KR100401960B1 - Dielectric filter and communication system - Google Patents

Abstract

The present invention provides a dielectric filter which narrows the pitch of the inner conductor forming hole in the dielectric block and suppresses deterioration of the filter characteristic due to the decrease in Qodd when miniaturized, and a communication device including the same.

Inside the substantially rectangular parallelepiped dielectric block 1, the inner conductor forming holes 2a and 2b are formed with the axes substantially parallel to each other and the inner conductors 3a and 3b formed on the inner surface thereof. Although the outer conductor is formed, when the distance between the arrangement direction of the inner conductor forming hole is pitch p and the width perpendicular to the arrangement direction of the inner conductor forming hole is d, the p / d is 0.6 or less and the adjacent inner conductor The axis of the forming hole is eccentric to be far from the thickness direction.

Description

Dielectric filter and communication system

The present invention relates to a dielectric filter formed by forming an inner conductor forming hole in which an inner conductor is formed on an inner surface of the dielectric block, and forming an outer conductor on an outer surface of the dielectric block, and a communication device including the same.

19 shows a configuration example of a conventional dielectric filter. Here, FIG. 19A is a rear view of the dielectric filter, FIG. 19B is a top view, FIG. 19C is a front view, and FIG. 19D is a right side view. Inside the dielectric block 1 having a substantially rectangular parallelepiped shape, inner conductor forming holes 2a and 2b having inner conductors 3a and 3b formed on inner surfaces thereof are formed. In addition, an outer conductor is formed on the outer surface (surface 6) of the dielectric block 1. An inner conductor non-forming portion g is formed near one end of the inner conductor forming holes 2a and 2b, and this portion is used as an open end of the inner conductor as a resonant line.

In a conventional dielectric filter using a dielectric block, the axial length of the inner conductor forming hole is inevitably determined by the resonance frequency, but the size of the width of the dielectric block (width in the arrangement direction of the inner conductor forming hole) is determined by design. . Therefore, narrowing the axial spacing (resonator pitch) of the inner conductor forming holes 2a and 2b and reducing the width in the arrangement direction of the inner conductor forming holes of the dielectric block is effective for miniaturization as a whole.

However, when the resonator pitch is narrowed, Q0 (Qodd) in the even mode is deteriorated, which causes a problem that the shoulder portion of the bandpass characteristic (the characteristic near the attenuation band of the passband) is deteriorated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric filter and communication device using the same which suppress deterioration of filter characteristics due to the decrease of the Qodd and aim at miniaturization as a whole.

1 is a projection view of a dielectric filter according to the first embodiment.

Fig. 2 shows the result obtained by obtaining the relationship of Qo with respect to the amount of eccentricity of the inner conductor forming hole whose inner diameter of the inner conductor forming hole of the dielectric filter is a parameter for a predetermined pitch.

Fig. 3 shows the result of obtaining the relationship of Qo with respect to the eccentricity of the inner conductor forming hole whose parameter is the inner diameter of the inner conductor forming hole of the same dielectric filter for different pitches.

Fig. 4 shows the result of obtaining the relationship of Qo with respect to the amount of eccentricity of the inner conductor forming hole whose parameter is the inner diameter of the inner conductor forming hole of the same dielectric filter for different pitches.

Fig. 5 shows the result of obtaining the relationship of Qo with respect to the amount of eccentricity of the inner conductor forming hole whose parameter is the inner diameter of the inner conductor forming hole of the same dielectric filter for the different pitches.

Fig. 6 shows the result of obtaining the relationship of Qo with respect to the amount of eccentricity of the inner conductor forming hole whose parameter is the inner diameter of the inner conductor forming hole of the same dielectric filter for different pitches.

Fig. 7 shows the result of obtaining the relation of Qo with respect to the amount of eccentricity of the inner conductor forming hole with respect to the inner diameter of the predetermined inner conductor forming hole, using the pitch of the same dielectric filter as a parameter.

Fig. 8 shows the result of obtaining the relationship of Qo with respect to the amount of eccentricity of the inner conductor forming hole with respect to the inner diameter of the other inner conductor forming hole as a parameter.

Fig. 9 shows the result of obtaining the relationship of Qo with respect to the amount of eccentricity of the inner conductor forming hole, with the pitch of the same dielectric filter as the parameter for the inner diameter of the other inner conductor forming hole.

Fig. 10 shows the result of obtaining the relationship of Qo with respect to the amount of eccentricity of the inner conductor forming hole, with the pitch of the same dielectric filter as the parameter for the inner diameter of the other inner conductor forming hole.

