JP3967744B2 - Dielectric resonator type bandpass filter - Google Patents

Description

  The present invention relates to a dielectric resonator type band-pass filter, and more particularly to a dielectric resonator type band-pass filter with reduced amplitude deviation in the pass band.

In television broadcasting equipment or wireless communication equipment, bandpass filters such as transmission power, signals other than the target signal from received power, or noise removal, transmission power multiplexing, and reception power demultiplexing (Hereinafter referred to as BPF).
As this BPF, for example, a TM _01δ mode dielectric resonator or a dielectric resonator type BPF using a TE _01δ mode dielectric resonator is used.

In wireless communication and television broadcasting, W-CDMA and OFDM modulation schemes of multilevel digital modulation schemes are used.
In a BPF that passes a modulated wave according to such a modulation method, a bit error occurs if the amplitude deviation of the pass band is large.
However, the above-described dielectric resonator type BPF has a problem that it has a large amplitude deviation in the pass band and is not suitable for a BPF that allows a modulated wave to pass through the modulation method as described above.
The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a dielectric resonator type band in which the amplitude deviation in the pass band is smaller than that of a conventional band pass filter. It is to provide a pass filter.

Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
In order to achieve the above-mentioned object, the present invention is a dielectric resonator type bandpass filter, wherein n is an integer greater than or equal to 6 , and the first to nth elements are provided between the input terminal and the output terminal. N (1 ≦ i ≦ n) -th dielectric resonator, and the unloaded Q of the i (1 ≦ i ≦ n) th dielectric resonator is Q _u (i), By changing the resonance mode of the dielectric resonator, the size of the resonator, or the material of the dielectric, Q _u (1) <Q _u (2) <... <Q _u (n / 2), Q _u (N / 2 + 1)> Q _u (n / 2 + 2)>...> Q _u (n) is satisfied.
Also, the present invention, the n is 6, the first, second, fifth, and sixth resonator is TM _01Deruta mode dielectric resonator, said third and fourth resonant The resonator is a TE _01δ mode dielectric resonator.

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
According to the dielectric resonator type bandpass filter of the present invention, the amplitude deviation in the passband can be made smaller than that of the conventional bandpass filter.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In all the drawings for explaining the embodiments, parts having the same functions are given the same reference numerals, and repeated explanation thereof is omitted.
1A and 1B are schematic diagrams for explaining a TM _01δ mode dielectric resonator, in which FIG. 1A is a front view and FIG. 1B is a top view. In FIG. 1, 3 is a TM _01δ mode dielectric resonator, and 2 is a casing. In addition, although the housing | casing 2 is comprised with the metal plate which has predetermined | prescribed thickness, it represents with a mere line in FIG.
Generally, the height H of the _{TM 01Deruta} mode dielectric resonator, λo / 4, _{TM 01δ} mode dielectric also the length S of the cavity of the housing 2 side, are .lamda.o / 4.
Here, _λo is the free space wavelength of the use center frequency (fo) of the TM _01δ mode dielectric resonator. In FIG. 1, the solid line represents the electric field component, and the wavy line represents the magnetic field component.
The unloaded Q (Q _u ) of the TM _01δ mode dielectric resonator shown in FIG. 1 is obtained by the following equation (1).
[Equation 1]
Q _u ≈84 × S (cm) × √fo (MHz) (1)
Here, fo is a use center frequency of the TM _01δ mode dielectric resonator.

Further, as shown in the TM _01δ mode dielectric resonator (R _{n + 1} ) in FIG. 2, the length of one side parallel to the direction along the signal path in the resonator housing 2 is changed to 1.4S. In this case, the no-load Q is obtained by the following equation (2).
[Equation 2]
Q _u ≈42 × S (cm) × √fo (MHz) × √ (1.4) (2)
Thus, when the length of one side parallel to the direction along the signal path in the case of the TM _01δ mode dielectric resonator is increased, the unloaded Q (Q _u ) is increased. Although not shown, when the length of one side parallel to the direction along the signal path is reduced, the no-load Q (Q _u ) is reduced.
However, when the volume of the TM _01δ mode dielectric resonator is increased, the use center frequency (fo) is decreased.
Of _{TM 01Deruta} mode dielectric resonator 2 to return to the original frequency using the center frequency (fo) of _{(R n + 1)} is, _{TM 01δ} mode dielectric of _{TM 01Deruta} mode dielectric resonator 2 _{(R n + 1)} The diameter φd _L of the body resonance element 3 may satisfy the following expression (3).
[Equation 3]
φd _S ≈√ (1.4 × S / S) × φd _L
φd _S ≈√ (1.4) × φd _L (3)
Where φd _S is the diameter of the TM _01δ mode dielectric resonator 3 of the TM _01δ mode dielectric resonator (R _n ) of FIG.

