Filter

1. A filter which suspends propagation of an electromagnetic wave of a predetermined frequency band in one of a signal line and a power supply line, the filter comprising:

a conductor connected to the one of the signal line and the power supply line, and configured to include a linear portion, a first portion of the linear portion with an end portion connected to the one of the signal line and the power supply line having a first width, and a second portion different from the first portion of the linear portion having a second width different from the first width; and

a second conductor arranged so as to surround the linear portion in a layer where the linear portion is formed in a substrate where the filter is formed,

wherein the second conductor is a ground conductor.

2. The filter according to claim 1 , wherein the first width is narrower than the second width.

3. The filter according to claim 2 , wherein the first portion is longer than the second portion.

4. The filter according to claim 1 , wherein the first portion and the second portion are equal in length.

5. The filter according to claim 1 , wherein the first width is wider than the second width.

6. The filter according to claim 5 , wherein the first portion is shorter than the second portion.

7. The filter according to claim 1 , wherein the layer where the linear portion is formed is different from a layer of the one of the signal line and the power supply line, out of layers included in the substrate where the filter is formed.

8. The filter according to claim 1 , wherein the second conductor is further arranged into a planar shape in a second layer between the linear portion and the one of the signal line and the power supply line.

9. The filter according to claim 1 , wherein the second conductor is further arranged into a planar shape in a second layer on a side opposite to a layer where the one of the signal line and the power supply line is formed when viewed from the layer where the linear portion is formed.