JPS62246Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a support device for positioning a dielectric resonator used in a high frequency bandpass filter.

Recently, in order to improve the reception of television broadcasts, a transmitting/receiving system using the SHF band is being put to practical use, and inexpensive bandpass filters are required for this type of equipment. Bandpass filters have been developed for this purpose, and their structure can be explained in principle by the layout diagrams, characteristic diagrams, and equivalent circuit diagrams shown in Figures 1 to 3.

In FIG. 1, strip lines 2 and 3 are provided on a dielectric substrate placed in a cavity surrounded by a conductor wall, which will be described later. 8 and 9 are disc-shaped dielectric resonators.
If the natural resonance frequencies of dielectric resonators 8 and 9 are the same, by selecting the distances D ₁ , D ₂ and l as shown in Fig. 1a, an output with the characteristics shown in Fig. 2a can be obtained. It will be done. On the other hand, if the distance l between both dielectrics 8 and 9 is selected to be small as shown in FIG. 1b, an output with bimodal characteristics as shown in FIG. 2b can be obtained.
Conversely, if the distance l is chosen to be large as shown in FIG. 1c, an output with a single peak characteristic with a narrow band can be obtained as shown in FIG. 2c. That is, adjusting the distance between both dielectric resonators corresponds to adjusting the coupling capacitor _C3 in the equivalent circuit of FIG. Further, selecting the distances D ₁ and D ₂ between the strip lines 2 and 3 and the dielectric resonators 8 and 9 corresponds to selecting taps of the inductances L ₁ and L ₂ to match the circuit impedance. Further, if the wavelength of the wave at the natural resonant frequency of the dielectric resonator is λ, then the dielectric resonator 8 is placed on a line connecting points substantially at a distance of λ/4 from the tip of each stripline 2 and 3.
It has been found that the maximum output can be obtained by arranging the centers of 9 and 9. However, as described above, adjustment is not easy because the positional relationship between the dielectric resonators and the positional relationship between the resonators and the stripline must be selected.

The purpose of this proposal is to provide a simple structure that is easy to adjust for this purpose. Examples of the present invention will be described below with reference to the drawings.

FIG. 4 is a front view showing the bandpass filter according to the embodiment of the present invention with the top plate removed, and FIG. 5 is a sectional view taken along line A--A in FIG. 4. Reference numeral 1 denotes a dielectric substrate, the lower surface of which is coated with copper foil, and the upper surface of which is provided with a pair of strip lines 2 and 3 separated by a predetermined distance.
are formed in parallel. This dielectric substrate 1 is placed in a cavity 7 surrounded by a container 4 and a conductive wall such as a top plate 5 . strip line 2
Two disc-shaped dielectric resonators 8 and 9 are arranged on the dielectric substrate 1 between the resonators 8 and 3 with a predetermined interval as described above. The dielectric resonators 8 and 9 are housed in a plurality of circular holes 28 and 29 provided in the middle of a dielectric plate 20 extending between the striplines 2 and 3. The circular holes 28 and 29 have a diameter that allows the resonators 8 and 9 to be inserted therebetween. This plate 20 has notches 21 and 22 at both ends, as shown separately in FIG. These notches 21 and 22 are formed in the conductor container 4.
The plate body 20 is fixed to the container 4 by being engaged with the screws 11 and 12 that fix the dielectric substrate 1 to the bottom surface of the plate body 1 and being tightened together. The cutouts 21 and 22 may be elongated holes. Further, in order to securely fix the plate body 20 and the resonators 8 and 9, it is preferable to fix them with adhesive. Terminals 2' and 3' are terminals of the striplines 2 and 3. Terminal 2' is taken out from the cutout 4' of the container 4, and terminal 3' is soldered to the coaxial connector 10. Therefore, one of the terminals 2' and 3' and the conductor container 4 serve as a pair of input terminals, and the other of the terminals 2' and 3' serves as a pair of output terminals. Further, the conductor container 4 has screw holes 13' to 16' as necessary, and the top plate 5 has screw holes 13' to 16' as required.
3 to 16.

In the above structure, the distance between the centers of the holes 28 and 29 in the plate body 20 is selected to be a distance l that allows the resonator to be held to provide an optimum frequency characteristic as explained in FIG. In this way, the distance between the resonators can be fixed, and the distances and other positional relationships between the resonators 8 and 9 and the striplines 2 and 3 can then be finely selected. Therefore, the screws 11 and 12 are slightly loosened, the plate body 20 is slid to select a predetermined position, and the screws 11 and 12 are tightened so that the optimum output is obtained. In this way, dielectric resonators 8 and 9 are supported, and a bandpass filter is completed.

As described above, in the present invention, the distance between the plurality of resonators is first regulated, and then other elements are selected, so that adjustment is easy. Furthermore, since it is sufficient to provide a dielectric plate, the structure can be simplified.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the adjustment principle of a bandpass filter to which the present invention is applied, Figure 2 is an output characteristic diagram corresponding to each state in Figure 1, Figure 3 is an equivalent circuit diagram, and Figure 4. 5 is a sectional view taken along line A--A in FIG. 4, and FIG. 6 is a plan view showing the structure of the plate 20. DESCRIPTION OF SYMBOLS 1... Dielectric substrate, 2 and 3... Stripline, 7... Cavity chamber, 8 and 9... Dielectric resonator, 28 and 29... Hole in plate 20, 21 and 22... Notch. , 11 and 12...screws.

Claims (1)

[Scope of utility model registration request] A pair of strip lines are formed in parallel on a dielectric substrate at a predetermined distance apart, the dielectric substrate is placed in a cavity surrounded by a conductor wall, and a dielectric resonator is placed between the strip lines. In a bandpass filter, a plurality of striplines are arranged and fixed in series at a predetermined interval, one of the striplines and the conductor wall are used as input terminals, and the other of the striplines and the conductor wall are used as output terminals. , a dielectric plate extending between the strip lines, having a plurality of holes in the middle portion, and having notches or long holes at both ends; The dielectric resonators are arranged in series by accommodating the resonators, regulating the distance between the dielectric resonators, and fixing the plate to one surface of the conductor wall with screws inserted into the notches or slots. and the spacing between the striplines is selectively determined.