3A and 3B are schematic diagrams for explaining the TE _01δ mode dielectric resonator, in which FIG. 3A is a diagram seen from the front, and FIG. 3B is a diagram seen from above. In FIG. 1, 3 is a TM _01δ mode dielectric resonator, and 2 is a casing. In addition, although the housing | casing 2 is comprised with the metal plate which has predetermined | prescribed thickness, it represents with a mere line in FIG.
Generally, the height H of the _{TE 01Deruta} mode dielectric resonator, λo / 4, _{TE 01δ} mode dielectric also the length S of the cavity of the housing 2 side, are .lamda.o / 4.
Here, _λo is the free space wavelength of the used center frequency (fo) of the TE _01δ mode dielectric resonator. In FIG. 3, the solid line represents the electric field component, and the wavy line represents the magnetic field component.
In general, the unloaded Q (Q _u ) of the TE _01δ mode dielectric resonator shown in FIG. 3 is the unloaded Q (Q _C ) of the metal portion and the unloaded Q (Q _d ) of the TE _01δ mode dielectric resonator 5. ) Has the relationship of the following formula (4).
[Equation 4]
1 / Q _u = 1 / Q _C + 1 / Q _d
Q _u = (Q _C × Q _u ) / (Q _C + Q _u )
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ (4)
From this equation (4), the unloaded Q (Q _u ) of the TE _01δ mode dielectric resonator can be controlled by controlling the unloaded Q (Q _C ) of the metal part.

Further, as shown in the TE _01δ mode dielectric resonator (R _{n + 1} ) in FIG. 4, the length of one side parallel to the direction along the signal path in the resonator housing 2 is 1.4 S. As shown in the unloaded Q (Q _uL ) and the TE _01δ mode dielectric resonator (R _n ) in FIG. 4, the length of one side parallel to the direction along the signal path in the resonator housing 2 is In the case of S, there is a relationship of the following equation (5) between the unloaded Q (Q _uS ).
[Equation 5]
Q _uL > Q _uS
Q _{uL ≈√} (1.4 × S / S) × Q _uS
Q _{uL ≈√} (1.4) × Q _uS
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ (5)
Thus, when the length of one side parallel to the direction along the signal path in the case of the TE _01δ mode dielectric resonator is increased, the unloaded Q (Q _u ) increases. Although not shown, when the length of one side parallel to the direction along the signal path is reduced, the no-load Q (Q _u ) is reduced.
However, when the volume of the TE _01δ mode dielectric resonator is increased, the use center frequency (fo) is decreased.
Figure 4 of _{TE 01Deruta} mode dielectric resonator to return to the original frequency using the center frequency (fo) of _{(R n + 1), TE} 01δ mode dielectric of _{TE 01Deruta} mode dielectric resonator of FIG. 4 _{(R n + 1)} The diameter φd _L of the body resonance element 5 may satisfy the following expression (6).
[Equation 6]
φd _S ≈√ (1.4 × S / S) × φd _L
φd _S ≈√ (1.4) × φd _L (6)
Where φd _S is the diameter of the TE _01δ mode dielectric resonator 5 of the TE _01δ mode dielectric resonator (R _n ) of FIG.
On the other hand, the total transmission loss characteristic function (Li) of the resonance circuit is obtained by the following equation (7).
[Equation 7]
Li = 10 log {1+ [Q _L / (Q _L −Q _u )] ² + x ² } (7)
Here, x = Q _L (f / fo−fo / f), Q _L is a load Q, fo is a center frequency of use of the coaxial resonator, and f is an arbitrary frequency.