11 shows the relationship of the amount of eccentricity with respect to the pitch for obtaining the optimum Qodd.

12 shows the relationship of Qodd to pitch under the condition of obtaining an optimal Qodd.

13 shows a configuration of a dielectric filter according to the second embodiment.

14 shows a configuration of a dielectric filter according to the third embodiment.

15 shows a configuration of a dielectric filter according to the fourth embodiment.

16 shows the configuration of a dielectric filter according to the fifth embodiment.

17 shows the configuration of a dielectric duplexer according to the sixth embodiment.

18 is a block diagram showing a configuration of a communication device according to a seventh embodiment.

19 shows the structure of a conventional dielectric filter.

<Brief description of the main parts of the drawing>

1 Dielectric block 2 Internal conductor forming hole

3 Internal conductor 4 External conductor

5 input and output electrode

The present invention provides a dielectric filter having an internal conductor forming hole in which the axes are substantially parallel to each other and having internal conductors formed on an inner surface thereof, and an outer conductor formed on an outer surface of the dielectric block. When the pitch of the arrangement in the arrangement direction of the inner conductor forming holes is set to pitch, and the width perpendicular to the arrangement direction of the inner conductor forming hole is set to the thickness, the pitch / thickness is 0.6 or less, and the axes of the adjacent inner conductor forming holes are different from the thickness direction. Eccentric to move away.

This structure makes it possible to widen the interval between the inner conductor forming holes without making the pitch of the array direction of the inner conductor forming holes of the dielectric block extremely narrow, and to reduce the current concentration between adjacent inner conductor forming holes, thereby improving Qodd. . However, there is a constant relationship between the pitch / thickness value and the Qodd improvement effect. As described later, the internal conductor formation hole is eccentric under the pitch / thickness of 0.6 or less, thereby obtaining the Qodd improvement effect.

In addition, the present invention has an elliptical shape extending the cross section of the inner conductor forming hole in a direction perpendicular to the direction in which the inner conductor forming hole is arranged. This structure makes it possible to facilitate coupling of resonance periods by adjacent inner conductor forming holes.

Further, the present invention forms a communication device by forming the dielectric filter in a high frequency circuit portion which performs signal processing of a transmission signal or a reception signal, for example.

The structure and characteristic of the dielectric filter which concerns on embodiment of this invention are demonstrated with reference to FIGS.

1 is a projection view of a dielectric filter, FIG. 1A is a rear view of the dielectric filter, FIG. 1B is a top view, FIG. 1C is a front view, and FIG. 1D is a right side view. Inside the dielectric block 1 having a substantially rectangular parallelepiped shape, inner conductor forming holes 2a and 2b having inner conductors 3a and 3b formed on inner surfaces thereof are formed. An outer conductor is formed on the outer surface (surface 6) of the dielectric block 1. An inner conductor non-forming portion g is formed near one end of the inner conductor forming holes 2a and 2b, and this portion is used as an open end of the inner conductor as a resonant line. The inner conductor forming holes 2a and 2b are eccentric so as to be separated from each other by s at the center line in the arrangement direction of the inner conductor forming holes of the dielectric block 1. Therefore, the hole spacing L of the inner conductor forming hole is longer than the pitch p.

2 to 6 show the value of Qo for the value of the amount of eccentricity of the inner conductor forming hole (s) shown in FIG. 1 by varying the pitch in the range of 2.4 mm to 1.6 mm and parameterizing the inner diameter Ø of the inner conductor forming hole. This is the result.

In each of Figs. 2 to 6, "lower" is a distance in the bottom surface of the dielectric block of the inner conductor forming hole 2a in ha of FIG. 1, and "upper" is the other one in hb of FIG. This is the distance from the bottom surface of the central axis of the inner conductor forming hole 2b. "Up and down" is the eccentric amount of two inner conductor formation holes in the center (center height) of the dielectric block in s of FIG. "Hole spacing" is the spacing of the inner conductor forming holes at L in FIG. Qo is Q0 in even mode, and Qe is Q0 in odd mode. Here, among the sizes shown in FIG. 1, d is fixed at 4.0 mm, w is 6.0 mm, and the resonance frequency fo is set to 1920 [MHz].

7 to 10 show the relationship between Qo with respect to the amount of eccentricity with pitch as a parameter by changing the inner diameter Ø of the inner conductor forming hole in the range from 1.2 to 0.6. As apparent from these results, it can be seen that Qodd decreases as the amount of eccentricity becomes larger than zero when the pitch is 2.4 mm regardless of the inner diameter Ø.

