Bandpass filter
First Claim
1. A bandpass filter comprising a dielectric block having a top surface, a bottom surface and four side surfaces, said dielectric block being constituted of a first portion lying between a first cross-section of the dielectric block and a second cross-section of the dielectric block substantially parallel to the first cross-section and second and third portions divided by the first portion and metal plates formed on one or more of the surfaces of the dielectric block, thereby enabling the first portion of the dielectric block and the metal plates formed thereon to act as an evanescent waveguide, the second portion of the dielectric block and the metal plates formed thereon to act as a first resonator, and the third portion of the dielectric block and the metal plates formed thereon to act as a second resonator, the metal plates including at least one exciting electrode formed on the bottom surface which has the widest area.
1 Assignment
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Accused Products
Abstract
A highly compact band pass filter that has excellent mechanical strength is disclosed. A band pass filter according to the present invention employs a dielectric block of substantially rectangular prismatic shape constituted of a first portion lying between a first cross-section of the dielectric block and a second cross-section of the dielectric block substantially parallel to the first cross-section and second and third portions divided by the first portion and metal plates formed on surfaces of the dielectric block. The first portion of the dielectric block and the metal plates formed thereon are enabled to act as an evanescent waveguide. The second portion of the dielectric block and the metal plates formed thereon are enabled to act as a first resonator. The third portion of the dielectric block and the metal plates formed thereon are enabled to act as a second resonator. The metal plates include at least one exciting electrode formed on a first surface of the dielectric block which has the widest area. Thus a wide band characteristics can be obtained whereas the very thin dielectric block is used. Further, a high unloaded quality factor (Q0) can be obtained because the radiation loss is lowered when the thickness of the dielectric block is reduced.
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Citations
18 Claims
- 1. A bandpass filter comprising a dielectric block having a top surface, a bottom surface and four side surfaces, said dielectric block being constituted of a first portion lying between a first cross-section of the dielectric block and a second cross-section of the dielectric block substantially parallel to the first cross-section and second and third portions divided by the first portion and metal plates formed on one or more of the surfaces of the dielectric block, thereby enabling the first portion of the dielectric block and the metal plates formed thereon to act as an evanescent waveguide, the second portion of the dielectric block and the metal plates formed thereon to act as a first resonator, and the third portion of the dielectric block and the metal plates formed thereon to act as a second resonator, the metal plates including at least one exciting electrode formed on the bottom surface which has the widest area.
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5. A bandpass filter comprising:
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a dielectric block having a top surface, a bottom surface, first and second side surfaces opposite to each other and third and fourth side surfaces opposite to each other, the dielectric block being constituted of a first portion lying between a first cross-section of the dielectric block substantially parallel to the first side surface and a second cross-section of the dielectric block substantially parallel to the first cross-section, a second portion lying between the first side surface and the first cross-section, and a third portion lying between the second side surface and the second cross-section;
a first metal plate formed on the top surface of the dielectric block corresponding to the second portion;
a second metal plate formed on the top surface of the dielectric block corresponding to the third portion;
a third metal plate formed on the third side surface of the dielectric block corresponding to the second portion;
a fourth metal plate formed on the third side surface of the dielectric block corresponding to the third portion;
a fifth metal plate formed on the bottom surface of the dielectric block;
a first exciting electrode formed on the bottom surface of the dielectric block corresponding to the second portion; and
a second exciting electrode formed on the bottom surface of the dielectric block corresponding to the third portion. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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14. A bandpass filter, comprising:
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a plurality of quarter-wave dielectric resonators including at least first and second quarter-wave dielectric resonators located in line, each of which is constituted of metal plates formed on a top surface of a dielectric block, a bottom surface of the dielectric block opposite to the first surface, and a side surface of the dielectric block substantially perpendicular to the top and bottom surfaces, an evanescent waveguide interposed between adjacent quarter-wave dielectric resonators;
a first exciting electrode formed on the bottom surface of a portion of the dielectric block corresponding to the first quarter-wave dielectric resonator; and
a second exciting electrode formed on the bottom surface of another portion of the dielectric block corresponding to the second quarter-wave dielectric resonator. - View Dependent Claims (15, 16, 17, 18)
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Specification