Dielectric filter with through-hole having large and small diameter portions and a coupling adjustment portion
AssigneeMurata Manufacturing Co., Ltd.
InventorShohachi Nishijima
Life of this patent
Estimating the term…
Abstract
On the internal surface of each of the through-holes formed in a dielectric block, an internal conductor is formed, while on the external surface except the top surface, an external conductor is formed. The internal conductors, together with the external conductor and the dielectric block, form dielectric resonators with 1/4-wavelength using the top and bottom surfaces of the dielectric block as an open surface and a short surface, respectively. Each of the through-holes has a large-diameter hole portion and a small-diameter hole portion and also has a coupling adjustment hole portion for the purpose of a fine adjustment of electromagnetic coupling between adjacent the dielectric resonators.
Claims17
A dielectric filter, comprising:
- a dielectric block having a first surface and a second surface being opposite to said first surface;
- a plurality of dielectric resonators having through-holes which pass through from said first surface to said second surface and internal conductors which cover the internal surfaces of said through-holes;
- and
- an external conductor which covers the external surface of said dielectric block except for said first surface,
- wherein at least one of said through-holes has a large-diameter hole portion, a small-diameter hole portion which communicates with said large-diameter hole portion, and a shoulder portion which forms a transition between said large- and small-diameter hole portions;
- and
- wherein said at least one of said through-holes further comprises a coupling adjustment hole portion which communicates with said large- and small-diameter hole portions and can be adjusted in size for making a fine adjustment of electromagnetic coupling between adjacent said dielectric resonators, disposed at the side adjacent to said first surface of said dielectric block, and having a different diameter from those of said large-diameter hole portion and said small-diameter hole portion.
A method of adjusting characteristics of a dielectric filter, the dielectric filter comprising:
- a dielectric block having a first surface and a second surface being opposite to said first surface;
- a plurality of dielectric resonators having through-holes which pass through from said first surface to said second surface and internal conductors which cover the internal surfaces of said through-holes;
- and
- an external conductor which covers the external surface of said dielectric block except for said fist surface,
- wherein at least one of said through-holes has a large-diameter hole portion, a small-diameter hole portion which communicates with said large-diameter hole portion, and a shoulder portion which forms a transition between said large- and small-diameter hole portions;
- and
- wherein said at least one of said through-holes further comprises a coupling adjustment hole portion which communicates with said large- and small-diameter hole portions and can be adjusted in size for making a fine adjustment of electromagnetic coupling between adjacent said dielectric resonators, disposed at the side adjacent to said first surface of said dielectric block, and having a different diameter from those of said large-diameter hole portion and said small-diameter hole portion;
- said method comprising the step of roughly adjusting the electromagnetic coupling of dielectric resonators adjoining each other by adjusting the diameters of the large-diameter hole portion and the small-diameter hole portion.
Dependencies are inferred from the claim text.