Patent ID: 9666931
Date: 2017-05-30
CPC Classifications: H01P

Claim:
1. A radio frequency electric power conversion mechanism including a waveguide and a circuit board having a plurality of fiber reinforced resin boards, comprising: a monolithic microwave integrated circuit (MMIC); a first board made of fiber reinforced resin; a transmission line which is a strip-like foil or a wire made of an electric conductor, the transmission line being adhered to an upper surface of the first board and having one end connected to the MMIC; a first foil made of an electric conductor, the first foil being adhered to a lower surface of the first board and covering at least an area of the lower surface under a region where the transmission line is disposed; a second board made of fiber reinforced resin and adhered to a lower surface of the first foil; a second foil made of an electric conductor and adhered to a lower surface of the second board; a waveguide extending in a direction away from the upper surface of the first board and including a cavity having a square-shaped cross-section therein; and plural surface layer via holes each of which is a conductive tube or pole passing through at least the first board and the second board, connected to the second foil, and having an upper end exposed to a surface of the circuit board; wherein the waveguide has a square-shaped aperture on its lower end; at least part of the plural surface layer via holes constitute an array surrounding at least three sides of the other end of the transmission line; a lower end surface of the waveguide is adhered to upper end faces of the surface layer via holes constituting the array; the array includes a long side portion and a short side portion where the surface layer via holes are arranged along a long side and a short side of the aperture, respectively; the surface layer via holes constituting the array are not positioned inside the aperture, as seen through the waveguide guide; the array includes a gate portion where the surface via holes is not provided entirely on one of the long side portions or in part on the long side portions; the waveguide includes a notch opening toward the lower end surface in the side surface of the lower end of the waveguide; the transmission line passes through the gate portion and reaches the inside of the array, the notch is located over at least a region of the gate portion through which the transmission line passes; the second foil covers at least a region of the lower surface of the second board located on an inner side of the array; the MMIC is disposed in one of the upper and lower surfaces of the first or second board; the first foil, the second foil and the surface layer via holes constituting the array are grounded; a long side of a cross-section of the waveguide is equal to or larger than a half of a wavelength of a radio frequency electromagnetic wave in air, generated by the MMIC, and smaller than the wavelength; and a short side of the cross-section of the waveguide is equal to or larger than a quarter of the wavelength of the radio frequency electromagnetic wave in air, generated by the MMIC, and equal to or smaller than a half of the wavelength.