Leaky cable and method of manufacturing leaky cable

1 . A leaky cable having a structure configured to propagate electromagnetic waves, comprising:

a linear insulator; and

a metal layer formed on an outer peripheral surface of the insulator,

wherein a slot for leaking the electromagnetic waves is formed through the metal layer between an inner peripheral surface and an outer peripheral surface of the metal layer,

wherein the outer peripheral surface of the insulator is formed with unevenness that inhibits misalignment of the slot with respect to the insulator,

wherein a portion of the insulator protrudes from the inner peripheral surface toward the outer peripheral surface of the metal layer at a peripheral edge of the slot,

wherein the portion of the insulator that protrudes adheres at least a part of the end surface of the metal layer at the peripheral edge of the slot,

wherein a ratio of a thickness of the metal layer to a radial thickness of the insulator is between 0.2% and 40%, and

wherein the cable is configured to be bent to 90° without cracking or delaminating the metal layer at a bending radius of 2.5 times an outer diameter of the leaky cable.

2 . The leaky cable, according to claim 1 , wherein the insulator comprises thermoplastic resin, and a portion of the insulator is a solidified portion of molten resin melted by heat of a laser beam when forming the slot in the metal layer.

3 . The leaky cable, according to claim 1 , wherein the insulator is formed in a cylindrical shape, and a surface roughness of the outer peripheral surface of the insulator is larger than a surface roughness of the inner peripheral surface of the insulator.

4 . The leaky cable, according to claim 3 , wherein an area roughness of the outer peripheral surface of the insulator of a portion covered by the metal layer is 0.8 μm or more and 6.0 μm or less.

5 . The leaky cable, according to claim 1 , wherein the insulator is hollow.

6 . The leaky cable, according to claim 1 , wherein the structure configured to propagate the electromagnetic waves is a center conductor located in a center of the insulator.

7 . The leaky cable, according to claim 1 , wherein the portion of the insulator that protrudes adheres at least a part of the end surface of the metal layer at the peripheral edge of the slot to inhibit misalignment.

8 . The leaky cable, according to claim 1 , wherein the metal layer is formed by electroless plating on the outer peripheral surface of the insulator, and

wherein the unevenness on the outer peripheral surface of the insulator enhances adhesion strength between the insulator and the metal layer via an anchor effect.

9 . The leaky cable, according to claim 1 , wherein the portion of the insulator that protrudes covers an entire end surface of the metal layer from the inner peripheral surface to the outer peripheral surface at least a part of the peripheral edge of the slot.

10 . The leaky cable, according to claim 5 , wherein the insulator is hollow, and an outer diameter of the leaky cable is between 1 mm and 8 mm, and

wherein the leaky cable is configured to transmit the electromagnetic waves in a microwave band from 300 MHz to 3 THz.

11 . The leaky cable, according to claim 6 , wherein the center conductor comprises copper or aluminum, and the metal layer serves as an outer conductor, and

wherein the inner peripheral surface of the insulator is in contact with an outer peripheral surface of the center conductor.

12 . The leaky cable, according to claim 1 , wherein the structure configured to propagate the electromagnetic waves is a hollow cavity formed within the insulator.

13 . The leaky cable, according to claim 1 , wherein the insulator comprises polyethylene, polypropylene, or fluorinated resin, and

wherein the insulator has a low dielectric constant to suppress dielectric loss.