of frequencies,
An attenuation pole occurs.

On the other hand, in the pass band, the electromagnetic field generated in the (n + 3) -th resonator by the main coupling circuit and the electromagnetic field generated in the (n + 3) -th resonator by the sub-coupling circuit including the S-shaped loop element 6 Means that near the center frequency, they tend to cancel each other, and near the band edge of the pass band, tend to add to each other, and the deviation of the amplitude characteristic in the pass band becomes small. Similarly, the deviation of the group delay time characteristic in the pass band also becomes small. That is, in the group delay time compensation type BPF of the present embodiment, although the number of attenuation poles is limited to two or less, deviations of the amplitude characteristic and the group delay time characteristic in the pass band can both be improved.

When the compensation amount of the group delay time by the sub-coupling circuit including the S-shaped loop element 6 is smaller than the optimum value, the compensation amount is small and the group delay time characteristic is almost a bottom shape. FIG. 8 shows the group delay time characteristics in this state. When the compensation amount of the group delay time by the sub-coupling circuit including the S-shaped loop element 6 is an optimal amount, the flat portion of the group delay time characteristic becomes the widest. FIG. 9 shows the group delay time characteristics in this state. If the compensation amount of the group delay time by the sub-coupling circuit including the S-shaped loop element 6 is larger than the optimal amount, the compensation amount becomes overcompensated. FIG. 10 shows the group delay time characteristics in this state.
Shown in If a certain allowable ripple-like group delay time characteristic can be tolerated in the passband, the over-compensation type group delay time compensation type BPF has the widest group delay time characteristic. In FIGS. 5, 8 to 10, the solid line indicates the amplitude characteristic, and the broken line indicates the group delay time characteristic.

Further, the group delay time compensation type B of this embodiment
When the U-shaped loop element 7 is not provided in the PF and only the sub-coupling circuit including the capacitive element 5 and the S-shaped loop element 6 is provided, the attenuation outside the pass band is reduced.
However, by providing the U-shaped loop element 7, a pair of attenuation poles can be generated outside the pass band, and the attenuation characteristics outside the pass band can be improved. As described above, the U-shaped loop element 7 is provided to improve the attenuation characteristic outside the pass band, and
In the group delay time compensation type BPF of the present embodiment, if the attenuation outside the pass band satisfies the specification condition,
The U-shaped loop element 7 may not be provided, and only the sub-coupling circuit including the capacitive element 5 and the S-shaped loop element 6 may be provided.

[Embodiment 2] FIGS. 11 and 12 are cross-sectional views of main parts showing a schematic configuration of a group delay time compensating band-pass filter according to Embodiment 2 of the present invention. In addition, FIG.
FIG. 12A is a cross-sectional view of a main part of the same portion as FIG.
FIG. 12 is a sectional view of a main part of the same portion as that of FIG.
(B) is a fragmentary cross-sectional view of the same portion as in FIG. 28 (b),
FIG. 12C is a cross-sectional view of a main part of the same part as that of FIG. Also in the present embodiment, FIG.
The plan view of the same part as in FIG. 5 and the cross-sectional view of the main part of the same place as in FIG. 26 are the same as those in FIG. 25 and FIG.

In the resonator of the present embodiment, of the coaxial resonators arranged in a U-shape, two coaxial resonators located at the turning point are replaced with an n-th resonator (20d resonator). )When,
When the (n + 1) th resonator (resonator of 20e) is used, the (n-1) th resonator (resonator of 20c) includes:
The difference from the group delay time compensation type BPF of the first embodiment is that an S-shaped loop element 16 is used as a sub-coupling circuit between the (n + 2) th resonator (resonator of 20f).

In the group delay time compensating BPF of the present embodiment, the main coupling circuit connects the (n-1) th resonator and the (n + 2) th resonator to the (n + 2) th resonator. The generated electromagnetic field and the electromagnetic field generated in the (n + 2) -th resonator by the sub-coupling circuit including the S-shaped loop element 16 have phases opposite to each other. At frequency, an attenuation pole occurs.

Thus, in the group delay time compensation type BPF according to the present embodiment, the amplitude deviation and the group delay time deviation in the pass band can be reduced as in the first embodiment.