FIG. 5 is a schematic diagram showing a schematic configuration of a polarized quaternary dielectric resonator type BPF according to an embodiment of the present invention. FIG. 5 is a view of the inside of the dielectric resonator type BPF as seen from above.
In FIG. 5, 10 is an outer conductor, 11 is a partition, 15 is an input (or output) terminal, 16 is an output (or input) terminal, 21 and 22 are loop elements, and R1 and R4 are TM _01δ mode dielectric resonators. 3a and 3d are TM _01δ mode dielectric resonators, R2 and R3 are TE _01δ mode dielectric resonators, and 5b and 5c are TE _01δ mode dielectric resonators.
In addition, although the outer conductor 10 and the partition 11 are comprised with the metal plate which has predetermined | prescribed thickness, in FIG. 5, it represents with a mere line.
Here, the outer conductor 10 and the partition wall 11 constitute a housing of each resonator. The input terminal 15 and the output terminal 16 are each made of, for example, a coaxial plug, and the external conductors forming the respective coaxial plugs are connected to the external conductor 10 constituting the resonator.
In the polarized quaternary dielectric resonator type BPF shown in FIG. 5, four resonators (R1 to R4) are arranged between the input terminal 15 and the output terminal 16 in order from the first to the fourth. As shown by M ₁₂ , M ₂₃ , M ₃₄ , and M ₄₅ in FIG. 5, the resonators (R1 to R4) are mainly coupled by a magnetic coupling circuit.
Further, as indicated by _MC14 in FIG. 5, the resonator (R1) and the resonator (R4) are sub-coupled by a capacitive coupling circuit.
Furthermore, FIG. 6 shows an example of an equivalent circuit of the polarized quaternary dielectric resonator type BPF shown in FIG.

In the polarized fourth-order dielectric resonator type BPF shown in FIG. 5, when the unloaded Q of the i (1 ≦ i ≦ 4) th resonator is Q _u (i), the i th resonator Is set so as to satisfy the following equation (8).
[Equation 8]
Q _u (1) <Q _u (2)
Q _u (3)> Q _u (4)
Q _u (2) = Q _u (3) (8)
On the other hand, in the polarized quaternary dielectric resonator type BPF shown in FIG. 5, when the load Q of the i (1 ≦ i ≦ 4) th resonator is Q _L (i), the load Q is Generally, it is set as the following equation (9).
[Equation 9]
Q _L (1) <Q _L (2)
Q _L (3)> Q _L (4) (9)
FIG. 7 is a schematic diagram showing a schematic configuration of a conventional polarized quaternary dielectric resonator type BPF in the sense of comparison with the polarized quaternary dielectric resonator type BPF shown in FIG.
FIG. 7 is a view of the inside of the dielectric resonator type BPF as viewed from above, and the outer conductor 10 and the partition wall 11 are formed of a metal plate having a predetermined thickness. It is represented by a line.
In the polarized fourth-order dielectric resonator type BPF shown in FIG. 7, four TM _01δ mode dielectric resonators are _arranged between the input terminal 15 and the output terminal 16 in the order from the first to the fourth. (R1 to R4) are arranged in a U-shape, and as shown by M ₁₂ , M ₂₃ , M ₃₄ , and M ₄₅ in FIG. Is done.
Further, as indicated by _MC14 in FIG. 6, the resonator (R1) and the resonator (R4) are sub-coupled by a capacitive coupling circuit.

FIG. 8 is a graph showing the attenuation characteristics of an example of the polarized quaternary dielectric resonator type BPF shown in FIG. 5. The horizontal axis is frequency (MHz), the memory interval is 2 MHz, and the vertical axis is attenuation ( In dB, the memory interval is 5 dB, and the center frequency is 476 MHz.
In FIG. 8, the attenuation when the frequency is 473.2 MHz (point 2 in FIG. 8) is −0.6445 dB, and the attenuation when the frequency is 478.8 MHz (point 3 in FIG. 8), -0.6425 dB.
FIG. 9 is an enlarged graph of the graph shown in FIG. 8, where the horizontal axis memory interval is 2 MHz and the vertical axis memory interval is 1 dB.
As can be seen from the graph of FIG. 9, the attenuation when the frequency is 477.325 MHz (point 4 in FIG. 9) is −0.3193 dB, and the attenuation is 475.995 MHz (point 5 in FIG. 9). The amount is -0.766 dB, and when the frequency is between 473.2 MHz (point 2 in FIG. 9) to 478.8 MHz (point 3 in FIG. 9), the deviation of the attenuation is within about 0.5 dB. It has become.