11 shows the result of determining the optimum amount of eccentricity at which Qo becomes maximum when the pitch is changed with the inner diameter Ø of the inner conductor forming hole as a parameter. For example, if Ø = 1.0 mm and the pitch is 2.4 mm, Qo when the eccentricity is 0 mm is the maximum. Further, when Ø = 1.0 mm and a pitch of 2.2 mm, Qo when the amount of eccentricity is 0.1 mm becomes maximum.

As is apparent from this, when pitch / thickness = 2.4 / 4 = 0.6, when the inner conductor formation hole is eccentric, Qo decreases. On the contrary, when the pitch / thickness is 0.6 or less, the Qo improves when the inner conductor forming hole is eccentric.

FIG. 12 is a graph of optimal Qo for the case where the position of the inner conductor forming hole is eccentric and the Qo is optimized and the case where the eccentricity is not eccentric. The results also show that the effect of improving Qo due to the eccentricity is lost in a condition where the pitch is increased and the pitch / thickness exceeds 0.6 (that is, pitch = 2.4 mm).

The structure of the dielectric filter which concerns on 2nd Embodiment is shown in FIG. FIG. 13 is a view corresponding to FIG. 1A and viewed in the axial direction of the inner conductor forming hole. FIG. Unlike the structure shown in Fig. 1, the inner conductor forming holes 2a and 2b are formed in a cross-sectional elliptical shape extending in a direction perpendicular to the direction in which the inner conductor forming holes are arranged, respectively. The size represents a value in mm.

In this way, the cross-sectional shape of the inner conductor forming hole is deflected in a direction perpendicular to the direction in which the inner conductor forming hole is arranged, thereby improving the degree of freedom in filter design, combining the resonance period with a desired coupling degree, and optimizing Qo by upper and lower eccentricity. can do. In other words, the cross-sectional elliptical shape increases the mutual capacitance of the resonance period, but the eccentricity may be increased to design the same mutual capacitance as when the inner conductor forming hole of the circular cross section is formed. Therefore, the optimum Qo can be obtained after determining the size of the long diameter and the amount of eccentricity, respectively, and combining the resonance periods with a desired coupling degree.

The structural example of the dielectric filter which concerns on 3rd Embodiment is shown in FIG. 14A is a back view of the dielectric filter, FIG. 14B is a top view, FIG. 14C is a front view, and FIG. 14D is a right side view. Unlike the dielectric filter shown in Fig. 1, this example has a step structure in which the inner diameter of the inner conductor forming hole on the open end side is made thicker than on the short end side. Further, the inner diameter of the open end side is enlarged in the direction perpendicular to the arrangement direction of the inner conductor forming hole, and the center of the long axis of the open end side of each inner conductor forming hole is formed to be parallel to the center line in the thickness direction of the dielectric block. With this structure, the passband can be enlarged by increasing the capacitive coupling of the resonance period without lengthening the axis in the arrangement direction of the inner conductor forming hole.

15 shows a configuration of a dielectric filter according to the fourth embodiment. Unlike the dielectric filter having the structure shown in Fig. 1, the dielectric filter has the relationship between the open end and the short end of the two inner conductor forming holes in the opposite direction, and the two resonators are interdigitally coupled. Since the Qo of the resonator is determined by the cross-sectional shape of the inner conductor forming hole, the relationship between the pitch / thickness and the Qo improvement effect due to the eccentricity of the inner conductor forming hole is the same as in the above-described example, whether it is a comb line coupling or an interdigital coupling.

Fig. 16 is a view of the axial direction of the inner conductor formation holes of the dielectric filter according to the fifth embodiment. In this example, three inner conductor forming holes 2a, 2b, and 2c are formed in the dielectric block. This corresponds to having the two-stage resonator shown in FIG. 13 as three stages. Even when a three-stage resonator is constructed in this way, the axes of adjacent inner conductor forming holes are eccentric to be separated from each other in the thickness direction of the dielectric block, thereby minimizing the Qodd while reducing the overall size.

Next, a configuration example of the dielectric duplexer in the sixth embodiment will be described with reference to FIG.

17A is a front view of the mounting surface in front, FIG. 17B is a left side view, FIG. 17C is a right side view, and FIG. 17D is a top view. In the substantially rectangular parallelepiped dielectric block, a plurality of inner conductor formation holes represented by 2a to 2n are formed, and in 2a to 2i, inner conductors as resonant lines are formed with electrode non-forming portions near each end. These inner conductor forming holes have an elliptical shape in cross section extending both the open end side and the short end end in a direction perpendicular to the direction in which the inner conductor forming holes are arranged, and the inner diameter of the open end side is made thicker than the inner diameter of the short end side. The outer conductor 4 is formed on the outer surface (six sides) of the dielectric block, and the input / output electrodes 5rx, 5ant, and 5tx are formed at predetermined portions, respectively. In addition, the inner surface of the inner conductor forming holes 2j and 2m is formed on the entire surface using the inner conductor as the ground electrode. In addition, although inner conductors are formed on the inner surface of the inner conductor forming holes 2k and 2n, one end thereof is electrically connected to the input / output electrodes 5ant and 5tx, respectively.