FIGS. 13 to 16 are graphs showing frequency characteristics of an example of the group delay time compensation type BPF of the present embodiment. The graphs shown in FIGS. 13 to 16 show the (n-3) th resonator (resonator of 20a) and (n
It is a graph which shows the frequency characteristic at the time of using the U-shaped loop element 7 as a sub-coupling circuit between the (+4) th resonator (resonator of 20h). FIG. 13 is a graph showing the attenuation characteristics. The horizontal axis represents the frequency (MHz) and the memory interval is 2 MHz, and the vertical axis represents the attenuation (dB) and the memory interval is 5 dB.
It is. Also, the center frequency of the group delay time compensation type BPF is 207 MHz, and in FIG.
The attenuation at 03.544 MHz (point A in FIG. 13) is -29.038 dB, and the frequency is 210.45 dB.
The attenuation at 6 MHz (point B in FIG. 13) is −33.
968 dB. FIG. 14 is a graph showing the graph shown in FIG. 13 in an enlarged manner, and the memory interval on the horizontal axis is 2 MHz.
z, the memory interval on the vertical axis is 1 dB. As can be seen from the graph of FIG. 14, the attenuation is within 2 dB when the frequency is between 204.1 MHz (point A in FIG. 14) and 209.9 MHz (point B in FIG. 14). The delay deviation compensation type BPF has a small amplitude deviation in the pass band.

FIG. 15 is a graph showing phase characteristics.
The horizontal axis is the frequency (MHz) and the memory interval is 2 MHz, and the vertical axis is the angle and the memory interval is 90 °. In FIG. 15, when the frequency is 204.1 MHz (point A in FIG. 15), the phase is −31.884 °, and the frequency is 209.48 °.
The phase at 9 MHz (point B in FIG. 15) is -33.7.
75 °. FIG. 16 is a graph showing the group delay time characteristic, where the horizontal axis represents the frequency (MHz) and the memory interval is 2 MHz.
z, the vertical axis is the delay amount (ns), and the memory interval is 100 ns. In FIG. 16, the frequency is 204.1 MHz.
The delay amount at (point A in FIG. 16) is 288.124 n
s and the frequency is 209.9 MHz (point B in FIG. 16)
In this case, the delay amount is 282.774 ns. [Embodiment 3] FIGS. 17 and 18 are cross-sectional views of main parts showing a schematic configuration of a group delay time compensation band-pass filter according to Embodiment 3 of the present invention. FIG. 17 is a cross-sectional view of an essential part of the same portion as FIG. 27, and FIG.
FIG. 18B is a cross-sectional view of a main part of the same portion as FIG. 27A, and FIG.
FIG. 29 is a sectional view of a principal part at the same place as in FIG. 28 (c).
Also, in the present embodiment, the plan view of the same place as in FIG. 25 and the cross-sectional view of the main part of the same place as in FIG. 26 are the same as in FIG. 25 and FIG. I do. Group delay time compensation type BP of the present embodiment
F indicates two of the coaxial resonators arranged in a U-shape, the two coaxial resonators located at the turning point, being the n-th resonator (the resonator of 20d) and the (n + 1) -th resonator. Container (20
e), the (n−2) -th resonator (2)
0b resonator) and the (n + 3) th resonator (20 g resonator), the capacitive element 15 is used as a sub-coupling circuit.
F is different.

In the group delay time compensation type BPF of this embodiment, the (n + 3) th resonator is connected between the (n−2) th resonator and the (n + 3) th resonator by the main coupling circuit. The generated electromagnetic field and the electromagnetic field generated in the (n + 3) -th resonator by the sub-coupling circuit including the capacitive element 15 are in phase with each other, and thus are attenuated at a pair of frequencies where the amplitudes of both electromagnetic fields are equal to each other. No poles occur.

As a result, in the group delay time compensation type BPF of this embodiment, the amplitude deviation and the group delay time deviation in the pass band can be reduced as in the first embodiment.

[Embodiment 4] FIG. 19 shows a BPF composed of a magnetic coupling circuit in which coaxial resonators are cascaded in multiple stages.
FIG. 19A is a diagram for explaining the magnetic coupling of the coaxial resonators in FIG. 19A. FIG. 19A shows the coaxial resonators connected in multiple stages (FIG. 19 shows only the adjacent coaxial resonators of Rn and Rn + 1).
It is a top view which shows the internal structure of. Generally, the coupling attenuation (LM) between the coaxial resonator (Rn) and the coaxial resonator (Rn + 1) can be obtained by the following equation (1).

[0034]

LM = (54.6 * LC) * F (λ) / 2W (dB) (1) where F (λ) = (1− (λC / λ) ** 2) **
(1/2) LC is the distance between the inner conductors forming the coaxial resonator (Rn, Rn + 1), W is the width of the outer conductor 1, and λ
c (λc = 2W) is the wavelength of the cutoff frequency of the BPF.