FIG. 10 is a graph showing the attenuation characteristics of an example of the conventional polarized type fourth-order dielectric resonator type BPF shown in FIG. 7, where the horizontal axis is frequency (MHz), the memory interval is 2 MHz, and the vertical axis is attenuation. In quantity (dB), the memory interval is 5 dB, and the center frequency is 527.0 MHz.
In FIG. 10, the attenuation when the frequency is 524.2 MHz (point 2 in FIG. 10) is −0.9661 dB, and the attenuation when the frequency is 529.8 MHz (point 3 in FIG. 10), -0.667 dB.
FIG. 11 is an enlarged graph of the graph shown in FIG. 10, where the memory interval on the horizontal axis is 2 MHz and the memory interval on the vertical axis is 1 dB.
As can be seen from the graph of FIG. 11, when the frequency is between 524.2 MHz (point 2 in FIG. 11) and the frequency is 529.8 MHz (point 3 in FIG. 11), the deviation in attenuation is about 0.8 dB. It is within.
In this way, the polarized quaternary dielectric resonator type BPF shown in FIG. 5 has an amplitude deviation in the pass band that is larger than that of the conventional polarized quaternary dielectric resonator type BPF shown in FIG. You can see that it is getting smaller.
This is considered to be due to the following reasons.
In the polarized fourth-order dielectric resonator type BPF shown in FIG. 5, the unloaded Q (Q _u ) of the TE _01δ mode dielectric resonator ( R2, R3 ) is the same as that of the conventional polarized type shown in FIG. It is made larger than the unloaded Q (Q _u ) of the TM _01δ mode dielectric resonator ( R2, R3 ) of the fourth dielectric resonator type BPF. Accordingly, in the above-described equation (7), the value of [Q _L / (Q _L −Q _u )] becomes small, so that the attenuation (Li) becomes small.
The poled type quaternary dielectric resonator type resonators ( R2, R3 ) shown in FIG. 5 have an edge portion of the passband (a region of a frequency of fo ± 2.8 MHz, where fo is a center frequency). It is considered that the amplitude deviation in the pass band is smaller than that of the conventional polarized quaternary dielectric resonator type BPF shown in FIG.

FIG. 12 is a graph showing attenuation characteristics of another example of the polarized quaternary dielectric resonator type BPF shown in FIG. 5, where the horizontal axis is frequency (MHz), the memory interval is 2 MHz, and the vertical axis is attenuation. In quantity (dB), the memory interval is 5 dB, and the center frequency is 473 MHz.
FIG. 12 shows the characteristics of the output filter used in the terrestrial digital television set, and the attenuation when the frequency is 470.2 MHz (point 2 in FIG. 12) in FIG. The attenuation amount is −0.126 dB, and the attenuation when the frequency is 475.8 MHz (point 3 in FIG. 12) is −0.0955 dB.
FIG. 13 is an enlarged graph of the graph shown in FIG. 12, where the horizontal axis memory interval is 2 MHz and the vertical axis memory interval is 1 dB.
As can be seen from the graph of FIG. 13, when the frequency is between 470.2 MHz (point 2 in FIG. 13) and the frequency is 475.8 MHz (point 3 in FIG. 13), the deviation of the attenuation is about 0.1 dB. It is within.
FIG. 14 is a graph showing attenuation characteristics of another example of the polarized quaternary dielectric resonator type BPF shown in FIG. 5, the horizontal axis is frequency (MHz), the memory interval is 2 MHz, and the vertical axis is attenuation. In quantity (dB), the memory interval is 5 dB, and the center frequency is 473 MHz.
FIG. 14 shows the characteristics of the band-pass filter used in the antenna sharing device for the relay base of the terrestrial digital television. The frequency is 470.2 MHz (point 2 in FIG. 14). ) Is −0.3025 dB, and when the frequency is 475.8 MHz (point 3 in FIG. 14), the attenuation is −0.2025 dB.
FIG. 15 is an enlarged graph of the graph shown in FIG. 14, where the horizontal axis memory interval is 2 MHz and the vertical axis memory interval is 1 dB.
As can be seen from the graph of FIG. 15, when the frequency is between 470.2 MHz (point 2 in FIG. 15) and the frequency is 475.8 MHz (point 3 in FIG. 15), the deviation of the attenuation is about 0.3 dB. It is within.

