Antenna module, communication module, and communication device

1. An antenna module comprising:

a dielectric substrate having a multilayer structure;

a first radiation electrode in a first layer of the dielectric substrate, the first radiation electrode being configured to radiate a radio-frequency signal;

a ground electrode in a second layer of the dielectric substrate; and

at least one current-interrupting circuit element that is electrically connected to the ground electrode and that is configured to interrupt a current flowing through the ground electrode, wherein:

the at least one current-interrupting circuit element comprises a planar electrode that is parallel to the ground electrode and that has a first edge that is electrically connected to the ground electrode and a second edge that is electrically open, and

a dimension of the at least one current-interrupting circuit element in a direction from the first edge to the second edge is λ/4, where λ is a wavelength of the radio-frequency signal radiated from the first radiation electrode.

2. The antenna module according to claim 1 , wherein:

the planar electrode is a rectangular shape, the first and second edges of the planar electrode corresponding to short sides of the rectangular shape, and

a length of each long side of the planar electrode is greater than λ/2.

3. The antenna module according to claim 2 , wherein when viewed in a plan view in a direction normal to the dielectric substrate, the long sides of the planar electrode extend in a direction orthogonal to a direction in which the radio-frequency signal radiated from the first radiation electrode is polarized.

4. The antenna module according to claim 3 , wherein when viewed in the plan view, the first radiation electrode and the planar electrode are adjacent in the direction in which the radio-frequency signal radiated from the first radiation electrode is polarized.

5. The antenna module according to claim 1 , further comprising a second radiation electrode in a layer of the dielectric substrate,

wherein the at least one current-interrupting circuit element is between the first radiation electrode and the second radiation electrode.

6. The antenna module according to claim 5 , wherein:

the at least one current-interrupting circuit element comprises a first current-interrupting circuit element and a second current-interrupting circuit element, and

the first and second current-interrupting circuit elements are between the first and second radiation electrodes such that the edge of the first current-interrupting circuit element and the second edge of the second current-interrupting circuit element face each other.

7. The antenna module according to claim 6 , wherein part of the second edge of the first current-interrupting circuit element and part of the second edge of the second current-interrupting circuit element are electrically connected to each other.

8. The antenna module according to claim 6 , wherein the second edge of the first current-interrupting circuit element and the second edge of the second current-interrupting circuit element are each comb teeth-shaped.

9. The antenna module according to claim 5 , wherein:

the at least one current-interrupting circuit element comprises a first current-interrupting circuit element and a second current-interrupting circuit element, and

when the antenna module is viewed in a plan view in a direction normal to the dielectric substrate:

the second edge of the first current-interrupting circuit element faces the second radiation electrode,

the second edge of the second current-interrupting circuit element faces the first radiation electrode, and

with a side of the first radiation electrode and a side of the second radiation electrode facing each other, the first and second current-interrupting circuit elements are alternately disposed.

10. The antenna module according to claim 1 , further comprising:

a second radiation electrode adjacent to the first radiation electrode in a first direction; and

a third radiation electrode adjacent to the first radiation electrode in a second direction that is orthogonal to the first direction, wherein:

the at least one current-interrupting circuit element comprises a first current-interrupting circuit element and a second current-interrupting circuit element,

the first current-interrupting circuit element is between the first radiation electrode and the second radiation electrode, and

the second current-interrupting circuit element is between the first radiation electrode and the third radiation electrode.

11. A communication device comprising the antenna module according to claim 1 .

12. A communication module comprising:

an antenna module comprising a radiation electrode;

a mounting substrate comprising a ground electrode, the antenna module being mounted on the mounting substrate; and

at least one current-interrupting circuit element on the mounting substrate, the antenna module being surrounded by the at least one current-interrupting circuit element, wherein:

the at least one current-interrupting circuit element comprises a planar electrode that is parallel to the ground electrode and that has a first edge that is electrically connected to the ground electrode and a second edge that is electrically open, and

a dimension of the at least one current-interrupting circuit element in a direction from the first edge to the second edge is λ/4, where λ is a wavelength of a radio-frequency signal radiated from the radiation electrode.