Now, if W << λ, then F (λ) = 1, so equation (1) is expressed as equation (2) below.

[0036]

LM ≒ 54.6 * LC / 2W (dB) (2) The coaxial resonator (Rn) is obtained from the magnetic loss (LM) obtained by the above equation (2). ) And the coaxial resonator (Rn + 1) can be obtained by the following (3).

[0037]

Mm = 10 ** (-LM / 20) (3) Here, when the load Q (QL) is high, LC> W, and the BPF is large. In some cases. In such a case, the BPF can be reduced in size by interposing the interstage magnetic field coupling adjustment element between the adjacent coaxial resonators (Rn, Rn + 1).

FIG. 20 is a cross-sectional view showing a main part of a schematic configuration of a group delay time compensating band-pass filter according to a fourth embodiment of the present invention. FIG. 20 is a cross-sectional view showing the same part as FIG. It is. The group delay time compensating BPF of the present embodiment differs from the BPF of the second embodiment in that the coaxial resonator (20a
To 20h) are disposed at appropriate intervals, and an interstage magnetic field coupling adjustment element 51 is provided between adjacent coaxial resonators (20a to 20h).
Is a band-pass filter that obtains required electrical characteristics.

FIG. 21 is a diagram showing an example of the inter-stage magnetic field coupling adjusting element 51 shown in FIG. 20. FIG. 21 (a) is a plan view showing the internal structure, and FIG. a) F-
It is sectional drawing which shows the principal part cross section cut | disconnected by F 'line. The inter-stage magnetic field coupling adjustment element 51 shown in FIG. 21 is composed of two conductor plates (52, 53) arranged at a predetermined distance (54 in FIG. 21) at the center. These two conductor plates (5
2, 53) are electrically and mechanically connected to the upper and lower walls of the outer conductor 1 and have two conductor plates (5, 53).
2, 53) is connected to the partition 2 or the external conductor 1
Electrically and mechanically. Interstage magnetic field coupling adjusting element 5 composed of these two conductor plates (52, 53)
When 1 is provided, the magnetic coupling coefficient (Mmi) between the coaxial resonator (Rn) and the coaxial resonator (Rn + 1) can be obtained by the following (4).

[0040]

Mmi = Mm × (Iw / W) (4) where Iw is the width of the predetermined interval (54 in FIG. 21). . As can be seen from the above equation (4), when the interstage magnetic field coupling adjustment element 51 shown in FIG. 21 is provided, the magnetic coupling coefficient between the coaxial resonator (Rn) and the coaxial resonator (Rn + 1) is reduced. The distance (54 in FIG. 21) can be appropriately adjusted according to the width (Iw).

FIG. 22 is a view showing another example of the inter-stage magnetic field coupling adjusting element 51 shown in FIG. 20. FIG. 22 (a) is a plan view showing the internal structure, and FIG. G in FIG.
It is sectional drawing which shows the principal part cross section cut | disconnected by the -G 'line. The interstage magnetic field coupling adjusting element 51 shown in FIG. 22 is formed of a strip-shaped, round-bar-shaped, or square-bar-shaped conductor 57, and the conductor 57 is electrically and mechanically formed on the upper and lower walls of the outer conductor 1. Connected. By appropriately adjusting the size of the conductor 57 or by appropriately increasing or decreasing the number of conductors 57 arranged between the adjacent coaxial resonator (Rn) and the coaxial resonator (Rn + 1), the magnetic coupling coefficient is increased. Can be adjusted to the required value.

FIG. 23 is a view showing another example of the inter-stage magnetic field coupling adjusting element 51 shown in FIG. 20. FIG. 23 (a) is a plan view showing the internal structure, and FIG. H in FIG.
It is sectional drawing which shows the principal part cross section cut | disconnected by the -H 'line. In the inter-stage magnetic field coupling adjusting element 51 shown in FIG. 23, a coupling adjusting screw 58 is provided between the coaxial resonator (Rn) and the coaxial resonator (Rn + 1), and the insertion length of the coupling adjusting screw 58 is appropriately changed. By doing so, the magnetic coupling coefficient can be adjusted to a required value. The connection adjusting screw 58 shown in FIG. 23 is, as shown in FIG.
May be combined with the interstage magnetic field coupling adjustment element 51 shown in FIG.

As described above, the invention made by the present inventor is:
Although a specific description has been given based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the invention.