FIG. 16 is a schematic diagram showing a schematic configuration of a polarized sixth-order dielectric resonator type BPF according to an embodiment of the present invention. FIG. 16 is a view of the inside of the dielectric resonator type BPF as seen from above.
In FIG. 16, 10 is an external conductor, 11 is a partition, 15 is an input (or output) terminal, 16 is an output (or input) terminal, 21 and 22 are loop elements, and R1 and R6 are TM _01δ mode dielectric resonators. 3a and 3f are TM _01δ mode dielectric resonators, R2 to R5 are TE _01δ mode dielectric resonators, and 5b to 5e are TE _01δ mode dielectric resonators.
Note that the outer conductor 10 and the partition 11 are made of a metal plate having a predetermined thickness, but are represented by simple lines in FIG.
In the polarized sixth-order dielectric resonator type BPF shown in FIG. 16, six resonators (R1 to R6) are arranged between the input terminal 15 and the output terminal 16 in order from the first to the sixth. As shown by M ₁₂ , M ₂₃ , M ₃₄ , M ₄₅ , and M ₅₆ in FIG. 16, the resonators (R 1 to R 6) are mainly coupled by a magnetic coupling circuit.
Further, as shown in _{M 16} in FIG. 16, between the resonator (R1) and the resonator (R6) is subcombination with magnetic coupling circuit, as shown in _{M C25} of FIG. 16, the resonator (R2) And the resonator (R5) are sub-coupled by a capacitive coupling circuit.
Further, FIG. 17 shows an example of an equivalent circuit of the polarized sixth-order dielectric resonator type BPF shown in FIG.
In the polarized sixth-order dielectric resonator type BPF shown in FIG. 16, when the unloaded Q of the i (1 ≦ i ≦ 6) th resonator is Q _u (i), the i th resonator Is set so as to satisfy the following expression (10).
Here, in the dielectric resonator type BPF shown in FIG. 16, since the dielectric constant of the TE _01δ mode dielectric resonator (5b to 5e) is the same, the size of the TE _01δ mode dielectric resonator (R3, R4) is large. This is larger than that of the TE _01δ mode dielectric resonator (R2, R5).
FIG. 16 illustrates a case where the length of one side parallel to the direction along the signal path of the casing of the TE _01δ mode dielectric resonator (R3, R4) is _1.4S .
[Equation 10]
Q _u (1) <Q _u (2) <Q _u (3)
Q _u (4)> Q _u (5)> Q _u (6)
Q _u (3) = Q _u (4) (10)

FIG. 18 is a graph showing the attenuation characteristics of an example of the polarized sixth-order dielectric resonator type BPF shown in FIG. 16, where the horizontal axis is frequency (MHz), the memory interval is 2 MHz, and the vertical axis is attenuation ( dB), the memory interval is 5 dB, and the center frequency is 473.5 MHz.
In FIG. 18, the attenuation when the frequency is 470.7 MHz (point 2 in FIG. 18) is −0.3738 dB, and the attenuation when the frequency is 476.3 MHz (point 3 in FIG. 18), -0.2364 dB.
FIG. 19 is an enlarged graph of the graph shown in FIG. 18. The horizontal axis memory interval is 2 MHz, and the vertical axis memory interval is 1 dB.
As can be seen from the graph of FIG. 19, when the frequency is between 470.7 MHz (point 2 in FIG. 19) and the frequency is 476.3 MHz (point 3 in FIG. 19), the deviation of the attenuation is within 0.2 dB. It has become.

