Multi-layer resin substrate having grounding conductors configured to form triplate line sections and microstrip sections
A flat cable includes a plurality of resin layers that are flexible and stacked together, a line conductor, and grounding conductors. The flat cable includes a triplate line in which both surfaces of the line conductor oppose the corresponding grounding conductors, and a microstrip line in which only one of the surfaces of the line conductor opposes the corresponding grounding conductor. A width of the line conductor in the microstrip line is greater than a width of the line conductor in the triplate line, and the flat cable is bent at a position where the microstrip line is provided.
1. A resin multilayer substrate comprising:
a plurality of resin layers that are flexible and stacked on top of each other;
a line conductor stacked on one of the plurality of resin layers; and
a pair of grounding conductors, each of which is stacked on a different one of the plurality of resin layers at a position different from a position of the line conductor in a direction in which the plurality of resin layers are stacked; wherein
the resin multilayer substrate includes a triplate line in which both surfaces of the line conductor oppose the corresponding pair of grounding conductors, and a microstrip line which is connected to the triplate line and in which only one of the surfaces of the line conductor opposes the corresponding grounding conductor;
a width of the line conductor in the microstrip line is greater than a width of the line conductor in the triplate line;
the resin multilayer substrate is bent at a position where the microstrip line is provided; and
in the triplate line, a length of the pair of grounding conductors in an extending direction of the line conductor is greater than a length of at least one of the pair of grounding conductors in a width direction of the line conductor.
2. The resin multilayer substrate according to claim 1 , wherein:
the pair of grounding conductors included in the triplate line include a first grounding conductor and a second grounding conductor; and
the microstrip line includes:
a first microstrip line in which the first grounding conductor opposes the line conductor; and
a second microstrip line in which the second grounding conductor opposes the line conductor.
3. The resin multilayer substrate according to claim 1 , wherein a reduced thickness portion is provided at a position where the microstrip line is provided.
4. The resin multilayer substrate according to claim 1 , wherein:
the pair of grounding conductors include a first grounding conductor and a second grounding conductor; and
in the triplate,
the first grounding conductor includes a plurality of openings arranged along the line conductor;
the second grounding conductor opposes the line conductor over an entire area of the line conductor;
a width of the line conductor is increased at positions where the line conductor opposes corresponding ones of the plurality of openings; and
a distance between the first grounding conductor and the line conductor is smaller than a distance between the second grounding conductor and the line conductor.
5. The resin multilayer substrate according to claim 1 , wherein the plurality of resin layers include via holes and via-hole conductors provided in the via holes.
6. The resin multilayer substrate according to claim 5 , wherein pad conductors are provided on the plurality of resin layers to cover the via holes.
7. The resin multilayer substrate according to claim 1 , wherein one of the pair of grounding conductors extends over an entire area or substantially an entire area of the triplate line.
8. The resin multilayer substrate according to claim 1 , wherein one of the pair of grounding conductors extends over an entire area or substantially an entire area of the triplate line and the microstrip line.
9. An electronic apparatus comprising:
the resin multilayer substrate according to claim 1 ; and
a circuit element arranged so as to oppose the resin multilayer substrate.
10. The electronic apparatus according to claim 9 , wherein
the resin multilayer substrate includes a region in which one principal surface of the resin multilayer substrate is valley-folded;
the microstrip line is configured such that the corresponding grounding conductor is disposed near the one principal surface in the region; and
the circuit element includes a high-frequency circuit, and is disposed adjacent to the one principal surface of the resin multilayer substrate.
11. The electronic apparatus according to claim 9 , wherein
the resin multilayer substrate includes a region in which one principal surface of the resin multilayer substrate is mountain-folded;
the microstrip line is configured such that the corresponding grounding conductor is disposed near the one principal surface in the region; and
the circuit element includes a metal body, and is disposed adjacent to the other principal surface of the resin multilayer substrate.
12. The electronic apparatus according to claim 9 , wherein
the resin multilayer substrate includes a region in which one principal surface of the resin multilayer substrate is valley-folded and a region in which the one principal surface is mountain-folded; and
the microstrip line is configured such that the line conductor is disposed near the other principal surface of the resin multilayer substrate at a side opposite to a side of the one principal surface in the region in which the one principal surface is mountain-folded and the region in which the one principal surface is valley-folded; and
a radius of curvature of the resin multilayer substrate is greater in the region in which the one principal surface is valley-folded than in the region in which the one principal surface is mountain-folded.
13. The electronic apparatus according to claim 9 , wherein:
the pair of grounding conductors included in the triplate line include a first grounding conductor and a second grounding conductor; and
the microstrip line includes:
a first microstrip line in which the first grounding conductor opposes the line conductor; and
a second microstrip line in which the second grounding conductor opposes the line conductor.
14. The electronic apparatus according to claim 9 , wherein a reduced thickness portion is provided at a position where the microstrip line is provided.
15. The electronic apparatus according to claim 9 , wherein:
the pair of grounding conductors include a first grounding conductor and a second grounding conductor; and
in the triplate line,
the first grounding conductor includes a plurality of openings arranged along the line conductor;
the second grounding conductor opposes the line conductor over an entire area of the line conductor;
a width of the line conductor is increased at positions where the line conductor opposes corresponding ones of the plurality of openings; and
a distance between the first grounding conductor and the line conductor is smaller than a distance between the second grounding conductor and the line conductor.
16. The electronic apparatus according to claim 9 , wherein the plurality of resin layers include via holes and via-hole conductors provided in the via holes.
17. The electronic apparatus according to claim 16 , wherein pad conductors are provided on the plurality of resin layers to cover the via holes.
18. The electronic apparatus according to claim 9 , wherein one of the pair of grounding conductors extends over an entire area or substantially an entire area of the triplate line.
19. The electronic apparatus according to claim 9 , wherein one of the pair of grounding conductors extends over an entire area or substantially an entire area of the triplate line and the microstrip line.