[0044]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows. According to the present invention, in a band-pass filter using a λ / 4 coaxial resonator, it is possible to reduce an amplitude deviation and a group delay time deviation in a pass band and obtain a steep attenuation characteristic.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing a schematic configuration of a group delay time compensation band-pass filter according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part showing a schematic configuration of a group delay time compensating band-pass filter according to the first embodiment of the present invention.

FIG. 3 is a circuit diagram showing an equivalent circuit of the elliptic function band-pass filter using the conventional coaxial resonator shown in FIGS. 25 to 28;

FIG. 4 is a conversion equivalent circuit of the equivalent circuit shown in FIG. 3;

FIG. 5 is a graph showing amplitude deviation characteristics and group delay time deviation characteristics in a pass band in the band pass filters shown in FIGS. 25 to 28.

FIG. 6 is a circuit diagram showing an equivalent circuit of the group delay time compensation band-pass filter according to the first embodiment.

FIG. 7 is a conversion equivalent circuit of the equivalent circuit shown in FIG. 6;

FIG. 8 is a diagram illustrating a group within a pass band when the compensation amount of the group delay time by the sub-coupling circuit including the S-shaped loop element is smaller than the optimal size in the group delay time compensation type band pass filter according to the first embodiment; 5 is a graph showing a delay time deviation characteristic.

FIG. 9 is a diagram illustrating a group within a pass band when the compensation amount of the group delay time by the sub-coupling circuit including the S-shaped loop element is the optimal size in the group delay time compensation type band pass filter according to the first embodiment; 5 is a graph showing a delay time deviation characteristic.

FIG. 10 is a diagram illustrating a group in a pass band when the compensation amount of the group delay time by the sub-coupling circuit including the S-shaped loop element is larger than the optimum amount in the group delay time compensation band pass filter according to the first embodiment; 5 is a graph showing a delay time deviation characteristic.

FIG. 11 is a cross-sectional view of a main part showing a schematic configuration of a group delay time compensating band-pass filter according to a second embodiment of the present invention.

FIG. 12 is a cross-sectional view of a main part showing a schematic configuration of a group delay time compensating band-pass filter according to a second embodiment of the present invention.

FIG. 13 is a graph showing an attenuation characteristic of an example of a group delay time compensation type bandpass filter according to the second embodiment.

FIG. 14 is a graph showing the graph of FIG. 13 in an enlarged manner.

FIG. 15 is a graph showing phase characteristics of an example of a group delay time compensation type bandpass filter according to the second embodiment.

FIG. 16 is a graph showing a group delay time characteristic of an example of the group delay time compensation type bandpass filter according to the second embodiment.

FIG. 17 is a sectional view of a principal part showing a schematic configuration of a group delay time compensation type bandpass filter according to a third embodiment of the present invention.

FIG. 18 is a sectional view of a principal part showing a schematic configuration of a group delay time compensating band-pass filter according to a third embodiment of the present invention.

FIG. 19 is a diagram for explaining magnetic coupling of the coaxial resonator in the BPF configured by cascading the coaxial resonator in the magnetic coupling circuit in multiple stages.

FIG. 20 is a cross-sectional view illustrating a main part of a schematic configuration of a group delay time compensation band-pass filter according to a fourth embodiment of the present invention.

21 is a diagram illustrating an example of the interstage magnetic field coupling adjustment element illustrated in FIG. 20;

22 is a diagram showing another example of the interstage magnetic field coupling adjusting element shown in FIG. 20.

FIG. 23 is a diagram showing another example of the interstage magnetic field coupling adjusting element shown in FIG. 20;

24 is a diagram showing another example of the interstage magnetic field coupling adjustment element shown in FIG. 20.

FIG. 25 is a plan view showing an upper surface of an elliptic function band-pass filter using a conventional coaxial resonator.

26 is a fragmentary cross-sectional view showing a schematic configuration of the bandpass filter shown in FIG. 25.

FIG. 27 is a cross-sectional view of a principal part showing a schematic configuration of the bandpass filter shown in FIG. 25.