In the above description, the fourth-order and sixth-order polarized dielectric resonator type BPFs have been described. However, the present invention is not limited to the fourth-order and sixth-order dielectric resonators shown in FIGS. It can also be applied to the type BPF.
FIG. 20 is a schematic diagram showing a schematic configuration of a fourth-order dielectric resonator type BPF according to an embodiment of the present invention.
The fourth-order dielectric resonator type BPF shown in FIG. 20 is similar to FIG. 7 in that a capacitive coupling circuit that sub-couples between the dielectric resonator (R1) and the dielectric resonator (R4) is omitted. The other configuration is the same as that of the polar quaternary dielectric resonator type BPF shown in FIG. 7 except for the polar type quaternary dielectric resonator type BPF shown in FIG. Is omitted.
FIG. 21 is a schematic diagram showing a schematic configuration of a sixth-order dielectric resonator type BPF according to an embodiment of the present invention.
A sixth-order dielectric resonator type BPF shown in FIG. 21 includes a magnetic coupling circuit that sub-couples between the dielectric resonator (R1) and the dielectric resonator (R6), and the dielectric resonator (R2). This is different from the polar sixth-order dielectric resonator type BPF shown in FIG. 16 in that the capacitive coupling circuit that sub-couples with the dielectric resonator (R5) is omitted. Since this is the same as the polarized sixth-order dielectric resonator type BPF shown in FIG. 16, detailed description thereof will not be repeated.
20 and 21 are views of the inside of the dielectric resonator type BPF as viewed from above, and the outer conductor 10 and the partition 11 are made of a metal plate having a predetermined thickness. 20, in FIG. 21, it is represented by a simple line.

In the above description, the fourth-order or sixth-order dielectric resonator type BPF has been described. However, the present invention can also be applied to, for example, an eighth-order dielectric resonator type BPF.
In this case, when the number of resonators is n and the unloaded Q of the i (1 ≦ i ≦ n) th resonator is Q _u (i), the resonance mode of the dielectric resonator is determined as the resonator. The unloaded Q of the i-th resonator may be set so that the following equation (11) is satisfied by changing the size of the dielectric material or the dielectric material.
[Equation 11]
Q _u (1) <Q _u (2) <... <Q _u (n / 2)
Q _u (n / 2 + 1)> Q _u (n / 2 + 2)>...> Q _u (n)
Q _u (n / 2) = Q _u (n / 2 + 1)
... (11)
That is, as shown in FIG. 22, changing the material of the dielectric resonator type BPF having six _{TE 01Deruta} mode dielectric resonators (R1~R6), _{TE 01δ} mode dielectric resonator element (5 a to 5 f) However, the above-described expression (12) may be satisfied.

FIG. 22 is a schematic diagram showing a schematic configuration of a sixth-order dielectric resonator type BPF according to an embodiment of the present invention. In FIG. 22, 10 is an external conductor, 11 is a partition, 15 is an input (or output) terminal, 16 is an output (or input) terminal, 21 and 22 are loop elements, and R1 to R6 are TE _01δ mode dielectric resonators. Reference numerals 5a to 5f denote TE _01δ mode dielectric resonant elements.
FIG. 22 is a view of the inside of the dielectric resonator type BPF as viewed from above. Further, the outer conductor 10 and the partition wall 11 are formed of a metal plate having a predetermined thickness. It is represented by a line.
In FIG. 22, when the dielectric constants of the TE _01δ mode dielectric resonator elements (5a to 5f) are ε1 to ε6, ε1 to ε6 satisfy the following expression (12).
[Equation 12]
ε1 <ε2 <ε3
ε4>ε5> ε6
ε1 = ε6
ε2 = ε5
ε3 = ε4 (12)
In the sixth-order dielectric resonator type BPF shown in FIG. 22, instead of changing the material of the TE _01δ mode dielectric resonator elements (5a to 5f), the size of the dielectric resonator type is changed to the above ( You may make it satisfy | fill 12) Formula.
Further, in the sixth-order dielectric resonator type BPF shown in FIG. 22, instead of the six TE _01δ mode dielectric resonators (R1 to R6), six TM _01δ mode dielectric resonators (R1 to R6) are used. May be used.

