High-frequency line transducer, having an electrode opening surrounded by inner and outer vias

A communication apparatus comprising:

• a high-frequency component which includes:
• a substrate;
• a transmission line disposed on a first surface of the substrate;
• a first ground electrode disposed on the first surface of the substrate;
• a second ground electrode disposed on a second surface of the substrate, the second surface being opposite the first surface;
• a waveguide positioned so as to oppose the second ground electrode, the waveguide having an opening;
• an electrode opening having a periphery disposed on the second surface of the substrate, the periphery of the electrode opening being centered at substantially one quarter of a signal wavelength from the opening of the waveguide;
• and
• a plurality of via holes disposed along the periphery of the electrode opening, the plurality of via holes electrically connecting the first ground electrode to the second ground electrode;
• a signal processing circuit connected to the high-frequency component;
• and
• an antenna connected to the high-frequency component,
• wherein the electrode opening has an inner and an outer periphery and the plurality of via holes are disposed in an array on the inner and the outer periphery of the electrode opening.