First and second dielectric waveguides disposed in respective multi-layer substrates which are connected by a connection structure having choke structures therein
Provided is a structure configured to electrically connect multi-layer dielectric waveguides, each including a dielectric waveguide formed of conductor patterns and vias in a laminating direction of the multi-layer dielectric substrate, in which the vias for forming part of a waveguide wall of each of the dielectric waveguides are arranged in a staggered pattern in the multi-layer dielectric substrate side having choke structures formed so as to electrically connect the waveguides to each other.
1. A connection structure for dielectric waveguides, comprising:
a first multi-layer dielectric substrate, which includes a first dielectric waveguide having a first opening portion, and is configured to propagate a high-frequency signal therethrough; and
a second multi-layer dielectric substrate, which includes a second dielectric waveguide having a second opening portion, is arranged to be opposed to the first multi-layer dielectric substrate so that the first opening portion and the second opening portion are opposed to each other through a first space therebetween, and is configured to propagate the high-frequency signal therethrough,
wherein the first multi-layer dielectric substrate includes:
a first surface-layer conductor, which is provided so as to cover a surface of the first multi-layer dielectric substrate, the surface being opposed to the second multi-layer dielectric substrate, has the first opening portion formed therethrough, and has first cutouts formed at two positions spaced by λ/4 away from edges of the first opening portion so as to be opposed to each other through the first opening portion therebetween;
a first inner-layer conductor, which is provided in the first multi-layer dielectric substrate so as to be opposed to the first surface-layer conductor, and has a first conductor removed portion formed at a position opposed to the first opening portion; and
a plurality of first conductor columns, which are provided to extend from the first surface-layer conductor through the first inner-layer conductor in a laminating direction of the first multi-layer dielectric substrate so as to surround all sides of a perimeter of the first opening portion, and are arranged so as to form a waveguide wall of the first dielectric waveguide,
wherein the first multi-layer dielectric substrate has choke structures at two positions opposed to each other through the first opening portion therebetween,
wherein the choke structures include first choke passages, each having a length of λ/4, and second choke passages, each having a length of λe/4,
wherein each of the first choke passages is formed as a space from each of the edges of the first opening portion to a corresponding one of the first cutouts in the first space,
wherein each of the second choke passages is formed as a space surrounded by a plurality of third conductor columns provided along an edge of each of the first cutouts, which is on a side opposite to a side on which the first dielectric waveguide is located, so as to connect the first surface-layer conductor and the first inner-layer conductor and the first conductor columns in a second space between the first surface-layer conductor and the first inner-layer conductor,
wherein a part of the first conductor columns is arranged at a position spaced by λe/4 away from each of the first cutouts toward the first opening portion, in which λ is a free-space wavelength of a signal wave, and λe is an effective wavelength in the dielectric substrates.
2. The connection structure for dielectric waveguides according to claim 1 , wherein each of the first opening portion and the second opening portion is formed in a rectangular shape so that a short-side length of each of the first opening portion and the second opening portion in a short-axis direction is formed to be one-half or smaller of a long-side length of each of the first opening portion and the second opening portion in a long-axis direction.
3. The connection structure for dielectric waveguides according to claim 1 , wherein each of the first opening portion and the second opening portion is formed in an oval shape so that a short-axis length of each of the first opening portion and the second opening portion in a short-axis direction is formed to be one-half or smaller of a long-axis length of each of the first opening portion and the second opening portion in a long-axis direction.
4. The connection structure for dielectric waveguides according to claim 1 , wherein each of the first cutouts is formed in a U-shape with rounded corners through removal of part of the first surface-layer conductor with a given width so as to be spaced by λ/4 away from each of the edges of the first opening portion at a position opposed to a center of the first opening portion in the long-axis direction and so as to be spaced by λ/8 or less away from each of the edges of the first opening portion at positions opposed to edges of the first opening portion in the long-axis direction.
5. The connection structure for dielectric waveguides according to claim 1 , wherein the first opening portion has an opening area larger than each of an opening area of the second opening portion and an opening area of the first conductor removed portion.
6. The connection structure for dielectric waveguides according to claim 1 ,
wherein the second multi-layer dielectric substrate includes:
a second surface-layer conductor provided so as to cover a surface of the second multi-layer dielectric substrate, which is opposed to the first multi-layer dielectric substrate; and
a second inner-layer conductor, which is provided in the second multi-layer dielectric substrate so as to be opposed to the second surface-layer conductor, and has a second conductor removed portion formed at a position opposed to the second opening portion, and
wherein the second opening portion has an opening area smaller than each of an opening area of the second conductor removed portion and an opening area of the first conductor removed portion.
7. The connection structure for dielectric waveguides according to claim 1 ,
wherein the first multi-layer dielectric substrate further includes a first short-circuit conductor arranged so as to be opposed to a surface opposite to a surface on which the first surface-layer conductor is provided with respect to the first inner-layer conductor, and
wherein a plurality of fourth conductor columns are provided to pass from the first inner-layer conductor to the first short-circuit conductor so as to surround the first conductor removed portion.
8. The connection structure for dielectric waveguides according to claim 1 , wherein a dielectric is provided in a region of the first space other than regions in which the first opening portion and the first choke passages are formed.