Further, as shown in FIG. 23, a dielectric resonator type BPF having two TM _01δ mode dielectric resonators (R1, R6) and four TE _01δ mode dielectric resonators (R2 to R5). In this case, the material of the TE _01δ mode dielectric resonant element (5b to 5e) may be changed to satisfy the above-described expression (11).
FIG. 23 is a schematic diagram showing a schematic configuration of a sixth-order dielectric resonator type BPF according to an embodiment of the present invention. 23, 10 is an external conductor, 11 is a partition, 15 is an input (or output) terminal, 16 is an output (or input) terminal, 21 and 22 are loop elements, and R1 and R6 are TM _01δ mode dielectric resonators. 3a and 3f are TM _01δ mode dielectric resonators, R2 to R5 are TE _01δ mode dielectric resonators, and 5b to 5e are TE _01δ mode dielectric resonators.
FIG. 23 is a view of the inside of the dielectric resonator type BPF as viewed from above. Further, the outer conductor 10 and the partition wall 11 are formed of a metal plate having a predetermined thickness. It is represented by a line.
In the dielectric resonator type BPF shown in FIG. 23, when the dielectric constants of the TE _01δ mode dielectric resonator elements (5b to 5e) are ε2 to ε5, respectively, ε2 to ε5 satisfy the following equation (13). To do.
[Equation 13]
ε2 <ε3
ε4> ε5
ε2 = ε5
ε3 = ε4 (13)

FIG. 24 is a schematic diagram showing a schematic configuration of an eighth-order dielectric resonator type BPF according to an embodiment of the present invention. 24, 10 is an external conductor, 11 is a partition, 15 is an input (or output) terminal, 16 is an output (or input) terminal, 21 and 22 are loop elements, and R1 and R8 are TM _01δ mode dielectric resonators. 3a and 3h are TM _01δ mode dielectric resonators, R2 to R7 are TE _01δ mode dielectric resonators, and 5b to 5g are TE _01δ mode dielectric resonators.
FIG. 24 is a view of the inside of the dielectric resonator type BPF as viewed from above. Further, the outer conductor 10 and the partition wall 11 are formed of a metal plate having a predetermined thickness. It is represented by a line.
In the dielectric resonator type BPF shown in FIG. 24, when the dielectric constants of the TE _01δ mode dielectric resonator elements (5b to 5i) are ε2 to ε7, respectively, ε2 to ε7 satisfy the following expression (14). To do.
[Formula 14]
ε2 = ε3 <ε4
ε5> ε6 = ε7
ε4 = ε5 (14)
That is, in the dielectric resonator type BPF shown in FIG. 24, since the dielectric constants of the TE _01δ mode dielectric resonator elements (5b, 5c, 5f, 5g) are the same, the TE _01δ mode dielectric resonator (R3, R3) The size of R6) is made larger than that of the TE _01δ mode dielectric resonator (R2, R5) so as to satisfy the above-described equation (11).
FIG. 24 illustrates a case where the length of one side parallel to the direction along the signal path of the casing of the TE _01δ mode dielectric resonator (R3, R6) is _1.4S .

Hereinafter, a magnetic coupling circuit that mainly couples the resonators (R1 to R6) in the present embodiment will be described.
As the magnetic coupling circuit for main coupling between the dielectric resonators, for example, as shown in FIG. 25, a partition wall 11 having a window 20 may be used.
In addition, in the polarized sixth-order dielectric resonator type BPF shown in FIG. 16, as a magnetic coupling circuit for sub-coupling between the resonator (R1) and the resonator (R6), for example, as shown in FIG. Such a loop element (U-shaped loop element) 25 having a structure in which both ends of the loop element are electrically and mechanically connected to the partition wall 11 at the same position above and below (or right and left) the partition wall 11 may be used.
Further, in the polarized sixth-order dielectric resonator type BPF shown in FIG. 16, as a capacitive coupling circuit that sub-couples between the resonator (R2) and the resonator (R5), for example, as shown in FIG. A loop element (S-shaped loop element) 26 having a structure in which both ends of the loop element are electrically and mechanically connected to the partition wall 11 at different positions on the left and right (or top and bottom) of the partition wall 11 may be used.
As mentioned above, the invention made by the present inventor has been specifically described based on the above embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Of course.