28 is a fragmentary cross-sectional view showing a schematic configuration of the bandpass filter shown in FIG. 25.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... External conductor, 2 ... Partition, 5, 5a, 5b, 15 ... Capacitance element which comprises a sub-coupling circuit, 6, 16 ... S-shaped loop element which comprises a sub-coupling circuit, 7 ... Sub-coupling circuit U-shaped loop element, 8, 8a, 8b ... input (or output) coupling loop, 9a to 9h ... lock nut, 11a ...
Input (or output) terminal, 11b ... output (or input)
Terminals, 20a to 20h, Rn, Rn + 1 ... coaxial resonator,
21a-21h drive screw, 22a-22h resonance frequency adjustment element, 23a-23h internal conductor, 51 interstage magnetic field coupling adjustment element, 52, 53 conductor plate, 54 spacing
57: conductor, 58: coupling adjusting screw.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01P 1/20 H01P 1/205 H01P 9/00

Claims (4)

(57) [Claims] 1. An outer conductor and first to Nth N -shaped conductors provided in the outer conductor.
(N ≧ 6) -th coaxial resonator and two coaxial resonators located at a U-shaped turning point,
When the n-th (n <N) -th and (n + 1) -th coaxial resonators are respectively used, the first to (n−1) th coaxial resonators
And the (n + 2) th to Nth coaxial resonances
And a partition provided between the coaxial resonators and a main coupling between the coaxial resonators by a magnetic coupling circuit.
A delay compensated bandpass filter, wherein the (n-1) th coaxial resonator and (n + 2) -th between coaxial resonators and subcombinations by capacitive element, the (n-2) th The length of the inner conductor of each coaxial resonator is set between the coaxial resonator and the (n + 3) th coaxial resonator.
Direction, and a portion penetrating the partition wall
The length of the inner conductor of each coaxial resonator of the partition wall
Both ends are electrically connected to the partition at different positions in the upper and lower directions.
A group delay time compensating band-pass filter characterized by being sub-coupled by an S-shaped loop element which is mechanically and mechanically connected . 2. An outer conductor and first to Nth N -shaped conductors provided in the outer conductor.
(N ≧ 6) -th coaxial resonator and two coaxial resonators located at a U-shaped turning point,
When the n-th (n <N) -th and (n + 1) -th coaxial resonators are respectively used, the first to (n−1) th coaxial resonators
And the (n + 2) th to Nth coaxial resonances
And a partition provided between the coaxial resonators and a main coupling between the coaxial resonators by a magnetic coupling circuit.
A delay compensated bandpass filter, wherein the (n-1) th coaxial resonator and (n + 2) -th between the coaxial resonators, and the (n-2) th coaxial resonator ( n + 3) th between the coaxial resonators, each of the
While being provided in the longitudinal direction of the internal conductor of the axial resonator,
With the part penetrating the partition wall as a boundary, each of the partition walls
At different positions in the longitudinal direction of the inner conductor of the coaxial resonator,
A group delay time compensating band-pass filter , wherein both ends are sub-coupled by an S-shaped loop element electrically and mechanically connected to the partition . 3. An outer conductor and first to Nth N -shaped conductors provided in the outer conductor.
(N ≧ 6) -th coaxial resonator and two coaxial resonators located at a U-shaped turning point,
When the n-th (n <N) -th and (n + 1) -th coaxial resonators are respectively used, the first to (n−1) th coaxial resonators
And the (n + 2) th to Nth coaxial resonances
And a partition provided between the coaxial resonators and a main coupling between the coaxial resonators by a magnetic coupling circuit.
A delay compensated bandpass filter, wherein the (n-1) th coaxial resonator and (n + 2) -th between the coaxial resonators, and the (n-2) th coaxial resonator ( A group delay time compensating band-pass filter characterized by sub-coupling with an (n + 3) th coaxial resonator by a capacitive element. 4. A outer conductor, the inside outer conductor, N from the first provided in a U-shape
(N ≧ 6) -th coaxial resonator and two coaxial resonators located at a U-shaped turning point,
When the n-th (n <N) -th and (n + 1) -th coaxial resonators are respectively used, the first to (n−1) th coaxial resonators
And the (n + 2) th to Nth coaxial resonances
And a partition provided between the coaxial resonators and a main coupling between the coaxial resonators by a magnetic coupling circuit.
A delay time compensating band-pass filter, wherein a length of an internal conductor of each of the coaxial resonators extends between the (n-1) th coaxial resonator and the (n + 2) th coaxial resonator.
Direction, and a portion penetrating the partition wall
The length of the inner conductor of each coaxial resonator of the partition wall
Both ends are electrically connected to the partition at different positions in the upper and lower directions.
Manner, that is by-linked by the loop element of the S-shaped which is mechanically connected to between the (n-2) th coaxial resonator and (n + 3) th coaxial resonators subcombination by capacitive element Characteristic group delay time compensation type band pass filter.