High-frequency module
A high-frequency module includes a substrate, an integrated circuit mounted to the substrate, a cylindrical shield enclosing the integrated circuit to block radio waves, a casing provided on an opposite side of the substrate relative to the shield to block radio waves, and a choke portion provided in an inner wall of the casing, the inner wall being opposed to the shield, or provided in the substrate, with a predetermined gap being formed relative to the shield, to create an antiphase in radio waves having a predetermined frequency emitted from the integrated circuit into a space above the substrate.
1. A high-frequency module wherein the module comprises:
a substrate;
an integrated circuit mounted to the substrate;
a cylindrical shield enclosing the integrated circuit to block radio waves;
a casing provided on an opposite side of the substrate relative to the shield to block radio waves; and
a choke portion provided in an inner wall of the casing that is opposed to the shield or provided in the substrate with a predetermined gap relative to the shield to create an antiphase in radio waves having a predetermined frequency, the radio waves being emitted from the integrated circuit into a space above the substrate, wherein
the choke portion is a groove that is recessed from an end face of the casing in a direction opposite to the shield, the end face being opposed to the shield, and
the groove configuring the choke portion is formed of a cylindrical inner frame and a cylindrical outer frame projecting from an inner wall of the casing toward the substrate.
2. The high-frequency module according to claim 1 , wherein the choke portion allows the radio waves having an antiphase to suppress radio waves from leaking through the gap between the choke portion and the shield.
3. The high-frequency module according to claim 1 , wherein the choke portion has a depth corresponding to ¼ of a wavelength of the radio waves having a predetermined frequency when passing through the choke portion, the radio waves being emitted from the integrated circuit into the space above the substrate.
4. The high-frequency module according to claim 1 , wherein the shield has an end portion on an opposite side of the choke portion, the end portion being connected to a ground wiring of the substrate or connected to the casing.
5. The high-frequency module according to claim 1 , wherein the groove configuring the choke portion is provided between the cylindrical inner frame and the cylindrical outer frame which project from the inner wall of the casing toward the substrate.
6. The high-frequency module according to claim 1 , wherein the choke portion is configured by a dielectric body extending from an end face of the substrate, the end face being opposed to the shield, in a direction opposite to the shield, a plurality of via holes juxtaposed outside the dielectric body, and a ground wiring connecting between the plurality of via holes.
7. The high-frequency module according to claim 6 , wherein the dielectric body forms the substrate.
8. The high-frequency module according to claim 6 , wherein the plurality of via holes are provided with a gap formed therebetween, the gap being not more than ¼ of a wavelength of the radio waves having a predetermined frequency when passing through the dielectric body, the radio waves being emitted from the integrated circuit into the space above the substrate.
9. The high-frequency module according to claim 6 , wherein the choke portion has an L shape in a cross-sectional view of the substrate.
10. The high-frequency module according to claim 6 , wherein the shield is integrally formed with the casing.