It is a schematic diagram for explaining a TM _01δ mode dielectric resonator. It is a schematic diagram for _{demonstrating} the no-load Q of a TM _{01 (delta)} mode dielectric resonator. It is a schematic diagram for _{demonstrating a TE01 (delta)} mode dielectric resonator. It is a schematic diagram for _{demonstrating} the no-load Q of a TE _{01 (delta)} mode dielectric resonator. It is a schematic diagram which shows schematic structure of the polar 4th order dielectric resonator type | mold BPF of the Example of this invention. FIG. 6 is a circuit diagram showing an equivalent circuit of the polarized quaternary dielectric resonator type BPF shown in FIG. 5. It is a schematic diagram which shows schematic structure of the conventional polar type | mold 4th order dielectric resonator type | mold BPF. 6 is a graph showing an attenuation characteristic of an example of a polarized quaternary dielectric resonator type BPF shown in FIG. 5. It is a graph which expands and shows the graph shown in FIG. It is a graph which shows the attenuation | damping characteristic of an example of the conventional polarized quaternary dielectric resonator type BPF shown in FIG. It is a graph which expands and shows the graph shown in FIG. 6 is a graph showing the attenuation characteristics of another example of the polarized quaternary dielectric resonator type BPF shown in FIG. 5. It is a graph which expands and shows the graph shown in FIG. 6 is a graph showing the attenuation characteristics of another example of the polarized quaternary dielectric resonator type BPF shown in FIG. 5. It is a graph which expands and shows the graph shown in FIG. It is a schematic diagram which shows schematic structure of the polar 6th order dielectric resonator type | mold BPF of the Example of this invention. FIG. 17 is a circuit diagram showing an equivalent circuit of the polarized sixth-order dielectric resonator type BPF shown in FIG. 16. FIG. 17 is a graph showing an attenuation characteristic of an example of a polarized sixth-order dielectric resonator type BPF shown in FIG. 16. It is a graph which expands and shows the graph shown in FIG. It is a schematic diagram which shows schematic structure of the 4th dielectric resonator type | mold BPF of the Example of this invention. It is a schematic diagram which shows schematic structure of the 6th dielectric resonator type | mold BPF of the Example of this invention. It is a schematic diagram which shows schematic structure of the 6th dielectric resonator type | mold BPF of the Example of this invention. It is a schematic diagram which shows schematic structure of the 6th dielectric resonator type | mold BPF of the Example of this invention. It is a schematic diagram which shows schematic structure of the 8th dielectric resonator type | mold BPF of the Example of this invention. It is a figure which shows an example of the magnetic coupling circuit which mainly couples between each resonator in the dielectric resonator type | mold BPF of the Example of this invention. It is a figure which shows an example of the magnetic coupling circuit which carries out the sub coupling between two resonators in the 6th dielectric resonator type | mold BPF of the Example of this invention. It is a figure which shows an example of the capacitive coupling circuit which carries out a sub coupling between two resonators in the 6th dielectric resonator type | mold BPF of the Example of this invention.

Explanation of symbols

2 _Housing 3, 3a, 3d, 3f, 3h TM _01δ mode dielectric resonant element 5, 5a to 5g TE _01δ mode dielectric resonant element 10 External conductor 11 Bulkhead 15 Input (or output) terminal 16 Output (or input) terminal 20 Window 21, 22 Loop element 25 Capacitance element constituting sub-coupling circuit 26 S-shaped loop element constituting sub-coupling circuit R1-R6 Resonator

Claims (2)

When n is an integer greater than or equal to 6, n dielectric resonators are arranged between the input terminal and the output terminal in order from the first to the nth,
When the unloaded Q of the i (1 ≦ i ≦ n) th dielectric resonator is Q _u (i), the resonance mode, the size of the resonator, or the dielectric Change body materials,
Q _u (1) <Q _u (2) <... <Q _u (n / 2),
A dielectric resonator type band-pass filter satisfying Q _u (n / 2 + 1)> Q _u (n / 2 + 2)>...> Q _u (n). N is 6;
The first, second, fifth, and sixth resonators are TM _01δ mode dielectric resonators;
The dielectric resonator type bandpass filter according to claim 1, wherein the third and fourth resonators are TE _01δ mode dielectric resonators.

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