The input / output electrode 5rx is capacitively coupled to the open end of the inner conductor of the inner surface of the inner conductor forming holes 2a and 2b, respectively. In addition, the inner conductor formed in the inner conductor forming hole 2k is an excitation line and interdigitally coupled with the resonant line by the inner conductor of the inner surface of the inner conductor forming holes 2e and 2f, respectively. Similarly, the inner conductors formed in the inner conductor forming holes 2n are interdigitally coupled to the resonant lines by the inner conductors on the inner surface of the inner conductor forming holes 2h and 2i as excitation lines, respectively.

With this structure, the five-stage resonator by the inner conductor forming holes 2a to 2e serves as a receiving filter, the input / output electrode 5rx serves as a receiving signal output terminal, and the input / output electrode 5ant serves as an antenna terminal. The input / output electrode 5rx and the second stage resonator are skipped and coupled, and attenuation poles are generated on the low side of the reception band (side adjacent to the transmission band) to improve the attenuation characteristics. Further, the four stage resonator by the inner conductor forming holes 2f to 2i acts as a transmission filter. Among these, the resonator by the inner conductor forming hole 2i acts as a trap filter, and improves the attenuation characteristic of the high band side (side adjacent to the receiving band) of the transmission band.

In this way, the axis of the short-circuit end side of the inner conductor forming hole formed in the dielectric block is eccentric to be away from the direction perpendicular to the direction in which the inner conductor forming hole is arranged, thereby shortening the width of the inner conductor forming hole in the arrangement direction and miniaturizing the whole.

An example of the configuration of a communication device according to a seventh embodiment will be described with reference to FIG. 18. In Fig. 18, ANT is a transmit / receive antenna, DPX is a duplexer, BPFa and BPFb are a band pass filter, AMPa and AMPb are an amplifying circuit, MIXa and MIXb are a mixer, OSC is an oscillator, and SYN is a frequency synthesizer, respectively.

The MIXa mixes the modulated signal and the signal output from the SYN, and the BPFa passes only the transmission frequency band among the mixed output signals from the MIXa, and the AMPa power amplifies it and transmits it from the ANT through the DPX. AMPb amplifies the received signal output from the DPX. The BPFb only passes the reception frequency band among the reception signals output from the AMPb. MIXb mixes the frequency signal and the received signal output from the SYN and outputs the intermediate frequency signal IF.

As the DPX, a dielectric duplexer shown in Fig. 17 is used. As the BPFa and the BPFb, the dielectric filters shown in Figs. 1 and 13 to 16 are used.

According to the present invention, the interval between the inner conductor forming holes can be widened without making the pitch of the inner conductor forming holes of the dielectric block extremely narrow, and current concentration between adjacent inner conductor forming holes is alleviated to improve Qodd. . As a result, insertion loss can be reduced over a predetermined passband.

Further, according to the present invention, the cross section of the inner conductor forming hole has an elliptical shape extending in a direction perpendicular to the direction in which the inner conductor forming hole is arranged, thereby increasing the coupling of resonance periods by adjacent inner conductor forming holes, thereby making it easier to widen. Can be planned.

In addition, according to the present invention, it is possible to easily configure a communication device that can be miniaturized as a whole, including a dielectric filter having a small size and low insertion loss.

Claims (3)

A dielectric filter having a structure in which a substantially rectangular parallelepiped dielectric block has an inner conductor forming hole in which the axes are substantially parallel to each other and an inner conductor is formed on an inner surface thereof, and an outer conductor is formed on an outer surface of the dielectric block. When the intervals in the arrangement direction of the inner conductor forming holes are set to pitch and the width perpendicular to the arrangement direction of the inner conductor forming holes is set to a thickness, the pitch / thickness is 0.6 or less and the axes of adjacent inner conductor forming holes are the thickness direction. And an eccentricity away from each other. The dielectric filter according to claim 1, wherein the cross section of the inner conductor forming hole is formed in an elliptical shape extending in a direction perpendicular to the direction in which the inner conductor forming hole is arranged. A communication device comprising the dielectric filter of claim 1.